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Disclosure - Segment Reporting - Segment Result and Reconciliations to GAAP - Core Earnings Adjustments (Detail) link:presentationLink link:calculationLink link:definitionLink 996385 - Disclosure - Segment Reporting - Segment Results and Reconciliations to GAAP - Reportable Segment Significant Operating Expenses (Detail) link:presentationLink link:calculationLink link:definitionLink 996395 - Disclosure - Segment Reporting - Core Earnings Adjustments to GAAP (Detail) link:presentationLink link:calculationLink link:definitionLink 996405 - Disclosure - Segment Reporting - Core Earnings Adjustments to GAAP (Parenthetical) (Detail) link:presentationLink link:calculationLink link:definitionLink Financial asset, 61 to 90 days past due. Financial Asset61 To90 Days Past Due [Member] Financial Asset, 61 to 90 Days Past Due [Member] Increase (Decrease) in Interest Payable, Net Increase (decrease) in accrued interest payable Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax Total gains (losses) on cash flow hedges Segments [Domain] Segments ASU 2020-04 [Member Accounting Standard Update 202004 [Member] Accounting Standard Update 202004. Concentration Risk Type [Axis] Concentration Risk Type Charge-offs (as a result of lower recovery expectations) Financing Receivable, Allowance for Credit Loss, Writeoff, Total Financing Receivable, Allowance for Credit Loss, Writeoff Disposal of a subsidiary, net of cash disposed of. Disposal Of A Subsidiary, Net Of Cash Disposed Of Disposal of a subsidiaries, net of cash disposed of Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year Total Private Education Loan Credit Quality Indicators by Origination Year Three Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs Balance, end of period Balance, beginning of period Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Preferred Stock, Shares Issued Preferred stock, shares issued Statement of Financial Position Location, Balance [Domain] Balance Sheet Location Seasoning thirteen thru twenty four. Seasoning Thirteen Thru Twenty Four [Member] 13-24 Payments [Member] Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery, Total Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery Net charge-offs Noninterest Income Expenses Other Operating Income Expenses Noninterest Income Expenses Other Operating Income Expenses Other income Interest Receivable and Other Assets Other assets Total Other Financing receivable before allowance for credit loss and fee change amount Financing Receivable Before Allowance For Credit Loss And Fee Change Amount Change Modified Loans [Member] Modified loans. Shares Acquired, Average Cost Per Share Average purchase price per share Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment Equity [Abstract] Entity Current Reporting Status Entity Current Reporting Status Class of Financing Receivable [Axis] Class of Financing Receivable Financing Receivable, Percent Past Due Loans delinquent, percentage Fair Value, Inputs, Level 2 [Member] Level 2 [Member] Deferred Tax Assets, Net of Valuation Allowance Total deferred tax assets Commitments and Contingencies Disclosure [Text Block] Commitments, Contingencies and Guarantees Cash Flow Hedging [Member] Cash Flow [Member] Common Stock, Shares Authorized Common stock, shares authorized Total "Core Earnings" adjustments to GAAP. Core Earnings Adjustments To Gaap Core Earnings adjustments to GAAP Total Core Earnings adjustments to GAAP Accounts receivable Accounts Receivable, after Allowance for Credit Loss Accounts Receivable, after Allowance for Credit Loss, Total Investment, Policy [Policy Text Block] Investments Product and Service [Axis] Product and Service Loans Insured or Guaranteed by Government Authorities [Axis] Loans Insured or Guaranteed by Government Authorities Document Fiscal Period Focus Document Fiscal Period Focus Entity Shell Company Entity Shell Company Dividends, Common Stock, Cash Dividends paid Common stock Not for profit. Not For Profit [Member] Not For Profit [Member] Cash and Cash Equivalent Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value, Total Represents a portion of financing receivables that are loans in repayment. Financing Receivables Loans In Repayment [Member] Financing Receivables, Loans In Repayment [Member] Schedule of Maturities of Long-Term Debt [Table Text Block] Expected Maturities of Long-term Borrowings Net Assets Net assets of consolidated variable interest entities Net Assets, Beginning Balance Net Assets, Ending Balance Cybersecurity Risk Management, Strategy, and Governance [Abstract] Common Stock, Shares, Issued Common stock, shares issued Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag] Cybersecurity Risk Board of Directors Oversight [Text Block] Statement [Table] Statement [Table] Changes Measurement [Member] Difference [Member] Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Increases resulting from tax positions taken during the current period Internal Revenue Service (IRS) [Member] Federal [Member] Interest Receivable Accrued interest receivable Reclassifications for core to gaap accounting. Reclassifications For Core To Gaap Accounting [Member] Reclassifications [Member] Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year Total Private Education Loan Credit Quality Indicators by Origination Year Five Proceeds from Accounts Receivable Securitization Borrowings collateralized by loans in trust - issued Statement [Line Items] Statement [Line Items] Treasury Stock, Value, Acquired, Cost Method Common stock repurchased, value Common stock repurchased Business Combination [Domain] Business Acquisition, Acquiree Entity Filer Category Entity Filer Category Reclassifications Reclassification, Comparability Adjustment [Policy Text Block] Loan, Net Charge-Offs in Year Five Financing Receivable Allowance for Credit Losses Write Offs Four Years Before Latest Fiscal Year Financing receivable allowance for credit losses write offs four years before latest fiscal year. Interest Income (Expense), Operating [Abstract] Interest income: Financing Receivable, Past Due [Table] Schedule Of Financing Receivables Past Due [Table] Liabilities and Equity Total liabilities and equity Gain (Loss) on Disposition of Stock in Subsidiary Gain on sale of subsidiaries, net (Gain) on sale of subsidiaries, net Gain on sale of subsidiary Debt Instrument [Line Items] Debt Instrument [Line Items] Private education loan ABCP facilities. Private Education Loan A B C P Facilities [Member] Private Education Loan ABCP Facilities [Member] Financing Receivable, Allowance for Credit Loss, Recovery Recoveries (cash collected) Reclassification of the expected future recoveries on charged-off loans Reclassification of the expected future recoveries on previously fully charged-off loans Credit Concentration Risk [Member] Credit Concentration Risk [Member] Changes in unrecognized tax benefits Effective Income Tax Rate Reconciliation, Tax Contingency, Percent Effective Income Tax Rate Reconciliation, Tax Contingency, Percent, Total Noninterest Income Total other income (loss) Total other income (loss) 2028 Long-Term Debt, Maturity, Year Three Aggregate principal amount of debt maturing in 2027 Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract] Derivative Assets: Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Fair Value, by Balance Sheet Grouping [Table Text Block] Fair Values of Financial Assets and Liabilities, Including Derivative Financial Instruments Hedging Relationship [Axis] Fair Value [Member] In-school/Grace/Deferment/Forbearance [Member] School or grace or deferment or forbearance School Or Grace Or Deferment Or Forbearance [Member] School/Grace/Deferment [Member] Cybersecurity Risk Third Party Oversight and Identification Processes [Flag] Private education loan securitizations. Private Education Loan Securitizations [Member] Private Education Loan Securitizations [Member] Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) [Table Text Block] Impact of Derivatives on Other Comprehensive Income (Equity) Derivative [Line Items] Derivative [Line Items] Loans receivable for previously fully charged off loans. Loans Receivable For Previously Fully Charged Off Loans [Member] Loans Receivable For Previously Fully Charged Off Loans [Member] Extinguishment of Debt, Amount Debt principal repurchased Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Statutory federal rate Financing Receivable, before Allowance for Credit Loss, Fee and Loan in Process Total Loans, gross Cybersecurity Risk Management Third Party Engaged [Flag] Documents Incorporated by Reference [Text Block] Documents Incorporated by Reference Goodwill Goodwill Goodwill, Total Goodwill, Beginning Balance Goodwill, Ending Balance Effective Income Tax Rate Reconciliation, Percent Effective tax rate Income taxes paid Income Taxes Paid Income Tax Jurisdiction [Axis] Income Tax Authority Summary of significant accounting policies. Summary Of Significant Accounting Policies [Line Items] Summary Of Significant Accounting Policies [Line Items] Effective Income Tax Rate Reconciliation, Tax Credit, Energy-Related, Amount Energy-related tax credits, amount Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Restricted Cash and Investments Net Income (Loss) Available to Common Stockholders, Basic [Abstract] Numerator: Loan, Net Charge-Offs in Year Prior Financing Receivable Allowance for Credit Losses Write Offs Five or More Years Before Latest Fiscal Year Financing receivable allowance for credit losses write offs five or more years before latest fiscal year. Summary of Performance and Related Loan Status of Loans Modified Summary of Performance and Related Loan Status of Loans Modified [Table Text Block] Summary of performance and related loan status of loans modified. Tax Effected Capital Loss Carryforwards Tax effected capital loss carryforwards. Net capital loss carryovers, Tax-Effected Securities Financing Transaction [Axis] Securities Financing Transaction Additional Paid in Capital, Common Stock Additional paid-in capital Repayment. Repayment [Member] Repayment [Member] Tax credit carryover. Tax Credit Carryover Tax credit carryovers Deferred tax assets student loan premiums and discounts net. Deferred Tax Assets Education Loan Premiums And Discounts Net Education loan premiums and discounts, net Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation Shares repurchased related to employee stock-based compensation plans Adjustments required to reconcile core earnings. Adjustments Required To Reconcile Core Earnings [Line Items] Adjustments Required To Reconcile Core Earnings [Line Items] Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down Charge-offs Derivative Asset, Subject to Master Netting Arrangement, Liability Offset Impact of master netting agreements, Assets Schedule of Extinguishment of Debt [Table Text Block] Summary of Activity Related to Senior Unsecured Debt Repurchases Forbearance. Forbearance [Member] Forbearance [Member] Significant Accounting Policies [Text Block] Significant Accounting Policies Loan Modifications, Amortized Cost Financing Receivable, Troubled Debt Restructuring, Premodification Modified loans Finite-Lived Intangible Asset, Useful Life Estimated weighted average life of education loans Share Repurchase