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Financial Asset61 To90 Days Past Due [Member] Financial Asset, 61 to 90 Days Past Due [Member] Scenario [Axis] Scenario Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Impact of Derivatives on Balance Sheet Financing Receivable, Modified in Period, Amount Modified Loans (Amortized Cost) Common Stock, Dividends, Per Share, Cash Paid Dividends per common share Dividends per share Loans Classified as Held for sale [Member] Loans classified as held for sale. Loans Classified as Held for Sale [Member] Financial Asset, Not Past Due [Member] Financing Asset, Not Past Due [Member] Preferred Stock, Shares Issued Preferred stock, shares issued Seasoning thirteen thru twenty four. Seasoning Thirteen Thru Twenty Four [Member] 13-24 Payments [Member] Debt Disclosure [Text Block] Borrowings Other income Noninterest Income Expenses Other Operating Income Expenses Noninterest Income Expenses Other Operating Income Expenses Debt, Long-Term and Short-Term, Combined Amount Total Share Repurchase Program, Authorized, Amount Authorized multi-year share repurchased program amount 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. Modified Loans [Member] Modified [Member] Loans held for sale Loan, Held-for-Sale, Fair Value Disclosure Commitments and Contingencies Commitments and contingencies Weighted Average Number of Shares Outstanding, Diluted Average common and common equivalent shares outstanding Weighted average shares used to compute diluted EPS Not Designated as Hedging Instrument [Member] Trading [Member] APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Stock-based compensation expense APIC, Share-Based Payment Arrangement, Increase for Cost Recognition, Total Total "Core Earnings" adjustments to GAAP. Core Earnings Adjustments To Gaap Core Earnings adjustments to GAAP Total Core Earnings adjustments to GAAP Not for profit. Not For Profit [Member] Not For Profit [Member] Preferred Stock, Shares Outstanding Preferred Stock, Shares Outstanding, Beginning Balance Preferred Stock, Shares Outstanding, Ending Balance Preferred stock, shares outstanding Represents a portion of financing receivables that are loans in repayment. Financing Receivables Loans In Repayment [Member] Financing Receivables, Loans In Repayment [Member] Payments of Ordinary Dividends, Common Stock Common dividends paid Fair Value, Recurring [Member] Fair Value Measurements Recurring [Member] Fair Value Measurement and Measurement Inputs, Recurring and Nonrecurring [Text Block] Fair Value Measurements Contractual Interest Rate Reduction [Member] Interest Rate Concession [Member] Consolidated Entities [Domain] Consolidated Entities Common Stock, Shares, Issued Common stock, shares issued Segment Reporting [Line Items] Segment Reporting Information [Line Items] Other Expenses Other/remaining expenses Debt Instrument, Face Amount Debt principal amount Net tax effect Income tax expense Net tax effect Income tax expense (benefit) Counterparty Name [Domain] Counterparty Name Proceeds from (Repayments of) Commercial Paper Asset-backed commercial paper conduits, net Proceeds from (Repayments of) Commercial Paper, Total Reclassifications for core to gaap accounting. Reclassifications For Core To Gaap Accounting [Member] Reclassifications [Member] Fair Value Hedging [Member] Fair Value [Member] 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 Loan, Net Charge-Offs in Year Five Class of Financing Receivable [Axis] Class of Financing Receivable Private education loan ABCP facilities. Private Education Loan A B C P Facilities [Member] Private Education Loan ABCP Facilities [Member] Operating Segments [Member] Operating Segments [Member] School or grace or deferment or forbearance School Or Grace Or Deferment Or Forbearance [Member] School/Grace/Deferment [Member] In-school/Grace/Deferment/Forbearance [Member] Private education loan securitizations. Private Education Loan Securitizations [Member] Private Education Loan Securitizations [Member] 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] Payment for (Proceeds from) Other Investing Activity Other investing activities, net 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 Loan, Net Charge-Offs in Year Prior 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 Net charge-offs Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery Schedule of Long-Term Debt Instruments [Table] Debt Instrument [Table] Income Statement [Abstract] Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down Charge-offs Charge-offs (par) Repayment. Repayment [Member] Repayment [Member] Derivative Asset (Liability) Net, Measurement Input [Extensible Enumeration] Adjustments required to reconcile core earnings. Adjustments Required To Reconcile Core Earnings [Line Items] Adjustments Required To Reconcile Core Earnings [Line Items] Loan Restructuring Modification [Axis] Loan Restructuring Modification Forbearance. Forbearance [Member] Forbearance [Member] Restricted Investments Benefit and insurance-related investments Gain (Loss) on Derivative Instruments, Net, Pretax Gains (losses) on derivative and hedging activities, net Mark-to-market gains (losses) recognized Gain (Loss) on Derivative Instruments, Net, Pretax, Total Goodwill Goodwill [Text Block] Series A Junior Participating Preferred Stock [Member] Series A Junior Participating Preferred Stock [Member] Series A junior participating preferred stock. Earnings Per Share, Basic Earnings Per Share, Basic, Total Basic earnings per common share Basic earnings per common share Document Period End Date Document Period End Date Document Information [Table] Document Information [Table] Other Noninterest Expense Other operating expenses Open market share repurchases. Open Market Share Repurchases [Member] Open Market Repurchases [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Common Stock, Shares Authorized Common stock, shares authorized 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 