Legal Entity [Axis] Statements of Net Assets Available for Benefits [Abstract] Net assets available for benefits Beginning of year End of year Statements of Changes in Net Assets Available for Benefits [Abstract] Investment income Contributions Total Additions Total Deductions Net increase Plan Description [Abstract] Summary of Significant Accounting Policies [Abstract] Fair Value Measurements [Abstract] Investment Type [Axis] Fair Value Hierarchy and NAV [Axis] Plan Termination [Abstract] Related-Party Transactions and Party-In-Interest Transactions [Abstract] Income Tax Status [Abstract] Subsequent Events [Abstract] Schedule H, Line 4i - Schedule of Assets (Held at End of Year) [Abstract] Statistical Measurement [Axis] Document Type Document Period End Date Document Fiscal Year Focus Entity Registrant Name Entity Central Index Key Amendment Flag Assets: Investments, at fair value Investments at fair value Notes receivable from participants Additions Investment income: Net appreciation in fair value of investments Dividends and interest Other income Interest on notes receivable from participants Contributions: Employer Participant Rollover Deductions Benefits paid to participants Administrative expenses Transfers to other plans (see Note 1) Net assets available for benefits: Navient 401(k) Savings Plan [Member] Plan Description Summary of Significant Accounting Policies Fair Value Measurements Statements of Net Assets Available for Benefits Measured at Fair Value Plan Termination Related-Party Transactions and Party-In-Interest Transactions Income Tax Status Subsequent Events Schedule H, Line 4i - Schedule of Assets (Held at End of Year) Identity of issuer, borrower, or similar entity Description of Investment Participation status Current value Party-in-interest Plan participants Total Participant Loans, interest rate Interest rate on loans Mutual Funds [Member] Common Stock Fund [Member] Self-directed Brokerage Account [Member] Investments In Fair Value Hierarchy [Member] Common Collective Trust [Member] Common Collective Funds [Member] Level 1 [Member] Level 2 [Member] Level 3 [Member] Investment, Identifier [Axis] Employee Benefit Plan Participant [Member] Minimum [Member] Maximum [Member] EBP, Accounting Policy, Accounting Standard Update, and Change in Accounting Principle [Abstract] EBP, Description, Available [true false] Employee service (in Hours) (in Hours) Number of employees transferred (in Employee) Percentage of participant contribution Employee age limit to participate in plan (in Age) Percentage of participants contribution Percentage of increase in participants contribution each year Maximum employee contribution of eligible compensation Participant contribution, threshold limit Period of service required for participant's for matching employer contribution Employer matching contribution for first five percent of participant's compensation Percentage of participants eligible for 100% of employer matching contribution Vesting period of service required from participants for matching contribution and related earnings from employer Reduction in employer contribution (in Dollars) Forfeited nonvested account (in Dollars) Maximum percentage participants may borrow Participants maximum borrowings amount (in Dollars) Maximum number of loans outstanding (in Loan) Notes receivable from participants, minimum term Notes receivable from participants, maximum term Maximum repayment term for loans, if loan used to purchase principal residence Partial loan repayment amount (in Dollars) Normal retirement (in Age) Percentage of vested plan participants Shares held (in Shares) Estimated fair value Number of units purchased (in Shares) Purchase of company stock Number of units sold (in Shares) Sale of company stock Dividend income Tax determination letter, obtained Tax determination letter date EBP, Tax Qualification Status [Extensible Enumeration] Name of Plan Employer Identification Number Plan Number Basis of accounting Fair value measurements Investment valuation and income recognition Notes receivable from participants Contributions Use of estimates Risks and uncertainties Benefit payments Entity [Domain] EBP, Statement of Net Asset Available for Benefit [Table] Statements of Net Assets Available for Benefits [Abstract] EBP, Statement of Change in Net Asset Available for Benefit [Table] Statements of Changes in Net Assets Available for Benefits [Abstract] EBP, Description of Plan [Table] Plan Description [Abstract] EBP, Accounting Policy [Table] Summary of Significant Accounting Policies [Abstract] EBP, Investment, Fair Value and NAV [Table] Fair Value Measurements [Abstract] Plan Termination [Abstract] EBP, Related Party and Party-in-Interest Transactions [Table] Related-Party Transactions and Party-In-Interest Transactions [Abstract] EBP, Tax Status [Table] Income Tax Status [Abstract] EBP, Subsequent Event [Table] Subsequent Events [Abstract] EBP, Schedule of Asset Held for Investment [Table] Schedule H, Line 4i - Schedule of Assets (Held at End of Year) [Abstract] EBP, Accounting Policy [Line Items] Investments [Domain] Fair Value Hierarchy and NAV [Domain] Statistical Measurement [Domain] Percentage of a participant’s account balance that is nonforfeitable upon termination of the employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Participant eligible to participate upon completing the schedules service in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Percentage of employer matching contribution for the first five percent of eligible participant compensation to employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Disclosure of accounting policy for fair value measurements of financial and non-financial assets, liabilities and instruments classified in shareholders' equity. Disclosures include, but are not limited to, how an entity that manages a group of financial assets and liabilities on the basis of its net exposure measures the fair value of those assets and liabilities (employee benefit plan (EBP). Percentage of eligible compensation increase in contributed for participant automatically enrolled in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Maximum number of loans outstanding of participants. Percentage of participant's eligible for 100% of employer matching contribution towards participant's compensation to employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Vesting case of normal retirement of death or disability (employee benefit plan (EBP)). Period of repayment of loan, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Period of repayment of loan, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Period of repayment of loan, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Number of employees transferred under employee benefit plan during the year. Partial repayment amount for loans of participants. Employee age limit to participate in the employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Period of service of participants to be eligible for employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Minimum vesting period of service required from participants for matching contribution and Related earnings from employer. Participant-directed Investments [Member] Mutual Funds [Member] Common/Collective Trust [Member] FID FRDM RETIRE D [Member] Self-Directed Brokerage Account [Member] BROKERAGELINK [Member] NAVIENT STOCK FUND [Member] SP 500 INDEX PL CL C [Member] PUTNAM STABLE VALUE [Member] DODGE & COX INCOME X [Member] qualified FID FRDM 2045 CP D [Member] AS SPL SM CAP VAL E [Member] FID FRDM 2025 CP D [Member] FID BALANCED K [Member] FID FRDM 2070 CP D [Member] FID FRDM 2065 CP D [Member] FID FRDM 2055 CP D [Member] FID OTC POOL A [Member] COL OVERSEAS VAL R [Member] VICTORY S ESTB VAL Y [Member] FID FRDM 2035 CP D [Member] AF WASH MUTL INV R6 [Member] FID FRDM 2040 CP D [Member] FID CONTRA POOL CL A [Member] JH ENTERPRISE III [Member] FID FRDM 2020 CP D [Member] LOOMIS SM CP GRTH N [Member] FID FRDM 2060 CP D [Member] FID FRDM 2015 CP D [Member] SP SMALL CP IND CL C [Member] VANG VMMR-FED MMKT [Member] SP MID CAP IDX CL C [Member] FID FRDM 2050 CP D [Member] FID FRDM 2030 CP D [Member] FID INFL PR BD IDX [Member] SP INTL INDEX C [Member] Common Stock Fund [Member] FID FRDM 2010 CP D [Member] FID US BOND IDX [Member] PGIM GLB TOT RTN Z [Member] Investments In Fair Value Hierarchy Member EBP, Change in Net Asset Available for Benefit, Increase from Interest Income on Note Receivable from Participant EBP, Investment, Sold, Number of Shares EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Investment, Plan Interest in Master Trust, Fair Value EBP, Employer Contribution, Participant Compensation Matched, Percentage EBP, Participant Contribution, Automatic, Deferral Rate Fair Value, Inputs, Level 3 [Member] EBP, Tax Qualification Status [Extensible Enumeration] Employee Benefit Plan Number Of Employees Transferred EBP, Plan Number EBP, Risk and Uncertainty [Policy Text Block] EBP, Change in Net Asset Available for Benefit, Decrease [Abstract] EBP, Note Receivable from Participant [Policy Text Block] EBP, Investment, Fair Value and NAV [Table Text Block] EBP, Related Party and Party-in-Interest Transactions [Text Block] Employee Benefit Plan Increase In Automatic Deferral Rate Each Year Employee Benefit Plan Partial Loan Repayment Employee Benefit Plan Participant Age Limit To Participate In Plan EBP, Description, Available [true false] EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Gain (Loss) on Investment EBP, Related Party and Party-in-Interest Transactions [Line Items] Employee Benefit Plan Normal Retirement Employee Benefit Plan Participant Member Fair Value, Inputs, Level 1 [Member] EBP, Change