Navient (NAVI) 10-K 26 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2018	Jan. 31, 2019	Jun. 29, 2018
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Trading Symbol	NAVI
Entity Registrant Name	NAVIENT CORP
Entity Central Index Key	1,593,538
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		244,507,321
Entity Public Float			$ 3.4

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Assets
Loans, net	$ 94,498	$ 105,122
Investments
Available-for-sale	0	2
Other	226	386
Total investments	226	388
Cash and cash equivalents	1,286	1,518
Restricted cash and cash equivalents	3,976	3,128
Goodwill and acquired intangible assets, net	786	810
Other assets	3,404	4,025
Total assets	104,176	114,991
Liabilities
Short-term borrowings	5,422	4,771
Long-term borrowings	93,519	105,012
Other liabilities	1,688	1,723
Total liabilities	100,629	111,506
Commitments and contingencies
Equity
Common stock, par value $0.01 per share; 1.125 billion shares authorized: 445 million and 440 million shares issued, respectively	4	4
Additional paid-in capital	3,145	3,077
Accumulated other comprehensive income (net of tax expense of $35 and $36, respectively)	113	61
Retained earnings	3,218	3,004
Total Navient Corporation stockholders’ equity before treasury stock	6,480	6,146
Less: Common stock held in treasury at cost: 198 million and 177 million shares, respectively	(2,961)	(2,692)
Total Navient Corporation stockholders’ equity	3,519	3,454
Noncontrolling interest	28	31
Total equity	3,547	3,485
Total liabilities and equity	104,176	114,991
FFELP Loans [Member]
Assets
Loans, net	72,253	81,703
Private Education Loans [Member]
Assets
Loans, net	22,245	23,419
Assets and Liabilities of Consolidated Variable Interest Entities [Member]
Assets
Loans, net	91,619	98,596
Investments
Restricted cash	3,928	3,091
Other assets, net	956	1,160
Liabilities
Short-term borrowings	4,341	2,906
Long-term borrowings	82,738	89,317
Net assets of consolidated variable interest entities	9,424	10,624
Assets and Liabilities of Consolidated Variable Interest Entities [Member] | FFELP Loans [Member]
Assets
Loans, net	71,921	77,710
Assets and Liabilities of Consolidated Variable Interest Entities [Member] | Private Education Loans [Member]
Assets
Loans, net	$ 19,698	$ 20,886

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Allowance for loans losses	$ 1,286	$ 1,367
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,125,000,000	1,125,000,000
Common stock, shares issued	445,000,000	440,000,000
Tax expense for accumulated other comprehensive income	$ 35	$ 36
Common stock held in treasury	198,000,000	177,000,000
FFELP Loans [Member]
Allowance for loans losses	$ 76	$ 60
Private Education Loans [Member]
Allowance for loans losses	$ 1,201	$ 1,297

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest income:
Total interest income	$ 4,908	$ 4,383	$ 4,146
Cash and investments	97	43	22
Total interest expense	3,668	2,971	2,441
Net interest income	1,240	1,412	1,705
Less: provisions for loan losses	370	426	429
Net interest income after provisions for loan losses	870	986	1,276
Other income (loss):
Servicing revenue	274	290	304
Asset recovery and business processing revenue	430	475	390
Other income	17	9	7
Gains on sales of loans and investments		3
Gains (losses) on debt repurchases	19	(3)	1
Gains (losses) on derivative and hedging activities, net	(38)	22	117
Total other income	702	796	819
Expenses:
Salaries and benefits	507	519	500
Other operating expenses	477	447	451
Total operating expenses	984	966	951
Goodwill and acquired intangible asset impairment and amortization expense	47	23	36
Restructuring/other reorganization expenses	13	29
Total expenses	1,044	1,018	987
Income before income tax expense	528	764	1,108
Income tax expense	133	472	427
Net income (loss)	$ 395	$ 292	$ 681
Basic earnings per common share	$ 1.52	$ 1.06	$ 2.15
Average common shares outstanding	260	275	316
Diluted earnings per common share	$ 1.49	$ 1.04	$ 2.12
Average common and common equivalent shares outstanding	264	281	322
Dividends per common share	$ 0.64	$ 0.64	$ 0.64
FFELP Loans [Member]
Interest income:
Total interest income	$ 3,027	$ 2,693	$ 2,528
Less: provisions for loan losses	70	42	43
Private Education Loans [Member]
Interest income:
Total interest income	1,778	1,634	1,587
Less: provisions for loan losses	299	382	383
Other Loans [Member]
Interest income:
Total interest income	$ 6	$ 13	$ 9

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 395	$ 292	$ 681
Other comprehensive income:
Gains on derivatives	66	89	91
Reclassification adjustments for derivative (gains) losses included in net income (interest expense)	(15)	(1)	(1)
Total gains on derivatives	51	88	90
Income tax expense	(12)	(33)	(33)
Other comprehensive income, net of tax expense	39	55	57
Total comprehensive income	$ 434	$ 347	$ 738

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Millions	Total	Open Market Repurchases [Member]	Derivative Contract Settlement [Member]	Common Stock [Member]	Treasury Stock [Member]	Treasury Stock [Member]Open Market Repurchases [Member]	Treasury Stock [Member]Derivative Contract Settlement [Member]	Common Stock Shares Outstanding [Member]	Common Stock Shares Outstanding [Member]Open Market Repurchases [Member]	Common Stock Shares Outstanding [Member]Derivative Contract Settlement [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Total Stockholders' Equity [Member]	Total Stockholders' Equity [Member]Open Market Repurchases [Member]	Total Stockholders' Equity [Member]Derivative Contract Settlement [Member]	Noncontrolling Interest [Member]
Beginning Balance, Value at Dec. 31, 2015	$ 3,933			$ 4	$ (1,425)						$ 2,967	$ (51)	$ 2,414	$ 3,909			$ 24
Beginning Balance, Shares at Dec. 31, 2015				430,561,656	(82,350,868)			348,210,788
Comprehensive income:
Net income	681												681	681
Other comprehensive income (loss), net of tax	57											57		57
Total comprehensive income	738													738
Cash dividends:
Common stock	(201)												(201)	(201)
Dividend equivalent units related to employee stock-based compensation plans	(4)												(4)	(4)
Issuance of common shares	$ 35										35			35
Issuance of common shares, Shares	5,476,010			5,476,010				5,476,010
Tax impact of employee stock-based compensation plans	$ (6)										(6)			(6)
Stock-based compensation expense	26										26			26
Repurchase of common stock:
Common stock repurchased		$ (755)				$ (755)		$ (755)							$ (755)
Common stock repurchased, Shares						(59,625,325)		(59,625,325)	(59,625,325)
Shares repurchased related to employee stock-based compensation plans	$ (43)				$ (43)									(43)
Shares repurchased related to employee stock-based compensation plans, Shares	(3,197,355)				(3,197,355)			(3,197,355)
Ending Balance, Value at Dec. 31, 2016	$ 3,723			$ 4	$ (2,223)						3,022	6	2,890	3,699			24
Ending Balance, Shares at Dec. 31, 2016				436,037,666	(145,173,548)			290,864,118
Comprehensive income:
Net income	292												292	292
Other comprehensive income (loss), net of tax	55											55		55
Total comprehensive income	347													347
Cash dividends:
Common stock	(176)												(176)	(176)
Dividend equivalent units related to employee stock-based compensation plans	(2)												(2)	(2)
Issuance of common shares	$ 20										20			20
Issuance of common shares, Shares	3,680,479			3,680,479				3,680,479
Stock-based compensation expense	$ 35										35			35
Repurchase of common stock:
Common stock repurchased	(440)				$ (440)			$ (440)						(440)
Common stock repurchased, Shares					(29,646,374)			(29,646,374)
Shares repurchased related to employee stock-based compensation plans	$ (29)				$ (29)									(29)
Shares repurchased related to employee stock-based compensation plans, Shares	(1,847,651)				(1,847,651)			(1,847,651)
Noncontrolling interest in Earnest uponacquisition	$ 7																7
Ending Balance, Value at Dec. 31, 2017	3,485			$ 4	$ (2,692)						3,077	61	3,004	3,454			31
Ending Balance, Shares at Dec. 31, 2017				439,718,145	(176,667,573)			263,050,572
Comprehensive income:
Net income	395												395	395
Other comprehensive income (loss), net of tax	39											39		39
Total comprehensive income	434													434
Cash dividends:
Common stock	(166)												(166)	(166)
Dividend equivalent units related to employee stock-based compensation plans	(2)												(2)	(2)
Issuance of common shares	$ 43										43			43
Issuance of common shares, Shares	5,659,681			5,659,681				5,659,681
Stock-based compensation expense	$ 25										25			25
Repurchase of common stock:
Common stock repurchased		$ (160)	$ (60)			$ (160)	$ (60)	$ (220)							$ (160)	$ (60)
Common stock repurchased, Shares						(13,131,159)	(4,312,192)	(17,443,351)	(13,131,159)	(4,312,192)
(Gain)/loss on settlement	4				$ 4									4
Shares repurchased related to employee stock-based compensation plans	$ (53)				$ (53)									(53)
Shares repurchased related to employee stock-based compensation plans, Shares	(3,829,629)				(3,829,629)			(3,829,629)
Purchase of noncontrolling interest	$ (3)																(3)
Reclassification from adoption of ASU No. 2018-02	(13)											13	(13)
Ending Balance, Value at Dec. 31, 2018	$ 3,547			$ 4	$ (2,961)						$ 3,145	$ 113	$ 3,218	$ 3,519			$ 28
Ending Balance, Shares at Dec. 31, 2018				445,377,826	(197,940,553)			247,437,273

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Dividends per common share	$ 0.64	$ 0.64	$ 0.64
Retained Earnings [Member]
Dividends per common share	0.64	0.64	0.64
Total Stockholders' Equity [Member]
Dividends per common share	$ 0.64	$ 0.64	$ 0.64

Consolidated Statements of Cash

Consolidated Statements of Cash Flows $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Operating activities
Net income	$ 395	$ 292	$ 681
Adjustments to reconcile net income to net cash provided by operating activities:
(Gains) losses on debt repurchases	(19)	3	(1)
Goodwill and acquired intangible asset impairment and amortization expense	47	23	36
Stock-based compensation expense	25	35	26
Mark-to-market (gains)/losses on derivative and hedging activities, net	37	(83)	(328)
Less: provisions for loan losses	370	426	429
(Increase) in accrued interest receivable	(125)	(29)	(26)
Increase (decrease) in accrued interest payable	58	11	(92)
Decrease in other assets	321	485	628
Increase (decrease) in other liabilities	31	(5)	(6)
Total net cash provided by operating activities	1,140	1,158	1,347
Investing activities
Education loans acquired	(3,652)	(7,371)	(3,683)
Principal payments on education loans	13,973	14,738	14,923
Other investing activities, net	(76)	(88)	(7)
Proceeds from sales and maturities of other securities	115	23	49
Purchase of subsidiaries, net of cash and restricted cash acquired		(184)
Total net cash provided by investing activities	10,360	7,118	11,282
Financing activities
Borrowings collateralized by loans in trust - issued	9,006	8,440	6,691
Borrowings collateralized by loans in trust - repaid	(14,057)	(13,919)	(13,226)
Long-term notes issued	495	1,613	1,231
Long-term notes repaid	(2,947)	(1,464)	(2,603)
Other financing activities, net	(162)	(33)	(238)
Common stock repurchased	(220)	(440)	(755)
Common dividends paid	(166)	(176)	(201)
Total net cash used in financing activities	(10,884)	(8,342)	(13,103)
Net increase (decrease) in cash, cash equivalents, restricted cash and restricted cash equivalents	616	(66)	(474)
Cash, cash equivalents, restricted cash and restricted cash equivalents at beginning of period	4,646	4,712	5,186
Cash, cash equivalents, restricted cash and restricted cash equivalents at end of period	5,262	4,646	4,712
Cash disbursements made (refunds received) for:
Interest	3,460	2,872	2,301
Income taxes paid	57	157	249
Income taxes received	(6)	(1)	(4)
Reconciliation of the Consolidated Statements of Cash Flows to the Consolidated Balance Sheets:
Cash and cash equivalents	1,286	1,518	1,253
Restricted cash and restricted cash equivalents	3,976	3,128	3,459
Cash, cash equivalents, restricted cash and restricted cash equivalents at end of period	5,262	4,646	4,712
Noncash activity
Investing activity - Education loans		1,746
Operating activity - Other assets acquired and other liabilities assumed, net		137
Financing activity - Borrowings assumed in acquisition of education loans		1,883
Asset-backed Securities, Securitized Loans and Receivables [Member]
Financing activities
Asset-backed commercial paper conduits, net	$ (2,833)	$ (2,363)	$ (4,002)