Statement of Stockholders' Equity [Abstract] Net positive exposure on foreign currency swaps Foreign Currency Fair Value Hedge Derivative at Fair Value, Net, Total Foreign Currency Fair Value Hedge Derivative at Fair Value, Net Total loans, gross Financing Receivable, before Allowance for Credit Loss Total Loans, gross Ending total loans Financing Receivable, before Allowance for Credit Loss, Ending Balance Financing Receivable, before Allowance for Credit Loss, Beginning Balance Financial asset, 31 to 60 days past due. Financial Asset31 To60 Days Past Due [Member] Financial Asset, 31 to 60 Days Past Due [Member] School/Deferment. School Deferment [Member] School/Deferment [Member] Other Revenue (Loss) Other revenue (loss). Other revenue (loss) Asset recovery and business processing revenue. Asset Recovery And Business Processing Revenue Asset recovery and business processing revenue Financing Receivable, Held-for-Sale [Policy Text Block] Loans Held for Sale Assets Total assets Total assets Title of 12(b) Security Title of 12(b) Security Goodwill, Ending Balance Goodwill, Beginning Balance Goodwill Goodwill, Total Preferred Stock, Value, Issued Series A Junior Participating Preferred Stock, par value $0.20 per share; 2 million shares authorized at December 31, 2021; no shares issued or outstanding Payments for Repurchase of Common Stock Common stock repurchased No Trading Symbol Flag No Trading Symbol Flag Preferred Stock Purchase Rights [Member] Preferred Stock Purchase Rights [Member] Preferred stock purchase rights. Derivative, Notional Amount Total Derivative Notional Values Antidilutive Securities, Name [Domain] Private education loan securitizations repurchase facility. Private Education Loan Securitizations Repurchase Facility [Member] Private Education Loan Asset-backed Securitization Repurchase Facilities [Member] Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery [Abstract] Charge-offs: Interest Paid, Excluding Capitalized Interest, Operating Activity Interest paid Dividends, Cash [Abstract] Cash dividends: Goodwill [Line Items] FFELP loans member. F F E L P Loans [Member] FFELP Loans [Member] Facilities [Member] A B C P Facilities [Member] A B C P Facilities. 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 Treasury Stock, Value, Acquired, Cost Method Common stock repurchased, value Common stock repurchased Directors or Officers [Member] Directors or Officers. Measurement Input, Discount for Lack of Marketability [Member] Bid/ask adjustment to discount rate [Member] Total interest expense Interest Expense, Operating, Total Interest Expense, Operating Provision For Education Loans [Member] Provision for education loans. Class of Treasury Stock [Table] Class Of Treasury Stock [Table] Adjustments for core to GAAP accounting. Adjustments For Core To Gaap Accounting [Member] Total Adjustments [Member] Steve Hauber [Member] Steve Hauber. Steve Hauber [Member] Segment Reporting [Table Text Block] Asset Information for Loans Segment Derivative, Fair Value, Amount Offset Against Collateral, Net Net positive exposure related to corporate derivatives Exposure, net of collateral Derivative, Fair Value, Amount Offset Against Collateral, Net, Total Beginning Balance, Value Ending Balance, Value Equity, Attributable to Parent Equity, Attributable to Parent, Total Increase (Decrease) in Interest Payable, Net Increase (decrease) in accrued interest payable Common stock shares outstanding. Common Stock Shares Outstanding [Member] Common Stock Shares Outstanding [Member] Valuation Approach and Technique [Domain] Valuation Approach and Technique Treasury Stock, Common [Member] Treasury Stock [Member] Included in Earnings Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Table Text Block] Direct Operating Costs Direct operating expenses Direct Operating Costs, Total Consolidation loans member. Consolidation Loans [Member] Consolidation Loans [Member] Consolidation Loans [Member] Fair Value, by Balance Sheet Grouping [Table Text Block] Fair Values of Financial Assets and Liabilities, Including Derivative Financial Instruments Earnings Per Share [Text Block] Earnings (Loss) per Common Share Long-Term Debt, Fair Value Long-term borrowings, Fair Value Estimate of Fair Value Measurement [Member] Fair Value [Member] Number of Reportable Segments Number of reportable segments Derivative Instruments, Gain (Loss) [Table] Derivative Instruments Gain Loss By Hedging Relationship By Income Statement Location By Derivative Instrument Risk [Table] Basis of Accounting, Policy [Policy Text Block] Basis of Presentation Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs Balance, end of period Balance, beginning of period Long-term debt Long-Term Debt, Total Long-term borrowings, Carrying Value Long-term borrowings Represents a portion of financing receivables that are current. Financing Receivables Current [Member] Financing Receivables, Current [Member] 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 Securities Financial Transaction [Axis] Securities financial transaction. Secured Debt [Member] Secured Borrowings [Member] Allowance for Credit Losses [Text Block] Allowance for Loan Losses - Education Loans Stock, Class of Stock [Table] Schedule Of Stock By Class [Table] Seasoning twenty five thru thirty six. Seasoning Twenty Five Thru Thirty Six [Member] 25-36 Payments [Member] Financial Asset, Aging [Domain] Financial Asset, Aging School type. School Type [Member] School Type [Member] Derivative Credit Risk Valuation Adjustment, Derivative Assets Decrease in valuation due to net credit risk adjustments 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) Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Comprehensive income (loss): Schedule Of Credit Exposure Related To Our Derivative Counterparties. Schedule Of Credit Exposure Related To Our Derivative Counterparties Table [Text Block] Schedule of Credit Exposure Related to Our Derivative Counterparties 