in Net Asset Available for Benefit, Increase EBP, Change in Net Asset Available for Benefit, Decrease from Administrative Expense EBP, Summary of Accounting Policy [Text Block] EBP, Asset Held for Investment, Plan Interest in Master Trust, Participation Status [Extensible Enumeration] EBP, Tax Status [Text Block] EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment [Abstract] EBP, Note Receivable from Participant Employee Benefit Plan Note Receivable From Participant Account Maximum Borrowing Term EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Excluding Rollover EBP, Change in Net Asset Available for Benefit, Decrease from Payment to Participant Employee Benefit Plan Vesting Period Of Service Required From Participants For Matching Contribution And Related Earnings From Employer EBP, Change in Net Asset Available for Benefit, Increase from Contribution EBP001 Member EBP, Investment, Excluding Plan Interest in Master Trust, Fair Value EBP, Note Receivable from Participant, Account, Maximum Borrowing, Amount EBP, Investment, Current Value, Type [Extensible Enumeration] EBP, Asset [Abstract] EBP, Investment, Purchased, Number of Shares EBP, Use of Estimate [Policy Text Block] EBP, Change in Net Asset Available for Benefit, Increase from Dividend Income on Investment EBP, Participant Contribution, Pretax, Maximum Annual Compensation to Total Compensation, Percentage EBP, Change in Net Asset Available for Benefit, Transfer to (from) Plan EBP, Investment Acquired, Excluding Plan Interest in Master Trust, Cost EBP, Asset Held for Investment, Participant Loan, after Deemed Distribution EBP, Subsequent Event [Line Items] EBP, Description of Plan [Text Block] Document Fiscal Year Focus Employee Benefit Plan Note Receivable From Participant Account Minimum Borrowing Term EBP, Tax Determination Letter, Date EBP, Asset Held for Investment, Participant Loan, Interest Rate EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment EBP, Subsequent Event [Text Block] EBP, Note Receivable from Participant, Account, Maximum Borrowing, to Total Account, Percentage Common Collective Trust Member EBP, Forfeited Nonvested Account Minimum [Member] Employee Benefit Plan Maximum Percentage Of Participants Eligible For One Hundred Percentage Of Employer Matching Contribution EBP, Investment, Issuer Name [Extensible Enumeration] EBP, Plan Termination [Text Block] Employee Benefit Plan Employer Matching Contribution To First Five Percent Of Participants Compensation EBP, Change in Net Asset Available for Benefit, Increase from Contribution [Abstract] EBP, Investment, Number of Shares EBP, Description of Plan [Line Items] EBP, Asset Held for Investment, Party-in-Interest [true false] Employee Benefit Plan Maximum Number Of Loans Outstanding EBP, Change in Net Asset Available for Benefit, Increase from Employer Contribution, Cash Fair Value, Inputs, Level 2 [Member] Employee Benefit Plan Service Period Of Participants To Be Eligible For Matching Contribution From Employer EBP, Investment Sold, Excluding Plan Interest in Master Trust, Selling Price EBP, Change in Net Asset Available for Benefit, Decrease EBP, Basis of Accounting [Policy Text Block] EBP, Investment, Fair Value and NAV [Line Items] EBP, Asset Held for Investment EBP, Statement of Net Asset Available for Benefit [Line Items] EBP, Net Asset Available for Benefit EBP, Investment [Policy Text Block] Maximum [Member] EBP, Schedule of Asset Held for Investment [Line Items] Document Type EBP, Change in Net Asset Available for Benefit, Increase from Interest and Dividend Income on Investment Employee Benefit Plan Fair Value Measurement Policy Text Block Entity Tax Identification Number EBP, Contribution [Policy Text Block] Additions Abstract Amendment Flag EBP, Tax Status [Line Items] Document Period End Date EBP, Investment, Fair Value and NAV [Text Block] EBP, Schedule of Asset Held for Investment [Table Text Block] EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Other Investment Income (Loss) Entity Central Index Key EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value Employee Benefit Plan Defined Contribution Plan Hours Of Service Requirement EBP, Risk and Uncertainty, Concentration of Investment, Benchmark Threshold Percentage Employee Benefit Plan Note Receivable From Participant Principal Residence Maximum Borrowing Term Investment, Identifier [Axis] EBP, Forfeited Nonvested Account, Decrease from Employer Contribution EBP, Change in Net Asset Available for Benefit, Increase (Decrease) [Abstract] EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Rollover EBPParticipant Account Vested Percentage Upon Plan Termination EBP, Plan Name EBP, Payment to Participant [Policy Text Block] Entity Registrant Name EBP, Change in Net Asset Available for Benefit, Increase (Decrease) EBP, Tax Determination Letter, Obtained [true false]