Organization and Business

Organization and Business	12 Months Ended
	Dec. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Business	1. Navient’s Business Navient is a leading provider of education loan management and business processing solutions for education, healthcare, and government clients at the federal, state, and local levels. We help our clients and millions of Americans achieve financial success through services and support. Headquartered in Wilmington, Delaware, Navient also employs team members in western New York, northeastern Pennsylvania, Indiana, Tennessee, Texas, Virginia, Wisconsin, California and other locations. With a focus on data-driven insights, service, compliance and innovative support, Navient: • owns $94.5 billion of education loans; • originates Private Education Loans; • services and performs asset recovery activities on its own portfolio of education loans, as well as education loans owned by other institutions including the United States Department of Education (“ED”); and • provides revenue cycle management and business processing services to federal, state and municipal clients, public authorities and healthcare organizations.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Significant Accounting Policies	2. Use of Estimates Our financial reporting and accounting policies conform to generally accepted accounting principles in the United States of America (“GAAP”). The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Uncertain and volatile market and economic conditions increase the risk and complexity of the judgments in these estimates and actual results could differ from estimates. Key accounting policies that include the most significant judgments, estimates and assumptions include the allowance for loan losses, the amortization of loan premiums and discounts using the effective interest rate method, goodwill and intangible asset impairment assessment and fair value measurement. Consolidation The consolidated financial statements include the accounts of Navient Corporation and its majority-owned and controlled subsidiaries and those Variable Interest Entities (“VIEs”) for which we are the primary beneficiary, after eliminating the effects of intercompany accounts and transactions. We consolidate any VIEs where we have determined we are the primary beneficiary. A VIE is a legal entity that does not have sufficient equity at risk to finance its own operations, or whose equity holders do not have the power to direct the activities that most significantly affect the economic performance of the entity, or whose equity holders do not share proportionately in the losses or benefits of the entity. The primary beneficiary of the VIE is the entity which has both: (1) the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and (2) the obligation to absorb losses or receive benefits of the entity that could potentially be significant to the VIE. As it relates to our securitizations and other secured borrowing facilities that are VIEs as of December 31, 2018, we are the servicer of the related education loan assets and own the Residual Interest of the securitization trusts and secured borrowing facilities. As a result, we are the primary beneficiary and consolidate those VIEs. 2. Fair Value Measurement We use estimates of fair value in applying various accounting standards for our financial statements. Fair value measurements are used in one of four ways: • In the consolidated balance sheet with changes in fair value recorded in the consolidated statement of income; • In the consolidated balance sheet with changes in fair value recorded in the accumulated other comprehensive income section of the consolidated statement of changes in stockholders’ equity; • In the consolidated balance sheet for instruments carried at lower of cost or fair value with impairment charges recorded in the consolidated statement of income; and • In the notes to the financial statements. Fair value is defined as the price to sell an asset or transfer a liability in an orderly transaction between willing and able market participants. In general, our policy in estimating fair value is to first look at observable market prices for identical assets and liabilities in active markets, where available. When these are not available, other inputs are used to model fair value such as prices of similar instruments, yield curves, volatilities, prepayment speeds, default rates and credit spreads, relying first on observable data from active markets. Depending on current market conditions, additional adjustments to fair value may be based on factors such as liquidity and credit spreads. Transaction costs are not included in the determination of fair value. When possible, we seek to validate the model’s output to market transactions. Depending on the availability of observable inputs and prices, different valuation models could produce materially different fair value estimates. The values presented may not represent future fair values and may not be realizable. We categorize our fair value estimates based on a hierarchical framework associated with three levels of price transparency utilized in measuring financial instruments at fair value. Classification is based on the lowest level of input that is significant to the fair value of the instrument. The three levels are as follows: • Level 1 — Quoted prices (unadjusted) in active markets for identical assets or liabilities that we have the ability to access at the measurement date. The types of financial instruments included in level 1 are highly liquid instruments with quoted prices. • Level 2 — Inputs from active markets, other than quoted prices for identical instruments, are used to determine fair value. Significant inputs are directly observable from active markets for substantially the full term of the asset or liability being valued. • Level 3 — Pricing inputs significant to the valuation are unobservable. Inputs are developed based on the best information available. However, significant judgment is required by us in developing the inputs. Loans Loans, consisting primarily of federally insured education loans and Private Education Loans, that we have the ability and intent to hold for the foreseeable future are classified as held-for-investment and are carried at amortized cost. Amortized cost includes the unamortized premiums, discounts, and capitalized origination costs and fees, all of which are amortized to interest income as further discussed below. Loans which are held-for-investment also have an allowance for loan loss as needed. Any loans we have not classified as held-for-investment are classified as held-for-sale and carried at the lower of cost or fair value. Loans are classified as held-for-sale when we have the intent and ability to sell such loans. Loans which are held-for-sale do not have the associated premium, discount, and capitalized origination costs and fees amortized into interest income. In addition, once a loan is classified as held-for-sale, there is no further adjustment to the loan’s allowance for loan losses that existed immediately prior to the reclassification to held-for-sale. 2. Allowance for Loan Losses Purchased Credit Impaired (“PCI”) Loans Loans acquired with evidence of deterioration of credit quality since origination for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable are PCI loans accounted for under Accounting Standard Codification (“ASC”) 310-30, “Loans and Debt Securities Acquired with Deteriorated Credit Quality.” When considering whether evidence of credit quality deterioration exists as of the purchase date, the Company considers loan guarantees and the following credit attributes: delinquency status, use of forbearance, recent borrower FICO scores, use of loan modification programs, and borrowers who have filed for bankruptcy. The Company aggregates loans with common risk characteristics into pools and accounts for each pool as a single asset with a single composite interest rate and an aggregate expectation of cash flows. The pools are initially recorded at fair value. The Company recognizes interest income based on each pool’s effective interest rate which is based on our estimate of all cash flows expected to be received and includes an assumption about prepayment rates. The pools are tested quarterly for impairment by re-estimating the future cash flows to be received from the pools. If the new estimated cash flows result in a pool’s effective interest rate increasing, then this new yield is used prospectively over the remaining life of the pool. If the new estimated cash flows result in a pool’s effective interest rate decreasing, the pool is impaired and written down through a valuation allowance to maintain the effective interest rate. Loans classified as PCI do not have charge-offs reported nor are they reported as Trouble Debt Restructuring (“TDR”) loans. Based on the credit attributes discussed above, we determined that $261 million principal amount of Private Education Loans acquired in 2017 are accounted for as PCI loans with a fair value and resulting carry value of $101 million as of the acquisition date. As of acquisition, this portfolio’s contractually required payments receivable (the total undiscounted amount of all uncollected contractual principal and interest payments both past due and scheduled for the future, adjusted for prepayments) was $411 million with an estimated accretable yield (income expected to be recognized in future periods) of $108 million. As of December 31, 2018, the carrying amount was $82 million with no valuation allowance recorded. Purchased Non-Credit Impaired Loans Loans acquired that do not have evidence of credit deterioration since origination are recorded at fair value with no allowance for loan losses established at the acquisition date. Loan premiums and discounts are amortized as a part of interest income using the interest method under ASC 310-20, “Nonrefundable Fees and Other Costs.” An allowance for loan losses would be established if incurred losses in the loans exceed the remaining unamortized discount recorded at the time of acquisition (i.e., the next two years of expected charge-offs as well as any additional TDR allowance required is greater than the remaining discount). As a result of this policy, to the extent that actual charge-offs exceed any related allowance for loan losses recognized post-acquisition, provision for loan losses is recorded when the loans are charged off. Charge-offs are recorded through the allowance for loan losses. In 2017, we acquired Private Education Loans with an unpaid principal balance of $2.8 billion at a discount of $424 million and FFELP Loans with an unpaid principal balance of $3.5 billion at a discount of $47 million, that are accounted for under this policy. No allowance for loan losses has been established for these loans as of December 31, 2018, as the remaining purchased discount associated with the Private Education Loans of $326 million and FFELP Loans of $37 million as of December 31, 2018 remains greater than the incurred losses. Allowance for Private Education Loan Losses We consider a loan to be impaired when, based on current information, a loss has been incurred and it is probable that we will not receive all contractual amounts due. When making our assessment as to whether a loan is impaired, we also take into account more than insignificant delays in payment. We generally evaluate impaired loans on an aggregate basis by grouping similar loans. Impaired loans also include those loans which are individually assessed for impairment at a loan level, such as in a troubled debt restructuring (“TDR”). We maintain an allowance for loan losses at an amount sufficient to absorb losses incurred in our portfolios at the reporting date based on a projection of estimated probable credit losses incurred in the portfolio. 2. Our Private Education Loan portfolio contains TDR and non-TDR loans. For customers experiencing financial difficulty, certain Private Education Loans for which we have granted a forbearance of greater than three months, an interest rate reduction or an extended repayment plan are classified as TDRs. The allowance requirements are different based on these designations. In determining the allowance for loan losses on our non-TDR portfolio, we estimate the principal amount of loans that will default over the next two years (two years being the expected period between a loss event and default) and how much we expect to recover over time related to the defaulted amount. Expected defaults less our expected recoveries equal the allowance related to this portfolio. Our historical experience indicates that, on average, the time between the date that a customer experiences a default causing event (i.e., the loss trigger event) and the date that we charge off the unrecoverable portion of that loan is two years. Separately, for our TDR portfolio, we estimate an allowance amount sufficient to cover life-of-loan expected losses through an impairment calculation based on the difference between the loan’s basis and the present value of expected future cash flows (which would include life-of-loan default and recovery assumptions) discounted at the loan’s original effective interest rate. Our TDR portfolio is comprised mostly of loans with forbearance usage greater than three months and interest rate reductions. The separate allowance estimates for our TDR and non-TDR portfolios are combined into our total allowance for Private Education Loan losses. In estimating both the non-TDR and TDR allowance amounts, we start with historical experience of customer default behavior. We make judgments about which historical period to start with and then make further judgments about whether that historical experience is representative of future expectations and whether additional adjustments may be needed to those historical default rates. We also take the economic environment into consideration when calculating the allowance for loan losses. We analyze key economic statistics and the effect we expect them to have on future defaults. Key economic statistics analyzed as part of the allowance for loan losses are primarily unemployment rates. Our allowance for loan losses is estimated using an analysis of delinquent and current accounts. Our model is used to estimate the likelihood that a loan may progress through the various delinquency stages and ultimately charge off. The evaluation of the allowance for loan losses is inherently subjective, as it requires material estimates that may be susceptible to significant changes. The estimate for the allowance for loan losses is subject to a number of assumptions. If actual future performance in delinquency, charge-offs and recoveries are significantly different than estimated, this could materially affect our estimate of the allowance for loan losses and the related provision for loan losses on our income statement. We determine the collectability of our Private Education Loan portfolio by evaluating certain risk characteristics. We consider school type, credit score (FICO), existence of a cosigner, loan status and loan seasoning as the key credit quality indicators because they have the most significant effect on our determination of the adequacy of our allowance for loan losses. The type of school customers attend can have an impact on their graduation rate and job prospects after graduation and therefore affects their ability to make payments. Credit scores are an indicator of the credit worthiness of a customer and the higher the credit score the more likely it is the customer will be able to make all of their contractual payments. Loan status affects the credit risk because a past due loan is more likely to result in a credit loss than an up-to-date loan. Additionally, loans in a deferred payment status have different credit risk profiles compared with those in current payment status. Of the portfolio in repayment, loan seasoning is an important factor. It affects credit risk because a loan with a history of making payments generally has a lower incidence of default than a loan with a history of making infrequent or no payments. The existence of a cosigner lowers the likelihood of default. We monitor and update these credit quality indicators in the analysis of the adequacy of our allowance for loan losses on a quarterly basis. To estimate the probable credit losses incurred in the loan portfolio at the reporting date, we use historical experience of customer payment behavior in connection with the key credit quality indicators and incorporate management expectations regarding macroeconomic and collection performance factors. Our model is based upon the most recent twelve months of actual collection experience as the starting point for the non-TDR portfolio and the most recent approximate 15 years for the TDR portfolio and applies expected macroeconomic changes and collection procedure changes to estimate expected losses caused by loss events incurred as of the balance sheet date. Our model for the non-TDR portfolio places a greater emphasis on the more recent default experience rather than the default experience for older historical periods, as we believe the more recent default experience is more indicative of the probable losses incurred in the loan portfolio today that will default over the next two years. The TDR portfolio uses a longer historical default experience since we are projecting life of loan remaining losses. Similar to estimating defaults, we use historical customer payment behavior to estimate the timing and amount of future recoveries on charged-off loans. We use judgment in determining whether historical performance is 2. representative of what we expect to collect in the future. We then apply the default and collection rate projections to each category of loans. Once the quantitative calculation is performed, we review the adequacy of the allowance for loan losses and determine if qualitative adjustments need to be considered. Additionally, we consider changes in laws and regulations that could potentially impact the allowance for loan losses. Our collection policies allow for periods of nonpayment for customers requesting additional payment grace periods upon leaving school or experiencing temporary difficulty meeting payment obligations. This is referred to as forbearance status and is considered in our allowance for loan losses. The loss confirmation period is in alignment with our typical collection cycle and takes into account these periods of nonpayment. Our allowance for Private Education Loan losses also provides for possible additional future charge-offs as they occur related to the receivable for partially charged-off Private Education Loans. At the end of each month, for loans that are 212 days past due, we charge off the estimated loss of a defaulted loan balance. Actual recoveries are applied against the remaining loan balance that was not charged off. We refer to this remaining loan balance as the “receivable for partially charged-off loans.” If actual periodic recoveries are less than expected, the difference is immediately charged off through the allowance for loan losses with an offsetting reduction in the receivable for partially charged-off Private Education Loans. If actual periodic recoveries are greater than expected, they will be reflected as a recovery through the allowance for Private Education Loan losses once the cumulative recovery amount exceeds the cumulative amount originally expected to be recovered. Allowance for FFELP Loan Losses FFELP Loans are insured as to their principal and accrued interest in the event of default subject to a Risk Sharing level based on the date of loan disbursement. These insurance obligations are supported by contractual rights against the United States. For loans disbursed after October 1, 1993, and before July 1, 2006, we receive 98 percent reimbursement on all qualifying default claims. For loans disbursed on or after July 1, 2006, we receive 97 percent reimbursement. For loans disbursed prior to October 1, 1993, we receive 100 percent reimbursement. Similar to the allowance for Private Education Loan losses, the allowance for FFELP Loan losses uses historical experience of customer default behavior and a two-year loss confirmation period to estimate the credit losses incurred in the loan portfolio at the reporting date. We apply the default rate projections, net of applicable Risk Sharing, to each category for the current period to perform our quantitative calculation. Once the quantitative calculation is performed, we review the adequacy of the allowance for loan losses and determine if qualitative adjustments need to be considered. For FFELP Loans that have lost their government insurance and have been charged off, any subsequent cash recoveries benefit the allowance for loan losses when received. Investments Our available-for-sale investment portfolio consists of investments that are carried at fair value, with the temporary changes in fair value carried as a separate component of stockholders’ equity, net of taxes. The amortized cost of debt securities in this category is adjusted for the amortization of related premiums and discounts, which are amortized using the effective interest rate method. Other-than-temporary impairment is evaluated by considering several factors, including the length of time and extent to which the fair value has been less than the amortized cost basis, the financial condition and near-term prospects of the security (considering factors such as adverse conditions specific to the security and ratings agency actions), and the intent and ability to retain the investment to allow for an anticipated recovery in fair value. The entire fair value loss on a security that is other-than-temporary impairment is recorded in earnings if we intend to sell the security or if it is more likely than not that we will be required to sell the security before the expected recovery of the loss. However, if the impairment is other-than-temporary, and those two conditions do not exist, the portion of the impairment related to credit losses is recorded in earnings and the impairment related to other factors is recorded in other comprehensive income. Securities classified as trading are accounted for at fair value with unrealized gains and losses included in investment income. Securities that we have the intent and ability to hold to maturity are classified as held-to-maturity and are accounted for at amortized cost unless the security is determined to have an other-than-temporary impairment. In this case it is accounted for in the same manner described above. 2. We also have other investments, primarily a receivable for cash collateral posted to derivative counterparties. Cash and Cash Equivalents Cash and cash equivalents can include term federal funds, Eurodollar deposits, commercial paper, asset-backed commercial paper, CDs, treasuries and money market funds with original terms to maturity of less than three months. Restricted Cash and Investments Restricted cash primarily includes amounts held in education loan securitization trusts and other secured borrowings. This cash must be used to make payments related to trust obligations. Amounts on deposit in these accounts are primarily the result of timing differences between when principal and interest is collected on the trust assets and when principal and interest is paid on trust liabilities. Securities pledged as collateral related to our derivative portfolio, where the counterparty has rights to replace the securities, are classified as restricted. When the counterparty does not have these rights, the security is recorded in investments and disclosed as pledged collateral in the notes. Additionally, certain counterparties require cash collateral pledged to us to be segregated and held in restricted cash accounts. Goodwill and Acquired Intangible Assets Goodwill is not amortized but is tested periodically for impairment. We test goodwill for impairment annually as of October 1 at the reporting unit level, which is the same as or one level below a business segment. Goodwill is also tested at interim periods if an event occurs or circumstances change that would indicate the carrying amount may be impaired. We complete a goodwill impairment analysis which may be a qualitative or a quantitative two-step analysis depending on the facts and circumstances associated with the reporting unit. In conjunction with a qualitative impairment analysis, we assess relevant qualitative factors to determine whether it is “more-likely-than-not” that the fair value of a reporting unit is less than its carrying amount. The “more-likely-than-not” threshold is defined as having a likelihood of more than 50 percent. In conjunction with a quantitative impairment analysis, we complete Step 1 of the goodwill impairment analysis. Step 1 consists of a comparison of the fair value of the reporting unit to the reporting unit’s carrying value, including goodwill. If the carrying value of the reporting unit exceeds the fair value, Step 2 in the goodwill impairment analysis is performed to measure the amount of impairment loss, if any. Step 2 of the goodwill impairment analysis compares the implied fair value of the reporting unit’s goodwill to the carrying value of the reporting unit’s goodwill. The implied fair value of goodwill is determined in a manner consistent with determining goodwill in a business combination. If the carrying amount of the reporting unit’s goodwill exceeds the implied fair value of the goodwill, an impairment loss is recognized in an amount equal to that excess. If, based on first assessing impairment utilizing a qualitative approach, we determine it is “more-likely-than-not” that the fair value of the reporting unit is less than its carrying amount, we will also complete a quantitative impairment analysis. Acquired intangible assets include, but are not limited to, trade names, customer and other relationships, and non-compete agreements. Acquired intangible assets with finite lives are amortized over their estimated useful lives in proportion to their estimated economic benefit. Finite-lived acquired intangible assets are reviewed for impairment using an undiscounted cash flow analysis when an event occurs or circumstances change indicating the carrying amount of a finite-lived asset or asset group may not be recoverable. If the carrying amount of the asset or asset groups exceeds the undiscounted cash flows, the fair value of the asset or asset group is determined using an acceptable valuation technique. An impairment loss would be recognized if the carrying amount of the asset 2. Securitization Accounting Our securitizations use a two-step structure with a special purpose entity that legally isolates the transferred assets from us, even in the event of bankruptcy. Transactions receiving sale treatment are also structured to ensure that the holders of the beneficial interests issued are not constrained from pledging or exchanging their interests, and that we do not maintain effective control over the transferred assets. If these criteria are not met, then the transaction is accounted for as an on-balance sheet secured borrowing. In all cases, irrespective of whether they qualify as accounting sales our securitizations are legally structured to be sales of assets that isolate the transferred assets from us. If a securitization qualifies as a sale, we then assess whether we are the primary beneficiary of the securitization trust (VIE) and are required to consolidate such trust. If we are the primary beneficiary, then no gain or loss is recognized. See “Consolidation” of this Note 2 for additional information regarding the accounting rules for consolidation when we are the primary beneficiary of these trusts. Irrespective of whether a securitization receives sale or on-balance sheet treatment, our continuing involvement with our securitization trusts is generally limited to: • Owning equity certificates or other certificates of certain trusts and, in certain cases, securities retained for the purpose of complying with risk retention requirements under securities laws. • Lending to certain trusts, under a revolving credit, amounts necessary to cover temporary cash flow needs of the trust. These amounts are repaid to us on subordinated basis with interest at a market rate. • The servicing of the education loan assets within the securitization trusts, on both a pre- and post-default basis. • Our acting as administrator for the securitization transactions we sponsored, which includes remarketing certain bonds at future dates. • Our responsibilities relative to representation and warranty violations. • Temporarily advancing to the trust certain borrower benefits afforded the borrowers of education loans that have been securitized. These advances subsequently are returned to us in the next quarter. • Certain back-to-back derivatives entered into by us contemporaneously with the execution of derivatives by certain Private Education Loan securitization trusts. • The option held by us to buy certain delinquent loans from certain Private Education Loan securitization trusts. • The option to exercise the clean-up call and purchase the education loans from the trust when the asset balance is 10 percent or less of the original loan balance. • The option, on some trusts, to purchase education loans aggregating up to 10 percent of the trust’s initial pool balance. • The option (in certain trusts) to call rate reset notes in instances where the remarketing process has failed. The investors of the securitization trusts have no recourse to our other assets should there be a failure of the trusts to pay when due. Generally, the only arrangements under which we have to provide financial support to the trusts are representation and warranty violations requiring the buyback of loans. Under the terms of the transaction documents of certain trusts, we have, from time to time, exercised our options to purchase delinquent loans from Private Education Loan trusts, to purchase the remaining loans from trusts once the loan balance falls below 10 percent of the original amount, to purchase education loans up to 10 percent of the trust’s initial balance, or to call rate reset notes. Certain trusts maintain financial arrangements with third parties also typical of securitization transactions, such as derivative contracts (swaps) and bond insurance policies that, in the case of a counterparty failure, could adversely impact the value of any Residual Interest. 2. We do not record servicing assets or servicing liabilities when our securitization trusts are accounted for as on-balance sheet secured financings. As of December 31, 2018, we have $19 million of servicing assets on our balance sheet, of which $9 million is related to Residual Interests in FFELP Loan securitization trusts we sold in 2013 and $10 million is related to the acquisition of Earnest in 2017. Education Loan Interest Income For loans classified as held-for-investment, we recognize education loan interest income as earned, adjusted for the amortization of premiums (which includes purchased premiums and capitalized direct origination costs), discounts and Repayment Borrower Benefits. These adjustments result in income being recognized based upon the expected yield of the loan over its life after giving effect to expected prepayments. We amortize premium and discount on education loans using a Constant Prepayment Rate (“CPR”) which measures the rate at which loans in the portfolio pay down principal compared to their stated terms. In determining the CPR, we only consider payments made in excess of contractually required payments. This would include loan consolidation and other early payoff activity. For Repayment Borrower Benefits, the estimates of their effect on education loan yield are based on analyses of historical payment behavior of customers who are eligible for the incentives and its effect on the ultimate qualification rate for these incentives. We regularly evaluate the assumptions used to estimate the prepayment speeds and the qualification rates used for Repayment Borrower Benefits. In instances where there are changes to the assumptions, amortization is adjusted on a cumulative basis to reflect the change since the acquisition of the loan. Additionally, interest earned on education loans reflects potential non-payment adjustments in accordance with our uncollectible interest recognition policy. We do not amortize any premiums, discounts or other adjustments to the basis of education loans when they are classified as held-for-sale. See “Allowance for Loan Losses – Purchased Credit Impaired (‘PCI’) Loans” and “–Purchased Non-Credit Impaired Loans” of this Note 2 for discussion of the interest income methodology related to those portfolios. Interest Expense Interest expense is based upon contractual interest rates adjusted for the amortization of debt issuance costs, premiums and discounts. Our interest expense may also be adjusted for net payments/receipts related to interest rate and foreign currency swap agreements that qualify and are designated as hedges. Interest expense also includes the amortization of deferred gains and losses on closed hedge transactions that qualified as hedges. Amortization of debt issuance costs, premiums, discounts and te

Education Loans

Education Loans	12 Months Ended
	Dec. 31, 2018
Receivables [Abstract]
Education Loans	3. Education loans consist of FFELP and Private Education Loans. There are three principal categories of FFELP Loans: Stafford, PLUS, and FFELP Consolidation Loans. Generally, Stafford and PLUS Loans have repayment periods of between 5 and 10 years. FFELP Consolidation Loans have repayment periods of 12 to 30 years. FFELP Loans do not require repayment, or have modified repayment plans, while the customer is in-school and during the grace period immediately upon leaving school. The customer may also be granted a deferment or forbearance for a period of time based on need, during which time the customer is not considered to be in repayment. Interest continues to accrue on loans in the in-school, deferment and forbearance period. FFELP Loans obligate the customer to pay interest at a stated fixed rate or a variable rate reset annually (subject to a cap) on July 1 of each year depending on when the loan was originated and the loan type. FFELP Loans disbursed before April 1, 2006 earn interest at the greater of the borrower’s rate or a floating rate based on the Special Allowance Payment (“SAP”) formula, with the interest earned on the floating rate that exceeds the interest earned from the customer being paid directly by ED. For loans disbursed after April 1, 2006, FFELP Loans effectively only earn at the SAP rate, as the excess interest earned when the borrower rate exceeds the SAP rate (Floor Income) is required to be rebated to ED. FFELP Loans are insured as to their principal and accrued interest in the event of default subject to a Risk Sharing level based on the date of loan disbursement. These insurance obligations are supported by contractual rights against the United States. For loans disbursed after October 1, 1993 and before July 1, 2006, we receive 98 percent reimbursement on all qualifying default claims. For loans disbursed on or after July 1, 2006, we receive 97 percent reimbursement. 3. Private Education Loans bear the full credit risk of the customer. Private Education Refinance Loans generally have a fixed interest rate with the remaining Private Education Loans generally at a variable rate indexed to LIBOR or Prime indices. The majority of loans in our portfolio are cosigned. Similar to FFELP loans, Private Education Loans are generally non-dischargeable in bankruptcy. Most loans have repayment terms of 10 to 15 years or more, and for loans made prior to 2009, payments are typically deferred until after graduation. However, since 2009 we began to encourage interest-only or fixed payment options while the customer is enrolled in school. The estimated weighted average life of education loans in our portfolio was approximately 6 years and 7 years at December 31, 2018 and 2017, respectively. The following table reflects the distribution of our education loan portfolio by program. December 31, 2018 Year Ended December 31, 2018 (Dollars in millions) Ending Balance % of Balance Average Balance Average Effective Interest Rate FFELP Stafford and Other Education Loans, net (1) $ 24,641 26 % $ 26,612 3.98 % FFELP Consolidation Loans, net 47,612 50 50,359 3.91 Private Education Loans, net 22,245 24 23,281 7.64 Total education loans, net $ 94,498 100 % $ 100,252 4.79 % December 31, 2017 Year Ended December 31, 2017 (Dollars in millions) Ending Balance % of Balance Average Balance Average Effective Interest Rate FFELP Stafford and Other Education Loans, net (1) $ 28,409 27 % $ 30,462 2.94 % FFELP Consolidation Loans, net 53,294 51 54,527 3.30 Private Education Loans, net 23,419 22 23,762 6.88 Total education loans, net $ 105,122 100 % $ 108,751 3.98 % (1) Primarily Stafford Loans, but also includes federally guaranteed PLUS and HEAL Loans. As of both December 31, 2018 and 2017, 86 percent of our education loan portfolio was in repayment.