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 Entity Interactive Data Current Entity Interactive Data Current Provisions for loan losses Less: provisions for loan losses Total provision Goodwill [Table] Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Common Stock, Value, Issued Common stock, par value $0.01 per share, 1.125 billion shares authorized: 468 million and 467 million shares issued, respectively Schedule of Earnings (Loss) per Common Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] School/grace/deferment. School Grace Deferment [Member] School/Grace/Deferment [Member] Liabilities Total liabilities Federal education loans segment. Federal Education Loans Segment [Member] Federal Education Loans [Member] 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 Debt, Fair Value Short-term borrowings, Fair Value Product and Service Product and Service [Axis] Retained Earnings (Accumulated Deficit), Total Retained Earnings (Accumulated Deficit) Retained earnings Fair Value, Inputs, Level 3 [Member] Level 3 [Member] 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 Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Derivative Notional Values Operating Expenses Total operating expenses Operating expenses Proceeds from Accounts Receivable Securitization Borrowings collateralized by loans in trust - issued Share Price Closing price of common stock Hedging Relationship [Domain] Hedging Relationship Fair Value, by Balance Sheet Grouping [Table] Fair Value By Balance Sheet Grouping [Table] Period of hardship forbearance of payments. Period of Hardship Forbearance of Payments Period of hardship forbearance of payments Stock Issued During Period, Shares, New Issues Issuance of common shares, Shares Common shares issued Private Education Loans One [Member] Private education loans one. Private Education Loans [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) 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 Disposal of subsidiaries, net of cash and restricted cash disposed of Disposal of Subsidiaries Net of Cash and Restricted Cash Disposed of Disposal of subsidiaries net of cash and restricted cash disposed of. Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts Notes And Loans Receivable [Line Items] Cash Restricted Cash Restricted cash Restricted Cash, Total Other Assets, Miscellaneous Other Other Assets, Miscellaneous, Total Financial Liabilities Fair Value Disclosure Total interest-bearing liabilities, Fair Value Derivative Liability Derivative Liability, Total Derivative values (as carried on balance sheet), Liabilities Long-term unsecured notes issued Proceeds from Issuance of Unsecured Debt Derivative Liability, Statement of Financial Position [Extensible Enumeration] Derivative Liability, Statement of Financial Position [Extensible Enumeration] Income Taxes Income Tax, Policy [Policy Text Block] Financing Receivable, Year One, Originated, Current Fiscal Year Total Private Education Loan Credit Quality Indicators by Origination Year One Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV Short-Term Debt, Type [Axis] Short-Term Debt, Type Finance receivable percentage of loan type. Finance Receivable Percentage of Loan Type Loan Modifications, % of Loan Type Weighted Average Number of Shares Outstanding, Diluted, Adjustment Dilutive potential common shares Weighted Average Number of Shares Outstanding, Diluted, Adjustment, Total Labor and Related Expense Salaries and benefits Financing Receivable, Percent Past Due Loans delinquent, percentage Short term unsecured debt. Short Term Unsecured Debt [Member] Short Term Senior Unsecured Debt [Member] Long-Term Fixed Rate Debt [Member] Fixed Interest Rate Debt [Member] Fixed interest rate debt. Concentration Risk Type [Domain] Concentration Risk Type Information Technology and Data Processing Information technology expenses Additions (subtractions) for core to GAAP accounting. Additions Subtractions For Core To Gaap Accounting [Member] Additions (Subtractions) [Member] Share Repurchase Program [Axis] Derivative [Line Items] Derivative [Line Items] Stockholders' Equity, Other Other 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 Other noninterest income loss. Other Noninterest Income loss Total other income Liabilities and Equity Total liabilities and equity Below 640 [Member] Below six four zero. Below Six Four Zero [Member] 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] 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): Document Fiscal Period Focus Document Fiscal Period Focus Derivatives, Fair Value [Line Items] Derivatives Fair Value [Line Items] Loans Loans, net Loans, Carrying Value Loans, net Short-term debt Short-Term Debt, Total Short-term borrowings, Carrying Value Short-term borrowings Financing Receivable, before Allowance for Credit Loss, Fee and Loan in Process Total Loans, gross 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 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 Financing Receivable, Originated, More than Five Years before Current Fiscal Year Total Private Education Loan Credit Quality Indicators by Origination Year Prior Increase in accrued interest receivable Increase (Decrease) in Accrued Interest Receivable, Net Decrease in accrued interest receivable For profit. For Profit [Member] For Profit [Member] Income Tax Paid, before Refund Received Income taxes paid Interest Receivable and Other Assets Other assets Total Other 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 Entity Current Reporting Status Entity Current Reporting Status Derivative asset at fair value including accrued interest. Derivative Asset At Fair Value Including Accrued Interest Derivative asset at fair value including accrued interest Fair Value, Inputs, Level 1 [Member] Level 1 [Member] Class of Stock [Domain] Class of Stock Private education refinance loan. Private Education Refinance Loan [Member] Private Education Refinance Loans [Member] Schedule of loans by type. Schedule Of Loans By Type Table [Text Block] Loans Type Loans Insured or Guaranteed by Government Authorities [Domain] Loans Insured or Guaranteed by Government Authorities Financial Instrument [Axis] Financial Instrument Gains Losses Recognized In Net Income On Derivatives Gains losses recognized in net income on derivatives. Gains (losses) recognized in net income on derivatives Assets, Fair Value Disclosure Total Total interest income Interest income Interest Income, Operating Interest Income, Operating, Total 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 Total Net Charge-Offs Gross Paydowns of Debt Gross paydowns of debt. Gross paydowns Document Transition Report Document Transition Report Commitments and Contingencies Disclosure [Abstract] Interest income, net of discount accretion and premium amortization from the cash and investment portfolio. Cash And Investments Interest Income Loss Cash and investments 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 Loan Modifications, Amortized Cost Financing Receivable Modifications Pre Modification Recorded Investment Financing receivable, modifications, pre-modification, recorded investment. 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] Equity Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Payment Deferral [Member] More Than an Insignificant Payment Delay [Member] Common Stock [Member] Common Stock [Member] Derivative Instruments and Hedging Activities Disclosure [Text Block] Derivative Financial Instruments Seasoning one thru twelve. Seasoning One Thru Twelve [Member] 1-12 Payments [Member] Weighted Average Number of Shares Outstanding, Diluted, Adjustment [Abstract] Effect of dilutive securities: Noninterest Expense [Abstract] Expenses: 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 Financing receivable allowance for credit losses write offs in current fiscal year. Financing Receivable Allowance for Credit Losses Write Offs in Current Fiscal Year Loan, Net Charge-Offs in Year One Healthcare services. Healthcare Services [Member] Healthcare Services [Member] 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 Federal Family Education Loan Program (FFELP) Guaranteed Loans [Member] FFELP Loans [Member] Represents a portion of financing receivables that are in forbearance. Financing Receivables Forbearance Loans In Repayment [Member] Financing Receivables, Forbearance, Loans In Repayment [Member] Assets Assets [Abstract] 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) Loan Restructuring Modification [Domain] Loan Restructuring Modification Entity Central Index Key Entity Central Index Key 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] Restructuring Charges Restructuring/other reorganization expenses Restructuring Charges, Total Antidilutive Securities [Axis] Class of Stock [Line Items] Class of Stock [Line Items] Fair Value Hedge Liabilities Carrying Value Consolidation Items Consolidation Items [Axis] Current Fiscal Year End Date Current Fiscal Year End Date Derivative [Table] Derivative [Table] Document Quarterly Report Document Quarterly Report Transfers in and/or out of level 3 Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers, Net Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers, Net, Total Dividend, Share-Based Payment Arrangement, Shares Dividend equivalent units related to employee stock-based compensation plans Fair Value, Inputs, Level 2 [Member] Level 2 [Member] Unsecured Debt [Member] Total Unsecured Borrowings [Member] Long Term Senior Unsecured Debt [Member] Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Net cash provided by operating activities Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Earnings Per Share, Diluted Earnings Per Share, Diluted, Total Diluted earnings per common share Diluted earnings per common share 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 [Member] Seasoning [Member] Repayments. Financing Receivable, Allowance for Credit Loss [Line Items] Financing Receivable Allowance For Credit Losses [Line Items] Financing Receivable, Allowance for Credit Losses [Line Items] Preferred stock, par value Preferred Stock, Par or Stated Value Per Share Cash Flow Hedging [Member] Cash Flow [Member] Net income (loss) Net income Net income (loss) Private Education Recent In-School Loans [Member] Private education recent In-school loans. Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax Net changes in cash flow hedges, net of tax Net changes in cash flow hedges, net of tax Increase (Decrease) in Other Operating Assets Increase (Decrease) in Other Operating Assets, Total Decrease (increase) in other assets Commitments and Contingencies Disclosure [Text Block] Commitments, Contingencies and Guarantees Loans receivable and investments fair value disclosure. Loans Receivable And Investments Fair Value Disclosure Total earning assets, Fair Value Other Contract [Member] Other [Member] 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 Loan, Net Charge-Offs in Year Two 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 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 Mark Heleen [Member] Mark Heleen [Member] Comprehensive Income (Loss), Net of Tax, Attributable to Parent Total comprehensive income (loss) Variable Interest Entity, Primary Beneficiary [Member] Assets and Liabilities of Consolidated Variable Interest Entities [Member] Interest Rate reduction and extended maturity. Interest Rate Reduction and Extended Maturity [Member] Combination Rate Reduction and Term Extension [Member] Measurement Frequency [Domain] Measurement Frequency Schedule of Variable Interest Entities [Table Text Block] Financing VIEs Scenario Scenario [Domain] Accumulated Other Comprehensive Income (Loss) [Member] Equity Components [Axis] Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Cash flows from investing activities Education loan. Education Loan [Member] Education Loan Portfolio [Member] Statement of Cash Flows [Abstract] Fair Value Hierarchy and NAV Fair Value Hierarchy