Program [Axis] Share Repurchase Program Series A junior participating preferred stock. Series A Junior Participating Preferred Stock [Member] Series A Junior Participating Preferred Stock [Member] Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge Gains (losses) recognized in net income on hedged items Cybersecurity Risk Management, Strategy, and Governance [Table] Schedule of Earnings (Loss) per Common Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Trademarks and Trade Names [Member] Trademarks and Trade Names [Member] Percentage of trusts assets that triggers clean-up call. Percentage Of Trusts Assets That Triggers Clean Up Call Percentage of trust's asset balance needed to trigger clean-up call Open market share repurchases. Open Market Share Repurchases [Member] Open Market Repurchases [Member] Earnings Per Share, Basic Earnings Per Share, Basic, Total Basic earnings (loss) per common share Tabular disclosure of the reconciliation of the company's "Core Earnings" segment totals to its consolidated operating results in accordance with GAAP. Segment Results And Reconciliations To Gaap Table [Text Block] Segment Results and Reconciliations to GAAP Payment status (Amortized Cost) Financing Receivable, Modified, Accumulated Financial asset, 31 to 60 days past due. Financial Asset31 To60 Days Past Due [Member] Financial Asset, 31 to 60 Days Past Due [Member] Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Adjustments to reconcile net income (loss) to net cash provided by operating activities: Hedging Designation [Domain] Hedging Designation Federal Income Tax Paid, Federal, after Refund Received Income Tax Paid, Federal, after Refund Received, Total Domestic Tax Jurisdiction [Member] Federal [Member] School/Deferment [Member] School Deferment [Member] School/Deferment. Regulatory expenses non deductible for income tax purposes. Regulatory Expenses Non Deductible For Income Tax Purposes Regulatory expenses non deductible for income tax purposes Share Repurchase Program [Domain] Share Repurchase Program Financing Receivable, Allowance for Credit Loss [Line Items] Financing Receivable Allowance For Credit Losses [Line Items] Financing Receivable, Allowance for Credit Losses [Line Items] Effective Income Tax Rate Reconciliation, Tax Credit, Other, Amount Other, amount Revenue Recognition, Interest [Policy Text Block] Education Loan Interest Income Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Increases resulting from tax positions taken during a prior period Summary of operating loss and credit carryforwards. Summary Of Operating Loss And Credit Carryforwards Table [Text Block] Summary of Operating Loss and Credit Carryovers Accounting Standards Update [Axis] Accounting Standards Update Other Revenue (Loss) Other revenue (loss). Other revenue Consolidation Items [Domain] Consolidation Items Entity Small Business Entity Small Business Asset recovery and business processing revenue. Asset Recovery And Business Processing Revenue Asset recovery and business processing revenue Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Derivative Notional Values Hedging Designation [Axis] Hedging Designation Short-Term Debt [Member] Short-term borrowings [Member] More Than an Insignificant Payment Delay [Member] Payment Deferral [Member] Retained Earnings (Accumulated Deficit) Retained earnings Reduction in equity (retained earnings), net of tax resulted from current expected credit losses Retained Earnings (Accumulated Deficit), Total Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-Based Compensation Cost Stock-based compensation plans Repayments of Unsecured Debt Long-term unsecured notes repaid Net adjustment resulting from change in charge off rate as percentage of average loans in repayment. Net Adjustment Resulting From Change In Charge Off Rate As Percentage Of Average Loans In Repayment Net adjustment resulting from the change in charge-off rate as a percentage of average loans in repayment (annualized) Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Offsetting [Abstract] Current Foreign Tax Expense (Benefit) Foreign Preferred stock purchase rights. Preferred Stock Purchase Rights [Member] Preferred Stock Purchase Rights [Member] Asset-Backed Securities, Securitized Loans and Receivables [Member] Asset-backed Securities, Securitized Loans and Receivables [Member] Organization, Consolidation and Presentation of Financial Statements [Abstract] Private education loan securitizations repurchase facility. Private Education Loan Securitizations Repurchase Facility [Member] Private Education Loan Asset-backed Securitization Repurchase Facilities [Member] Derivative Asset, Including Not Subject to Master Netting Arrangement, after Offset and Deduction Net position, Assets Derivative Asset, Including Not Subject to Master Netting Arrangement, after Offset and Deduction, Total Weighted Average Number of Shares Outstanding, Diluted, Adjustment Dilutive potential common shares Dilutive potential common shares Amendment Flag Amendment Flag Product and Service [Domain] Product and Service FFELP loans member. F F E L P Loans [Member] FFELP Loans [Member] A B C P Facilities [Member] A B C P Facilities [Member] A B C P Facilities. Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Statutory federal rate, amount FFELP loan securitizations. F F E L P Loan Securitizations [Member] FFELP Loan Securitizations [Member] Sum of cash and investments, including restricted cash and investments, as of the balance sheet date. Cash And Investments Including Restricted Cash And Investments Cash and investments Earnings Per Share, Policy [Policy Text Block] Earnings (Loss) per Common Share Entity Address, Postal Zip Code Entity Address, Postal Zip Code Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Total net cash provided by operating activities Directors or Officers [Member] Directors or Officers. Common Stock [Member] Common Stock [Member] Charge-offs: Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery [Abstract] Adjustments for core to GAAP accounting. Adjustments For Core To Gaap Accounting [Member] Total Adjustments [Member] Cybersecurity Risk Role of Management [Text Block] State and Local Government [Member] State and Local Government. State And Local Government [Member] 2026 Long-Term Debt, Maturity, Year One Aggregate principal amount of debt maturing in 2025 Steve Hauber [Member] Steve Hauber. Hedging Relationship Hedging Relationship [Domain] Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Impact of Derivatives on Balance Sheet Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity Total adjustments Asset Recovery and Business Processing Revenue Disclosure of accounting policy for asset recovery and business processing revenue. Asset Recovery And Business Processing Revenue Policy [Text Block] Portion at Fair Value Measurement [Member] Fair Value Disclosure Item Amounts [Default] Portion at Fair Value Measurement [Member] [Default] Entity Address, Address Line One Entity Address, Address Line One Deferred Tax Liabilities, Gross Total deferred tax liabilities Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV Short-Term Debt, Fair Value Short-term borrowings, Fair Value Goodwill and acquired intangible assets gross. Goodwill and Acquired Intangible Assets Gross Goodwill and acquired intangible assets fully impaired Earnings Per Share [Abstract] Income Tax, Policy [Policy Text Block] Income Taxes Tolling Authorities. Tolling Authorities [Member] Tolling Authorities [Member] Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag] Supplemental Cash Flow Information [Abstract] Supplemental disclosure of cash flow information: Goodwill, Impaired, Method for Fair Value Determination Goodwill impaired method for fair value determination Common stock shares outstanding. Common Stock Shares Outstanding [Member] Common Stock Shares Outstanding [Member] Derivative Asset Derivatives at fair value Derivative values (as carried on balance sheet), Assets Percentage Of Education Loan Portfolio In Repayment Percentage of education loan portfolio in repayment. Percentage of education loan portfolio in repayment Federal Family Education Loan Program (FFELP) Guaranteed Loans [Member] FFELP Loans [Member] Statement of Financial Position Location, Balance [Axis] Balance Sheet Location Investment Type [Axis] Investment Type Consolidation loans member. Consolidation Loans [Member] Consolidation Loans [Member] Consolidation Loans [Member] Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block] Effective Income Tax Rate Reconciliation, State and Local Jurisdiction, Contribution Greater than 50 Percent, Tax Effect [Extensible Enumeration] Foreign Currency Fair Value Hedge Derivative at Fair Value, Net Net positive exposure on foreign currency swaps Foreign Currency Fair Value Hedge Derivative at Fair Value, Net, Total Document Type Document Type Goodwill and Intangible Assets, Policy [Policy Text Block] Goodwill and Acquired Intangible Assets After 2027 Finite Lived Intangible Asset Expected Amortization After Year Two Finite lived intangible asset expected amortization after year two. Income Taxes Paid, Net Income taxes paid Income taxes paid (net of refunds received) Modified Loans (Amortized Cost) Financing Receivable, Modified in Period, Amount Entity Central Index Key Entity Central Index Key Hedged Liability, Fair Value Hedge, Cumulative Increase (Decrease) Hedge Basis Adjustments Derivative Asset, Fair Value of Collateral Total collateral held Reversal of allowance related to loan sale. Reversal Of Allowance Related To Loan Sale Reversal of allowance related to loan sales Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block] Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract] Derivative Liabilities: Represents a portion of financing receivables that are current. Financing Receivables Current [Member] Financing Receivables, Current [Member] Equity, Class of Treasury Stock [Line Items] Equity, Class of Treasury Stock [Line Items] Tabular disclosure of the company's "Core Earnings" adjustments to GAAP. Summary Of Core Earnings Adjustments To Gaap Table [Text Block] Core Earnings Adjustments to GAAP Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers, Net Transfers in and/or out of level 3 Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers, Net, Total Valuation Approach and Technique [Axis] Valuation Approach and Technique Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Net increase (decrease) in cash, cash equivalents, restricted cash and restricted cash equivalents Regulatory expenses related to resolution of state attorneys general litigation and investigations. Regulatory Expenses Related To Resolution Of State Attorneys General Litigation And Investigations Regulatory expenses related to resolution of state attorneys general litigation and investigations Deferred tax liabilities market value adjustments. Deferred Tax Liabilities Market Value Adjustments Market value adjustments on education loans, investments and derivatives Interest Income, Operating Total interest income Interest Income, Operating, Total Intangible Assets, Net (Including Goodwill) Goodwill and acquired intangible assets, net Intangible Assets, Net (Including Goodwill), Total Goodwill and acquired intangible assets Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Securities