Allowance for Loan Losses

Allowance for Loan Losses	12 Months Ended
	Dec. 31, 2018
Receivables [Abstract]
Allowance for Loan Losses	4. Our provisions for loan losses represent the periodic expense of maintaining an allowance sufficient to absorb incurred probable losses, net of expected recoveries, in the held-for-investment loan portfolios. The evaluation of the provisions for loan losses is inherently subjective, as it requires material estimates that may be susceptible to significant changes. We segregate our Private Education Loan portfolio in two classes of loans in monitoring and assessing credit risk — Troubled Debt Restructurings (“TDRs”) and Non-TDRs. We believe that the allowance for loan losses is appropriate to cover probable losses incurred in the loan portfolios. 4. Allowance for Loan Losses Metrics Year Ended December 31, 2018 (Dollars in millions) FFELP Loans Private Education Loans Other Loans Total Allowance for Loan Losses Beginning balance $ 60 $ 1,297 $ 10 $ 1,367 Total provision 70 299 1 370 Net adjustment resulting from the change in the charge- off rate (1) — (32 ) — (32 ) Net charge-offs remaining (2) (54 ) (371 ) (2 ) (427 ) Total net charge-offs (54 ) (403 ) (2 ) (459 ) Reclassification of interest reserve (3) — 8 — 8 Ending balance $ 76 $ 1,201 $ 9 $ 1,286 Allowance Ending Balance: Individually evaluated for impairment — TDR $ — $ 1,100 $ 8 $ 1,108 Collectively evaluated for impairment: Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans 76 101 1 178 Purchased Non-Credit Impaired Loans acquired at a discount (4) — — — — Purchased Credit Impaired Loans (4) — — — — Ending total allowance $ 76 $ 1,201 $ 9 $ 1,286 Loans Ending Balance: Individually evaluated for impairment — TDR $ — $ 10,336 $ 28 $ 10,364 Collectively evaluated for impairment: Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans 68,880 11,464 51 80,395 Purchased Non-Credit Impaired Loans acquired at a discount (4) 2,850 2,180 — 5,030 Purchased Credit Impaired Loans (4) — 225 — 225 Ending total loans (5) $ 71,730 $ 24,205 $ 79 $ 96,014 Net charge-offs as a percentage of average loans in repayment, excluding the net adjustment resulting from the change in the charge-off rate (1) .09 % 1.66 % — % Net adjustment resulting from the change in charge-off rate as a percentage of average loans in repayment (1) — % .14 % — % Allowance coverage of charge-offs 1.4 3.0 — Allowance as a percentage of the ending total loan balance .11 % 4.96 % 11.52 % Allowance as a percentage of the ending loans in repayment .13 % 5.45 % 11.52 % Ending total loans (5) $ 71,730 $ 24,205 $ 79 Average loans in repayment $ 62,927 $ 22,312 $ 75 Ending loans in repayment $ 59,551 $ 22,037 $ 79 (1) In third-quarter 2018, the portion of the loan amount charged off at default on Private Education Loans increased from 79 percent to 80.5 percent. This charge resulted in a $32 million reduction to the balance of the receivable for partially charged-off loan balance. (2) Charge-offs are reported net of expected recoveries. For Private Education Loans, the expected recovery amount is transferred to the receivable for partially charged-off loan balance. Charge-offs include charge-offs against the receivable for partially charged-off loans which represents the difference between what was expected to be recovered and any shortfalls in what was actually recovered in the period. See “Receivable for Partially Charged-Off Private Education Loans” for further discussion. (3) Represents the additional allowance related to the amount of uncollectible interest reserved within interest income that is transferred in the period to the allowance for loan losses when interest is capitalized to a loan’s principal balance. (4) The Purchased Credit Impaired Loans’ losses are not provided for by the allowance for loan losses in the above table as these loans are separately reserved for, if needed. No allowance for loan losses has been established for these loans as of December 31, 2018. The losses of the Purchased Non-Credit Impaired Loans acquired at a discount are not provided for by the allowance for loan losses in the above table as the remaining purchased discount associated with the FFELP and Private Education Loans of $37 million and $326 million, respectively, as of December 31, 2018 is greater than the incurred losses and as a result no allowance for loan losses has been established for these loans as of December 31, 2018. (5) Ending total loans for Private Education Loans includes the receivable for partially charged-off loans. 4. Year Ended December 31, 2017 (Dollars in millions) FFELP Loans Private Education Loans Other Loans Total Allowance for Loan Losses Beginning balance $ 67 $ 1,351 $ 15 $ 1,433 Total provision 42 382 2 426 Charge-offs (1) (49 ) (443 ) (7 ) (499 ) Reclassification of interest reserve (2) — 7 — 7 Ending balance $ 60 $ 1,297 $ 10 $ 1,367 Allowance Ending Balance: Individually evaluated for impairment - TDR $ — $ 1,171 $ 9 $ 1,180 Collectively evaluated for impairment: Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans 60 126 1 187 Purchased Non-Credit Impaired Loans acquired at a discount (3) — — — — Purchased Credit Impaired Loans (3) — — — — Ending total allowance $ 60 $ 1,297 $ 10 $ 1,367 Loans Ending Balance: Individually evaluated for impairment - TDR $ — $ 10,921 $ 30 $ 10,951 Collectively evaluated for impairment: Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans 77,860 11,861 40 89,761 Purchased Non-Credit Impaired Loans acquired at a discount (3) 3,237 2,610 — 5,847 Purchased Credit Impaired Loans (3) — 248 — 248 Ending total loans (4) $ 81,097 $ 25,640 $ 70 $ 106,807 Charge-offs as a percentage of average loans in repayment .07 % 1.98 % 5.39 % Allowance coverage of charge-offs 1.2 2.9 1.5 Allowance as a percentage of the ending total loan balance .07 % 5.06 % 14.32 % Allowance as a percentage of the ending loans in repayment .09 % 5.66 % 14.32 % Ending total loans (4) $ 81,097 $ 25,640 $ 70 Average loans in repayment $ 68,318 $ 22,342 $ 130 Ending loans in repayment $ 67,853 $ 22,924 $ 70 (1) Charge-offs are reported net of expected recoveries. For Private Education Loans, the expected recovery amount is transferred to the receivable for partially charged-off loan balance. Charge-offs include charge-offs against the receivable for partially charged-off loans which represents the difference between what was expected to be recovered and any shortfalls in what was actually recovered in the period. See “Receivable for Partially Charged-Off Private Education Loans” for further discussion. (2) Represents the additional allowance related to the amount of uncollectible interest reserved within interest income that is transferred in the period to the allowance for loan losses when interest is capitalized to a loan’s principal balance. (3) The Purchased Credit Impaired Loans’ losses are not provided for by the allowance for loan losses in the above table as these loans are separately reserved for, if needed. No allowance for loan losses has been established for these loans as of December 31, 2017. The losses of the Purchased Non-Credit Impaired Loans acquired at a discount are not provided for by the allowance for loan losses in the above table as the remaining purchased discount associated with the FFELP and Private Education Loans of $43 million and $392 million, respectively, as of December 31, 2017 is greater than the incurred losses and as a result no allowance for loan losses has been established for these loans as of December 31, 2017. (4) Ending total loans for Private Education Loans includes the receivable for partially charged-off loans. 4. Year Ended December 31, 2016 (Dollars in millions) FFELP Loans Private Education Loans Other Loans Total Allowance for Loan Losses Beginning balance $ 78 $ 1,471 $ 15 $ 1,564 Total provision 43 383 3 429 Charge-offs (1) (54 ) (513 ) (3 ) (570 ) Reclassification of interest reserve (2) — 10 — 10 Ending balance $ 67 $ 1,351 $ 15 $ 1,433 Allowance Ending Balance: Individually evaluated for impairment - TDR $ — $ 1,190 $ 11 $ 1,201 Collectively evaluated for impairment 67 161 4 232 Ending total allowance $ 67 $ 1,351 $ 15 $ 1,433 Loans Ending Balance: Individually evaluated for impairment - TDR $ — $ 11,165 $ 32 $ 11,197 Collectively evaluated for impairment 86,918 13,983 132 101,033 Ending total loans (3) $ 86,918 $ 25,148 $ 164 $ 112,230 Charge-offs as a percentage of average loans in repayment .07 % 2.20 % 2.10 % Allowance coverage of charge-offs 1.2 2.6 7.0 Allowance as a percentage of the ending total loan balance .08 % 5.37 % 9.35 % Allowance as a percentage of the ending loans in repayment .09 % 6.10 % 9.35 % Ending total loans (3) $ 86,918 $ 25,148 $ 164 Average loans in repayment $ 72,714 $ 23,275 $ 104 Ending loans in repayment $ 70,557 $ 22,150 $ 164 (1) Charge-offs are reported net of expected recoveries. For Private Education Loans, the expected recovery amount is transferred to the receivable for partially charged-off loan balance. Charge-offs include charge-offs against the receivable for partially charged-off loans which represents the difference between what was expected to be recovered and any shortfalls in what was actually recovered in the period. See “Receivable for Partially Charged-Off Private Education Loans” for further discussion. (2) Represents the additional allowance related to the amount of uncollectible interest reserved within interest income that is transferred in the period to the allowance for loan losses when interest is capitalized to a loan’s principal balance. (3) Ending total loans for Private Education Loans includes the receivable for partially charged-off loans. 4. Key Credit Quality Indicators FFELP Loans are substantially insured and guaranteed as to their principal and accrued interest in the event of default. The key credit quality indicator for this portfolio is loan status. The impact of changes in loan status is incorporated quarterly into the allowance for loan losses calculation. FFELP Loan Delinquencies December 31, 2018 December 31, 2017 December 31, 2016 (Dollars in millions) Balance % Balance % Balance % Loans in-school/grace/deferment (1) $ 3,793 $ 4,711 $ 5,871 Loans in forbearance (2) 8,386 8,533 10,490 Loans in repayment and percentage of each status: Loans current 53,500 89.8 % 59,264 87.3 % 61,977 87.8 % Loans delinquent 31-60 days (3) 1,964 3.4 2,638 3.9 2,820 4.0 Loans delinquent 61-90 days (3) 910 1.5 1,763 2.6 1,325 1.9 Loans delinquent greater than 90 days (3) 3,177 5.3 4,188 6.2 4,435 6.3 Total FFELP Loans in repayment 59,551 100 % 67,853 100 % 70,557 100 % Total FFELP Loans, gross 71,730 81,097 86,918 FFELP Loan unamortized premium 599 666 879 Total FFELP Loans 72,329 81,763 87,797 FFELP Loan allowance for losses (76 ) (60 ) (67 ) FFELP Loans, net $ 72,253 $ 81,703 $ 87,730 Percentage of FFELP Loans in repayment 83.0 % 83.7 % 81.2 % Delinquencies as a percentage of FFELP Loans in repayment 10.2 % 12.7 % 12.2 % FFELP Loans in forbearance as a percentage of loans in repayment and forbearance 12.3 % 11.2 % 12.9 % (1) Loans for customers who may still be attending school or engaging in other permitted educational activities and are not yet required to make payments on their loans, e.g., residency periods for medical students or a grace period for bar exam preparation, as well as loans for customers who have requested and qualify for other permitted program deferments such as military, unemployment, or economic hardships. (2) Loans for customers who have used their allowable deferment time or do not qualify for deferment, that need additional time to obtain employment or who have temporarily ceased making full payments due to hardship or other factors such as disaster relief. (3) The period of delinquency is based on the number of days scheduled payments are contractually past due. 4. For Private Education Loans, the key credit quality indicators are FICO scores, school type, the existence of a cosigner, the loan status and loan seasoning. The FICO scores and school type are assessed at origination. The other Private Education Loan key quality indicators can change and are incorporated quarterly into the allowance for loan losses calculation. The following table highlights the principal balance (excluding the receivable for partially charged-off loans) of our Private Education Loan portfolio stratified by the key credit quality indicators. Private Education Loans Credit Quality Indicators TDRs December 31, 2018 December 31, 2017 (Dollars in millions) Balance (2) % of Balance Balance (2) % of Balance Credit Quality Indicators Original Winning FICO Scores: FICO 640 and above $ 9,133 92 % $ 9,647 92 % FICO below 640 836 8 889 8 Total $ 9,969 100 % $ 10,536 100 % School Type: Not-for-profit $ 7,888 79 % $ 8,247 78 % For-profit 2,081 21 2,289 22 Total $ 9,969 100 % $ 10,536 100 % Cosigners: With cosigner $ 6,172 62 % $ 6,441 61 % Without cosigner 3,797 38 4,095 39 Total $ 9,969 100 % $ 10,536 100 % Seasoning (1) 1-12 payments $ 335 3 % $ 506 5 % 13-24 payments 436 4 644 6 25-36 payments 660 7 947 9 37-48 payments 934 10 1,271 12 More than 48 payments 7,178 72 6,691 63 Not yet in repayment 426 4 477 5 Total $ 9,969 100 % $ 10,536 100 % (1) Number of months in active repayment for which a scheduled payment was received. (2) Balance equals the gross Private Education Loans. 4. Private Education Loans Credit Quality Indicators Non-TDRs December 31, 2018 December 31, 2017 (Dollars in millions) Balance (2) % of Balance Balance (2) % of Balance Credit Quality Indicators Original Winning FICO Scores: FICO 640 and above $ 13,087 96 % $ 13,752 96 % FICO below 640 475 4 592 4 Total $ 13,562 100 % $ 14,344 100 % School Type: Not-for-profit $ 11,953 88 % $ 12,431 87 % For-profit 1,609 12 1,913 13 Total $ 13,562 100 % $ 14,344 100 % Cosigners: With cosigner $ 6,961 51 % $ 9,193 64 % Without cosigner 6,601 49 5,151 36 Total $ 13,562 100 % $ 14,344 100 % Seasoning (1) 1-12 payments $ 3,353 25 % $ 1,424 10 % 13-24 payments 486 3 437 3 25-36 payments 322 2 466 3 37-48 payments 383 3 867 6 More than 48 payments 8,626 64 10,566 74 Not yet in repayment 392 3 584 4 Total $ 13,562 100 % $ 14,344 100 % (1) Number of months in active repayment for which a scheduled payment was received. (2) 4. Private Education Loan Delinquencies TDRs December 31, 2018 December 31, 2017 December 31, 2016 (Dollars in millions) Balance % Balance % Balance % Loans in-school/grace/deferment (1) $ 426 $ 477 $ 579 Loans in forbearance (2) 518 681 588 Loans in repayment and percentage of each status: Loans current 7,890 87.4 % 8,333 88.9 % 8,273 85.8 % Loans delinquent 31-60 days (3) 344 3.8 351 3.7 412 4.3 Loans delinquent 61-90 days (3) 235 2.6 207 2.2 267 2.8 Loans delinquent greater than 90 days (3) 556 6.2 487 5.2 686 7.1 Total TDR loans in repayment 9,025 100 % 9,378 100 % 9,638 100 % Total TDR loans, gross 9,969 10,536 10,805 TDR loans unamortized discount (212 ) (225 ) (237 ) Total TDR loans 9,757 10,311 10,568 TDR loans receivable for partially charged-off loans 367 385 360 TDR loans allowance for losses (1,100 ) (1,171 ) (1,190 ) TDR loans, net $ 9,024 $ 9,525 $ 9,738 Percentage of TDR loans in repayment 90.5 % 89.0 % 89.2 % Delinquencies as a percentage of TDR loans in repayment 12.6 % 11.1 % 14.2 % Loans in forbearance as a percentage of TDR loans in repayment and forbearance 5.4 % 6.8 % 5.7 % (1) Deferment includes customers who have returned to school or are engaged in other permitted educational activities and are not yet required to make payments on their loans, e.g., residency periods for medical students or a grace period for bar exam preparation. (2) Loans for customers who have requested extension of grace period generally during employment transition or who have temporarily ceased making full payments due to hardship or other factors such as disaster relief, consistent with established loan program servicing policies and procedures. (3) The period of delinquency is based on the number of days scheduled payments are contractually past due. 4. Private Education Loan Delinquencies Non-TDRs December 31, 2018 December 31, 2017 December 31, 2016 (Dollars in millions) Balance % Balance % Balance % Loans in-school/grace/deferment (1) $ 392 $ 584 $ 814 Loans in forbearance (2) 158 214 202 Loans in repayment and percentage of each status: Loans current 12,851 98.8 % 13,257 97.9 % 12,233 97.8 % Loans delinquent 31-60 days (3) 71 .5 120 .9 110 .9 Loans delinquent 61-90 days (3) 32 .3 59 .4 54 .4 Loans delinquent greater than 90 days (3) 58 .4 110 .8 115 .9 Total non-TDR loans in repayment 13,012 100 % 13,546 100 % 12,512 100 % Total non-TDR loans, gross 13,562 14,344 13,528 Non-TDR loans unamortized discount (547 ) (699 ) (220 ) Total non-TDR loans 13,015 13,645 13,308 Non-TDR loans receivable for partially charged-off loans 307 375 455 Non-TDR loans allowance for losses (101 ) (126 ) (161 ) Non-TDR loans, net $ 13,221 $ 13,894 $ 13,602 Percentage of non-TDR loans in repayment 95.9 % 94.4 % 92.5 % Delinquencies as a percentage of non-TDR loans in repayment 1.2 % 2.1 % 2.2 % Loans in forbearance as a percentage of non- TDR loans in repayment and forbearance 1.2 % 1.6 % 1.6 % (1) Deferment includes customers who have returned to school or are engaged in other permitted educational activities and are not yet required to make payments on their loans, e.g., residency periods for medical students or a grace period for bar exam preparation. (2) Loans for customers who have requested extension of grace period generally during employment transition or who have temporarily ceased making full payments due to hardship or other factors such as disaster relief, consistent with established loan program servicing policies and procedures. (3) The period of delinquency is based on the number of days scheduled payments are contractually past due. Receivable for Partially Charged-Off Private Education Loans At the end of each month, for loans that are 212 or more days past due, we charge off the estimated loss of a defaulted loan balance. Actual recoveries are applied against the remaining loan balance that was not charged off. We refer to this remaining loan balance as the “receivable for partially charged-off loans.” If actual periodic recoveries are less than expected, the difference is immediately charged off through the allowance for Private Education Loan losses with an offsetting reduction in the receivable for partially charged-off Private Education Loans. If actual periodic recoveries are greater than expected, they will be reflected as a recovery through the allowance for Private Education Loan losses once the cumulative recovery amount exceeds the cumulative amount originally expected to be recovered. 4. The following table summarizes the activity in the receivable for partially charged-off loans. Years Ended December 31, (Dollars in millions) 2018 2017 2016 Receivable at beginning of period $ 760 $ 815 $ 881 Expected future recoveries of current period defaults (1) 89 110 128 Recoveries (2) (139 ) (155 ) (181 ) Charge-offs (3) (36 ) (10 ) (13 ) Receivable at end of period $ 674 $ 760 $ 815 (1) Represents our estimate of the amount to be collected in the future. (2) Current period cash collections. (3) Represents the current period recovery shortfall — the difference between what was expected to be collected and what was actually collected. Additionally, in third-quarter 2018, the portion of the loan amount charged off at default increased from 79 percent to 80.5 percent. This change resulted in a $32 million reduction to the balance of the receivable for partially charged-off loans. These amounts are included in total charge-offs as reported in the “Allowance for Private Education Loan Losses” table. Troubled Debt Restructurings (“TDRs”) We sometimes modify the terms of loans for customers experiencing financial difficulty. Where we have granted either a forbearance of greater than three months, an interest rate reduction or an extended repayment plan, these are classified as TDRs. Approximately 65 percent and 61 percent of the loans granted forbearance have qualified as a TDR loan at December 31, 2018, and 2017, respectively. The unpaid principal balance of TDR loans that were in an interest rate reduction plan as of December 31, 2018 and 2017 was $1.8 billion and $2.7 billion, respectively. At December 31, 2018 and 2017, all of our TDR loans had a related allowance recorded. The following table provides the recorded investment, unpaid principal balance and related allowance for our TDR loans. TDRs (Dollars in millions) December 31, 2018 December 31, 2017 Recorded investment (1) $ 10,326 $ 10,890 Total ending loans (2) $ 10,336 $ 10,921 Related allowance $ 1,100 $ 1,171 (1) Recorded investment is equal to the unpaid principal balance (which includes the receivable for partially charged-off loans), accrued interest and unamortized discount. (2) Total ending loans includes the receivable for partially charged-off loans. 4. The following table provides the average recorded investment and interest income recognized for our TDR loans. Years Ended December 31, (Dollars in millions) 2018 2017 2016 Average recorded investment $ 10,637 $ 10,989 $ 11,078 Interest income recognized $ 764 $ 708 $ 667 The following table provides the amount of loans modified in the periods presented that resulted in a TDR. Additionally, the table summarizes charge-offs occurring in the TDR portfolio, as well as TDRs for which a payment default occurred in the current period within 12 months of the loan first being designated as a TDR. We define payment default as 60 days past due for this disclosure. Years Ended December 31, (Dollars in millions) 2018 2017 2016 Modified loans (1) $ 596 $ 816 $ 1,169 Charge-offs (2) $ 343 $ 346 $ 382 Payment-default $ 142 $ 181 $ 265 (1) Represents period ending balance of loans that have been modified during the period and resulted in a TDR. (2) Represents loans that charged off that were classified as TDRs. Accrued Interest Receivable The following table provides information regarding accrued interest receivable on our Private Education Loans. (Dollars in millions) Total Greater Than 90 Days Past Due Allowance for Uncollectible Interest December 31, 2018 TDR $ 205 $ 26 $ 23 Non-TDR 149 3 4 Total $ 354 $ 29 $ 27 December 31, 2017 TDR $ 196 $ 20 $ 20 Non-TDR 187 4 6 Total $ 383 $ 24 $ 26 December 31, 2016 TDR $ 192 $ 28 $ 23 Non-TDR 199 5 7 Total $ 391 $ 33 $ 30