and NAV [Domain] Financing Receivable, Modified, Subsequent Default Payment default Payment Default (Par) 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 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] Restricted Cash and Cash Equivalent Restricted cash and cash equivalents Restricted Cash and Cash Equivalents, Total Restricted cash and restricted cash equivalents Allowance at end of period Allowance for loans losses Financing Receivable, Allowance for Credit Loss Loan allowance for losses Allowance for loans losses Beginning balance Business processing. Business Processing [Member] Business Processing [Member] Floor Income Contracts [Member] Interest Rate Floor [Member] Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year Total Private Education Loan Credit Quality Indicators by Origination Year Two 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] Preferred stock, shares authorized Preferred Stock, Shares Authorized Preferred stock, shares authorized 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] John Kane [Member] John Kane [Member] Collateral pledged to others. Collateral Pledged To Others [Abstract] Collateral pledged to others: Derivative Contract [Domain] Derivative Contract Class of Stock [Axis] Class of Stock Derivative Instruments, Gain (Loss) [Table Text Block] Mark-to-Market Impact of Derivatives on Statements of Income Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Securities not included in the computation of diluted earnings per share 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 Counterparty Name [Axis] Counterparty Name Number of Operating Segments Number of reportable operating segments AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) [Member] Provision for Loan and Lease Losses [Abstract] Provision: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity Total adjustments Parent [Member] Total Stockholders' Equity [Member] Derivative, Net Liability Position, Aggregate Fair Value Derivative liability at fair value including accrued interest and premium receivable Noninterest Income Total other income (loss) Total other income (loss) Concentration Risk Benchmark [Domain] Concentration Risk Benchmark Interest receivable and payable and other assets. Interest Receivable And Payable And Other Assets Other assets, net Other assets Interest Receivable Accrued interest receivable 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 Assets Impairment And Amortization Expense Goodwill and acquired intangible asset impairment and amortization expense Goodwill and acquired intangible asset impairment and amortization Goodwill and acquired intangible asset impairment and amortization Counter party. Counter Party [Member] Counterparties [Member] Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements Settlements Financing Receivable, Held-for-Sale Held for sale loan amount Loans held for sale Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year Total Private Education Loan Credit Quality Indicators by Origination Year Five Hedging Designation [Axis] Hedging Designation Hedging Designation Hedging Designation [Domain] Intangible Asset, Goodwill and Other [Abstract] Document Type Document Type Gross charge-offs Financing Receivable, Allowance for Credit Loss, Writeoff Charge-offs (as a result of lower recovery expectations) 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 Cross Currency Interest Rate Contract [Member] Cross-Currency Interest Rate Swaps [Member] Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Cash flows from operating activities (Gain) on sale of subsidiary Gain on sale of subsidiaries, net Gain (loss) on sale of subsidiaries, net Gain on sale of subsidiary Cosigners [Member] Cosigners. Cosigners [Member] Financing Receivable, Allowance for Credit Loss [Table Text Block] Allowance for Credit Losses and Recorded Investments in Loans Internal Credit Assessment [Axis] Internal Credit Assessment Financing Receivable, Allowance for Credit Loss, Recovery Recoveries (cash collected) Dividends, Common Stock, Cash Dividends paid Common stock 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] Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year Total Private Education Loan Credit Quality Indicators by Origination Year Three Segment Reporting [Table] Schedule Of Segment Reporting Information By Segment [Table] Securities Act File Number Entity File Number Loan status. Loan Status [Member] Loan Status [Member] Location, Statement of Income, Balance [Axis] Retained Earnings [Member] Retained Earnings [Member] Seasoning more than forty eight. Seasoning More Than Forty Eight [Member] More than 48 Payments [Member] Proceeds from (Payment for) Other Financing Activity Other financing activities, net Transferable tax credits purchases Transferable Tax Credits Purchases Transferable tax credits purchases. Payment for Acquisition, Loan, Held-for-Investment Education loans originated and acquired Entity Registrant Name Entity Registrant Name Class of Treasury Stock [Table Text Block] Common Share Repurchases, Issuances and Dividends Paid Accounting Policies [Abstract] Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net Income (Loss), Including Portion Attributable to Noncontrolling Interest, Total Net income Net income Other Segment [Member] Other Operating Segment [Member] Shares Acquired, Average Cost Per Share Average purchase price per share Derivative Liability, Fair Value of Collateral Total collateral pledged Net Assets Net assets of consolidated variable interest entities Net Assets, Beginning Balance Net Assets, Ending Balance 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 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 Entity Address, Address Line One Entity Address, Address Line One 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: 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 Loan, Net Charge-Offs in Year Four Fico. Fico [Member] FICO Scores [Member] Loans Insured or