not included in the computation of diluted earnings per share Seasoning twenty five thru thirty six. Seasoning Twenty Five Thru Thirty Six [Member] 25-36 Payments [Member] School type. School Type [Member] School Type [Member] Common Stock, Par or Stated Value Per Share Common stock, par value Accounting Standards Update [Domain] Accounting Standards Update Other comprehensive income (loss), net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Total Liabilities [Abstract] Liabilities Goodwill [Line Items] Goodwill [Line Items] Increase (decrease) in other liabilities Increase (Decrease) in Other Operating Liabilities Increase (Decrease) in Other Operating Liabilities, Total Reduction in revenue from wind-down of pandemic-related contracts Decrease in Revenue from Wind-down of Pandemic-related Contracts Decrease in revenue from wind-down of pandemic-related contracts. Percentage of insurance reimbursement receivable. Percentage Of Insurance Reimbursement Receivable Percentage reimbursement on all qualifying default claims period Noninterest Income [Abstract] Other income (loss): Securities fair value on balance sheet securitization derivatives. Securities Fair Value On Balance Sheet Securitization Derivatives Securities at fair value - on-balance sheet securitization derivatives (not recorded in financial statements) Parent [Member] Total Stockholders' Equity [Member] Document Financial Statement Error Correction Document Financial Statement Error Correction [Flag] Schedule Of Credit Exposure Related To Our Derivative Counterparties Schedule Of Credit Exposure Related To Our Derivative Counterparties. Schedule Of Credit Exposure Related To Our Derivative Counterparties Table [Text Block] Debt Disclosure [Abstract] Net changes in cash flow hedges, net of tax Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax Net changes in cash flow hedges, net of tax Summary of Amortized Cost Basis of Loans to Borrowers Summary of Amortized Cost Basis of Loans to Borrowers [Table Text Block] Summary of amortized cost basis of loans to borrowers. Derivative [Table] Derivative [Table] Fair Value Measurement and Measurement Inputs, Recurring and Nonrecurring [Text Block] Fair Value Measurements Loans disbursed prior to October One Nineteen Hundred Ninety Three. Loans Disbursed Prior To October One Nineteen Hundred Ninety Three [Member] Loans Disbursed prior to October 1, 1993 [Member] Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities Decreases related to settlements with taxing authorities Estimate of Fair Value Measurement [Member] Fair Value [Member] Derivative, Notional Amount Notional of interest rate swaps entered into by the trusts to swap Prime to LIBOR Total Derivative Notional Values Legal settlements Payments for Legal Settlements Net impact of goodwill and acquired intangible assets. Net Impact Of Goodwill And Acquired Intangibles [Member] Net Impact of Goodwill and Acquired Intangible Assets [Member] Net Impact of Goodwill and Acquired Intangible Assets [Member] Accrual of loss contingency. Accrual Of Loss contingency Accrual of loss contingency Current Fiscal Year End Date Current Fiscal Year End Date Schedule of Long-Term Debt Instruments [Table] Debt Instrument [Table] School/grace/deferment. School Grace Deferment [Member] School/Grace/Deferment [Member] Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Government Services Business Held For Sale Deferred tax assets tax deferred expense reserves and accruals government services business held for sale. Government services business held for sale Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Not Offset Cash collateral (held) pledged, Liabilities Cash (right to receive return of cash collateral is recorded in investments) Deferred Income Taxes and Other Tax Receivable, Current Income tax asset, net Receivables [Abstract] Customer Relationships [Member] Customer, Services And Lending Relationships [Member] Fair Value, by Balance Sheet Grouping [Table] Fair Value By Balance Sheet Grouping [Table] Entity Address, State or Province Entity Address, State or Province Line of Credit Facility, Remaining Borrowing Capacity Maximum unused capacity Federal education loans segment. Federal Education Loans Segment [Member] Federal Education Loans [Member] Information Technology and Data Processing Information technology expenses Finite lived intangible asset expected amortization after year three. Finite Lived Intangible Asset Expected Amortization After Year Three After 2027 Financial Liabilities Fair Value Disclosure Total interest-bearing liabilities, Fair Value Preferred Stock, Shares Outstanding Preferred stock, shares outstanding Preferred Stock, Shares Outstanding, Beginning Balance Preferred Stock, Shares Outstanding, Ending Balance Total comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent On-balance sheet securitization trust debt included in projected principal paydowns in 2026 On-balance sheet securitization trust debt included in projected principal paydowns in following year. On Balance Sheet Securitization Trust Debt Included In Projected Principal Paydowns Fair Value, Net Derivative Asset (Liability), Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Fair Value, Net Derivative Asset (Liability), Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Dilutive effect of restricted stock, restricted stock units, performance stock units, and Employee Stock Purchase Plan ("ESPP") Carrying values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments. Derivative Assets Liabilities At Carrying Value Net Derivative financial instruments, Carrying Value Increase (Decrease) in Accrued Interest Receivable, Net (Increase) decrease in accrued interest receivable Fair Value Hedge Liabilities Carrying Value Accounts Receivable [Member] Accounts Receivable [Member] Share-Based Payment Arrangement, Shares Withheld for Tax Withholding Obligation Shares repurchased related to employee stock-based compensation plans Shares repurchased related to employee stock-based compensation plans, Shares Internal Credit Assessment [Axis] Internal Credit Assessment Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount State income taxes, net of federal income tax effect, amount Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other, Amount Other, amount Increase (decrease) in revenue Increase (Decrease) in Revenue Increase (decrease) in revenue. Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Schedule of Deferred Tax Assets and Liabilities Period of hardship forbearance of payments Period of Hardship Forbearance of Payments Period of hardship forbearance of payments. Long-Term Debt, Fair Value Long-term borrowings, Fair Value Interest Expense, Operating Total interest expense Total interest expense Securities Financing Transaction [Table] Security Financing Transaction [Table] Interest Income (Expense), after Provision for Loan Loss Net interest income (loss) after provisions for loan losses Net interest income (loss) after provisions for loan losses Allowance for loan and lease losses write offs including expected future recoveries. Allowance For Loan And Lease Losses Write Offs Including Expected Future Recoveries Total Unsecured Debt Issuance of unsecured debt Unsecured Debt, Total Antidilutive Securities [Axis] Antidilutive Securities Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards [Line Items] Unrecognized Tax Benefits, Increase Resulting from Settlements with Taxing Authorities Increases related to settlements with taxing authorities Losses on debt repurchases Losses on debt repurchases Losses on debt repurchases Gain (Loss) on Repurchase of Debt Instrument State and Local Jurisdiction [Member] State and Local Jurisdiction [Member] Expense Related to Distribution or Servicing and Underwriting Fees Servicing expenses AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) [Member] Customer [Domain] Customer Derivative Liability Derivative Liability, Total Derivative values (as carried on balance sheet), Liabilities Unrecognized Tax Benefits, Decrease Resulting from Current Period Tax Positions Reduction in current year provision for income tax expense Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name Treasury Stock, Common, Shares Treasury Stock, Common, Shares Common stock held in treasury Treasury Stock, Common, Shares Federal Provision or Benefit from Federal Income Tax Provision or benefit from federal income tax. Payment for Acquisition, Loan, Held-for-Investment Education loans originated and acquired Unsecured Debt [Member] Total Unsecured Borrowings [Member] Long Term Senior Unsecured Debt [Member] Preferred Stock, Value, Issued Series A Junior Participating Preferred Stock, par value $0.20 per share; 2 million shares authorized; no shares issued or outstanding Schedule of Financial Instruments Owned and Pledged as Collateral [Table Text Block] Collateral Held and Pledged Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Deferred provision/(benefit): Remaining loan losses provision. Remaining Loan Losses Provision Remaining provision Organization and business. Organization And Business [Line Items] Organization And Business [Line Items] Minimum [Member] Minimum [Member] Disallowed interest expense carry forwards. Disallowed Interest Expense Carry Forwards State IRC § 163(j) disallowed interest expense carryovers, Gross Class of Treasury Stock [Table] Class Of Treasury Stock [Table] Financial Instrument [Axis] Financial Instrument Derivative Asset, Subject to Master Netting Arrangement, before Offset Derivative assets Derivative Asset (Liability) Net, Valuation Technique [Extensible Enumeration] Derivative Asset (Liability) Net, Valuation Technique [Extensible List] Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year Total Private Education Loan Credit Quality Indicators by Origination Year Two Loan Modifications, % of Loan Type Finance Receivable Percentage of Loan Type Finance receivable percentage of loan type. Provision for Loan and Lease Losses [Abstract] Provision: Amortization of Intangible Assets Amortization of acquired intangible assets Fair Value, Inputs, Level 3 [Member] Level 3 [Member] Segment Reporting [Abstract] Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Valuation of Financial Instruments that are Marked-to-Market on Recurring Basis Short term unsecured debt. Short Term Unsecured Debt [Member] Short Term Senior Unsecured Debt [Member] Fixed interest rate debt. Fixed Interest Rate Debt [Member] Long-Term Fixed Rate Debt [Member] Number of state attorneys general under agreement Number of State Attorneys General under agreement. Number Of State Attorneys General Under Agreement Other Other Assets, Miscellaneous Other Assets, Miscellaneous, Total Additions (subtractions) for core to GAAP accounting. Additions Subtractions For Core To Gaap Accounting [Member] Additions (Subtractions) [Member] Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities Accrued expenses not currently deductible Loans and leases receivable gross carrying amount percent. Loans And Leases Receivable Gross Carrying Amount Percent Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent Operating Loss Carryforwards Net operating loss carryovers, Gross Total other income (loss) Other Noninterest Income loss Other noninterest income loss. Below six four zero. Below Six Four Zero [Member] Below 640 [Member] Restricted Cash and Cash Equivalent Restricted cash and cash equivalents Restricted cash and restricted cash equivalents Restricted Cash and Cash Equivalents, Total Common stock par value point zero one per share. Common Stock Par Value Point Zero One Per Share [Member] Common Stock Par Value. 