Business Combinations, Goodwill

Business Combinations, Goodwill and Acquired Intangible Assets	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Business Combinations, Goodwill and Acquired Intangible Assets	5. Business Combinations Acquisitions are accounted for under the acquisition method of accounting as defined in ASC 805, “Business Combinations.” The Company allocates the purchase price to the fair value of the acquired tangible assets, liabilities and identifiable intangible assets as of the acquisition date as determined by an independent appraiser. Acquisition of Earnest In November 2017, Navient acquired a 95 percent majority controlling interest in Earnest for approximately $149 million in cash. Earnest is a leading financial technology and education finance company that originates Private Education Refinance Loans. We engaged an independent appraiser to assist in the valuation of the assets acquired and liabilities assumed including identifiable intangible assets. In November 2018, the Company finalized its purchase price allocation for Earnest, which resulted in an excess purchase price over fair value of net assets acquired, or goodwill, of $77 million. The results of operations of Earnest have been included in Navient’s consolidated financial statements since the acquisition date and are reflected in Navient’s Consumer Lending segment and its Private Education Refinance Loans reporting unit. Navient has not disclosed the pro forma impact of this acquisition to the results of operations for the year ended December 31, 2017, as the pro forma impact was deemed immaterial. Identifiable intangible assets at the acquisition date included definite life intangible assets with an aggregate fair value of approximately $20 million primarily including the Earnest trade name and developed technology. The intangible assets will be amortized over a period of 5 to 10 years based on the estimated economic benefit derived from each of the underlying assets. Acquisition of Duncan Solutions In July 2017, Navient acquired a 100 percent controlling interest in Duncan Solutions for approximately $86 million in cash. Duncan Solutions is a leading transportation revenue management company serving municipalities and toll authorities, offering a range of technology-enabled products and services to support its clients’ parking and tolling operations. We engaged an independent appraiser to assist in the valuation of the assets acquired and liabilities assumed including identifiable intangible assets. In July 2018, the Company finalized its purchase price allocation for Duncan Solutions, which resulted in an excess purchase price over the fair value of net assets acquired, or goodwill, of $39 million. The results of operations of Duncan Solutions have been included in Navient’s consolidated financial statements since the acquisition date and are reflected in Navient’s Business Processing segment and its Government Services reporting unit. Navient has not disclosed the pro forma impact of this acquisition to the results of operations for the year ended December 31, 2017, as the pro forma impact was deemed immaterial. Identifiable intangible assets at the acquisition date include definite life intangible assets with an aggregate fair value of approximately $33 million primarily including customer relationships, developed technology and the Duncan Solutions trade name. The intangible assets will be amortized over a period of 2 to 10 years based on the estimated economic benefit derived from each of the underlying assets. 5. Goodwill Goodwill resulting from our acquisitions is assigned to a reporting unit or units. A reporting unit is the same or one level below an operating segment. As discussed in “Note 12 – Segment Reporting," we have the following new reportable operating segments effective first-quarter 2018: Federal Education Loans, Consumer Lending, Business Processing and Other. As a result of this change in our reporting structure, our reporting units with goodwill as of December 31, 2018 include (1) FFELP Loans (inclusive of the former FFELP Loans reporting unit and the related internal loan servicing which was formerly a part of the old Servicing reporting unit), (2) Federal Education Loan Servicing (inclusive of the former Servicing reporting unit except for the internal loan servicing that was moved to the FFELP loans reporting unit), (3) Private Education Loans, (4) Private Education Refinance Loans ( formerly called the Earnest reporting unit), (5) Government Services (inclusive of the former Asset Recovery – Gila reporting unit and other government services lines of businesses previously included in our Asset Recovery – Contingency reporting unit) and (6) Healthcare Services (formerly called the Asset Recovery – Xtend Healthcare reporting unit). This change in composition of our reporting units required a reallocation of $50 million of goodwill from our former Servicing reporting unit to the newly comprised FFELP Loans and Federal Education Loan Servicing reporting units, which were allocated $37 million and $13 million, respectively. In connection with the reallocation of goodwill, we assessed relevant qualitative factors to determine whether it was “more-likely-than-not” that the fair values of the FFELP Loans and Federal Education Loan Servicing reporting units were less than their respective carrying values at March 31, 2018. No goodwill was deemed impaired after assessing these relevant qualitative factors. The change in our reporting structure also resulted in a change in the composition of the former Asset Recovery – Contingency reporting unit (now referred to as the Federal Education Loan Asset Recovery reporting unit), which did not have any goodwill. In connection with the realignment of our reportable segments, components of this reporting unit were moved to the Government Services reporting unit. Since the composition of the Government Services reporting unit, which had a goodwill balance, changed as a result of our new reporting structure, we assessed relevant qualitative factors to determine whether it was “more-likely-than-not” that the fair value of the Government Services reporting unit was less than its carrying value at March 31, 2018. No goodwill was deemed impaired after assessing these relevant qualitative factors. The following table summarizes our goodwill, accumulated impairments and net goodwill for our reporting units and reportable segments as of December 31, 2018. 5. As of December 31, 2018 (Dollars in millions) Gross Accumulated Impairments and Other Adjustments Net Federal Education Loans reportable segment: FFELP Loans $ 231 $ (4 ) $ 227 Federal Education Loan Servicing 13 — 13 Total Federal Education Loans reportable segment 244 (4 ) 240 Consumer Lending reportable segment: Private Education Loans (1) 147 (41 ) 106 Private Education Refinance Loans 77 — 77 Total Consumer Lending reportable segment 224 (41 ) 183 Business Processing reportable segment: Government Services 272 (136 ) 136 Healthcare Services 106 — 106 Total Business Processing reportable segment 378 (136 ) 242 Total $ 846 $ (181 ) $ 665 As of December 31, 2017 (Dollars in millions) Gross Accumulated Impairments and Other Adjustments Net FFELP Loans reportable segment 194 (4 ) 190 Private Education Loans reportable segment: Private Education Loans (1) 147 (41 ) 106 Earnest 87 — 87 Total Private Education Loans reportable segment 234 (41 ) 193 Business Services reportable segment: Servicing 50 — 50 Asset Recovery - Contingency 136 (136 ) — Asset Recovery - Gila 160 — 160 Asset Recovery - Xtend Healthcare 108 — 108 Total Business Services reportable segment 454 (136 ) 318 Total $ 882 $ (181 ) $ 701 (1) In conjunction with our Separation from SLM BankCo in 2014, we removed $41 million of goodwill from our balance sheet as required under ASC 350, “Intangibles — Goodwill and Other.” This goodwill was allocated to the consumer banking business retained by SLM BankCo based on relative fair value. 5. Interim Goodwill Impairment Testing – Third-Quarter 2018 In third-quarter 2018, we wrote off a $16 million toll services relationship intangible asset as a result of receiving a notice of termination related to a toll services contract in our Government Services reporting unit. As a result of this termination, we also performed a valuation of the Government Services reporting unit, which has $136 million of goodwill and concluded the goodwill was not impaired as the fair value of the reporting unit was 56 percent greater than the book basis. We estimated the fair value of the reporting unit utilizing a market approach which applies market-based revenue, EBITDA and net income multiples from comparable publicly-traded companies to the reporting unit’s revenue, EBITDA and net income indicators. Annual Goodwill Impairment Testing – October 1, 2018 We perform our goodwill impairment testing annually in the fourth quarter as of October 1. As part of the 2018 annual impairment testing associated with our FFELP Loans, Federal Education Loan Servicing (both inclusive of portions of the former Servicing reporting unit), and Private Education Loans reporting units, we assessed relevant qualitative factors to determine whether it is “more-likely-than-not” that the fair value of an individual reporting unit is less than its carrying value. We considered the amount of excess fair values over the carrying values of the FFELP Loans, Servicing and the Private Education Loans reporting units as of October 1, 2016 when we last performed a Step 1 goodwill impairment test. The fair values of these reporting units at October 1, 2016 were substantially in excess of their carrying amounts. In addition, the cash flows for our FFELP Loans and Private Education Loans reporting units are very predictable and the outlook and associated cash flow projections of these reporting units have not changed significantly since our 2016 assessment. No goodwill was deemed impaired for the reporting units after assessing these relevant qualitative factors. We also performed a qualitative assessment for the Federal Education Loan Servicing reporting unit and concluded that it is “more-likely-than-not” that the fair value of the reporting unit exceeded its carrying amount. The remaining goodwill in this reporting unit was not impaired. In conjunction with 2018 annual impairment testing, we also assessed relevant qualitative factors to determine whether it is “more-likely-than-not” that the fair values of the Private Education Refinance Loans and the Government Services reporting units are less than their respective carrying values. For the Private Education Refinance Loans reporting unit, we considered the current status and outlook for this reporting unit since our November 2017 acquisition of Earnest and our 2018 launch of our Navi Refinance Loan product including origination volume, our ability to issue private credit ABS comprised entirely of the reporting unit’s refinance loans and the acquisition value of Earnest. Loan origination volume has exceeded the acquisition plan. Accordingly, the outlook of this reporting unit has improved since our 2017 acquisition of Earnest and the launch of the Navi Refinance Loan product. No goodwill was deemed impaired for the Private Education Refinance Loans reporting unit. We performed goodwill impairment testing in association with the Government Services reporting unit in third-quarter 2018 as discussed above. In conjunction with annual impairment testing, we assessed the outlook for this reporting unit in comparison with the outlook as of third-quarter 2018, 2018 earnings, and the current customer base and revenue backlog. Goodwill was not deemed to be impaired for this reporting unit after assessing these relevant qualitative factors. We performed a valuation as of October 1, 2018 of the Healthcare Services reporting unit, which has $106 million of goodwill. We concluded the goodwill was not impaired as the fair value of the reporting unit was 28 percent greater than the carrying value of this reporting unit. We estimated the fair value of the reporting unit utilizing a market approach which applies market-based revenue, EBITDA and net income multiples from comparable publicly-traded companies to the reporting unit’s revenue, EBITDA and net income indicators. We also considered the current regulatory and legislative environment, the current economic environment, our 2018 earnings and 2019 expected earnings. We view these factors as favorable. Although our market capitalization was less than our book equity during fourth-quarter 2018, it was concluded that our market capitalization in relation to our book equity does not indicate impairment of our reporting units’ respective goodwill at December 31, 2018. 5. Acquired Intangible Assets Acquired intangible assets include the following: As of December 31, 2018 As of December 31, 2017 (Dollars in millions) Cost Basis (1) Accumulated Impairment and Amortization (1) Net Cost Basis (1) Accumulated Impairment and Amortization (1) Net Customer, services and lending relationships $ 284 $ (226 ) $ 58 $ 292 $ (234 ) $ 58 Favorable lease 1 — 1 1 — 1 Non-competes 3 (3 ) — 2 (2 ) — Software and technology 115 (90 ) 25 104 (85 ) 19 Trade names and trademarks (2) 61 (24 ) 37 48 (18 ) 30 Total acquired intangible assets $ 464 $ (343 ) $ 121 $ 447 $ (339 ) $ 108 (1) Accumulated impairment and amortization include impairment amounts only if the acquired intangible asset has been deemed partially impaired. When an acquired intangible asset is considered fully impaired and no longer in use, the cost basis and any accumulated amortization related to the asset is written off. (2) During 2016 we reclassified certain trade names from indefinite life to definite life intangible assets and began to amortize these assets over their expected benefit period. We recorded amortization of acquired intangible assets from continuing operations totaling $31 million, $23 million and $29 million in 2018, 2017 and 2016, respectively. We will continue to amortize our intangible assets with definite useful lives over their remaining estimated useful lives. We estimate amortization expense associated with these intangible assets will be $26 million, $22 million, $19 million, $16 million and $38 million in 2019, 2020, 2021, 2022 and after 2022, respectively. As discussed above, we wrote off a $16 million toll services relationship acquired intangible asset in its entirety due to the termination of a significant toll services contract in our Government Services reporting unit.

Borrowings

Borrowings	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Borrowings	6. Borrowings consist of secured borrowings issued through our securitization program, borrowings through secured facilities, unsecured notes issued by us, and other interest-bearing liabilities related primarily to obligations to return cash collateral held. 6. The following table summarizes our borrowings. December 31, 2018 December 31, 2017 (Dollars in millions) Short Term Long Term Total Short Term Long Term Total Unsecured borrowings: Senior unsecured debt (1) $ 817 $ 10,674 $ 11,491 $ 1,306 $ 12,624 $ 13,930 Total unsecured borrowings 817 10,674 11,491 1,306 12,624 13,930 Secured borrowings: FFELP Loan securitizations (2) — 66,318 66,318 — 71,208 71,208 Private Education Loan securitizations (3) 300 12,985 13,285 686 12,646 13,332 FFELP Loan — other facilities 2,927 2,625 5,552 1,536 6,830 8,366 Private Education Loan — other facilities 1,114 1,266 2,380 684 1,710 2,394 Other (4) 267 — 267 538 — 538 Total secured borrowings 4,608 83,194 87,802 3,444 92,394 95,838 Total before hedge accounting adjustments 5,425 93,868 99,293 4,750 105,018 109,768 Hedge accounting adjustments (3 ) (349 ) (352 ) 21 (6 ) 15 Total $ 5,422 $ 93,519 $ 98,941 $ 4,771 $ 105,012 $ 109,783 (1) Includes principal amount of $817 million and $1.3 billion of short-term debt as of December 31, 2018 and 2017, respectively. Includes principal amount of $10.8 billion and $12.7 billion of long-term debt as of December 31, 2018 and 2017, respectively. (2) Includes $244 million of long-term debt related to the FFELP Loan asset-backed securitization repurchase facilities (“FFELP Loan Repurchase Facilities”) as of December 31, 2018. (3) Includes $300 million and $686 million of short-term debt related to the Private Education Loan asset-backed securitization repurchase facilities (“Private Education Loan Repurchase Facilities”) as of December 31, 2018 and 2017, respectively. Includes $2.0 billion and $1.3 billion of long-term debt related to the Private Education Loan Repurchase Facilities as of December 31, 2018 and 2017, respectively. (4) “Other” primarily includes the obligation to return cash collateral held related to derivative exposures. 6. Short-term Borrowings Short-term borrowings have a remaining term to maturity of one year or less. The following tables summarize outstanding short-term borrowings (secured and unsecured), the weighted average interest rates at the end of each period, and the related average balances and weighted average interest rates during the periods. December 31, 2018 Year Ended December 31, 2018 (Dollars in millions) Ending Balance Weighted Average Interest Rate Average Balance Weighted Average Interest Rate Private Education Loan securitizations (1) $ 300 5.23 % $ 536 4.72 % FFELP Loan — other facilities 2,927 3.10 1,137 2.79 Private Education Loan — other facilities 1,114 3.63 847 3.40 Senior unsecured debt 814 4.92 2,021 5.90 Other interest-bearing liabilities 267 2.39 292 1.73 Total short-term borrowings $ 5,422 3.56 % $ 4,833 4.35 % Maximum outstanding at any month end $ 6,363 December 31, 2017 Year Ended December 31, 2017 (Dollars in millions) Ending Balance Weighted Average Interest Rate Average Balance Weighted Average Interest Rate Private Education Loan securitizations (1) $ 686 4.65 % $ 706 4.32 % FFELP Loan — other facilities 1,536 2.11 261 1.26 Private Education Loan —other facilities 684 2.92 572 2.42 Senior unsecured debt 1,327 8.06 1,197 6.80 Other interest-bearing liabilities 538 1.33 458 1.27 Total short-term borrowings $ 4,771 4.16 % $ 3,194 4.22 % Maximum outstanding at any month end $ 4,771 (1) Relates to Private Education Loan Repurchase Facilities. 6. Long-term Borrowings The following tables summarize outstanding long-term borrowings, the weighted average interest rates at the end of the periods, and the related average balances during the periods. December 31, 2018 Weighted Average Year Ended December 31, 2018 (Dollars in millions) Ending Balance (1) Interest Rate (2) Average Balance Floating rate notes: U.S. dollar-denominated: Interest bearing, due 2019-2083 $ 74,842 3.38 % $ 80,189 Non-U.S. dollar-denominated: Interest bearing, due 2023-2040 4,064 .66 4,919 Total floating rate notes 78,906 3.24 85,108 Fixed rate notes: U.S. dollar-denominated: Interest bearing, due 2020-2059 14,431 5.57 13,814 Non-U.S.-dollar denominated: Interest bearing, due 2034 182 2.49 273 Total fixed rate notes 14,613 5.53 14,087 Total long-term borrowings $ 93,519 3.60 % $ 99,195 December 31, 2017 Weighted Average Year Ended December 31, 2017 (Dollars in millions) Ending Balance (1) Interest Rate (2) Average Balance Floating rate notes: U.S. dollar-denominated: Interest bearing, due 2018-2083 $ 83,209 2.31 % $ 86,186 Non-U.S. dollar-denominated: Interest bearing, due 2023-2041 6,423 .37 7,355 Total floating rate notes 89,632 2.17 93,541 Fixed rate notes: U.S. dollar-denominated: Interest bearing, due 2019-2058 15,114 5.60 15,266 Non-U.S.-dollar denominated: Interest bearing, due 2034-2035 266 2.72 281 Total fixed rate notes 15,380 5.55 15,547 Total long-term borrowings $ 105,012 2.67 % $ 109,088 (1) Ending balance is expressed in U.S. dollars using the spot currency exchange rate. Includes fair value adjustments under hedge accounting for notes designated as the hedged item in a fair value hedge. (2) Weighted average interest rate is stated rate relative to currency denomination of debt. 6. As of December 31, 2018, the expected maturities of our long-term borrowings are shown in the following table. Expected Maturity (Dollars in millions) Senior Unsecured Debt Secured Borrowings (1) Total (2) Year of Maturity 2019 $ — $ 10,274 $ 10,274 2020 2,046 9,814 11,860 2021 1,434 6,357 7,791 2022 1,736 6,215 7,951 2023 1,496 6,110 7,606 2024-2043 3,962 44,424 48,386 10,674 83,194 93,868 Hedge accounting adjustments 107 (456 ) (349 ) Total $ 10,781 $ 82,738 $ 93,519 (1) We view our securitization trust debt as long-term based on the contractual maturity dates which range from 2019 to 2083. However, we have projected the expected principal paydowns based on our current estimates regarding the securitized loans’ prepayment speeds for purposes of this disclosure to better reflect how we expect this debt to be paid down over time. The projected principal paydowns in year 2019 include $10.3 billion related to the securitization trust debt. (2) The aggregate principal amount of debt that matures in each period is $10.3 billion in 2019, $11.9 billion in 2020, $7.9 billion in 2021, $8.0 billion in 2022, $7.7 billion in 2023 and $48.8 billion in 2024-2043. 6. Variable Interest Entities We consolidate the following financing VIEs as of December 31, 2018 and 2017, as we are the primary beneficiary. As a result, these VIEs are accounted for as secured borrowings. December 31, 2018 Debt Outstanding Carrying Amount of Assets Securing Debt Outstanding (Dollars in millions) Short Term Long Term Total Loans Cash Other Assets, Net Total Secured Borrowings — VIEs: FFELP Loan securitizations (1) $ — $ 66,318 $ 66,318 $ 66,266 $ 3,181 $ 1,211 $ 70,658 Private Education Loan securitizations (2) 300 12,985 13,285 16,336 536 198 17,070 FFELP Loan — other facilities 2,927 2,625 5,552 5,656 132 162 5,950 Private Education Loan — other facilities 1,114 1,266 2,380 3,361 79 27 3,467 Total before hedge accounting adjustments 4,341 83,194 87,535 91,619 3,928 1,598 97,145 Hedge accounting adjustments — (456 ) (456 ) — — (642 ) (642 ) Total $ 4,341 $ 82,738 $ 87,079 $ 91,619 $ 3,928 $ 956 $ 96,503 December 31, 2017 Debt Outstanding Carrying Amount of Assets Securing Debt Outstanding (Dollars in millions) Short Term Long Term Total Loans Cash Other Assets, Net Total Secured Borrowings — VIEs: FFELP Loan securitizations (1) $ — $ 71,208 $ 71,208 $ 72,145 $ 2,335 $ 1,078 $ 75,558 Private Education Loan securitizations (2) 686 12,646 13,332 17,739 484 237 18,460 FFELP Loan — other facilities 1,536 3,999 5,535 5,565 204 156 5,925 Private Education Loan — other facilities 684 1,710 2,394 3,147 68 31 3,246 Total before hedge accounting adjustments 2,906 89,563 92,469 98,596 3,091 1,502 103,189 Hedge accounting adjustments — (246 ) (246 ) — — (342 ) (342 ) Total $ 2,906 $ 89,317 $ 92,223 $ 98,596 $ 3,091 $ 1,160 $ 102,847 (1) Includes $244 (2) Includes $300 million of short-term debt, $2.0 billion of long-term debt and $115 million of restricted cash related to the Private Education Loan Repurchase Facilities as of December 31, 2018. Includes $686 million of short-term debt, $1.3 billion of long-term debt and $96 million of restricted cash related to the Private Education Loan Repurchase Facilities as of December 31, 2017. 6. Secured Facilities and Unsecured Debt FFELP Loans — Other Facilities We have various secured borrowing facilities that we use to finance our FFELP Loans. Liquidity is available under these secured credit facilities to the extent we have eligible collateral and available capacity. The maximum borrowing capacity under these facilities will vary and is subject to each agreement’s borrowing conditions. These include but are not limited to the facility’s size, current usage and the availability and fair value of qualifying unencumbered FFELP Loan collateral. Our borrowings under these facilities are non-recourse. The maturity dates on these facilities range from November 2019 to April 2020. The interest rate on certain facilities can increase under certain circumstances. The facilities are subject to termination under certain circumstances. As of December 31, 2018, there was approximately $5.6 billion outstanding under these facilities, with approximately $6.0 billion of assets securing these facilities. As of December 31, 2018, the maximum unused capacity under these facilities was $752 million. As of December 31, 2018, we had $332 million of unencumbered FFELP Loans. FFELP Loan ABS Repurchase Facilities In 2018, we closed a $0.9 billion FFELP Loan ABS Repurchase Facility that provides liquidity for the acquisition of certain Navient-sponsored auction rate securities. Borrowings under the facility are secured by the auction rate securities. The lenders also have unsecured recourse to Navient Corporation as guarantor for any shortfall in amounts payable. Because the facility is secured by Navient-sponsored instruments issued in previous securitizations, we show the debt as part of FFELP Loan securitizations in the Secured Borrowings table above. As of December 31, 2018, there was approximately $0.2 billion outstanding under this facility. Private Education Loans — Other Facilities We have various secured borrowing facilities that we use to finance our Private Education Loans. Liquidity is available under these secured credit facilities to the extent we have eligible collateral and available capacity. The maximum borrowing capacity under these facilities will vary and is subject to each agreement’s borrowing conditions. These include but are not limited to the facility’s size, current usage and the availability and fair value of qualifying unencumbered Private Education Loan collateral. Our borrowings under these facilities are non-recourse. The maturity dates on these facilities range from June 2019 to June 2020. The interest rate on certain facilities can increase under certain circumstances. The facilities are subject to termination under certain circumstances. As of December 31, 2018, there was approximately $2.4 billion outstanding under these facilities, with approximately $3.5 billion of assets securing these facilities. As of December 31, 2018, the maximum unused capacity under these facilities was $635 million. As of December 31, 2018, we had $2.6 billion of unencumbered Private Education Loans. Private Education Loan ABS Repurchase Facilities Since the fourth quarter of 2015, we have closed on $3.2 billion of Private Education Loan ABS Repurchase Facilities. These repurchase facilities are collateralized by Residual Interests in previously issued Private Education Loan ABS trusts. The lenders also have unsecured recourse to Navient Corporation as guarantor for any shortfall in amounts payable. Because these facilities are secured by the Residual Interests in previous securitizations, we show the debt as part of Private Education Loan securitizations in the Secured Borrowings table above. As of December 31, 2018, there was approximately $2.3 billion outstanding. Senior Unsecured Debt We issued $500 million, $1.6 billion and $1.3 billion of unsecured debt in 2018, 2017 and 2016, respectively. 6. Debt Repurchases The following table summarizes activity related to our senior unsecured debt and ABS repurchases. “Gains (losses) on debt repurchases” is shown net of hedging-related gains and losses. Years Ended December 31, (Dollars in millions) 2018 2017 2016 Debt principal repurchased $ 2,809 $ 513 $ 1,467 Gains (losses) on debt repurchases 19 (3 ) 1