Guaranteed by Government Authorities [Axis] Loans Insured or Guaranteed by Government Authorities Fair Value, Recurring and Nonrecurring [Table] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Proceeds from payments on education loans. Proceeds From Payments On Education Loans Proceeds from payments on education loans Segments Segments [Axis] Repayments of Accounts Receivable Securitization Borrowings collateralized by loans in trust - repaid Long-Term Floating Rate Debt [Member] Floating Interest Rate Debt [Member] Floating interest rate debt. Supplemental Cash Flow Information [Abstract] Supplemental disclosure of cash flow information: Gross issunaces Gross Issuance of Debt During Period Gross issuance of debt during period. Entity Small Business Entity Small Business Credit Concentration Risk [Member] Credit Concentration Risk [Member] Dilutive effect of restricted stock, restricted stock units, performance stock units, and Employee Stock Purchase Plan ("ESPP") Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Interest Income (Expense), Operating Net interest income (loss) Stockholders' Equity before Treasury Stock Total stockholders' equity before treasury stock Long-Term Debt, Type [Axis] Long-Term Debt, Type Significant Accounting Policies [Text Block] Significant Accounting Policies Financial asset, 90 days past due. Financial Asset90 Days Past Due [Member] Financial Asset, 90 Days Past Due [Member] Consolidation Items [Domain] Consolidation Items Treasury Stock, Shares, Acquired Common stock repurchased, shares Common stock repurchased, shares 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] Eliminations And Reconciling Items Adjustments [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Earnings Per Share [Abstract] Derivative Asset Derivatives at fair value Derivative values (as carried on balance sheet), Assets Measurement Input, Constant Prepayment Rate [Member] Constant Prepayment Rate [Member] Corporate expenses Corporate expenses. Corporate expenses Financing Receivable Credit Quality Indicators [Table Text Block] Private Education Loan Portfolio Stratified by Key Credit Quality Indicators Equity [Abstract] Product and Service [Domain] Product and Service Equity [Text Block] Stockholders' Equity Measurement Frequency [Axis] Measurement Frequency Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Cash flows from financing activities Intangible Asset, Including Goodwill, after Accumulated Amortization Goodwill and acquired intangible assets, net Intangible Assets, Net (Including Goodwill), Total Goodwill and acquired intangible assets Consolidated Entities [Axis] Consolidated Entities Discount On Transferable Tax Credits Discount on transferable tax credits. Discount on transferable credits purchased Financing Receivable, Past Due [Table Text Block] Age Analysis of Past Due Loans Delinquencies Non-U.S. Doller Denominated Debt [Member] Foreign Currency Doller Denominated Debt [Member] Foreign currency Doller denominated debt. Liabilities [Abstract] Liabilities Derivative Assets (Liabilities), at Fair Value, Net Derivative financial instruments, Fair Value Derivative Assets (Liabilities), at Fair Value, Net, Total Interest and Dividend Income, Operating Total interest income Entity Tax Identification Number Entity Tax Identification Number Treasury Stock, Common, Shares Common stock held in treasury Treasury Stock, Common, Shares Treasury Stock, Common, Shares Accounts Receivable [Member] Accounts Receivable [Member] Valuation Approach and Technique [Axis] Valuation Approach and Technique Deferred Income Taxes and Other Tax Receivable, Current Income tax asset, net Derivative Instrument Derivative Instrument [Axis] Equity, Class of Treasury Stock [Line Items] Equity, Class of Treasury Stock [Line Items] Equity Component [Domain] Equity Component Entity Address, City or Town Entity Address, City or Town 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 Measurement Input Type [Domain] Measurement Input Type Income Tax Paid, after Refund Received Income taxes paid Income Taxes Paid, Net, Total Income taxes paid for transferable credits purchases Stock Issued During Period, Value, New Issues Issuance of common shares Segments [Domain] Segments Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Concentration Risk Type Concentration Risk Type [Axis] Schedule of Debt [Table Text Block] Company's Borrowings Long-Term Debt [Member] Long-term borrowings [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 Financing Receivable, Modified, Accumulated Payment status (Amortized Cost) Loans Antidilutive Security, Excluded EPS Calculation [Table] Measurement Basis [Axis] Weighted Average Number of Shares Outstanding, Diluted [Abstract] Denominator: Derivative assets Derivative Asset, Subject to Master Netting Arrangement, before Offset Statement [Table] Statement [Table] 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. Dividend equivalent units related to employee stock-based compensation plans Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income before income tax expense Derivative Asset, Subject to Master Netting Arrangement, Liability Offset Impact of master netting agreements, Assets Securities Financing Transaction [Line Items] Securities Financing Transaction [Line Items] 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 Change in balance during period Decrease in expected future recoveries on previously fully charged-off loans Entity Shell Company Entity Shell Company Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Net cash provided by investing activities Statement [Line Items] Statement [Line Items] Collateral Held [Axis] 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] Seasoning thirty seven thru forty eight. Seasoning Thirty Seven Thru Forty Eight [Member] 37-48 Payments [Member] Financing Receivable, Allowance for Credit Loss [Roll Forward] Allowance for Loan Losses 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] Schedule