01 Per Share [Member] Financial Asset Acquired and No Credit Deterioration [Member] Non-PCD Portfolio [Member] Non-PCD Portfolio [Member] Commitments and Contingencies Commitments and contingencies Fair value net derivative asset (liability) measured on recurring basis unobservable input reconciliation gains (losses). Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Input Reconciliation Gains Losses [Abstract] Total gains/(losses): Auditor Firm ID Auditor Firm ID Costs Associated with Exit or Disposal Activities or Restructurings, Policy [Policy Text Block] Restructuring and Other Reorganization Expenses Forecast [Member] Proceeds from Issuance of Unsecured Debt Long-term unsecured notes issued Short-term borrowings, Carrying value Short-term borrowings Short-Term Debt, Total Short-term debt Schedule of Goodwill [Table Text Block] Summary of Goodwill for Each Reporting Units and Reportable Segments Credit Loss Status [Axis] Credit Loss Status Loss contingency settlement penalty Loss contingency settlement penalty. Loss Contingency Settlement Penalty Period of hardship forbearance of payments for borrowers of substantial payments Period of Hardship Forbearance of Payments for Borrowers of Substantial Payments Period of hardship forbearance of payments for borrowers of substantial payments. Carrying value of assets excluding goodwill and acquired intangible assets, and other assets. Earning Assets Total earning assets, Carrying Value Total earning assets, Carrying Value Concentration Risk Benchmark [Axis] Concentration Risk Benchmark Gain (Loss) on Derivative Instruments, Net, Pretax, Total Mark-to-market gains (losses) recognized Gains on derivative and hedging activities, net Gains (losses) on derivative and hedging activities, net 2027 Long-Term Debt, Maturity, Year Two Aggregate principal amount of debt maturing in 2026 Variable Interest Entity, Primary Beneficiary [Member] Assets and Liabilities of Consolidated Variable Interest Entities [Member] Financing receivable Expected future recoveries on current period gross charge-offs Financing receivable expected future recoveries on current period gross charge-offs Expected future recoveries on current period gross charge-offs Securities Financing Transaction [Line Items] Securities Financing Transaction [Line Items] For profit. For Profit [Member] For Profit [Member] Interest and Dividend Income, Operating Total interest income Financing Receivable, Originated, More than Five Years before Current Fiscal Year Total Private Education Loan Credit Quality Indicators by Origination Year Prior Interest Income (Expense), Operating Net interest income (loss) Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest, Total Net income (loss) Total loans, gross Financing Receivable, before Allowance for Credit Loss Ending total loans Total Private Education Loan Credit Quality Indicators by Origination Year Derivative asset at fair value including accrued interest. Derivative Asset At Fair Value Including Accrued Interest Derivative asset at fair value including accrued interest Long-Term Debt, Type [Domain] Long-Term Debt, Type Private education refinance loan. Private Education Refinance Loan [Member] Private Education Refinance Loans [Member] Cybersecurity Risk Management Positions or Committees Responsible [Text Block] Weighted Average Number of Shares Outstanding, Basic Average common shares outstanding Weighted average shares used to compute basic EPS Weighted Average Number of Shares Outstanding, Basic, Total Schedule of loans by type. Schedule Of Loans By Type Table [Text Block] Loans Type Scenario [Axis] Scenario On or after July one two thousand six. On Or After July One Two Thousand Six [Member] On or After July 1 2006 [Member] Gains Losses Recognized In Net Income On Derivatives Gains losses recognized in net income on derivatives. Gains (losses) recognized in net income on derivatives Document Information [Line Items] Document Information [Line Items] Total Charge-Offs Financing Receivable Allowance for Credit Losses Write Offs by Orignination Year Financing receivable allowance for credit losses write offs by orignination year. Total Charge Offs Gross Paydowns of Debt Gross paydowns of debt. Gross paydowns Removal of intangible assets. Removal Of Intangible Assets Removal of intangible assets Other Stockholders' Equity, Other Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Reconciliations of Statutory U.S. Federal Income Tax Rates to Our Effective Tax Rate for Continuing Operations Segments [Axis] Segments Interest income, net of discount accretion and premium amortization from the cash and investment portfolio. Cash And Investments Interest Income Loss Cash and investments Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block] Deferred Tax Assets, Net [Abstract] Deferred tax assets: Loans Receivable, Fair Value Disclosure Loans receivable, Fair Value Long-term borrowings, Carrying value Long-term borrowings Total Long-term debt Interest expense and derivative instruments hedging activities. Interest Expense And Derivative Instruments Hedging Activities [Member] Interest Expense and Derivative Instruments Hedging Activities [Member] Schedule of Amount of Loans Modified and Payment Default Schedule of Amount of Loans Modified and Payment Default [Table Text Block] Schedule of amount of loans modified and payment default. Financing receivable, modifications, pre-modification, recorded investment. Financing Receivable Modifications Pre Modification Recorded Investment Loan Modifications, Amortized Cost APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Stock-based compensation expense APIC, Share-Based Payment Arrangement, Increase for Cost Recognition, Total Represents a portion of financing receivables that are 61 to 90 days past due. Financing Receivables61 To90 Days Past Due [Member] Financing Receivables, 61 to 90 Days Past Due [Member] Ending Balance, Value Equity, Attributable to Parent Equity, Attributable to Parent, Total Beginning Balance, Value Preferred Stock, Par or Stated Value Per Share Preferred stock, par value Schedule of Variable Interest Entities [Table Text Block] Financing VIEs Seasoning one thru twelve. Seasoning One Thru Twelve [Member] 1-12 Payments [Member] Foreign Currency Contracts, Liability, Fair Value Disclosure Euro and British Pound Sterling denominated bonds outstanding in securitization trusts Statement of Stockholders' Equity [Abstract] Excess of net asset fair value over carrying value. Excess Of Net Asset Fair Value Over Carrying Value Excess of net asset fair value over carrying value Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] Loan, Net Charge-Offs in Year One Financing Receivable Allowance for Credit Losses Write Offs in Current Fiscal Year Financing receivable allowance for credit losses write offs in current fiscal year. Debt, Long-Term and Short-Term, Combined Amount Total Outstanding borrowings under facility Valuation Approach and Technique [Domain] Valuation Approach and Technique Healthcare services. Healthcare Services [Member] Healthcare Services [Member] Use of Estimates, Policy [Policy Text Block] Use of Estimates Represents a portion of financing receivables that are in forbearance. Financing Receivables Forbearance Loans In Repayment [Member] Financing Receivables, Forbearance, Loans In Repayment [Member] Internal Credit Assessment [Domain] Internal Credit Assessment Treasury Stock [Member] Treasury Stock, Common [Member] 2030 Long-Term Debt, Maturity, Year Five Aggregate principal amount of debt maturing in 2029 Customer Relationship, Developed Technology and Tradename [Member] Customer Relationship, Developed Technology and Trade Name [Member] Customer Relationship, Developed Technology and Trade name. The principal balance of loans originated during the period. Principal Balance Of Loans Originated Loans originated Financing Receivable, Allowance for Credit Loss Allowance at end of period Allowance at beginning of period Allowance for loans losses Loan allowance for losses Technology and Trade Name. Technology and Trade Name [Member] Long-Term Debt, Weighted Average Interest Rate, at Point in Time Long-term Weighted Average Interest Rate Noncontrolling Interest [Member] Noncontrolling Interest [Member] Debt Instrument, Name [Domain] Debt Instrument, Name Debt Instrument, Collateral Amount Assets securing facility 2029 Long-Term Debt, Maturity, Year Four Aggregate principal amount of debt maturing in 2028 Intangible Asset, Acquired, Finite-Lived [Line Items] Acquired Finite-Lived Intangible Assets [Line Items] Total unencumbered loans at the balance sheet date. Unencumbered Loans Unencumbered Loans Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] Summary of Changes in Unrecognized Tax Benefits Derivative Instruments and Hedging Activities Disclosure [Abstract] Capital Loss Carryovers Capital loss carryovers. Net capital loss carryovers, Gross Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings Included in earnings Gains (losses) on derivative and hedging activities, net Increase (Decrease) in Other Operating Assets Decrease in other assets Increase (Decrease) in Other Operating Assets, Total Disallowed interest expense operating loss and credit carryovers. Disallowed Interest Expense Operating Loss And Credit Carryovers State IRC § 163(j) disallowed interest expense carryovers, Operating Loss and Credit carryovers Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Receivable [Policy Text Block] Loans Senior notes due December fifteen two thousand forty three. Senior Notes Due December Fifteen Two Thousand Forty Three [Member] Senior Notes Due December 15, 2043 [Member] Repayments. Repayments [Member] Seasoning [Member] Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Text Block] Loan Restructuring Modification [Axis] Loan Restructuring Modification Private education recent In-school loans. Private Education Recent In-School Loans [Member] Current State and Local Tax Expense (Benefit) State Cybersecurity Risk Management Expertise of Management Responsible [Text Block] Treasury Stock, Value Treasury Stock, Value, Total Less: Common stock held in treasury at cost: 371 million and 362 million shares, respectively Loans receivable and investments fair value disclosure. Loans Receivable And Investments Fair Value Disclosure Total earning assets, Fair Value Capital Loss and Credit Carryover Capital loss and credit carryover. Capital Loss and Credit Carryovers Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Other adjustments, amount Financing Receivable, Year One, Originated, Current Fiscal Year Total Private Education Loan Credit Quality Indicators by Origination Year One Loan, Net Charge-Offs in Year Two Financing Receivable Allowance for Credit Losses Write Offs in Fiscal Year Before Latest Fiscal Year Financing receivable allowance for credit losses write offs in fiscal year before latest fiscal year. Financing Receivable, Past