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	7. Risk Management Strategy We maintain an overall interest rate risk management strategy that incorporates the use of derivative instruments to minimize the economic effect of interest rate changes. Our goal is to manage interest rate sensitivity by modifying the repricing frequency and underlying index characteristics of certain balance sheet assets and liabilities so the net interest margin is not, on a material basis, adversely affected by movements in interest rates. We do not use derivative instruments to hedge credit risk. As a result of interest rate fluctuations, hedged assets and liabilities will appreciate or depreciate in market value. Income or loss on the derivative instruments that are linked to the hedged assets and liabilities will generally offset the effect of this unrealized appreciation or depreciation for the period the item is being hedged. We view this strategy as a prudent management of interest rate sensitivity. In addition, we utilize derivative contracts to minimize the economic impact of changes in foreign currency exchange rates on certain debt obligations that are denominated in foreign currencies. As foreign currency exchange rates fluctuate, these liabilities will appreciate and depreciate in value. These fluctuations, to the extent the hedge relationship is effective, are offset by changes in the value of the cross-currency interest rate swaps executed to hedge these instruments. Management believes certain derivative transactions entered into as hedges, primarily Floor Income Contracts and basis swaps, are economically effective; however, those transactions generally do not qualify for hedge accounting under GAAP (as discussed below) and thus may adversely impact earnings. 7. Although we use derivatives to minimize the risk of interest rate and foreign currency changes, the use of derivatives does expose us to both market and credit risk. Market risk is the chance of financial loss resulting from changes in interest rates, foreign exchange rates and market liquidity. Credit risk is the risk that a counterparty will not perform its obligations under a contract and it is limited to the loss of the fair value gain in a derivative that the counterparty owes us. When the fair value of a derivative contract is negative, we owe the counterparty and, therefore, have no credit risk exposure to the counterparty; however, the counterparty has exposure to us. We minimize the credit risk in derivative instruments by entering into transactions with highly rated counterparties that are reviewed regularly by our Credit Department. We also maintain a policy of requiring that all derivative contracts be governed by an International Swaps and Derivative Association Master Agreement. Depending on the nature of the derivative transaction, bilateral collateral arrangements related to Navient Corporation contracts generally are required as well. When we have more than one outstanding derivative transaction with the counterparty, and there exists legally enforceable netting provisions with the counterparty (i.e., a legal right to offset receivable and payable derivative contracts), the “net” mark-to-market exposure, less collateral the counterparty has posted to us, represents exposure with the counterparty. When there is a net negative exposure, we consider our exposure to the counterparty to be zero. At December 31, 2018 and 2017, we had a net positive exposure (derivative gain positions to us less collateral which has been posted by counterparties to us) related to Navient Corporation derivatives of $19 million and $24 million, respectively. Our on-balance sheet securitization trusts have $4.5 billion of Euro and British Pound Sterling denominated bonds outstanding as of December 31, 2018. To convert these non-U.S. dollar denominated bonds into U.S. dollar liabilities, the trusts have entered into foreign-currency swaps with highly-rated counterparties. In addition, the trusts have entered into $5.1 billion notional of interest rates swaps which are primarily used to convert Prime received on securitized education loans to LIBOR paid on the bonds. Our securitization trusts with swaps have ISDA documentation with protections against counterparty risk. The collateral calculations contemplated in the ISDA documentation of our securitization trusts require collateral based on the fair value of the derivative which may be adjusted for additional collateral based on rating agency criteria requirements considered within the collateral agreement. The trusts are not required to post collateral to the counterparties. At December 31, 2018 and 2017, the net positive exposure on swaps in securitization trusts was $7 million and $64 million, respectively. Accounting for Derivative Instruments Derivative instruments that are used as part of our interest rate and foreign currency risk management strategy include interest rate swaps, cross-currency interest rate swaps, and interest rate floor contracts with indices that relate to the pricing of specific balance sheet assets and liabilities. The accounting for derivative instruments requires that every derivative instrument, including certain derivative instruments embedded in other contracts, be recorded on the balance sheet as either an asset or liability measured at its fair value. As more fully described below, if certain criteria are met, derivative instruments are classified and accounted for by us as either fair value or cash flow hedges. If these criteria are not met, the derivative financial instruments are accounted for as trading. Fair Value Hedges Fair value hedges are generally used by us to hedge the exposure to changes in fair value of a recognized fixed rate asset or liability. We enter into interest rate swaps to economically convert fixed rate assets into variable rate assets and fixed rate debt into variable rate debt. We also enter into cross-currency interest rate swaps to economically convert foreign currency denominated fixed and floating debt to U.S. dollar denominated variable debt. For fair value hedges, we generally consider all components of the derivative’s gain and/or loss when assessing hedge effectiveness and generally hedge changes in fair values due to interest rates or interest rates and foreign currency exchange rates. 7. Cash Flow Hedges We use cash flow hedges to hedge the exposure to variability in cash flows for a forecasted debt issuance and for exposure to variability in cash flows of floating rate debt. This strategy is used primarily to minimize the exposure to volatility from future changes in interest rates. Gains and losses on the effective portion of a qualifying hedge are recorded in accumulated other comprehensive income and ineffectiveness is recorded immediately to earnings. In the case of a forecasted debt issuance, gains and losses are reclassified to earnings over the period which the stated hedged transaction affects earnings. If we determine it is not probable that the anticipated transaction will occur, gains and losses are reclassified immediately to earnings. In assessing hedge effectiveness, generally all components of each derivative’s gains or losses are included in the assessment. We generally hedge exposure to changes in cash flows due to changes in interest rates or total changes in cash flow. Trading Activities When derivative instruments do not qualify as hedges, they are accounted for as trading instruments where all changes in fair value are recorded through earnings. We sell interest rate floors (Floor Income Contracts) to hedge the embedded Floor Income options in education loan assets. The Floor Income Contracts are written options which have a more stringent hedge effectiveness hurdle to meet. Specifically, our Floor Income Contracts do not qualify for hedge accounting treatment because the pay down of principal of the education loans underlying the Floor Income embedded in those education loans does not exactly match the change in the notional amount of our written Floor Income Contracts. Additionally, the term, the interest rate index and the interest rate index reset frequency of the Floor Income Contracts can be different from that of the education loans. Therefore, Floor Income Contracts do not qualify for hedge accounting treatment and are recorded as trading instruments. Regardless of the accounting treatment, we consider these contracts to be economic hedges for risk management purposes. We use this strategy to minimize our exposure to changes in interest rates. We use basis swaps to minimize earnings variability caused by having different reset characteristics on our interest-earning assets and interest-bearing liabilities. The specific terms and notional amounts of the swaps are determined based on a review of our asset/liability structure, our assessment of future interest rate relationships, and on other factors such as short-term strategic initiatives. Hedge accounting requires that when using basis swaps, the change in the cash flows of the hedge effectively offset both the change in the cash flows of the asset and the change in the cash flows of the liability. Our basis swaps hedge variable interest rate risk; however, they generally do not meet this effectiveness criterion because the index of the swap does not exactly match the index of the hedged assets. Additionally, some of our FFELP Loans can earn at either a variable or a fixed interest rate depending on market interest rates and, therefore, swaps economically hedging these FFELP Loans do not meet the criteria for hedge accounting treatment. As a result, these swaps are recorded at fair value with changes in fair value reflected currently in the statement of income. 7. Summary of Derivative Financial Statement Impact The following tables summarize the fair values and notional amounts or number of contracts of all derivative instruments at December 31, 2018 and 2017, and their impact on other comprehensive income and earnings for 2018, 2017 and 2016. Impact of Derivatives on Consolidated Balance Sheet Cash Flow Fair Value Trading Total (Dollars in millions) Hedged Risk Exposure Dec. 31, 2018 Dec. 31, 2017 Dec. 31, 2018 Dec. 31, 2017 Dec. 31, 2018 Dec. 31, 2017 Dec. 31, 2018 Dec. 31, 2017 Fair Values (1) Derivative Assets: Interest rate swaps Interest rate $ — $ 95 $ 170 $ 290 $ 3 $ 7 $ 173 $ 392 Cross-currency interest rate swaps Foreign currency and interest rate — — 6 88 — — 6 88 Total derivative assets (2) — 95 176 378 3 7 179 480 Derivative Liabilities: Interest rate swaps Interest rate — (16 ) (34 ) (102 ) (45 ) (71 ) (79 ) (189 ) Floor Income Contracts Interest rate — — — — (53 ) (74 ) (53 ) (74 ) Cross-currency interest rate swaps Foreign currency and interest rate — — (639 ) (410 ) (26 ) (44 ) (665 ) (454 ) Other (3) Interest rate — — — — (4 ) (18 ) (4 ) (18 ) Total derivative liabilities (2) — (16 ) (673 ) (512 ) (128 ) (207 ) (801 ) (735 ) Net total derivatives $ — $ 79 $ (497 ) $ (134 ) $ (125 ) $ (200 ) $ (622 ) $ (255 ) (1) Fair values reported are exclusive of collateral held and pledged and accrued interest. Assets and liabilities are presented without consideration of master netting agreements. Derivatives are carried on the balance sheet based on net position by counterparty under master netting agreements, and classified in other assets or other liabilities depending on whether in a net positive or negative position. (2) The following table reconciles gross positions without the impact of master netting agreements to the balance sheet classification: Other Assets Other Liabilities (Dollar in millions) December 31, 2018 December 31, 2017 December 31, 2018 December 31, 2017 Gross position $ 179 $ 480 $ (801 ) $ (735 ) Impact of master netting agreements (22 ) (42 ) 22 42 Derivative values with impact of master netting agreements (as carried on balance sheet) 157 438 (779 ) (693 ) Cash collateral (held) pledged (266 ) (536 ) 188 235 Net position $ (109 ) $ (98 ) $ (591 ) $ (458 ) (3) 7. The above fair values at December 31, 2018 reflect rule changes adopted by clearing organizations that require entities to treat derivative assets, liabilities and the related variation margin as a settlement of the derivative position for legal and accounting purposes, rather than recording these positions on a gross basis with a related collateral receivable or payable. As a result, the tables above reflect a reduction of $183 million of derivative assets and $159 million of derivative liabilities as of December 31, 2018, that previously were reported on a gross basis but are now settled and not subject to collateral. The above fair values also include adjustments when necessary for counterparty credit risk for both when we are exposed to the counterparty, net of collateral postings, and when the counterparty is exposed to us, net of collateral postings. The net adjustments decreased the asset position at December 31, 2018 and December 31, 2017 by $26 million and $6 million, respectively. In addition, the above fair values reflect adjustments for illiquid derivatives as indicated by a wide bid/ask spread in the interest rate indices to which the derivatives are indexed. These adjustments decreased the overall net asset positions at December 31, 2018 and December 31, 2017 by $19 million and $30 million, respectively. Cash Flow Fair Value Trading Total (Dollars in billions) Dec. 31, 2018 Dec. 31, 2017 Dec. 31, 2018 Dec. 31, 2017 Dec. 31, 2018 Dec. 31, 2017 Dec. 31, 2018 Dec. 31, 2017 Notional Values: Interest rate swaps $ 21.4 $ 24.1 $ 10.3 $ 12.4 $ 66.9 $ 72.0 $ 98.6 $ 108.5 Floor Income Contracts — — — — 27.9 21.9 27.9 21.9 Cross-currency interest rate swaps — — 4.5 6.7 .2 .3 4.7 7.0 Other (1) — — — — .2 .5 .2 .5 Total derivatives $ 21.4 $ 24.1 $ 14.8 $ 19.1 $ 95.2 $ 94.7 $ 131.4 $ 137.9 (1) “Other” includes derivatives related to our Total Return Swap Facility. Impact of Derivatives on Consolidated Statements of Income Total Gains (Losses) (1) Years Ended December 31, (Dollars in millions) 2018 2017 2016 Fair Value Hedges (2) Interest Rate Swaps Gains (losses) recognized in net income on derivatives $ (137 ) $ (214 ) $ (288 ) Gains (losses) recognized in net income on hedged items 162 193 302 Net fair value hedge ineffectiveness gains (losses) 25 (21 ) 14 Cross currency interest rate swaps Gains (losses) recognized in net income on derivatives (311 ) 921 (319 ) Gains (losses) recognized in net income on hedged items 210 (954 ) 350 Net fair value hedge ineffectiveness gains (losses) (101 ) (33 ) 31 Total fair value hedges (76 ) (54 ) 45 Cash Flow Hedges (2) Interest rate swaps (3) — — — Total cash flow hedges — — — Trading Interest rate swaps 22 8 29 Floor income contracts 15 81 51 Cross currency interest rate swaps (3 ) 2 5 Other 4 (15 ) (13 ) Total trading derivatives 38 76 72 Gains (losses) on derivative and hedging activities, net $ (38 ) $ 22 $ 117 (1) Recorded in “Gains (losses) on derivative and hedging activities, net” in the consolidated statements of income. (2) The accrued interest income (expense) on fair value hedges and cash flow hedges is recorded in net interest income (expense) and is excluded from this table. (3) Represents ineffectiveness related to cash flow hedges. 7. Impact of Derivatives on Consolidated Statements of Changes in Stockholders’ Equity (net of tax) Years Ended December 31, (Dollars in millions) 2018 2017 2016 Total gains (losses) on cash flow hedges $ 50 $ 25 $ 26 Reclassification adjustments for derivative (gains) losses included in net income (interest expense) (1)(2) (11 ) 30 31 Total change in stockholders’ equity for unrealized gains (losses) on derivatives $ 39 $ 55 $ 57 (1) Includes net settlement income/expense. (2) We expect to reclassify $3 million of after-tax net losses from accumulated other comprehensive income to earnings during the next 12 months related to amortization of terminated hedge relationships. Collateral The following table details collateral held and pledged related to derivative exposure between us and our derivative counterparties. (Dollars in millions) December 31, 2018 December 31, 2017 Collateral held: Cash (obligation to return cash collateral is recorded in short-term borrowings) $ 266 $ 536 Securities at fair value — corporate derivatives (not recorded in financial statements) (1) — — Securities at fair value — on-balance sheet securitization derivatives (not recorded in financial statements) (2) 90 297 Total collateral held $ 356 $ 833 Derivative asset at fair value including accrued interest $ 210 $ 618 Collateral pledged to others: Cash (right to receive return of cash collateral is recorded in investments) $ 188 $ 235 Total collateral pledged $ 188 $ 235 Derivative liability at fair value including accrued interest and premium receivable $ 752 $ 659 (1) The Company has the ability to sell or re-pledge securities it holds as collateral. (2) The trusts do not have the ability to sell or re-pledge securities they hold as collateral. Our corporate derivatives contain credit contingent features. At our current unsecured credit rating, we have fully collateralized our corporate derivative liability position (including accrued interest and net of premiums receivable) of $87 million with our counterparties. Downgrades in our unsecured credit rating would not result in any additional collateral requirements. Trust related derivatives do not contain credit contingent features related to our or the trusts’ credit ratings.

Other Assets

Other Assets	12 Months Ended
	Dec. 31, 2018
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Other Assets	8. The following table provides the detail of our other assets. (Dollars in millions) December 31, 2018 December 31, 2017 Accrued interest receivable $ 1,999 $ 1,965 Benefit and insurance-related investments 470 481 Income tax asset, net (current and deferred) 271 380 Derivatives at fair value 157 438 Fixed assets, net 136 156 Accounts receivable 95 108 Other loans, net 69 59 Other 207 438 Total $ 3,404 $ 4,025

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Stockholders' Equity	9. Common Stock Our shareholders have authorized the issuance of 1.125 billion shares of common stock. The par value of Navient common stock is $0.01 per share. At December 31, 2018, 247 million shares were issued and outstanding and 22 million shares were unissued but encumbered for outstanding stock options, restricted stock units, performance stock units and dividend equivalent units for employee compensation and remaining authority for stock-based compensation plans. The stock-based compensation plans are described in “Note 11 — Stock-Based Compensation Plans and Arrangements.” Dividend and Share Repurchase Program In 2018, 2017 and 2016, we paid full-year common stock dividends of $0.64 per share. In 2018, 2017 and 2016, we repurchased 17.4 million, 29.6 million and 59.6 million shares of common stock, respectively, for $220 million, $440 million and $755 million, respectively. Our board of directors authorized a new $500 million share repurchase program in September 2018. As of December 31, 2018, the remaining common share repurchase authority was $440 million. The following table summarizes our common share repurchases and issuances. Years Ended December 31, 2018 2017 2016 Common stock repurchased (1) 17,443,351 29,646,374 59,625,325 Average purchase price per share $ 12.64 $ 14.85 $ 12.68 Shares repurchased related to employee stock-based compensation plans (2) 3,829,629 1,847,651 3,197,355 Average purchase price per share $ 13.71 $ 15.40 $ 13.21 Common shares issued (3) 5,659,681 3,680,479 5,476,010 (1) Common shares purchased under our share repurchase program. (2) Comprises shares withheld from stock option exercises and vesting of restricted stock for employees’ tax withholding obligations and shares tendered by employees to satisfy option exercise costs. (3) Common shares issued under our various compensation and benefit plans. The closing price of our common stock on December 31, 2018 was $8.81.

Earnings (Loss) per Common Shar

Earnings (Loss) per Common Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Earnings (Loss) per Common Share	10. Basic earnings (loss) per common share (“EPS”) are calculated using the weighted average number of shares of common stock outstanding during each period. A reconciliation of the numerators and denominators of the basic and diluted EPS calculations follows. Years Ended December 31, (In millions, except per share data) 2018 2017 2016 Numerator: Net income $ 395 $ 292 $ 681 Denominator: Weighted average shares used to compute basic EPS 260 275 316 Effect of dilutive securities: Dilutive effect of stock options, restricted stock, restricted stock units, performance stock units and Employee Stock Purchase Plan (“ESPP”) (1) 4 6 6 Dilutive potential common shares (2) 4 6 6 Weighted average shares used to compute diluted EPS 264 281 322 Basic earnings per common share $ 1.52 $ 1.06 $ 2.15 Diluted earnings per common share $ 1.49 $ 1.04 $ 2.12 (1) Includes the potential dilutive effect of additional common shares that are issuable upon exercise of outstanding stock options, restricted stock, restricted stock units, performance stock units and the outstanding commitment to issue shares under applicable ESPPs, determined by the treasury stock method. (2) For the years ended December 31, 2018, 2017 and 2016, stock options covering approximately 6 million, 5 million and 4 million shares, respectively, were outstanding but not included in the computation of diluted earnings per share because they were anti-dilutive.