of Financial Instruments Owned and Pledged as Collateral [Table Text Block] Collateral Held and Pledged Schedule of Other Assets [Table Text Block] Schedule of Other Assets Net interest income (loss) after provisions for loan losses Interest Income (Expense), after Provision for Loan Loss Net interest income (loss) after provisions for loan losses Debt Disclosure [Abstract] Increase (Decrease) in Other Operating Liabilities Increase (Decrease) in Other Operating Liabilities, Total (Decrease) in other liabilities 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 Repayments of Unsecured Debt Long-term unsecured notes repaid Derivative Asset (Liability) Net, Valuation Technique [Extensible Enumeration] Derivative Asset (Liability) Net, Valuation Technique [Extensible List] 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] AOCI Tax, Attributable to Parent Tax expense for accumulated other comprehensive loss 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 Concentration Risk Benchmark [Axis] Concentration Risk Benchmark Noninterest Expense Total expenses Financing Receivable, Transfer to Held-for-Sale, Allowance for Credit Loss, Expense Reversal Allowance for loan loss 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: Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation Shares repurchased related to employee stock-based compensation plans Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract] Ending balance of loans in repayment. Ending Balance Of Loans In Repayment Ending loans in repayment Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Investments Total investments Investments Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) [Table Text Block] Impact of Derivatives on Other Comprehensive Income (Equity) Collateral held. Collateral Held [Abstract] Collateral held: Liabilities, Fair Value Disclosure Total Liabilities, Fair Value Disclosure, Total Total 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 Private education loans. Private Education Loans [Member] Private Education Loans [Member] Private Education Loans Derivative Asset (Liability) Net, Measurement Input Derivatives Loans Receivable, Fair Value Disclosure Loans receivable, Fair Value Government services. Government Services [Member] Government Services [Member] Document Fiscal Year Focus Document Fiscal Year Focus 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) Common Stock, Shares, Outstanding Ending Balance, Shares Beginning Balance, Shares Equity, Including Portion Attributable to Noncontrolling Interest Ending Balance, Value Beginning Balance, Value Total equity Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract] Derivative Liabilities: Collaborative Arrangement and Arrangement Other than Collaborative [Table] 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. Net position, Assets Financial Instruments [Domain] Financial Instruments Statement of Comprehensive Income [Abstract] Security Financing Transaction [Table] Securities Financing Transaction [Table] Collateral Held [Domain] Net Fair Value Hedge Ineffectiveness Gains Losses Net fair value hedge ineffectiveness gains losses. Net fair value hedge ineffectiveness gains (losses) Net fair value hedge ineffectiveness gains (losses) Financing Receivable, Past Due [Line Items] Financing Receivable Recorded Investment Past Due [Line Items] Securities Financial Transaction [Domain] Securities financial transaction. Treasury Stock, Value Treasury Stock, Value, Total Less: Common stock held in treasury at cost: 374 million and 371 million shares, respectively Additional Paid in Capital, Common Stock Additional paid-in capital Certain loan modifications. Certain Loan Modifications [Member] Security Exchange Name Security Exchange Name Proceeds from Income Tax Refunds Income taxes refunded Measurement Input Type Measurement Input Type [Axis] Derivative Liability, Subject to Master Netting Arrangement, Asset Offset Impact of master netting agreements, Liabilities New Accounting Pronouncements, Policy [Policy Text Block] Recently Issued Accounting Pronouncements Changes Measurement [Member] Difference [Member] Entity Address, State or Province Entity Address, State or Province 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 Loan, Net Charge-Offs in Year Three Accounts Receivable, after Allowance for Credit Loss Accounts receivable Accounts Receivable, after Allowance for Credit Loss, Total Designated as Hedging Instrument [Member] Designated as Hedging Instrument [Member] Amendment Flag Amendment Flag Financial Asset, Aging [Axis] Financial Asset, Aging Summary of Goodwill for Each Reporting Units and Reportable Segments Goodwill [Table Text Block] Concentration Risk, Percentage Dimensions of concentration risk Noninterest Income [Abstract] Other income (loss): Debt Instrument [Axis] Debt Instrument 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] 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 Financing Receivable, Past Due [Table] Schedule Of Financing Receivables Past Due [Table] Financing Receivable Portfolio Segment [Domain] Financing Receivable Portfolio Segment Average balance of loans in repayment. Average Balance Of Loans In Repayment Average loans in repayment City Area Code City Area Code Internal Credit Assessment [Domain] Internal Credit Assessment Unallocated shared services expenses. Unallocated Shared Services Expenses Unallocated shared services expenses Reported Value Measurement [Member] Carrying Value [Member] Organization, Consolidation and Presentation of Financial Statements [Abstract] Class of Financing Receivable [Domain] Class of Financing Receivable Non-modified loans. Non-modified Loans [Member] Non-Modified [Member] Accounts and Financing Receivables [Table] Schedule Of Accounts Notes Loans And Financing Receivable [Table] Offsetting [Abstract] FFELP loan asset-backed securitizations repurchase facilities. F F E L P Loan Asset Backed Securitizations Repurchase Facilities [Member] FFELP