Due [Table Text Block] Age Analysis of Past Due Loans Delinquencies Description of Postemployment Benefits Description of post employment benefits Energy-related tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Energy-Related, Percent Energy-related tax credits Accounting Standards Update [Extensible Enumeration] Accounting Standards Update Extensible Enumeration Schedule of Acquired Finite-Lived Intangible Assets by Major Class [Table Text Block] Acquired Intangible Assets Entity Address, City or Town Entity Address, City or Town Mark Heleen [Member] Mark Heleen [Member] Mark Heleen [Member] Operating Loss Carryforwards, Valuation Allowance Valuation allowance, Operating loss and credit carryovers Number of reportable segments Number of Reportable Segments Security Exchange Name Security Exchange Name Combination Rate Reduction and Term Extension [Member] Interest Rate Reduction and Extended Maturity [Member] Interest Rate reduction and extended maturity. Effective Income Tax Rate Reconciliation, Other Adjustments, Percent Other, net Noninterest Expense [Abstract] Expenses: Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Current provision/(benefit): Deferred tax liabilities original issue discount on borrowings. Deferred Tax Liabilities Original Issue Discount On Borrowings Original issue discount on borrowings Education loan. Education Loan [Member] Education Loan Portfolio [Member] Counterparty Name [Axis] Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income (loss) before income tax expense (benefit) Concentration Risk Type [Domain] Concentration Risk Type Principal payments on education loans. Principal Payments On Education Loans Principal payments on education loans Antidilutive Securities, Name [Domain] Antidilutive Securities, Name Financial Asset, Not Past Due [Member] Financing Asset, Not Past Due [Member] Deferred Tax Assets, Goodwill and Intangible Assets Acquired intangible assets Total cost of shares repurchased divided by the total number of shares repurchased, for shares repurchased related to employee stock-based compensation plans. Shares Paid For Tax Withholding For Share Based Compensation Average Cost Per Share Average purchase price per share Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Cash, cash equivalents, restricted cash and restricted cash equivalents at end of period Cash, cash equivalents, restricted cash and restricted cash equivalents at beginning of period Total cash, cash equivalents, restricted cash and restricted cash equivalents at end of period Interest Paid, Excluding Capitalized Interest, Operating Activity Interest Represents a portion of financing receivables that are delinquent. Financing Receivables Delinquent Loans In Repayment [Member] Financing Receivables, Delinquent Loans in Repayment [Member] Other borrowings. Other Borrowings [Member] Other [Member] Measurement Basis [Axis] Measurement Basis Statistical Measurement [Domain] Statistical Measurement Document Period End Date Document Period End Date Business processing. Business Processing [Member] Business Processing [Member] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV Provision or Benefit from Income Tax [Abstract] Provision or benefit from income tax. Total provision/(benefit): ICFR Auditor Attestation Flag ICFR Auditor Attestation Flag Represents a portion of financing receivables that are 90 days past due. Financing Receivables90 Days Past Due [Member] Financing Receivables, 90 Days Past Due [Member] Transfers and Servicing of Financial Assets, Policy [Policy Text Block] Transfer of Financial Assets and Extinguishments of Liabilities John Kane [Member] John Kane [Member] John Kane [Member] Collateral pledged to others. Collateral Pledged To Others [Abstract] Collateral pledged to others: Credit Loss Status [Domain] Credit Loss Status Statement of Financial Position [Abstract] Cumulative Effect, Period of Adoption, Adjustment [Member] Cumulative Effect, Period of Adoption, Adjustment Cumulative Effect Period of Adoption Adjustment [Member] Private education loans non troubled debt restructuring. Private Education Loans Non Troubled Debt Restructuring [Member] Private Education Loans - Non-TDRs [Member] Non-TDR [Member] Mark-to-market gain or loss over life of contract. Mark To Market Gain Or Loss Over Life Of Contract Amount that will be equal to mark-to-market gain or loss over the life of the contract Antidilutive Security, Excluded EPS Calculation [Table] Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Class of Stock [Axis] Class of Stock Current Income Tax Expense (Benefit) Total current provision/(benefit) Cybersecurity Risk Management, Strategy, and Governance [Line Items] Not Designated as Hedging Instrument [Member] Trading [Member] Financial Asset, Aging [Domain] Financial Asset, Aging Short-Term Debt, Weighted Average Interest Rate, at Point in Time Short-term Weighted Average Interest Rate Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives Balance Sheet Location By Derivative Contract Type By Hedging Designation [Table] Liabilities Total liabilities Liabilities Financial Instruments Financial Instruments [Domain] Loss Contingency Estimate Of Possible Loss Related to Expected Legal Costs Loss contingency estimate of possible loss related to expected legal costs. Loss contingency estimate of possible loss related to expected legal costs Interest receivable and payable and other assets. Interest Receivable And Payable And Other Assets Other assets, net Other assets, Net Loss Contingency, Estimate of Possible Loss Probable contingency loss liability The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method. Also includes the amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Goodwill and acquired intangible asset impairment and amortization expense Goodwill and acquired intangible asset impairment and amortization Impairment of intagible assets Counter party. Counter Party [Member] Counterparties [Member] Derivative Liability, Statement of Financial Position [Extensible Enumeration] Derivative Liability, Statement of Financial Position [Extensible Enumeration] Derivative Instruments Gain Loss [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Restricted Cash Restricted cash Cash Restricted Cash, Total Financing Receivable Credit Quality Indicators [Table Text Block] Private Education Loan Portfolio Stratified by Key Credit Quality Indicators Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Input Reconciliation [Table] Market value adjustments on life insurance contracts Effective Income Tax Rate Reconciliation, Nondeductible Expense, Life Insurance, Percent Market value adjustments on life insurance contracts Percentage of threshold Goodwill Impairment Threshold Goodwill Impairment Threshold Finite-Lived Intangible Assets, Gross Intangible assets subject to amortization, Cost Basis Finite-Lived Intangible Assets, Gross, Total Repayments of Accounts Receivable Securitization Borrowings collateralized by loans in trust - repaid Weighted Average Number of Shares Outstanding, Diluted Average common and common equivalent shares outstanding Weighted average shares used to compute diluted EPS Direct Operating Costs Direct operating expenses Direct Operating Costs, Total Securities Act File Number Entity File Number Payments of Ordinary Dividends, Common Stock Common dividends paid Percentage of aggregate education loan to be purchase. Percentage Of Aggregate Education Loan To Be Purchase Percentage of aggregate education loan to purchase Derivative Instruments, Gain (Loss) [Table Text Block] Mark-to-Market Impact of Derivatives on Statements of Income Cover [Abstract] Senior unsecured debt. Senior Unsecured Debt [Member] Senior Unsecured Debt [Member] Notes receivable gross percentage of balance. Notes Receivable Gross Percentage Of Balance Total Private Education Loan Credit Quality Indicators by Origination Year, Percent Other Expenses Other/remaining expenses Payment Default (Par) Financing Receivable, Modified, Subsequent Default Payment default Private education non-refinance loans. Private Education Non-refinance Loans [Member] Percentage of Loan, Net Charge-Offs Financing Receivable, Allowance for Credit Losses, Percentage of Charge-Offs Financing receivable, allowance for credit losses, percentage of charge-offs. Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Change in Balance Sheet Carrying Value Associated with Level 3 Financial Instruments Carried at Fair Value on Recurring Basis Cumulative Effect, Period of Adoption [Axis] Cumulative Effect, Period of Adoption Option to exercise clean up call and purchase student loans from trust of original loan balance. Option To Exercise Clean Up Call And Purchase Education Loan From Trust Of Original Loan Balance Option to exercise clean-up call and purchase education loans from trust of original loan balance Cosigners. Cosigners [Member] Cosigners [Member] Financial Asset, Aging [Axis] Financial Asset, Aging Investments [Domain] Investments Derivative, Net Liability Position, Aggregate Fair Value Derivative liability at fair value including accrued interest and premium receivable Scenario [Domain] Scenario Disallowed interest expense carry forwards expiration period. Disallowed Interest Expense Carry Forwards Expiration Period State IRC § 163(j) disallowed interest expense carryovers, Expiration Number of Operating Segments Number of reportable operating segments Segment Reporting Disclosure [Text Block] Segment Reporting Schedule of Acquired Finite-Lived Intangible Asset by Major Class [Table] Schedule Of Acquired Finite Lived Intangible Asset By Major Class [Table] Other Contract [Member] Other [Member] Tax expense for accumulated other comprehensive loss AOCI Tax, Attributable to Parent Loan status. Loan Status [Member] Loan Status [Member] Derivative Assets (Liabilities), at Fair Value, Net Derivative financial instruments, Fair Value Derivative Assets (Liabilities), at Fair Value, Net, Total Short-Term Debt, Type [Domain] Short-Term Debt, Type Finite-Lived Intangible Assets, Net Intangible assets subject to amortization, Net Intangible assets Finite-Lived Intangible Assets, Net, Beginning Balance Finite-Lived Intangible Assets, Net, Ending Balance Business Combination, Series of Individually Immaterial Business Combinations [Member] Series of Individually Immaterial Business Acquisitions [Member] Seasoning more than forty eight. Seasoning More Than Forty Eight [Member] More than 48 Payments [Member] Transferable Tax Credits Purchases Transferable tax credits purchases. Transferable tax credits purchases Derivative Liability, Subject to Master Netting Arrangement, Asset Offset Impact of master netting agreements, Liabilities Private Education Loan Repurchase Facilities Private education loan repurchase facilities. Private Education Loan Repurchase Facilities [Member] Restructuring Charges Restructuring/other reorganization expenses Restructuring Charges, Total Transfers and Servicing of Financial Assets, Servicing of Financial Assets, Policy [Policy Text Block] Servicing Revenue Statute of limitation period for various combinations of open tax reviews of subsidiaries, tax years and jurisdictions. Statute Of Limitation Period For Open Tax Reviews Statute of limitation period for open tax reviews Short-Term Debt, Type [Axis] Short-Term Debt, Type New Accounting Pronouncements, Policy [Policy Text Block] Recently Issued Accounting Pronouncements Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Derivative Instruments, Gain (Loss) [Table] Derivative Instruments Gain Loss By Hedging Relationship By Income Statement Location By Derivative Instrument Risk [Table] Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other, Percent Other Equity [Member] Equity [Member] In school loans. In School Loans [Member] In School Loans [Member] Deferred Tax Asset, Tax Deferred Expense, Reserve and Accrual, Financing Receivable, Allowance for Credit Loss Loan reserves Loans receivable, weighted average period added to remaining life of loan Loans Receivable, Weighted Average Period Added to Remaining Life of Loan Loans receivable, weighted average period added to remaining life of loan. Income (Loss) from Continuing Operations before Income Taxes, Domestic Federal Loss from continuing operations before income tax benefit from U. S. operations Reported Value Measurement [Member] Carrying Value [Member] Mark-to-market gain (loss) on derivative and hedging activities net. Mark To Market Gain Loss On Derivative And Hedging Activities Net Mark-to-market (gains)/losses on derivative and hedging activities, net Loans In Repayment And Percentage Of Each Status [Abstract] Loans In Repayment And Percentage Of Each Status [Abstract] Loans in repayment and percentage of each status: Derivative Asset (Liability) Net, Measurement Input Derivatives Loan, Net Charge-Offs in Year Four Financing Receivable Allowance for Credit Losses Write Offs Three Years Before Latest Fiscal Year Financing receivable allowance for credit losses write offs three years before latest fiscal year. Common stock, shares outstanding Common Stock, Shares, Outstanding Ending Balance, Shares Beginning Balance, Shares Fico. Fico [Member] FICO Scores [Member] Cybersecurity Risk Management Processes Integrated [Flag] Document Transition Report Document Transition Report Operating loss carryforwards expiration year. Operating Loss Carryforwards Expiration Year Net operating loss, Expiration Deferred Tax Assets, Net Net deferred tax assets Operating Expenses Total operating expenses Operating expenses Payments for Repurchase of Common Stock Common stock repurchased Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Components of Provision for Income Tax Expense (Benefit) State Provision or Benefit from State Income Tax Provision or benefit from state income tax. Statement of Cash Flows [Abstract] Weighted Average Number of Shares Outstanding, Diluted, Adjustment [Abstract] Effect of dilutive securities: Stockholders' Equity before Treasury Stock Total Navient Corporation stockholders’ equity before treasury stock Floating interest rate debt. Floating Interest Rate Debt [Member] Long-Term Floating Rate Debt [Member] Current Federal Tax Expense (Benefit) Federal Stock Issued During Period, Value, New Issues Issuance of common shares Gross Issuance of Debt During Period Gross issuance of debt during period. Gross issunaces Executive compensation Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-Based Payment Arrangement, Percent Derivative Asset, Statement of Financial Position [Extensible Enumeration] Derivative Asset, Statement of Financial Position [Extensible Enumeration] Interest Rate Swap [Member] Interest Rate Swaps [Member] Gains (Losses) on Derivative and Hedging Activities, Net [Member] Equity [Text Block] Stockholders' Equity Accounts and Financing Receivables [Table] Schedule Of Accounts Notes Loans And Financing Receivable [Table] Earnings Per Share [Text Block] Earnings (Loss) per Common Share Unrecognized Tax Benefits that Would Impact Effective Tax Rate Unrecognized tax benefits recognition impact on effective tax rate Deferred Tax Liabilities, Other Other Cybersecurity Risk Management Processes Integrated [Text Block] Net income Net income (loss) Percentage of Principal Balance Of Loans Originated Percentage of principal balance of loans originated. Loans originated percentage Proceeds from (Payment for) Other Financing Activity Other financing activities, net Financial asset, 90 days past due. Financial Asset90 Days Past Due [Member] Financial Asset, 90 Days Past Due [Member] Schedule of Income Taxes Paid Net of Refunds Received Schedule of Income Taxes Paid Net of Refunds Received [Table Text Block] Schedule of income taxes paid net of refunds received. Effective Income Tax Rate Reconciliation Recognition Of Deferred Tax Asset On Government Services Business Basis Difference Effective income tax rate reconciliation recognition of deferred tax asset on government services business basis difference. Recognition of deferred tax asset on government services business basis difference Derivatives, Fair Value [Line Items] Derivatives Fair Value [Line Items] Assets [Abstract] Assets Income Tax Authority, Name [Axis] Income Tax Authority, Name Before hedge accounting adjustments. Before Hedge Accounting Adjustments [Member] Total Before Hedge Accounting Adjustments [Member] Represents the aggregate total of reconciling items and elimination items. Eliminations And Reconciling Items [Member] Adjustments [Member] Organization and Business. Organization And Business [Table] Organization And Business [Table] Document Fiscal Year Focus Document Fiscal Year Focus Financing Receivable, Modified [Table Text Block] Loans Modified Accounts for TDR Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Table Text Block] Included in Earnings Concentration Risk Benchmark [Domain] Concentration Risk Benchmark ASU 2022-02 [Member] Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Investing activities Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Reductions related to the lapse of statute of limitations Other Operating Segment [Member] Other Segment [Member] Deferred Federal Income Tax Expense (Benefit) Federal Corporate expenses Corporate expenses. 2026 Finite-Lived Intangible Asset, Expected Amortization, Year One Fair Value Measurement, Policy [Policy Text Block] Fair Value Measurement Fixed Maturities [Member] Fixed Maturities [Member] Other Liabilities Other liabilities Other Liabilities, Total Schedule of Other Assets [Table Text Block] Schedule of Other Assets Charge offs related to resolution of loans in bankruptcy Charge offs related to resolution of loans in bankruptcy. Charge Offs Related To Resolution Of Loans In Bankruptcy Fair Value Disclosures [Abstract] Commitments and Contingencies Disclosure [Abstract] Offsetting Assets [Table Text Block] Derivative Positions Net of Collateral Discount On Transferable Tax Credits Discount on transferable tax credits. Discount on transferable credits purchased Foreign currency Doller denominated debt. Foreign Currency Doller Denominated Debt [Member] Non-U.S. Doller Denominated Debt [Member] Debt Instrument [Axis] Debt Instrument Derivative Instrument [Axis] Derivative Instrument Assets, Fair Value Disclosure Total Derivatives, Policy [Policy Text Block] Derivative Accounting Concentration Risk, Percentage Dimensions of concentration risk Capital Loss Carryforwards, Valuation Allowance Capital loss carryforwards, valuation allowance. Valuation allowance, Capital loss and credit carryovers Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Total net cash provided by investing activities Title of 12(b) Security Title of 12(b) Security Schedule of Segment Reporting Information, by Segment [Table] Schedule Of Segment Reporting Information By Segment [Table] Derivative, Fair Value, Amount Offset Against Collateral, Net Net positive exposure related to corporate derivatives Derivative, Fair Value, Amount Offset Against Collateral, Net, Total Exposure, net of collateral Contractual Interest Rate Reduction [Member] Interest Rate Reduction [Member] Interest Rate Concession [Member] Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-Based Payment Arrangement, Amount Executive compensation, amount Derivative Instruments and Hedging Activities Disclosure [Text Block] Derivative Financial Instruments Unused authorization Share Repurchase Program, Remaining Authorized, Amount Remaining common stock repurchase authority Percentage to total student loans. Percentage To Education Loans Percentage to total education loans Long-Term Debt, Maturity, after Year Five Aggregate principal amount of debt maturing in [2030-2048] 2031-2050 Effective Income Tax Rate Reconciliation, Nondeductible Expense, Life Insurance, Amount Market value adjustments on life insurance contracts, amount Market value adjustments on life insurance contracts, amount Income Tax Disclosure [Text Block] Income Taxes Subsidiaries Held for Sale [Policy Text Block] Subsidiaries held for sale. Subsidiaries Held for Sale Private education loans troubled debt restructuring. Private Education Loans Troubled Debt Restructuring [Member] Private Education Loans - TDRs [Member] TDR [Member] Interest Expense [Member] Interest Expense [Member] Allowance for Credit Losses [Text Block] Allowance for Loan Losses Document Information [Table] Document Information [Table] Consolidated Entities [Axis] Consolidated Entities Reconciliation of Revenue from Segments to Consolidated [Table] Reconciliation Of Revenue From Segments To Consolidated [Table] Common shares that have not been issued but are encumbered to fulfill employee compensation obligations and remaining authority for stock-based compensation plans. Common Shares Unissued But Encumbered Common shares unissued but encumbered Dividends, Cash [Abstract] Cash dividends: Income Tax Disclosure [Abstract] Fair Value, Recurring and Nonrecurring [Table] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Business Combination [Text Block] Business Combinations and Divestitures, Goodwill and Acquired Intangible Assets Unrecognized Tax Benefits Unrecognized tax benefits at end of year Unrecognized tax benefits at beginning of year Unrecognized tax benefits Additional Paid-in Capital [Member] Additional Paid-In Capital [Member] Maximum remaining term for investment purchased for estimating at cost. Maximum Remaining Term For Investment Purchased For Estimating At Cost Maximum remaining term for investment purchased for estimating at cost Non cosigner loan. Non Cosigner Loan [Member] Without Cosigner [Member] Adjustments Required To Reconcile Core Earnings [Table] Adjustments Required To Reconcile Core Earnings [Table] Adjustments Required To Reconcile Core Earnings [Table] Dividend Equivalent Units Related to Employee Stock-Based Compensation Plans Dividend equivalent units related to employee stock-based compensation plans. Dividend equivalent units related to employee stock-based compensation plans Measurement Frequency [Domain] Measurement Frequency Share Repurchase Program, Authorized, Amount Authorized multi-year share repurchased program amount Statement of Income Location, Balance [Axis] Income Statement Location Financing receivable decrease in expected future recoveries on previous fully charged-off loans. Financing Receivable Decrease In Expected Future Recoveries On Previously Fully Charged Off Loans Decrease in expected future recoveries on previously fully charged-off loans Change in balance during period Trading Symbol Trading Symbol Proceeds from (Repayments of) Commercial