Stock-Based Compensation Plans

Stock-Based Compensation Plans and Arrangements	12 Months Ended
	Dec. 31, 2018
Postemployment Benefits [Abstract]
Stock-Based Compensation Plans and Arrangements	11. We have one active stock-based incentive plan that provides for grants of equity awards to our employees and non-employee directors in various forms including stock options, restricted stock awards, restricted stock units and performance stock units. We also maintain an ESPP. Shares issued under these plans may be either shares reacquired by us or shares that are authorized but unissued. Our Navient Corporation 2014 Omnibus Incentive Plan became effective on April 7, 2014, and 55 million shares are authorized to be issued from this plan as of December 31, 2018. Our Navient Corporation ESPP became effective on May 1, 2014, and 1 million shares are authorized to be issued from this plan as of December 31, 2018. For most awards, expense generally is recognized ratably over the vesting period net of estimated forfeitures, unless the employee meets certain retirement eligibility criteria. For employee awards that meet retirement eligibility criteria, we record the expense generally upon grant and for employees that become retirement eligible during the vesting period, we recognize expense from the grant date to the date on which the employee becomes retirement eligible. The total stock-based compensation cost recognized in 2018, 2017 and 2016 was $25 million, $35 million and $26 million, respectively. As of December 31, 2018, there was $12 million of total unrecognized compensation expense related to unvested stock awards, which is expected to be recognized over a weighted average period of 1.8 years. 11. Stock Options The exercise price of stock options equals the fair market value of our common stock on the date of grant. The maximum contractual term for stock options is 5 years for grants made since 2012, and 10 years for grants made prior to 2012. Most stock options are time-vested, with one-third vesting per year beginning with the first anniversary of the grant date. The fair values of the options granted in 2018, 2017 and 2016 were estimated as of the grant date using a Black-Scholes option pricing model with the following weighted average assumptions: Years Ended December 31, 2018 2017 2016 Expected life of the option 3.2 years 3.0 years 3.0 years Expected volatility 36 % 34 % 30 % Risk-free interest rate 2.27 % 1.44 % .90 % Expected dividend rate 4.70 % 4.13 % 6.97 % Weighted average fair value of options granted $ 2.59 $ 2.69 $ 1.01 The expected life is based in general on observed historical exercise patterns of SLM Corporation’s employees pre-Spin-Off (excluding employees who transitioned to SLM Bank) and Navient’s employees post-Spin-Off. The expected volatility is based in general on implied volatility from publicly-traded options on our stock at the grant date and historical volatility of our stock consistent with the expected life of the option. The risk-free interest rate is based on the U.S. Treasury spot rate at the grant date consistent with the expected life of the option. The dividend yield is based on the projected annual dividend payment per share based on the dividend amount at the grant date, divided by the stock price at the grant date. The following table summarizes Navient’s stock option activity in 2018. (Dollars in millions, except per share data) Number of Options Weighted Average Exercise Price per Share Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (1) Outstanding at December 31, 2017 14,183,726 $ 12.48 Granted 1,551,307 13.63 Exercised (2) (3,715,212 ) 10.53 Canceled (844,931 ) 16.69 Outstanding at December 31, 2018 (3) 11,174,890 $ 12.97 1.8 yrs. $ 4 Exercisable at December 31, 2018 7,500,940 $ 13.24 1.2 yrs. $ 4 (1) The aggregate intrinsic value represents the total intrinsic value (the aggregate difference between our closing stock price on December 31, 2018 and the exercise price of in-the-money options) that would have been received by the option holders if all in-the-money options had been exercised on December 31, 2018. (2) The total intrinsic value of Navient stock options exercised was $12 million, $9 million and $13 million for 2018, 2017 and 2016, respectively. (3) As of December 31, 2018, there was $1 million of unrecognized compensation cost related to stock options, which is expected to be recognized over a weighted average period of 1.9 years. Restricted Stock Restricted stock awards generally are granted to non-employee directors and generally vest upon the director’s election to the board. Outstanding restricted stock is entitled to dividend equivalent units that vest subject to the same vesting requirements or lapse of transfer restrictions, as applicable, as the underlying restricted stock award. The fair value of restricted stock awards is based on our stock price at the grant date. 11. The following table summarizes Navient’s restricted stock activity in 2018. Number of Shares Weighted Average Grant Date Fair Value Non-vested at December 31, 2017 — $ — Granted 55,503 13.56 Vested (1) (36,429 ) 13.52 Canceled (19,074 ) 13.63 Non-vested at December 31, 2018 (2) — $ — (1) The total fair value of Navient shares that vested was $1 million, $1 million and $1 million for 2018, 2017 and 2016, respectively. (2) As of December 31, 2018, there was no unrecognized compensation cost related to restricted stock. Restricted Stock Units and Performance Stock Units Restricted stock units (“RSUs”) and performance stock units (“PSUs”) are equity awards granted to employees that entitle the holder to shares of our common stock when the award vests. RSUs generally are time-vested, with one-third vesting per year beginning with the first anniversary of the grant date, while PSUs vest based on achieving certain corporate performance goals over a three-year performance period. Outstanding RSUs and PSUs are entitled to dividend equivalent units that vest subject to the same vesting requirements as the underlying award. The fair value of RSUs and PSUs is based on our stock price at the grant date. The following table summarizes Navient’s RSU and PSU activity in 2018. Number of RSUs/PSUs Weighted Average Grant Date Fair Value Outstanding at December 31, 2017 4,428,305 $ 13.33 Granted 1,884,580 12.97 Vested and converted to common stock (1) (1,598,227 ) 13.87 Forfeited (226,323 ) 21.65 Canceled (228,564 ) 12.89 Outstanding at December 31, 2018 (2) 4,259,771 $ 12.55 (1) The total fair value of Navient RSUs and PSUs that vested and converted to common stock was $22 million, $23 million and $30 million for 2018, 2017 and 2016, respectively. (2) As of December 31, 2018, there was $11 million of unrecognized compensation cost related to RSUs and PSUs, which is expected to be recognized over a weighted average period of 1.8 years.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	12. We use estimates of fair value in applying various accounting standards for our financial statements. We categorize our fair value estimates based on a hierarchical framework associated with three levels of price transparency utilized in measuring financial instruments at fair value. Education Loans Our FFELP Loans and Private Education Loans are accounted for at cost or at the lower of cost or market if the loan is held-for-sale. Fair values were determined by modeling loan cash flows using stated terms of the assets and internally-developed assumptions to determine aggregate portfolio yield, net present value and average life. FFELP Loans The significant assumptions used to determine fair value of our FFELP Loans are prepayment speeds, default rates, cost of funds, discount rate, capital levels and expected Repayment Borrower Benefits to be earned. In addition, the Floor Income component of our FFELP Loan portfolio is valued with option models using both observable market inputs and internally developed inputs. A number of significant inputs into the models are internally derived and not observable in active markets. While the resulting fair value can be validated against market transactions where we are a participant, these markets are not considered active. As such, these are level 3 valuations. Private Education Loans The significant assumptions used to determine fair value of our Private Education Loans are prepayment speeds, default rates, recovery rates, cost of funds, discount rate and capital levels. A number of significant inputs into the models are internally derived and not observable in active markets. While the resulting fair value can be validated against market transactions where we are a participant, these markets are not considered active. As such, these are level 3 valuations. Cash and Investments (Including “Restricted Cash and Investments”) Cash and cash equivalents are carried at cost. Carrying value approximates fair value. The fair value of investments in commercial paper, asset-backed commercial paper, or demand deposits that have a remaining term of less than 90 days when purchased are estimated to equal their cost and, when needed, adjustments for liquidity and credit spreads are made depending on market conditions and counterparty credit risks. No additional adjustments were deemed necessary. These are level 2 valuations. Borrowings Borrowings are accounted for at cost in the financial statements except when denominated in a foreign currency or when designated as the hedged item in a fair value hedge relationship. When the hedged risk is the benchmark interest rate (which for us is LIBOR) and not full fair value, the cost basis is adjusted for changes in value due to benchmark interest rates only. Foreign currency-denominated borrowings are re-measured at current spot rates in the financial statements. The full fair value of all borrowings is disclosed. Fair value was determined through standard bond pricing models and option models (when applicable) using the stated terms of the borrowings, observable yield curves, foreign currency exchange rates, volatilities from active markets or from quotes from broker-dealers. Fair value adjustments for unsecured corporate debt are made based on indicative quotes from observable trades and spreads on credit default swaps specific to the Company. Fair value adjustments for secured borrowings are based on indicative quotes from broker-dealers. These adjustments for both secured and unsecured borrowings are material to the overall valuation of these items and, currently, are based on inputs from inactive markets. As such, these are level 3 valuations. 12. Derivative Financial Instruments All derivatives are accounted for at fair value in the financial statements. The fair value of a majority of derivative financial instruments was determined by standard derivative pricing and option models using the stated terms of the contracts and observable market inputs. In some cases, we utilized internally developed inputs that are not observable in the market, and as such, classified these instruments as level 3 fair values. Complex structured derivatives or derivatives that trade in less liquid markets require significant estimates and judgment in determining fair value that cannot be corroborated with market transactions. When determining the fair value of derivatives, we take into account counterparty credit risk for positions where there is exposure to the counterparty on a net basis by assessing exposure net of collateral held. The net exposures for each counterparty are adjusted based on market information available for the specific counterparty, including spreads from credit default swaps. When the counterparty has exposure to us under derivatives with us, we fully collateralize the exposure, minimizing the adjustment necessary to the derivative valuations for our credit risk. While trusts that contain derivatives are not required to post collateral, when the counterparty is exposed to the trust the credit quality and securitized nature of the trusts minimizes any adjustments for the counterparty’s exposure to the trusts. The net credit risk adjustment (adjustments for our exposure to counterparties net of adjustments for the counterparties’ exposure to us) decreased the valuations at December 31, 2018 by $26 million. Inputs specific to each class of derivatives disclosed in the table below are as follows: • Interest rate swaps — Derivatives are valued using standard derivative cash flow models. Derivatives that swap fixed interest payments for LIBOR interest payments (or vice versa) and derivatives swapping quarterly reset LIBOR for daily reset LIBOR or one-month LIBOR were valued using the LIBOR swap yield curve which is an observable input from an active market. These derivatives are level 2 fair value estimates in the hierarchy. Other derivatives swapping LIBOR interest payments for another variable interest payment (primarily Prime) are valued using the LIBOR swap yield curve and observable market spreads for the specified index. The markets for these swaps are generally illiquid as indicated by a wide bid/ask spread. The adjustment made for liquidity decreased the valuations by $19 million at December 31, 2018. These derivatives are level 3 fair value estimates. • Cross-currency interest rate swaps — Derivatives are valued using standard derivative cash flow models. Derivatives hedging foreign-denominated bonds are valued using the LIBOR swap yield curve (for both USD and the foreign-denominated currency), cross-currency basis spreads and forward foreign currency exchange rates. These inputs are observable inputs from active markets. Therefore, the resulting valuation is a level 2 fair value estimate. Amortizing notional derivatives (derivatives whose notional amounts change based on changes in the balance of, or pool of, assets or debt) hedging trust debt use internally derived assumptions for the trust assets’ prepayment speeds and default rates to model the notional amortization. Management makes assumptions concerning the extension features of derivatives hedging rate-reset notes denominated in a foreign currency. These inputs are not market observable; therefore, these derivatives are level 3 fair value estimates. • Floor Income Contracts — Derivatives are valued using an option pricing model. Inputs to the model include the LIBOR swap yield curve and LIBOR interest rate volatilities. The inputs are observable inputs in active markets and these derivatives are level 2 fair value estimates. The carrying value of borrowings designated as the hedged item in a fair value hedge is adjusted for changes in fair value due to benchmark interest rates and foreign-currency exchange rates. These valuations are determined through standard bond pricing models and option models (when applicable) using the stated terms of the borrowings, and observable yield curves, foreign currency exchange rates and volatilities. 12. The following table summarizes the valuation of our financial instruments that are marked-to-market on a recurring basis. During 2018 and 2017, there were no significant transfers of financial instruments between levels. Fair Value Measurements on a Recurring Basis December 31, 2018 December 31, 2017 (Dollars in millions) Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets Available-for-sale investments: Other $ — $ — $ — $ — $ — $ 2 $ — $ 2 Total available-for-sale investments — — — — — 2 — 2 Derivative instruments: (1) Interest rate swaps — 171 2 173 — 388 4 392 Cross-currency interest rate swaps — — 6 6 — — 88 88 Total derivative assets (2) — 171 8 179 — 388 92 480 Total $ — $ 171 $ 8 $ 179 $ — $ 390 $ 92 $ 482 Liabilities (3) Derivative instruments (1) Interest rate swaps $ — $ (50 ) $ (29 ) $ (79 ) $ — $ (144 ) $ (45 ) $ (189 ) Floor Income Contracts — (53 ) — (53 ) — (74 ) — (74 ) Cross-currency interest rate swaps — (26 ) (639 ) (665 ) — (44 ) (410 ) (454 ) Other — — (4 ) (4 ) — — (18 ) (18 ) Total derivative liabilities (2) — (129 ) (672 ) (801 ) — (262 ) (473 ) (735 ) Total $ — $ (129 ) $ (672 ) $ (801 ) $ — $ (262 ) $ (473 ) $ (735 ) (1) Fair value of derivative instruments excludes accrued interest and the value of collateral. (2) See “Note 7 — Derivative Financial Instruments” for a reconciliation of gross positions without the impact of master netting agreements to the balance sheet classification. (3) Borrowings which are the hedged items in a fair value hedge relationship and which are adjusted for changes in value due to benchmark interest rates only are not carried at full fair value and are not reflected in this table. 12. The following tables summarize the change in balance sheet carrying value associated with level 3 financial instruments carried at fair value on a recurring basis. Year Ended December 31, 2018 Derivative Instruments (Dollars in millions) Interest Rate Swaps Cross Currency Interest Rate Swaps Other Total Derivative Instruments Balance, beginning of period $ (41 ) $ (322 ) $ (18 ) $ (381 ) Total gains/(losses): Included in earnings (1) 11 (433 ) 8 (414 ) Included in other comprehensive income — — — — Settlements 3 122 6 131 Transfers in and/or out of level 3 — — — — Balance, end of period $ (27 ) $ (633 ) $ (4 ) $ (664 ) Change in mark-to-market gains/(losses) relating to instruments still held at the reporting date (2) $ 13 $ (284 ) $ 14 $ (257 ) Year Ended December 31, 2017 Derivative Instruments (Dollars in millions) Interest Rate Swaps Cross Currency Interest Rate Swaps Other Total Derivative Instruments Balance, beginning of period $ (46 ) $ (1,243 ) $ (13 ) $ (1,302 ) Total gains/(losses): Included in earnings (1) — 803 (15 ) 788 Included in other comprehensive income — — — — Settlements 5 118 10 133 Transfers in and/or out of level 3 — — — — Balance, end of period $ (41 ) $ (322 ) $ (18 ) $ (381 ) Change in mark-to-market gains/(losses) relating to instruments still held at the reporting date (2) $ 5 $ 795 $ (5 ) $ 795 Year Ended December 31, 2016 Derivative Instruments (Dollars in millions) Interest Rate Swaps Cross Currency Interest Rate Swaps Other Total Derivative Instruments Balance, beginning of period $ (44 ) $ (903 ) $ (2 ) $ (949 ) Total gains/(losses): Included in earnings (1) 3 (428 ) (14 ) (439 ) Included in other comprehensive income — — — — Settlements 3 88 3 94 Transfers in and/or out of level 3 (3) (8 ) — — (8 ) Balance, end of period $ (46 ) $ (1,243 ) $ (13 ) $ (1,302 ) Change in mark-to-market gains/(losses) relating to instruments still held at the reporting date (2) $ 7 $ (340 ) $ (11 ) $ (344 ) (1) “Included in earnings” is comprised of the following amounts recorded in the specified line item in the consolidated statements of income: Years Ended December 31, (Dollars in millions) 2018 2017 2016 Gains (losses) on derivative and hedging activities, net $ (292 ) $ 906 $ (351 ) Interest expense (122 ) (118 ) (88 ) Total $ (414 ) $ 788 $ (439 ) (2) Recorded in “gains (losses) on derivative and hedging activities, net” in the consolidated statements of income. (3) Consumer Price Index/LIBOR basis swaps were transferred from level 3 to level 2 in the fourth quarter of 2016 due to the conclusion that these swaps now trade in an active market. 12. The following table presents the significant inputs that are unobservable or from inactive markets used in the recurring valuations of the level 3 financial instruments detailed above. (Dollars in millions) Fair Value at December 31, 2018 Valuation Technique Input Range (Weighted Average) Derivatives Prime/LIBOR basis swaps $ (27 ) Discounted cash flow Constant Prepayment Rate 7% Bid/ask adjustment to discount rate .08% — .08% (.08%) Cross-currency interest rate swaps (633 ) Discounted cash flow Constant Prepayment Rate 4% Other (4 ) Total $ (664 ) The significant inputs that are unobservable or from inactive markets related to our level 3 derivatives detailed in the table above would be expected to have the following impacts to the valuations: • Prime/LIBOR basis swaps — These swaps do not actively trade in the markets as indicated by a wide bid/ask spread. A wider bid/ask spread will result in a decrease in the overall valuation. In addition, the unobservable inputs include Constant Prepayment Rates of the underlying securitization trust the swap references. A decrease in this input will result in a longer weighted average life of the swap which will increase the value for swaps in a gain position and decrease the value for swaps in a loss position, everything else equal. The opposite is true for an increase in the input. • Cross-currency interest rate swaps — The unobservable inputs used in these valuations are Constant Prepayment Rates of the underlying securitization trust the swap references. A decrease in this input will result in a longer weighted average life of the swap. All else equal in a typical currency market, this will result in a decrease to the valuation due to the delay in the cash flows of the currency exchanges as well as diminished liquidity in the forward exchange markets as you increase the term. The opposite is true for an increase in the input. 12. The following table summarizes the fair values of our financial assets and liabilities, including derivative financial instruments. December 31, 2018 December 31, 2017 (Dollars in millions) Fair Value Carrying Value Difference Fair Value Carrying Value Difference Earning assets FFELP Loans $ 72,074 $ 72,253 $ (179 ) $ 82,271 $ 81,703 $ 568 Private Education Loans 22,958 22,245 713 24,421 23,419 1,002 Cash and investments (1) 5,488 5,488 — 5,034 5,034 — Total earning assets 100,520 99,986 534 111,726 110,156 1,570 Interest-bearing liabilities Short-term borrowings 5,418 5,422 4 4,783 4,771 (12 ) Long-term borrowings 92,173 93,519 1,346 104,921 105,012 91 Total interest-bearing liabilities 97,591 98,941 1,350 109,704 109,783 79 Derivative financial instruments Floor Income Contracts (53 ) (53 ) — (74 ) (74 ) — Interest rate swaps 94 94 — 203 203 — Cross-currency interest rate swaps (659 ) (659 ) — (366 ) (366 ) — Other (4 ) (4 ) — (18 ) (18 ) — Excess of net asset fair value over carrying value $ 1,884 $ 1,649 (1) “Cash and investments” includes available-for-sale investments whose cost basis is $0 million and $2 million at December 31, 2018 and 2017, respectively, versus a fair value of $0 million and $2 million at December 31, 2018 and 2017, respectively.

Commitments, Contingencies and

Commitments, Contingencies and Guarantees	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments, Contingencies and Guarantees	13. Legal Proceedings The Company has been named as defendant in a number of putative class action cases alleging violations of various state and federal consumer protection laws including the Telephone Consumer Protection Act (“TCPA”), the Consumer Financial Protection Act of 2010 (“CFPA”), the Fair Credit Reporting Act (“FCRA”), the Fair Debt Collection Practices Act (“FDCPA”) and various other state consumer protection laws. In January 2017, the Consumer Financial Protection Bureau (the “CFPB”) and Attorneys General for the State of Illinois and the State of Washington initiated civil actions naming Navient Corporation and several of its subsidiaries as defendants alleging violations of certain Federal and State consumer protection statutes, including the CFPA, FCRA, FDCPA and various state consumer protection laws. In October 2017, the Attorney General for the Commonwealth of Pennsylvania initiated a civil action against Navient Corporation and Navient Solutions, LLC (“Solutions”), containing similar alleged violations of the CFPA and the Pennsylvania Unfair Trade Practices and Consumer Protection Law. Additionally, the Attorneys General for the States of California and Mississippi recently initiated similar actions against the Company and certain subsidiaries alleging violations of various state and federal consumer protection laws. We refer to the Illinois, Pennsylvania, Washington, California, and Mississippi Attorneys General collectively as the “State Attorneys General.” In addition to these matters, a number of lawsuits have been filed by nongovernmental parties or, in the future, may be filed by additional governmental or nongovernmental parties seeking damages or other remedies related to similar issues raised by the CFPB and the State Attorneys General. As the Company has previously stated, we believe the suits improperly seek to impose penalties on Navient based on new, unannounced servicing standards applied retroactively only against one servicer, and that the allegations are false. We therefore have denied these allegations and intend to vigorously defend against the allegations in each of these cases. For additional information on these civil actions, please refer to section entitled “Regulatory Matters” below. 13. Commitments, Contingencies and Guarantees (Continued) At this point in time, the Company is unable to anticipate the timing of a resolution or the impact that these legal proceedings may have on the Company’s consolidated financial position, liquidity, results of operation or cash flows. As a result, it is not possible at this time to estimate a range of potential exposure, if any, for amounts that may be payable in connection with these matters and reserves have not been established. It is possible that an adverse ruling or rulings may have a material adverse impact on the Company. Regulatory Matters In addition, Navient and its subsidiaries are subject to examination or regulation by the SEC, CFPB, FFIEC, ED and various state agencies as part of its ordinary course of business. Items or matters similar to or different from those described above may arise during the course of those examinations. We also routinely receive inquiries or requests from various regulatory entities or bodies or government agencies concerning our business or our assets. Generally, the Company endeavors to cooperate with each such inquiry or request. As previously disclosed, the Company and various of its subsidiaries have been subject to the following investigations and inquiries: • In December 2013, Navient received Civil Investigative Demands (“CIDs”) issued by the Illinois Attorney General, the Washington Attorney General and multiple other state Attorneys General. According to the CIDs, the investigations were initiated to ascertain whether any practices declared to be unlawful under the Consumer Fraud and Deceptive Business Practices Act have occurred or are about to occur. The Company subsequently received separate but similar CIDs or subpoenas from the Attorneys General for the District of Columbia, Kansas, Oregon, Colorado, New Jersey and New York. We may receive additional CIDs or subpoenas from these or other Attorneys General with respect to similar or different matters. • In April 2014, Solutions received a CID from the CFPB as part of the CFPB’s separate investigation regarding allegations relating to Navient’s disclosures and assessment of late fees and other matters. Navient has received a series of supplemental CIDs on these matters. In August 2015, Solutions received a letter from the CFPB notifying Solutions that, in accordance with the CFPB’s discretionary Notice and Opportunity to Respond and Advise (“NORA”) process, the CFPB’s Office of Enforcement was considering recommending that the CFPB take legal action against Solutions. The NORA letter related to a previously disclosed investigation into Solutions’ disclosures and assessment of late fees and other matters and states that, in connection with any action, the CFPB may seek restitution, civil monetary penalties and corrective action against Solutions. The Company responded to the NORA letter in September 2015. • In November 2014, Navient’s subsidiary, Pioneer Credit Recovery, Inc. (“Pioneer”), received a CID from the CFPB as part of an investigation regarding Pioneer’s activities relating to rehabilitation loans and collection of defaulted student debt. • In December 2014, Solutions received a subpoena from the New York Department of Financial Services (the “NY DFS”) as part of the NY DFS’s inquiry with regard to whether persons or entities have engaged in fraud or misconduct with respect to a financial product or service under New York Financial Services Law or other laws. In January 2017, the CFPB initiated a civil action naming Navient Corporation and several of its subsidiaries as defendants alleging violations of Federal and State consumer protection statutes, including the DFPA, FCRA, FDCPA and various state consumer protection laws. The CFPB, Washington Attorney General and Illinois Attorney General lawsuits relate to matters which were covered under the CIDs or the NORA letter discussed above. In addition, various State Attorneys General have filed suits alleging violations of various state and federal consumer protection laws covering matters similar to those covered by the CIDs or the NORA letter. As stated above, we have denied these allegations and intend to vigorously defend against the allegations in each of these cases. 13. Commitments, Contingencies and Guarantees (Continued) Under the terms of the Separation and Distribution Agreement between the Company and SLM BankCo, Navient has agreed to indemnify SLM BankCo for all claims, actions, damages, losses or expenses that may arise from the conduct of activities of pre-Spin-Off SLM BankCo occurring prior to the Spin-Off other than those specifically excluded in the Separation and Distribution Agreement. As a result, subject to the terms, conditions and limitations set forth in the Separation and Distribution Agreement, Navient has agreed to indemnify and hold harmless Sallie Mae and its subsidiaries, including Sallie Mae Bank from liabilities arising out of the regulatory matters and CFPB and State Attorneys General lawsuits mentioned above. Navient has asserted various claims for indemnification against Sallie Mae and Sallie Mae Bank for such specifically excluded items arising out of the CFPB and the State Attorneys General lawsuits if and to the extent any indemnified liabilities exist now or in the future. Navient has no additional reserves related to indemnification matters with SLM BankCo as of December 31, 2018. OIG Audit The Office of the Inspector General (the “OIG”) of ED commenced an audit regarding Special Allowance Payments (“SAP”) on September 10, 2007. In September 2013, we received the final audit determination of Federal Student Aid (the “Final Audit Determination”) on the final audit report issued by the OIG in August 2009 related to this audit. The Final Audit Determination concurred with the final audit report issued by the OIG and instructed us to make adjustment to our government billing to reflect the policy determination. In August 2016, we filed our notice of appeal to the Administrative Actions and Appeals Service Group of ED. A hearing was held in April 2017 and a ruling has not yet been issued. We continue to believe that our SAP billing practices were proper, considering then-existing ED guidance and lack of applicable regulations. The Company established a reserve for this matter in 2014 and does not believe, at this time, that an adverse ruling would have a material effect on the Company as a whole. Contingencies In the ordinary course of business, we and our subsidiaries are defendants in or parties to pending and threatened legal actions and proceedings including actions brought on behalf of various classes of claimants. These actions and proceedings may be based on alleged violations of consumer protection, securities, employment and other laws. In certain of these actions and proceedings, claims for substantial monetary damage are asserted against us and our subsidiaries. We and our subsidiaries are also subject to potential unasserted claims by third parties. In the ordinary course of business, we and our subsidiaries are subject to regulatory examinations, information gathering requests, inquiries and investigations. In connection with formal and informal inquiries in these cases, we and our subsidiaries receive requests, subpoenas and orders for documents, testimony and information in connection with various aspects of our regulated activities. We are required to establish reserves for litigation and regulatory matters where those matters present loss contingencies that are both probable and estimable. When loss contingencies are not both probable and estimable, we do not establish reserves. In view of the inherent difficulty of predicting the outcome of such litigation and regulatory matters, we cannot predict what the eventual outcome of the pending matters will be, what the timing or the ultimate resolution of these matters will be, or what the eventual loss, fines or penalties, if any, related to each pending matter may be. Based on current knowledge, reserves have been established for certain litigation, regulatory matters, and unasserted contract claims where the loss is both probable and estimable. Based on current knowledge, management does not believe that loss contingencies, if any, arising from pending investigations, litigation or regulatory matters will have a material adverse effect on our consolidated financial position, liquidity, results of operations or cash flows, except as otherwise disclosed. As of June 30, 2018, we concluded that a contingency loss was no longer probable of occurring. Accordingly, the related $40 million contingency reserve was released as a reduction of operating expenses in the second quarter of 2018.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	14. Reconciliations of the statutory U.S. federal income tax rates to our effective tax rate for continuing operations follow: Years Ended December 31, 2018 2017 2016 Statutory rate 21.0 % 35.0 % 35.0 % DTA Remeasurement Loss (1) — 27.2 — State tax, net of federal benefit 3.9 .7 3.8 Other, net .3 (1.1 ) (.3 ) Effective tax rate 25.2 % 61.8 % 38.5 % (1) The TCJA, enacted on December 22, 2017, made significant changes to all aspects of income taxation, including a reduction to the corporate federal statutory tax rate. GAAP requires the effects of the TCJA to be recognized in the period the law is enacted, even though the effective date of the law for most provisions is January 1, 2018. The primary impact to us is the reduction to the corporate federal statutory tax rate from 35 percent to 21 percent as of January 1, 2018. This rate reduction required us to remeasure our deferred tax asset at December 31, 2017, at the 21 percent corporate federal statutory tax rate and resulted in a DTA Remeasurement Loss of $208 million for GAAP, which is reflected as incremental income tax expense in the fourth quarter of 2017. Income tax expense consists of: December 31, (Dollars in millions) 2018 2017 2016 Current provision/(benefit): Federal $ 71 $ 77 $ 246 State 13 (3 ) 47 Foreign 3 3 1 Total current provision/(benefit) 87 77 294 Deferred provision/(benefit): Federal 33 385 115 State 13 11 18 Foreign — (1 ) — Total deferred provision/(benefit) 46 395 133 Provision for income tax expense/(benefit) $ 133 $ 472 $ 427 14. The tax effect of temporary differences that give rise to deferred tax assets and liabilities include the following: December 31, (Dollars in millions) 2018 2017 Deferred tax assets: Loan reserves $ 292 $ 317 Education loan premiums and discounts, net 48 52 Operating loss and credit carryovers 18 22 Stock-based compensation plans 16 18 Accrued expenses not currently deductible 14 24 Other 18 14 Total deferred tax assets 406 447 Deferred tax liabilities: Market value adjustments on education loans, investments and derivatives 46 14 Acquired intangible assets 12 3 Original issue discount on borrowings 7 11 Debt repurchases 6 8 Other 13 19 Total deferred tax liabilities 84 55 Net deferred tax assets $ 322 $ 392 Included in operating loss and credit carryovers is a valuation allowance of $43 million and $42 million as of December 31, 2018 and 2017, respectively, against a portion of the Company’s federal and state deferred tax assets. The valuation allowance is primarily attributable to deferred tax assets for federal and state net operating loss carryforwards that management believes it is more likely than not will expire prior to being realized. The ultimate realization of the deferred tax assets is dependent upon the generation of future taxable income of the appropriate character (i.e. capital or ordinary) during the period in which the temporary differences become deductible. Factors generally considered by management include (but are not limited to): any changes in economic conditions, the scheduled reversals of deferred tax liabilities, and the history of positive taxable income available for net operating loss carrybacks in evaluating the realizability of the deferred tax assets. As of December 31, 2018, we have gross federal net operating loss (“NOL”) carryforwards of $78 million (which begin to expire in 2031) and gross state NOL carryforwards of $640 million (which begin to expire in 2021). Tax-effected NOL amounts of $16 million (federal) and $42 million (state) have corresponding valuation allowances of $0 million (federal) and $40 million (state). As of December 31, 2018, we have gross federal and state capital loss carryforwards of $10 million (which begin to expire in 2021). Tax-effected capital loss amount of $3 million (federal and state) has a corresponding valuation allowance of $3 million (federal and state). 14. Accounting for Uncertainty in Income Taxes The following table summarizes changes in unrecognized tax benefits: December 31, (Dollars in millions) 2018 2017 2016 Unrecognized tax benefits at beginning of year $ 57.4 $ 73.0 $ 56.3 Increases resulting from tax positions taken during a prior period 8.0 .7 19.9 Decreases resulting from tax positions taken during a prior period (.3 ) (1.8 ) (5.6 ) Increases resulting from tax positions taken during the current period 3.8 4.4 4.4 Decreases related to settlements with taxing authorities (1.4 ) (5.1 ) (.1 ) Increases related to settlements with taxing authorities — — — Reductions related to the lapse of statute of limitations (1.8 ) (13.8 ) (1.9 ) Unrecognized tax benefits at end of year $ 65.7 $ 57.4 $ 73.0 As of December 31, 2018, the gross unrecognized tax benefits are $65.7 million. Included in the $65.7 million are $51.9 million of unrecognized tax benefits that, if recognized, would favorably impact the effective tax rate. The Company or one of its subsidiaries files income tax returns at the U.S. federal level, in most U.S. states, and various foreign jurisdictions. All periods prior to 2015 are closed for federal examination purposes. Various combinations of subsidiaries, tax years, and jurisdictions remain open for review, subject to statute of limitations periods (typically 3 to 4 prior years). We do not expect the resolution of open audits to have a material impact on our unrecognized tax benefits.