Loan Asset-backed Securitization Repurchase Facilities [Member] FFELP Loan Securitizations ABS Repurchase Facilities [Member] Hedging Relationship [Axis] Hedging Relationship Stafford loans member. Stafford Loans [Member] Stafford Loans [Member] Other Liabilities Other liabilities Other Liabilities, Total Common Stock, Par or Stated Value Per Share Common stock, par value Servicing revenue. Servicing Revenue Servicing revenue Net Impact of Derivative Accounting [Member] Net impact of derivative accounting. Net Impact Of Derivative Accounting [Member] Financing Receivable, Modified [Table Text Block] Loans Modified Accounts for TDR Consumer Lending Segment [Member] Consumer Lending Segment [Member] Consumer lending segment. Short-Term Debt, Type [Domain] Short-Term Debt, Type 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 Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract] Derivative Assets: Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration] Short-Term Debt [Member] Short-term borrowings [Member] Debt tranches default amount. Debt Tranches Default Amount Debt tranches default principal amount Derivative Asset, Fair Value of Collateral Total collateral held Segment Reporting [Text Block] Segment Reporting Cosigner loan. Cosigner Loan [Member] With Cosigner [Member] Derivative Instruments and Hedging Activities Disclosure [Abstract] Rehab Loans [Member] Rehab Loans [Member] Rehab loans. Investments and Cash, Total Investments and Cash Cash and investments Trading Symbol Trading Symbol Share Repurchase Program [Domain] Interest Income (Expense), Operating [Abstract] Interest income: Entity Emerging Growth Company Entity Emerging Growth Company FFELP loan ABCP facilities. F F E L P Loan A B C P Facilities [Member] FFELP Loan ABCP Facilities [Member] Additional Paid-in Capital [Member] Additional Paid-In Capital [Member] Total interest income Interest Income Operating on Education Loans Interest income operating on education loans. Receivables [Abstract] Net total derivatives Derivative, Fair Value, Net 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 Portion at Fair Value Measurement [Member] [Default] Portion at Fair Value Measurement [Member] Loans receivable, weighted average rate of interest. Loans Receivable, Weighted Average Rate of Interest Loans receivable, weighted average rate of interest Cover [Abstract] Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Unobservable Data Used in Recurring Valuations of Level 3 Charge-offs (par) Financing Receivable Modifications Impairment Write Down Financing receivable, modifications, impairment write down. Hedged Liability, Fair Value Hedge, Cumulative Increase (Decrease) Hedge Basis Adjustments 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] Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge Gains (losses) recognized in net income on hedged items 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 Long-Term Debt, Type [Domain] Long-Term Debt, Type 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 $4 and $1, respectively) Share-Based Payment Arrangement, Noncash Expense Stock-based compensation expense Share-Based Payment Arrangement, Noncash Expense, Total Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Financing Receivable, Allowance for Credit Loss [Table] Schedule Of Financing Receivable Allowance For Credit Losses [Table] Fair Value Disclosures [Abstract] Cash and Cash Equivalent Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value, Total 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) Net charge-offs as a percentage of average loans in repayment Hedge accounting adjustments. Hedge Accounting Adjustments [Member] Hedge Accounting Adjustments [Member] Share Repurchase Program, Remaining Authorized, Amount Remaining common stock repurchase authority Unused authorization Asset-Backed Securities, Securitized Loans and Receivables [Member] Asset-backed Securities, Securitized Loans and Receivables [Member] Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Net cash used in financing activities Private Education Legacy In-School Loans [Member] Private education legacy in-school loans. Offsetting Assets [Table Text Block] Derivative Positions Net of Collateral 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 Interest Rate Swap [Member] Interest Rate Swaps [Member] Consumer lending. Consumer Lending [Member] Consumer Lending [Member] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments Gain Loss [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Entity Filer Category Entity Filer Category Debt Instrument, Name [Domain] Debt Instrument, Name Financing Receivable, Troubled Debt Restructuring, Premodification Modified loans Loan Modifications, Amortized Cost Net Income (Loss) Available to Common Stockholders, Basic [Abstract] Numerator: Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization Fixed assets Property, Plant and Equipment, Net, Total Financing receivable modifications, charged off. Financing Receivable Modifications Charged Off Loans modified, charged off Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax Total gains (losses) on cash flow hedges Derivative Liability, Subject to Master Netting Arrangement, before Offset Derivative liabilities Derivative Asset, Statement of Financial Position [Extensible Enumeration] Derivative Asset, Statement of Financial Position [Extensible Enumeration] Other Assets Disclosure [Text Block] Other Assets Document Information [Line Items] Document Information [Line Items] Expense Related to Distribution or Servicing and Underwriting Fees Servicing expenses Segment Reporting [Abstract] Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year Total Private Education Loan Credit Quality Indicators by Origination Year Four Entity Address, Postal Zip Code Entity Address, Postal Zip Code 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 Statement of Financial Position [Abstract] Local Phone Number Local Phone Number