Paper Asset-backed commercial paper conduits, net Proceeds from (Repayments of) Commercial Paper, Total Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent Non-deductible regulatory-related expenses Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent, Total Total amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the next fiscal year through after the fifth fiscal year following the latest fiscal year. Long Term Debt Maturities Total before hedge accounting adjustments Seasoning thirty seven thru forty eight. Seasoning Thirty Seven Thru Forty Eight [Member] 37-48 Payments [Member] Derivative Asset (Liability) Net, Measurement Input [Extensible Enumeration] Derivative Asset (Liability) Net, Measurement Input [Extensible Enumeration] Represents the average balance of outstanding student loans during the period presented. Average Outstanding Education Loans Average Balance education loans Financing Receivable, Allowance for Credit Loss [Table Text Block] Allowance for Credit Losses and Recorded Investments in Loans Derivative Credit Risk Valuation Adjustment, Derivative Assets Decrease in valuation due to net credit risk adjustments Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Financing activities Fair Value, Recurring [Member] Fair Value Measurements Recurring [Member] Entity Ex Transition Period Entity Ex Transition Period ASC 815 - Derivatives and Hedging fair value adjustments. Asc Eight One Five Fair Value Adjustments Hedge accounting adjustments Accounting Standards Update 2016-13 [Member] ASU 2016-13 [Member] Financing Receivable Portfolio Segment [Domain] Financing Receivable Portfolio Segment Loans Receivable, Weighted Average Rate of Interest After Reduction Loans receivable, weighted average rate of interest after reduction Loans receivable, weighted average rate of interest after reduction Equity Components [Axis] Equity Components Represents a portion of financing receivables that are 31 to 60 days past due. Financing Receivables31 To60 Days Past Due [Member] Financing Receivables, 31 to 60 Days Past Due [Member] Equity Component [Domain] Equity Component Fico six four zero and above. Six Four Zero And Above [Member] 640 and Above [Member] Expected future recoveries on previously fully charged-off loans. Expected Future Recoveries On Previously Fully Charged Off Loans End of period expected future recoveries on previously fully charged-off loans Beginning of period expected future recoveries on previously fully charged-off loans Net charge offs as percentage of average loans in repayment excluding net adjustment resulting from change in charge off rate. Net Charge Offs As Percentage Of Average Loans In Repayment Excluding Net Adjustment Resulting From Change In Charge Off Rate Net charge-offs as a percentage of average loans in repayment, excluding the net adjustment resulting from the change in charge-off rate (annualized) Goodwill and Intangible Assets Disclosure [Abstract] Investments Investments Total investments Other Noninterest Expense Other operating expenses Other/remaining expenses Abstract element for reconciliation of consolidated statements of cash flows to consolidated balance sheets. Reconciliation Of Consolidated Statements Of Cash Flows To Consolidated Balance Sheets [Abstract] Reconciliation of the Consolidated Statements of Cash Flows to the Consolidated Balance Sheets: Document Annual Report Document Annual Report Business Combination [Axis] Business Acquisition Proceeds from Income Tax Refunds Income taxes received Derivative, Fair Value, Net Net total derivatives Ending balance of loans in repayment. Ending Balance Of Loans In Repayment Ending loans in repayment Customer [Axis] Customer Loans receivable for partially charged-off loans. Loans Receivable For Partially Charged Off Loans Loans receivable for partially charged-off loans Tax credit carryovers expiration year. Tax Credit Carryovers Expiration Year Credit carryovers, Expiration Loans Loans, net Loans, net Loans, Carrying Value Type of Borrower [Axis] Type of Borrower Collateral held. Collateral Held [Abstract] Collateral held: Effective Income Tax Rate Reconciliation, Tax Contingency, Amount Effective Income Tax Rate Reconciliation, Tax Contingency, Amount, Total Changes in unrecognized tax benefits, amount Statement of Comprehensive Income [Abstract] Financing Receivable, Allowance for Credit Loss [Roll Forward] Allowance for Loan Losses Maximum [Member] Maximum [Member] Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Cash Not Offset Cash (obligation to return cash collateral is recorded in short-term borrowings) Cash collateral (held) pledged, Assets Cross Currency Interest Rate Contract [Member] Cross-Currency Interest Rate Swaps [Member] Interest Expense {Member] Private education loans. Private Education Loans [Member] Private Education Loans [Member] Private Education Loans [Member] Total Liabilities, Fair Value Disclosure Total Liabilities, Fair Value Disclosure, Total Designated as Hedging Instrument [Member] Designated as Hedging Instrument [Member] Statistical Measurement [Axis] Statistical Measurement Government services. Government Services [Member] Government Services [Member] Finite-Lived Intangible Assets, Accumulated Amortization Intangible assets subject to amortization, Accumulated Impairment and Amortization Common Stock, Value, Issued Common stock, par value $0.01 per share; 1.125 billion shares authorized:467 million and 465 million shares issued, respectively Federal Government. Federal Government [Member] Federal Government [Member] Tax effected credit carryovers. Tax Effected Credit Carryovers Credit carryovers, Tax-Effected Financing Receivable, Allowance for Credit Loss [Table] Schedule Of Financing Receivable Allowance For Credit Losses [Table] Consolidation, Policy [Policy Text Block] Consolidation Equity, Including Portion Attributable to Noncontrolling Interest Ending Balance, Value Beginning Balance, Value Total equity Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Security Not Offset Securities at fair value - corporate derivatives (not recorded in financial statements) Net position, Assets Net position, Assets Derivative Fair Value Of Derivative Net Assets Amount Offset Against Collateral Derivative fair value of derivative net assets amount offset against collateral. Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Comprehensive income (loss): Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements Settlements Deferred Tax Assets, Operating Loss Carryforwards Operating loss and credit carryovers Deferred Tax Assets, Operating Loss Carryforwards, Total Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block] Operating loss and credit carryover. Operating Loss And Credit Carryover Operating Loss and Credit Carryovers Loans receivable repayment period. Loans Receivable Repayment Period Repayment term Net Fair Value Hedge Ineffectiveness Gains Losses Net fair value hedge ineffectiveness gains losses. Net fair value hedge ineffectiveness gains (losses) Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent State income taxes, net of federal income tax effect Capital Loss Carryforwards Expiration Year Capital loss carryforwards expiration year. Net capital loss, Expiration Entity Public Float Entity Public Float Preferred Stock, Shares Authorized Preferred stock, shares authorized Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class Certain Loan Modifications [Member] Certain loan modifications. Securities Financing Transaction [Domain] Securities Financing Transaction Schedule of Debt [Table Text Block] Company's Borrowings Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts Notes And Loans Receivable [Line Items] Entity Registrant Name Entity Registrant Name Debt Disclosure [Text Block] Borrowings Interest Expense, Policy [Policy Text Block] Interest Expense Deferred Tax Liabilities, Goodwill and Intangible Assets Acquired intangible assets Deferred Tax Liabilities, Goodwill and Intangible Assets, Total Loan, Net Charge-Offs in Year Three Financing Receivable Allowance for Credit Losses Write Offs Two Years Before Latest Fiscal Year Financing receivable, allowance for credit losses write offs two years before latest fiscal year. Software technology. Software Technology [Member] Software and Technology [Member] Entity Voluntary Filers Entity Voluntary Filers 2027 Finite-Lived Intangible Asset, Expected Amortization, Year Two Treasury Stock, Shares, Acquired Common stock repurchased, shares Common stock repurchased, shares Deferred State and Local Income Tax Expense (Benefit) State Other Assets Disclosure [Text Block] Other Assets Sale Of Equity Interests In Subsidiary Sale of equity interests in subsidiary. Sale of equity interests in subsidiary Cybersecurity Risk Management Positions or Committees Responsible [Flag] Consolidated Entities [Domain] Consolidated Entities Finite-Lived Intangible Asset, Expected Amortization, Year Three 2028 Income Tax Expense (Benefit) Provision for income tax expense/(benefit) Income tax expense (benefit) Net income tax effect Income tax expense (benefit) Measurement Frequency [Axis] Measurement Frequency Common Stock, Dividends, Per Share, Cash Paid Dividends per common share Dividends per share Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Unobservable Data Used in Recurring Valuations of Level 3 Federal education loan servicing. Federal Education Loan Servicing [Member] Federal Education Loan Servicing [Member] Loan status greater than Ninety Days delinquent Loan Status Greater Than Ninety Days Delinquent [Member] Greater than 90 days Delinquent [Member] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Compensation Related Costs, Policy [Policy Text Block] Accounting for Stock-Based Compensation Average balance of loans in repayment. Average Balance Of Loans In Repayment Average loans in repayment Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated Other Comprehensive Income (Loss), Net of Tax, Total Accumulated other comprehensive income (net of tax expense of $1 and $1, respectively) Consolidation Items [Axis] Consolidation Items Education Loan Portfolio By Program. Education Loan Portfolio By Program Table [Text Block] Education Loan Portfolio by Program Payment for (Proceeds from) Other Investing Activity Other investing activities, net Unallocated shared services expenses. Unallocated Shared Services Expenses Unallocated shared services expenses Class of Financing Receivable, Type of Borrower [Domain] Class of Financing Receivable, Type of Borrower Assets Assets Total assets Total assets Tax effected disallowed interest expense carryforwards. Tax Effected Disallowed Interest Expense Carryforwards State IRC § 163(j) disallowed interest expense carryovers, Tax-Effected State Income Tax Paid, State and Local, after Refund Received Income Tax Paid, State and Local, after Refund Received, Total Class of Financing Receivable [Domain] Class of Financing Receivable Disallowed interest expense carryforwards valuation allowance Disallowed Interest Expense Carryforwards Valuation Allowance State IRC § 163(j) disallowed interest expense carryovers, Corresponding Valuation Allowance Income Statement [Abstract] Financing Receivable, Past Due [Line Items] Financing Receivable Recorded Investment Past Due [Line Items] Non-modified Loans [Member] Non-modified loans. Derivative Liability, Fair Value of Collateral Total collateral pledged Loans disbursed after october one nineteen hundred ninety three and before july one two thousand six. Loans Disbursed After October One Nineteen Hundred Ninety Three And Before July One Two Thousand Six [Member] Loans Disbursed after October 1, 1993, and before July 1, 2006 [Member] Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Decreases resulting from tax positions taken during a prior period Reduce income tax liabilities from prior tax years Loans disbursed on or after July One Two Thousand Six. Loans Disbursed On Or After July One Two Thousand Six [Member] Loans Disbursed on or after July 1, 2006 [Member] Deferred Income Tax Expense (Benefit) Total deferred provision/(benefit) Weighted Average [Member] Weighted Average [Member] Gain (Loss) on Sales of Loans, Net, Total Gains on sale of education loans Gain (Loss) on Sales of Loans, Net Gains on sales of loans Tax effected operating loss carryforwards. Tax Effected Operating Loss Carryforwards Net operating loss carryovers, Tax-Effected FFELP loan asset-backed securitizations repurchase facilities. F F E L P Loan Asset Backed Securitizations Repurchase Facilities [Member] FFELP Loan FFELP Loan Securitizations ABS Repurchase Facilities [Member] Stock Issued During Period, Shares, New Issues Issuance of common shares, Shares Common shares issued Reimbursement on all qualifying default claims percentage. Reimbursement On All Qualifying Default Claims Percentage Percentage reimbursement on all qualifying default claims period Business Combination [Abstract] Earnings Per Share, Diluted Earnings Per Share, Diluted, Total Diluted earnings (loss) per common share Settlement payment Loss contingency settlement amount. Loss Contingency Settlement Amount Schedule of Segment Reporting Information, by Segment [Table Text Block] Asset Information for Loans Segment Operating Segments [Member] Operating Segments [Member] Stafford loans member. Stafford Loans [Member] Stafford Loans [Member] City Area Code City Area Code Servicing revenue Servicing revenue. Servicing Revenue Restricted Investments Benefit and insurance-related investments Net impact of derivative accounting. Net Impact Of Derivative Accounting [Member] Net Impact of Derivative Accounting [Member] Provisions for loan losses Total provision Less: provisions for loan losses Auditor Name Auditor Name Long-Term Borrowings [Member] Secured and Unsecured Long-Term Borowings [Member] Secured and unsecured long-term borowings. Consumer lending segment. Consumer Lending Segment [Member] Consumer Lending Segment [Member] Debt Instrument, Face Amount Amount of asset-backed securitization repurchase facility Debt principal amount Fair Value Hedging [Member] Fair Value [Member] Variable Interest Entity, Not Primary Beneficiary [Member] Securitization Trust [Member] Change in mark-to-market gains/(losses) relating to instruments still held at the reporting date. Change In Mark To Market Gains Losses Relating To Instruments Still Held At Reporting Date Change in mark-to-market gains/(losses) relating to instruments still held at the reporting date Counterparty Name [Domain] Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Percent Non-deductible goodwill impairment Interest Rate Floor [Member] Floor Income Contracts [Member] Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax Reclassification adjustments for derivative (gains) losses included in net income (interest expense) Debt tranches default amount. Debt Tranches Default Amount Debt tranches default principal amount Financing Receivable, Threshold Period Past Due, Writeoff Delinquency period (in days) Summary Of Significant Accounting Policies [Table] Summary Of Significant Accounting Policies [Table] Summary Of Significant Accounting Policies [Table] Cosigner loan. Cosigner Loan [Member] With Cosigner [Member] Rehab loans. Rehab Loans [Member] Rehab Loans [Member] Transfers and Servicing of Financial Assets, Transfers of Financial Assets, Policy [Policy Text Block] Securitization Accounting Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent Other Other Derivative Liability, Subject to Master Netting Arrangement, before Offset Derivative liabilities Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract] Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract] Cash and Cash Equivalents, Policy [Policy Text Block] Cash and Cash Equivalents Property, Plant and Equipment, Net Fixed assets Property, Plant and Equipment, Net, Total Deferred Foreign Income Tax Expense (Benefit) Foreign Noncontrolling Interest, Period Increase (Decrease) Net activity in noncontrolling interest Noncontrolling Interest, Period Increase (Decrease), Total FFELP loan ABCP facilities. F F E L P Loan A B C P Facilities [Member] FFELP Loan ABCP Facilities [Member] Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss) Included in other comprehensive income Interest income operating on education loans. Interest Income Operating on Education Loans Total interest income Retained Earnings [Member] Retained Earnings [Member] Represents the difference between the loan balance and the company's estimate of the amount to be collected in the future. Financing Receivable Expected Future Recoveries Of Current Period Defaults Expected future recoveries on current period gross charge-offs Expected future recoveries of current period defaults Decrease in valuation due to liquidity adjustments. Decrease In Valuation Due To Liquidity Adjustments Decrease in valuation due to liquidity adjustments Share-Based Payment Arrangement, Noncash Expense Stock-based compensation expense Share-Based Payment Arrangement, Noncash Expense, Total Loans Insured or Guaranteed by Government Authorities [Domain] Loans Insured or Guaranteed by Government Authorities Loans receivable, weighted average rate of interest Loans Receivable, Weighted Average Rate of Interest Loans receivable, weighted average rate of interest. Gain (Loss) on Derivative Instruments [Member] Gain (Losses) on Derivative Instruments [Member] Gains (losses) on derivative and hedging activities, net Fair Value, Inputs, Level 1 [Member] Level 1 [Member] Class of Stock [Line Items] Class of Stock [Line Items] Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total net cash used in financing activities Derivative Liability, Including Not Subject to Master Netting Arrangement, after Offset and Deduction Net position, Liabilities Derivative Liability, Including Not Subject to Master Netting Arrangement, after Offset and Deduction, Total Change in Unrecognized Tax Benefit, Reasonably Possible [Table] Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Table] Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year Total Private Education Loan Credit Quality Indicators by Origination Year Four Auditor Location Auditor Location Long-Term Debt [Member] Long-term borrowings [Member] Secured Debt [Member] Secured Borrowings [Member] Receivable with Imputed Interest, Effective Yield (Interest Rate) Average Effective Interest Rate of education loans Financing receivable, modifications, impairment write down. Financing Receivable Modifications Impairment Write Down Charge-offs (par) Derivative Contract [Domain] Derivative Contract Goodwill [Table] Schedule Of Goodwill [Table] Loan status current or Ninety Days or less delinquent. Loan Status Current Or Ninety Days Or Less Delinquent [Member] Current/90 Days or Less Delinquent [Member] Income Tax Jurisdiction [Domain] Income Tax Authority Entity Interactive Data Current Entity Interactive Data Current Deferred Tax Liabilities, Gross [Abstract] Deferred tax liabilities: Statement of Income Location, Balance [Domain] Income Statement Location Fair Value Measurement [Domain] Fair Value Measurement Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Operating activities Financing Receivable [Policy Text Block] Allowance for Loan Losses Amount before allocation of valuation allowances of deferred tax asset attributable to other deductible temporary differences. Deferred Tax Assets Other Including Valuation Allowance Other Loan Restructuring Modification [Domain] Loan Restructuring Modification Segment Reporting, Revenue Reconciling Item [Line Items] Segment Reporting Revenue Reconciling Item [Line Items] Segment Reporting, Revenue Reconciling Item [Line Items] Class of Treasury Stock [Table Text Block] Common Share Repurchases, Issuances and Dividends Paid Net charge offs as percentage of average loans in repayment. Net Charge Offs As Percentage Of Average Loans In Repayment Net charge-offs as a percentage of average loans in repayment (annualized) Hedge accounting adjustments. Hedge Accounting Adjustments [Member] Hedge Accounting Adjustments [Member] Cumulative Effect, Period of Adoption [Domain] Cumulative Effect, Period of Adoption Entity Tax Identification Number Entity Tax Identification Number Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Equity Share Price Closing price of common stock Option to purchase education loan of trust description. Option To Purchase Education Loan Of Trust Description Option to purchase education loan of the trust's initial pool balance Long-Term Debt, Type [Axis] Long-Term Debt, Type Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Organization and Business Private education legacy in-school loans. Private Education Legacy In-School Loans [Member] Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Education Loans Income Tax Authority, Name [Domain] Income Tax Authority, Name Percentage guaranteed as to principal and accrued interest by federal goverment in event of default Percentage Guaranteed as to Principal and Accrued Interest by Federal Goverment in Event of Default Percentage guaranteed as to principal and accrued interest by federal goverment in event of default. Local Phone Number Local Phone Number Schedule of Fair Value Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block] Carrying Value and Related Fair Value Hedging Adjustments of Liabilities Consumer lending. Consumer Lending [Member] Consumer Lending [Member] Weighted Average Number of Shares Outstanding, Diluted [Abstract] Denominator: Auditor Opinion [Text Block] Auditor Opinion Adjustment from change in charge off rate. Adjustment From Change In Charge Off Rate Adjustment resulting from the change in charge-off rate Adjustment resulting from the change in the charge-off rate Noninterest Expense Total expenses Accounting Policies [Abstract] Debt instrument maturities month year. Debt Instrument Maturities Month Year Facility maturity date Investments and Cash Cash and investments Investments and Cash, Total Loans modified, charged off Financing Receivable Modifications Charged Off Financing receivable modifications, charged off. Revenue from Contract with Customer, Excluding Assessed Tax Total Revenue Revenue Class of Stock [Domain] Class of Stock Labor and Related Expense Salaries and benefits Stock, Class of Stock [Table] Schedule Of Stock By Class [Table] After October one nineteen ninety three and before July one two thousand six. After October One Nineteen Ninety Three And Before July One Two Thousand Six [Member] After October 1 1993 and before July 1 2006 [Member] Entity Emerging Growth Company Entity Emerging Growth Company