Revenue from Contract with Cust

Revenue from Contract with Customers Accounted in Accordance with ASC 606	12 Months Ended
	Dec. 31, 2018
Revenue From Contract With Customer [Abstract]
Revenue from Contract with Customers Accounted in Accordance with ASC 606	15. Revenue from Contracts with Customers Accounted in Accordance with ASC 606 We account for certain contract revenue in accordance with ASC 606. Servicing contract revenue is not accounted for under ASC 606. Contract revenue earned by our Federal Education Loans segment is derived from asset recovery activities related to the collection of delinquent education loans on behalf of ED, Guarantor agencies and other institutions. Revenue earned by our Business Processing segment is derived from government services, which includes receivables management services and account processing solutions, and healthcare services, which includes revenue cycle management services. Most of our revenue is derived from long-term contracts, the duration of which is expected to span more than one year. These contracts are billable monthly, as services are rendered, based on a percentage of the balance collected or the transaction processed, a flat fee per transaction or a stated rate per the service performed. In accordance with ASC 606, the unit of account is a contractual performance obligation, a promise to provide a distinct good or service to a customer. The transaction price is allocated to each distinct performance obligation when or as the good or service is transferred to the customer and the obligation is satisfied. Distinct performance obligations are identified based on the services specified in the contract that are capable of being distinct such that the customer can benefit from the service on its own or together with other resources that are available from the Company or a third party, and are also distinct in the context of the contract such that the transfer of the services is separately identifiable from other services promised in the contract. Most of our contracts include integrated service offerings that include obligations that are not separately identifiable and distinct in the context of our contracts. Accordingly, our contracts generally have a single performance obligation. A limited number of full service offerings include multiple performance obligations. Substantially all our revenue from contracts with customers is variable revenue which is recognized over time as our customers receive and consume the benefit of our services in an amount consistent with monthly billings. Accordingly, we do not disclose variable consideration associated with the remaining performance obligation as we have recognized revenue in the amount we have the right to invoice for services performed. Our fees correspond to the value the customer has realized from our performance of each increment of the service (for example, an individual transaction processed or collection of a past due balance). 15. Revenue from Contracts with Customers Accounted in Accordance with ASC 606 (Continued) The following tables illustrate the disaggregation of revenue from contracts accounted for under ASC 606 with customers according to service type and client type by reportable operating segment. Revenue by Service Type Year Ended December 31, 2018 (Dollars in millions) Federal Education Loans Business Processing Total Revenue Federal Education Loan asset recovery services $ 91 $ — $ 91 Government services — 175 175 Healthcare services — 93 93 Total $ 91 $ 268 $ 359 Revenue by Client Type Year Ended December 31, 2018 (Dollars in millions) Federal Education Loans Business Processing Total Revenue Federal government $ 21 $ 7 $ 28 Guarantor agencies 58 — 58 Other institutions 12 — 12 State and local government — 92 92 Tolling authorities — 76 76 Hospitals and other healthcare providers — 93 93 Total $ 91 $ 268 $ 359 As of January 1, 2018, and December 31, 2018, there was $63 million and $74 million, respectively, of net accounts receivable related to these contracts. Navient had no material contract assets or contract liabilities.

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Segment Reporting	16. In the fourth quarter of 2017, Navient entered the Private Education Refinance Loan origination market. This new activity changed the way the Company manages the business, reviews operating performance and allocates resources. This resulted in the following four new reportable operating segments, effective first-quarter 2018: (1) Federal Education Loans (2) Consumer Lending (3) Business Processing and (4) Other. In connection with this change in reportable operating segments, there was also a change in how unallocated shared services expense is defined (which was previously referred to as overhead expense). The following table shows the realignment of our business lines (operating segments) from the prior reportable operating segments to the new reportable operating segments: Business Lines New Reportable Operating Segment Prior Reportable Operating Segment FFELP Loans Federal Education Loans FFELP Loans Federal Education Loans-Servicing Federal Education Loans Business Services Federal Education Loans-Asset Recovery Federal Education Loans Business Services Private Education Refinance Loans Consumer Lending Private Education Loans Private Education Loans-Other Consumer Lending Private Education Loans Non-Education Government Services Business Processing Business Services Non-Education Healthcare Services Business Processing Business Services Unallocated Shared Services Expenses Other Other Corporate Liquidity Portfolio Other Other These segments meet the quantitative thresholds for reportable operating segments. Accordingly, the results of operations of these reportable operating segments are presented separately. The underlying operating segments are used by the Company’s chief operating decision maker to manage the business, review operating performance and allocate resources, and qualify to be aggregated as part of the primary reportable operating segments. As discussed further below, we measure the profitability of our operating segments based on Core Earnings net income. Accordingly, information regarding our reportable operating segments is provided on a Core Earnings basis. As a result of this change in segment reporting in the first quarter of 2018, prior periods have been recast for comparison purposes. Federal Education Loans Segment In this segment, Navient holds and acquires FFELP Loans and performs servicing and asset recovery services on its own loan portfolio, federal education loans owned by ED and other institutions. Although FFELP Loans are no longer originated, we continue to pursue acquisitions of FFELP Loan portfolios as well as servicing and asset recovery services contracts. These acquisitions leverage our servicing scale and generate incremental earnings and cash flow. In this segment, we generate revenue primarily through net interest income on the FFELP Loan portfolio (after provision for loan losses) as well as servicing and asset recovery services revenue. This segment is expected to generate significant amounts of earnings and cash flow over the remaining life of the portfolio. The following table includes GAAP-basis asset information for our Federal Education Loans segment. December 31, (Dollars in millions) 2018 2017 FFELP Loans, net $ 72,253 $ 81,703 Cash and investments (1) 3,368 2,821 Other 2,100 2,601 Total assets $ 77,721 $ 87,125 (1) Includes restricted cash and investments. 16. Consumer Lending Segment In this segment, Navient holds, originates and acquires consumer loans and performs servicing activities on its own education loan portfolio. Originations and acquisitions leverage our servicing scale and generate incremental earnings and cash flow. In this segment, we generate revenue primarily through net interest income on the Private Education Loan portfolio (after provision for loan losses). This segment is expected to generate significant amounts of earnings and cash flow over the remaining life of the portfolio. The following table includes GAAP-basis asset information for our Consumer Lending segment. December 31, (Dollars in millions) 2018 2017 Private Education Loans, net $ 22,245 $ 23,419 Cash and investments (1) 732 706 Other 1,076 1,143 Total assets $ 24,053 $ 25,268 (1) Includes restricted cash and investments. Business Processing Segment In this segment, Navient performs revenue cycle management and business processing services for over 600 non-education related government and healthcare clients. Our integrated solutions technology and superior data driven approach allows state governments, agencies, court systems, municipalities, and toll authorities (Government Services) to reduce their operating expenses while maximizing revenue opportunities. Healthcare services include revenue cycle outsourcing, accounts receivable management, extended business office support and consulting engagements. We offer customizable solutions for our clients that include non-profit/religious-affiliated hospital systems, teaching hospitals, urban medical centers, for-profit healthcare systems, critical access hospitals, children’s hospitals and large physician groups. At December 31, 2018 and 2017, the Business Processing segment had total assets of $448 million and $466 million, respectively, on a GAAP basis. Other Segment Our Other segment primarily consists of our corporate liquidity portfolio and the repurchase of debt, unallocated expenses of shared services, restructuring/other reorganization expenses, and the deferred tax asset remeasurement loss recognized due to the enactment of the TCJA in the fourth quarter of 2017. Unallocated expenses of shared services are comprised of costs primarily related to certain executive management, the board of directors, accounting, finance, legal, human resources, compliance and risk management, regulatory-related costs, stock-based compensation expense, and information technology costs related to infrastructure and operations. Regulatory-related costs include actual settlement amounts as well as third-party professional fees we incur in connection with regulatory matters. At December 31, 2018 and 2017, the Other segment had total assets of $2.0 billion and $2.1 billion, respectively, on a GAAP basis. 16. Measure of Profitability We prepare financial statements and present financial results in accordance with GAAP. However, we also evaluate our business segments and present financial results on a basis that differs from GAAP. We refer to this different basis of presentation as Core Earnings. We provide this Core Earnings basis of presentation on a consolidated basis and for each business segment because this is what we review internally when making management decisions regarding our performance and how we allocate resources. We also refer to this information in our presentations with credit rating agencies, lenders and investors. Because our Core Earnings basis of presentation corresponds to our segment financial presentations, we are required by GAAP to provide Core Earnings disclosure in the notes to our consolidated financial statements for our business segments. Core Earnings are not a substitute for reported results under GAAP. We use Core Earnings to manage our business segments because Core Earnings reflect adjustments to GAAP financial results for two items, discussed below, that are mostly due to timing factors generally beyond the control of management. Accordingly, we believe that Core Earnings provide management with a useful basis from which to better evaluate results from ongoing operations against the business plan or against results from prior periods. Consequently, we disclose this information because we believe it provides investors with additional information regarding the operational and performance indicators that are most closely assessed by management. When compared to GAAP results, the two items we remove to result in our Core Earnings presentations are: 1. Mark-to-market gains/losses resulting from our use of derivative instruments to hedge our economic risks that do not qualify for hedge accounting treatment or do qualify for hedge accounting treatment but result in ineffectiveness; and 2. The accounting for goodwill and acquired intangible assets. While GAAP provides a uniform, comprehensive basis of accounting, for the reasons described above, our Core Earnings basis of presentation does not. Core Earnings are subject to certain general and specific limitations that investors should carefully consider. For example, there is no comprehensive, authoritative guidance for management reporting. Our Core Earnings are not defined terms within GAAP and may not be comparable to similarly titled measures reported by other companies. Accordingly, our Core Earnings presentation does not represent a comprehensive basis of accounting. Investors, therefore, may not be able to compare our performance with that of other financial services companies based upon Core Earnings. Core Earnings results are only meant to supplement GAAP results by providing additional information regarding the operational and performance indicators that are most closely used by management, our board of directors, credit rating agencies, lenders and investors to assess performance. 16. Segment Results and Reconciliations to GAAP Year Ended December 31, 2018 Adjustments (Dollars in millions) Federal Education Loans Consumer Lending Business Processing Other Total Core Earnings Reclassi- fications Additions/ (Subtractions) Total Adjustments (1) Total GAAP Interest income: Education loans $ 3,080 $ 1,778 $ — $ — $ 4,858 $ 17 $ (70 ) $ (53 ) $ 4,805 Other loans 4 2 — — 6 — — — 6 Cash and investments 46 13 — 38 97 — — — 97 Total interest income 3,130 1,793 — 38 4,961 17 (70 ) (53 ) 4,908 Total interest expense 2,467 1,013 — 192 3,672 8 (12 ) (4 ) 3,668 Net interest income (loss) 663 780 — (154 ) 1,289 9 (58 ) (49 ) 1,240 Less: provisions for loan losses 70 300 — — 370 — — — 370 Net interest income (loss) after provisions for loan losses 593 480 — (154 ) 919 9 (58 ) (49 ) 870 Other income (loss): Servicing revenue 262 12 — — 274 — — — 274 Asset recovery and business processing revenue 163 — 267 — 430 — — — 430 Other income (loss) 24 — — 6 30 (22 ) (29 ) (51 ) (21 ) Gains on debt repurchases — — — 9 9 13 (3 ) 10 19 Total other income (loss) 449 12 267 15 743 (9 ) (32 ) (41 ) 702 Expenses: Direct operating expenses 298 169 229 — 696 — — — 696 Unallocated shared services expenses — — — 288 288 — — — 288 Operating expenses 298 169 229 288 984 — — — 984 Goodwill and acquired intangible asset impairment and amortization — — — — — — 47 47 47 Restructuring/other reorganization expenses — — — 13 13 — — — 13 Total expenses 298 169 229 301 997 — 47 47 1,044 Income (loss) before income tax expense (benefit) 744 323 38 (440 ) 665 — (137 ) (137 ) 528 Income tax expense (benefit) (2) 164 71 8 (97 ) 146 — (13 ) (13 ) 133 Net income (loss) $ 580 $ 252 $ 30 $ (343 ) $ 519 $ — $ (124 ) $ (124 ) $ 395 (1) Core Earnings adjustments to GAAP: Year Ended December 31, 2018 (Dollars in millions) Net Impact of Derivative Accounting Net Impact of Acquired Intangibles Total Net interest income (loss) after provisions for loan losses $ (49 ) $ — $ (49 ) Total other income (loss) (41 ) — (41 ) Goodwill and acquired intangible asset impairment and amortization — 47 47 Total Core Earnings adjustments to GAAP $ (90 ) $ (47 ) (137 ) Income tax expense (benefit) (13 ) Net income (loss) $ (124 ) (2) Income taxes are based on a percentage of net income before tax for the individual reportable segment. 16. Year Ended December 31, 2017 Adjustments (Dollars in millions) Federal Education Loans Consumer Lending Business Processing Other Total Core Earnings Reclassi- fications Additions/ (Subtractions) Total Adjustments (1) Total GAAP Interest income: Education loans $ 2,679 $ 1,634 $ — $ — $ 4,313 $ 69 $ (55 ) $ 14 $ 4,327 Other loans 13 — — — 13 — — — 13 Cash and investments 29 5 — 9 43 — — — 43 Total interest income 2,721 1,639 — 9 4,369 69 (55 ) 14 4,383 Total interest expense 2,022 825 — 143 2,990 (8 ) (11 ) (19 ) 2,971 Net interest income (loss) 699 814 — (134 ) 1,379 77 (44 ) 33 1,412 Less: provisions for loan losses 44 382 — — 426 — — — 426 Net interest income (loss) after provisions for loan losses 655 432 — (134 ) 953 77 (44 ) 33 986 Other income (loss): Servicing revenue 280 10 — — 290 — — — 290 Asset recovery and business processing revenue 263 — 212 — 475 — — — 475 Other income (loss) 3 — — 16 19 (77 ) 89 12 31 Gains on sales of loans and investments 3 — — — 3 — — — 3 Losses on debt repurchases — — — (3 ) (3 ) — — — (3 ) Total other income (loss) 549 10 212 13 784 (77 ) 89 12 796 Expenses: Direct operating expenses 316 156 187 — 659 — — — 659 Unallocated shared services expenses — — — 307 307 — — — 307 Operating expenses 316 156 187 307 966 — — — 966 Goodwill and acquired intangible asset impairment and amortization — — — — — — 23 23 23 Restructuring/other reorganization expenses — — — 29 29 — — — 29 Total expenses 316 156 187 336 995 — 23 23 1,018 Income (loss) before income tax expense (benefit) 888 286 25 (457 ) 742 — 22 22 764 Income tax expense (benefit) (2) 321 103 9 58 491 — (19 ) (19 ) 472 Net income (loss) $ 567 $ 183 $ 16 $ (515 ) $ 251 $ — $ 41 $ 41 $ 292 (1) Core Earnings adjustments to GAAP: Year Ended December 31, 2017 (Dollars in millions) Net Impact of Derivative Accounting Net Impact of Acquired Intangibles Total Net interest income after provisions for loan losses $ 33 $ — $ 33 Total other income (loss) 12 — 12 Goodwill and acquired intangible asset impairment and amortization — 23 23 Total Core Earnings adjustments to GAAP $ 45 $ (23 ) 22 Income tax expense (benefit) (19 ) Net income (loss) $ 41 (2) Income taxes are based on a percentage of net income before tax for the individual reportable segment with the impact of the DTA Remeasurement Loss included in the Other segment 16. Year Ended December 31, 2016 Adjustments (Dollars in millions) Federal Education Loans Consumer Lending Business Processing Other Total Core Earnings Reclassi- fications Additions/ (Subtractions) Total Adjustments (1) Total GAAP Interest income: Education loans $ 2,395 $ 1,587 $ — $ — $ 3,982 $ 247 $ (114 ) $ 133 $ 4,115 Other loans 9 — — — 9 — — — 9 Cash and investments 16 2 — 4 22 — — — 22 Total interest income 2,420 1,589 — 4 4,013 247 (114 ) 133 4,146 Total interest expense 1,597 704 — 109 2,410 31 — 31 2,441 Net interest income (loss) 823 885 — (105 ) 1,603 216 (114 ) 102 1,705 Less: provisions for loan losses 46 383 — — 429 — — — 429 Net interest income (loss) after provisions for loan losses 777 502 — (105 ) 1,174 216 (114 ) 102 1,276 Other income (loss): Servicing revenue 289 15 — — 304 — — — 304 Asset recovery and business processing revenue 216 — 174 — 390 — — — 390 Other income (loss) — — — 14 14 (216 ) 326 110 124 Gains on debt repurchases — — — 1 1 — — — 1 Total other income (loss) 505 15 174 15 709 (216 ) 326 110 819 Expenses: Direct operating expenses 366 149 149 — 664 — — — 664 Unallocated shared services expenses — — — 287 287 — — — 287 Operating expenses 366 149 149 287 951 — — — 951 Goodwill and acquired intangible asset impairment and amortization — — — — — — 36 36 36 Restructuring/other reorganization expenses — — — — — — — — — Total expenses 366 149 149 287 951 — 36 36 987 Income (loss) before income tax expense (benefit) 916 368 25 (377 ) 932 — 176 176 1,108 Income tax expense (benefit) (2) 338 137 9 (139 ) 345 — 82 82 427 Net income (loss) $ 578 $ 231 $ 16 $ (238 ) $ 587 $ — $ 94 $ 94 $ 681 (1) Core Earnings adjustments to GAAP: Year Ended December 31, 2016 (Dollars in millions) Net Impact of Derivative Accounting Net Impact of Acquired Intangibles Total Net interest income after provisions for loan losses $ 102 $ — $ 102 Total other income (loss) 110 — 110 Goodwill and acquired intangible asset impairment and amortization — 36 36 Total Core Earnings adjustments to GAAP $ 212 $ (36 ) 176 Income tax expense (benefit) 82 Net income (loss) $ 94 (2) Income taxes are based on a percentage of net income before tax for the individual reportable segment. 16. Summary of Core Earnings Adjustments to GAAP Years Ended December 31, (Dollars in millions) 2018 2017 2016 Core Earnings net income $ 519 $ 251 $ 587 Core Earnings adjustments to GAAP: Net impact of derivative accounting (1) (90 ) 45 212 Net impact of goodwill and acquired intangible assets (2) (47 ) (23 ) (36 ) Net income tax effect (3) 13 19 (82 ) Total Core Earnings adjustments to GAAP (124 ) 41 94 GAAP net income $ 395 $ 292 $ 681 (1) Derivative accounting: (2) Goodwill and acquired intangible assets: (3) Net tax effect:

Quarterly Financial Information

Quarterly Financial Information (unaudited)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information (unaudited)	17. 2018 (Dollars in millions, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Net interest income $ 329 $ 298 $ 306 $ 307 Less: provisions for loan losses 87 112 85 85 Net interest income after provisions for loan losses 242 186 221 222 Other income 163 176 203 196 Gains (losses) on derivative and hedging activities, net 48 (40 ) 2 (48 ) Operating expenses 275 201 255 252 Goodwill and acquired intangible asset impairment and amortization expense 9 6 23 8 Restructuring/other reorganization expenses 7 2 1 4 Income tax expense 36 30 33 34 Net income $ 126 $ 83 $ 114 $ 72 Basic earnings per common share $ .48 $ .31 $ .44 $ .28 Diluted earnings per common share $ .47 $ .31 $ .43 $ .28 2017 (Dollars in millions, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Net interest income $ 340 $ 351 $ 355 $ 366 Less: provisions for loan losses 107 105 105 109 Net interest income after provisions for loan losses 233 246 250 257 Other income 168 187 238 181 Gains (losses) on derivative and hedging activities, net (16 ) (25 ) 25 38 Operating expenses 238 230 238 260 Goodwill and acquired intangible asset impairment and amortization expense 6 6 6 5 Restructuring/other reorganization expenses — — — 29 Income tax expense 53 60 93 266 Net income (loss) $ 88 $ 112 $ 176 $ (84 ) Basic earnings (loss) per common share $ .31 $ .40 $ .65 $ (.32 ) Diluted earnings (loss) per common share $ .30 $ .39 $ .64 $ (.32 )

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates Our financial reporting and accounting policies conform to generally accepted accounting principles in the United States of America (“GAAP”). The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Uncertain and volatile market and economic conditions increase the risk and complexity of the judgments in these estimates and actual results could differ from estimates. Key accounting policies that include the most significant judgments, estimates and assumptions include the allowance for loan losses, the amortization of loan premiums and discounts using the effective interest rate method, goodwill and intangible asset impairment assessment and fair value measurement.
Consolidation	Consolidation The consolidated financial statements include the accounts of Navient Corporation and its majority-owned and controlled subsidiaries and those Variable Interest Entities (“VIEs”) for which we are the primary beneficiary, after eliminating the effects of intercompany accounts and transactions. We consolidate any VIEs where we have determined we are the primary beneficiary. A VIE is a legal entity that does not have sufficient equity at risk to finance its own operations, or whose equity holders do not have the power to direct the activities that most significantly affect the economic performance of the entity, or whose equity holders do not share proportionately in the losses or benefits of the entity. The primary beneficiary of the VIE is the entity which has both: (1) the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and (2) the obligation to absorb losses or receive benefits of the entity that could potentially be significant to the VIE. As it relates to our securitizations and other secured borrowing facilities that are VIEs as of December 31, 2018, we are the servicer of the related education loan assets and own the Residual Interest of the securitization trusts and secured borrowing facilities. As a result, we are the primary beneficiary and consolidate those VIEs.
Fair Value Measurement	2. Fair Value Measurement We use estimates of fair value in applying various accounting standards for our financial statements. Fair value measurements are used in one of four ways: • In the consolidated balance sheet with changes in fair value recorded in the consolidated statement of income; • In the consolidated balance sheet with changes in fair value recorded in the accumulated other comprehensive income section of the consolidated statement of changes in stockholders’ equity; • In the consolidated balance sheet for instruments carried at lower of cost or fair value with impairment charges recorded in the consolidated statement of income; and • In the notes to the financial statements. Fair value is defined as the price to sell an asset or transfer a liability in an orderly transaction between willing and able market participants. In general, our policy in estimating fair value is to first look at observable market prices for identical assets and liabilities in active markets, where available. When these are not available, other inputs are used to model fair value such as prices of similar instruments, yield curves, volatilities, prepayment speeds, default rates and credit spreads, relying first on observable data from active markets. Depending on current market conditions, additional adjustments to fair value may be based on factors such as liquidity and credit spreads. Transaction costs are not included in the determination of fair value. When possible, we seek to validate the model’s output to market transactions. Depending on the availability of observable inputs and prices, different valuation models could produce materially different fair value estimates. The values presented may not represent future fair values and may not be realizable. We categorize our fair value estimates based on a hierarchical framework associated with three levels of price transparency utilized in measuring financial instruments at fair value. Classification is based on the lowest level of input that is significant to the fair value of the instrument. The three levels are as follows: • Level 1 — Quoted prices (unadjusted) in active markets for identical assets or liabilities that we have the ability to access at the measurement date. The types of financial instruments included in level 1 are highly liquid instruments with quoted prices. • Level 2 — Inputs from active markets, other than quoted prices for identical instruments, are used to determine fair value. Significant inputs are directly observable from active markets for substantially the full term of the asset or liability being valued. • Level 3 — Pricing inputs significant to the valuation are unobservable. Inputs are developed based on the best information available. However, significant judgment is required by us in developing the inputs.
Loans	Loans Loans, consisting primarily of federally insured education loans and Private Education Loans, that we have the ability and intent to hold for the foreseeable future are classified as held-for-investment and are carried at amortized cost. Amortized cost includes the unamortized premiums, discounts, and capitalized origination costs and fees, all of which are amortized to interest income as further discussed below. Loans which are held-for-investment also have an allowance for loan loss as needed. Any loans we have not classified as held-for-investment are classified as held-for-sale and carried at the lower of cost or fair value. Loans are classified as held-for-sale when we have the intent and ability to sell such loans. Loans which are held-for-sale do not have the associated premium, discount, and capitalized origination costs and fees amortized into interest income. In addition, once a loan is classified as held-for-sale, there is no further adjustment to the loan’s allowance for loan losses that existed immediately prior to the reclassification to held-for-sale.
Allowance for Loan Losses	2. Allowance for Loan Losses Purchased Credit Impaired (“PCI”) Loans Loans acquired with evidence of deterioration of credit quality since origination for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable are PCI loans accounted for under Accounting Standard Codification (“ASC”) 310-30, “Loans and Debt Securities Acquired with Deteriorated Credit Quality.” When considering whether evidence of credit quality deterioration exists as of the purchase date, the Company considers loan guarantees and the following credit attributes: delinquency status, use of forbearance, recent borrower FICO scores, use of loan modification programs, and borrowers who have filed for bankruptcy. The Company aggregates loans with common risk characteristics into pools and accounts for each pool as a single asset with a single composite interest rate and an aggregate expectation of cash flows. The pools are initially recorded at fair value. The Company recognizes interest income based on each pool’s effective interest rate which is based on our estimate of all cash flows expected to be received and includes an assumption about prepayment rates. The pools are tested quarterly for impairment by re-estimating the future cash flows to be received from the pools. If the new estimated cash flows result in a pool’s effective interest rate increasing, then this new yield is used prospectively over the remaining life of the pool. If the new estimated cash flows result in a pool’s effective interest rate decreasing, the pool is impaired and written down through a valuation allowance to maintain the effective interest rate. Loans classified as PCI do not have charge-offs reported nor are they reported as Trouble Debt Restructuring (“TDR”) loans. Based on the credit attributes discussed above, we determined that $261 million principal amount of Private Education Loans acquired in 2017 are accounted for as PCI loans with a fair value and resulting carry value of $101 million as of the acquisition date. As of acquisition, this portfolio’s contractually required payments receivable (the total undiscounted amount of all uncollected contractual principal and interest payments both past due and scheduled for the future, adjusted for prepayments) was $411 million with an estimated accretable yield (income expected to be recognized in future periods) of $108 million. As of December 31, 2018, the carrying amount was $82 million with no valuation allowance recorded. Purchased Non-Credit Impaired Loans Loans acquired that do not have evidence of credit deterioration since origination are recorded at fair value with no allowance for loan losses established at the acquisition date. Loan premiums and discounts are amortized as a part of interest income using the interest method under ASC 310-20, “Nonrefundable Fees and Other Costs.” An allowance for loan losses would be established if incurred losses in the loans exceed the remaining unamortized discount recorded at the time of acquisition (i.e., the next two years of expected charge-offs as well as any additional TDR allowance required is greater than the remaining discount). As a result of this policy, to the extent that actual charge-offs exceed any related allowance for loan losses recognized post-acquisition, provision for loan losses is recorded when the loans are charged off. Charge-offs are recorded through the allowance for loan losses. In 2017, we acquired Private Education Loans with an unpaid principal balance of $2.8 billion at a discount of $424 million and FFELP Loans with an unpaid principal balance of $3.5 billion at a discount of $47 million, that are accounted for under this policy. No allowance for loan losses has been established for these loans as of December 31, 2018, as the remaining purchased discount associated with the Private Education Loans of $326 million and FFELP Loans of $37 million as of December 31, 2018 remains greater than the incurred losses. Allowance for Private Education Loan Losses We consider a loan to be impaired when, based on current information, a loss has been incurred and it is probable that we will not receive all contractual amounts due. When making our assessment as to whether a loan is impaired, we also take into account more than insignificant delays in payment. We generally evaluate impaired loans on an aggregate basis by grouping similar loans. Impaired loans also include those loans which are individually assessed for impairment at a loan level, such as in a troubled debt restructuring (“TDR”). We maintain an allowance for loan losses at an amount sufficient to absorb losses incurred in our portfolios at the reporting date based on a projection of estimated probable credit losses incurred in the portfolio. 2. Our Private Education Loan portfolio contains TDR and non-TDR loans. For customers experiencing financial difficulty, certain Private Education Loans for which we have granted a forbearance of greater than three months, an interest rate reduction or an extended repayment plan are classified as TDRs. The allowance requirements are different based on these designations. In determining the allowance for loan losses on our non-TDR portfolio, we estimate the principal amount of loans that will default over the next two years (two years being the expected period between a loss event and default) and how much we expect to recover over time related to the defaulted amount. Expected defaults less our expected recoveries equal the allowance related to this portfolio. Our historical experience indicates that, on average, the time between the date that a customer experiences a default causing event (i.e., the loss trigger event) and the date that we charge off the unrecoverable portion of that loan is two years. Separately, for our TDR portfolio, we estimate an allowance amount sufficient to cover life-of-loan expected losses through an impairment calculation based on the difference between the loan’s basis and the present value of expected future cash flows (which would include life-of-loan default and recovery assumptions) discounted at the loan’s original effective interest rate. Our TDR portfolio is comprised mostly of loans with forbearance usage greater than three months and interest rate reductions. The separate allowance estimates for our TDR and non-TDR portfolios are combined into our total allowance for Private Education Loan losses. In estimating both the non-TDR and TDR allowance amounts, we start with historical experience of customer default behavior. We make judgments about which historical period to start with and then make further judgments about whether that historical experience is representative of future expectations and whether additional adjustments may be needed to those historical default rates. We also take the economic environment into consideration when calculating the allowance for loan losses. We analyze key economic statistics and the effect we expect them to have on future defaults. Key economic statistics analyzed as part of the allowance for loan losses are primarily unemployment rates. Our allowance for loan losses is estimated using an analysis of delinquent and current accounts. Our model is used to estimate the likelihood that a loan may progress through the various delinquency stages and ultimately charge off. The evaluation of the allowance for loan losses is inherently subjective, as it requires material estimates that may be susceptible to significant changes. The estimate for the allowance for loan losses is subject to a number of assumptions. If actual future performance in delinquency, charge-offs and recoveries are significantly different than estimated, this could materially affect our estimate of the allowance for loan losses and the related provision for loan losses on our income statement. We determine the collectability of our Private Education Loan portfolio by evaluating certain risk characteristics. We consider school type, credit score (FICO), existence of a cosigner, loan status and loan seasoning as the key credit quality indicators because they have the most significant effect on our determination of the adequacy of our allowance for loan losses. The type of school customers attend can have an impact on their graduation rate and job prospects after graduation and therefore affects their ability to make payments. Credit scores are an indicator of the credit worthiness of a customer and the higher the credit score the more likely it is the customer will be able to make all of their contractual payments. Loan status affects the credit risk because a past due loan is more likely to result in a credit loss than an up-to-date loan. Additionally, loans in a deferred payment status have different credit risk profiles compared with those in current payment status. Of the portfolio in repayment, loan seasoning is an important factor. It affects credit risk because a loan with a history of making payments generally has a lower incidence of default than a loan with a history of making infrequent or no payments. The existence of a cosigner lowers the likelihood of default. We monitor and update these credit quality indicators in the analysis of the adequacy of our allowance for loan losses on a quarterly basis. To estimate the probable credit losses incurred in the loan portfolio at the reporting date, we use historical experience of customer payment behavior in connection with the key credit quality indicators and incorporate management expectations regarding macroeconomic and collection performance factors. Our model is based upon the most recent twelve months of actual collection experience as the starting point for the non-TDR portfolio and the most recent approximate 15 years for the TDR portfolio and applies expected macroeconomic changes and collection procedure changes to estimate expected losses caused by loss events incurred as of the balance sheet date. Our model for the non-TDR portfolio places a greater emphasis on the more recent default experience rather than the default experience for older historical periods, as we believe the more recent default experience is more indicative of the probable losses incurred in the loan portfolio today that will default over the next two years. The TDR portfolio uses a longer historical default experience since we are projecting life of loan remaining losses. Similar to estimating defaults, we use historical customer payment behavior to estimate the timing and amount of future recoveries on charged-off loans. We use judgment in determining whether historical performance is 2. representative of what we expect to collect in the future. We then apply the default and collection rate projections to each category of loans. Once the quantitative calculation is performed, we review the adequacy of the allowance for loan losses and determine if qualitative adjustments need to be considered. Additionally, we consider changes in laws and regulations that could potentially impact the allowance for loan losses. Our collection policies allow for periods of nonpayment for customers requesting additional payment grace periods upon leaving school or experiencing temporary difficulty meeting payment obligations. This is referred to as forbearance status and is considered in our allowance for loan losses. The loss confirmation period is in alignment with our typical collection cycle and takes into account these periods of nonpayment. Our allowance for Private Education Loan losses also provides for possible additional future charge-offs as they occur related to the receivable for partially charged-off Private Education Loans. At the end of each month, for loans that are 212 days past due, we charge off the estimated loss of a defaulted loan balance. Actual recoveries are applied against the remaining loan balance that was not charged off. We refer to this remaining loan balance as the “receivable for partially charged-off loans.” If actual periodic recoveries are less than expected, the difference is immediately charged off through the allowance for loan losses with an offsetting reduction in the receivable for partially charged-off Private Education Loans. If actual periodic recoveries are greater than expected, they will be reflected as a recovery through the allowance for Private Education Loan losses once the cumulative recovery amount exceeds the cumulative amount originally expected to be recovered. Allowance for FFELP Loan Losses FFELP Loans are insured as to their principal and accrued interest in the event of default subject to a Risk Sharing level based on the date of loan disbursement. These insurance obligations are supported by contractual rights against the United States. For loans disbursed after October 1, 1993, and before July 1, 2006, we receive 98 percent reimbursement on all qualifying default claims. For loans disbursed on or after July 1, 2006, we receive 97 percent reimbursement. For loans disbursed prior to October 1, 1993, we receive 100 percent reimbursement. Similar to the allowance for Private Education Loan losses, the allowance for FFELP Loan losses uses historical experience of customer default behavior and a two-year loss confirmation period to estimate the credit losses incurred in the loan portfolio at the reporting date. We apply the default rate projections, net of applicable Risk Sharing, to each category for the current period to perform our quantitative calculation. Once the quantitative calculation is performed, we review the adequacy of the allowance for loan losses and determine if qualitative adjustments need to be considered. For FFELP Loans that have lost their government insurance and have been charged off, any subsequent cash recoveries benefit the allowance for loan losses when received.
Investments	Investments Our available-for-sale investment portfolio consists of investments that are carried at fair value, with the temporary changes in fair value carried as a separate component of stockholders’ equity, net of taxes. The amortized cost of debt securities in this category is adjusted for the amortization of related premiums and discounts, which are amortized using the effective interest rate method. Other-than-temporary impairment is evaluated by considering several factors, including the length of time and extent to which the fair value has been less than the amortized cost basis, the financial condition and near-term prospects of the security (considering factors such as adverse conditions specific to the security and ratings agency actions), and the intent and ability to retain the investment to allow for an anticipated recovery in fair value. The entire fair value loss on a security that is other-than-temporary impairment is recorded in earnings if we intend to sell the security or if it is more likely than not that we will be required to sell the security before the expected recovery of the loss. However, if the impairment is other-than-temporary, and those two conditions do not exist, the portion of the impairment related to credit losses is recorded in earnings and the impairment related to other factors is recorded in other comprehensive income. Securities classified as trading are accounted for at fair value with unrealized gains and losses included in investment income. Securities that we have the intent and ability to hold to maturity are classified as held-to-maturity and are accounted for at amortized cost unless the security is determined to have an other-than-temporary impairment. In this case it is accounted for in the same manner described above. 2. We also have other investments, primarily a receivable for cash collateral posted to derivative counterparties.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents can include term federal funds, Eurodollar deposits, commercial paper, asset-backed commercial paper, CDs, treasuries and money market funds with original terms to maturity of less than three months.
Restricted Cash and Investments	Restricted Cash and Investments Restricted cash primarily includes amounts held in education loan securitization trusts and other secured borrowings. This cash must be used to make payments related to trust obligations. Amounts on deposit in these accounts are primarily the result of timing differences between when principal and interest is collected on the trust assets and when principal and interest is paid on trust liabilities. Securities pledged as collateral related to our derivative portfolio, where the counterparty has rights to replace the securities, are classified as restricted. When the counterparty does not have these rights, the security is recorded in investments and disclosed as pledged collateral in the notes. Additionally, certain counterparties require cash collateral pledged to us to be segregated and held in restricted cash accounts.
Goodwill and Acquired Intangible Assets	Goodwill and Acquired Intangible Assets Goodwill is not amortized but is tested periodically for impairment. We test goodwill for impairment annually as of October 1 at the reporting unit level, which is the same as or one level below a business segment. Goodwill is also tested at interim periods if an event occurs or circumstances change that would indicate the carrying amount may be impaired. We complete a goodwill impairment analysis which may be a qualitative or a quantitative two-step analysis depending on the facts and circumstances associated with the reporting unit. In conjunction with a qualitative impairment analysis, we assess relevant qualitative factors to determine whether it is “more-likely-than-not” that the fair value of a reporting unit is less than its carrying amount. The “more-likely-than-not” threshold is defined as having a likelihood of more than 50 percent. In conjunction with a quantitative impairment analysis, we complete Step 1 of the goodwill impairment analysis. Step 1 consists of a comparison of the fair value of the reporting unit to the reporting unit’s carrying value, including goodwill. If the carrying value of the reporting unit exceeds the fair value, Step 2 in the goodwill impairment analysis is performed to measure the amount of impairment loss, if any. Step 2 of the goodwill impairment analysis compares the implied fair value of the reporting unit’s goodwill to the carrying value of the reporting unit’s goodwill. The implied fair value of goodwill is determined in a manner consistent with determining goodwill in a business combination. If the carrying amount of the reporting unit’s goodwill exceeds the implied fair value of the goodwill, an impairment loss is recognized in an amount equal to that excess. If, based on first assessing impairment utilizing a qualitative approach, we determine it is “more-likely-than-not” that the fair value of the reporting unit is less than its carrying amount, we will also complete a quantitative impairment analysis. Acquired intangible assets include, but are not limited to, trade names, customer and other relationships, and non-compete agreements. Acquired intangible assets with finite lives are amortized over their estimated useful lives in proportion to their estimated economic benefit. Finite-lived acquired intangible assets are reviewed for impairment using an undiscounted cash flow analysis when an event occurs or circumstances change indicating the carrying amount of a finite-lived asset or asset group may not be recoverable. If the carrying amount of the asset or asset groups exceeds the undiscounted cash flows, the fair value of the asset or asset group is determined using an acceptable valuation technique. An impairment loss would be recognized if the carrying amount of the asset
Securitization Accounting	2. Securitization Accounting Our securitizations use a two-step structure with a special purpose entity that legally isolates the transferred assets from us, even in the event of bankruptcy. Transactions receiving sale treatment are also structured to ensure that the holders of the beneficial interests issued are not constrained from pledging or exchanging their interests, and that we do not maintain effective control over the transferred assets. If these criteria are not met, then the transaction is accounted for as an on-balance sheet secured borrowing. In all cases, irrespective of whether they qualify as accounting sales our securitizations are legally structured to be sales of assets that isolate the transferred assets from us. If a securitization qualifies as a sale, we then assess whether we are the primary beneficiary of the securitization trust (VIE) and are required to consolidate such trust. If we are the primary beneficiary, then no gain or loss is recognized. See “Consolidation” of this Note 2 for additional information regarding the accounting rules for consolidation when we are the primary beneficiary of these trusts. Irrespective of whether a securitization receives sale or on-balance sheet treatment, our continuing involvement with our securitization trusts is generally limited to: • Owning equity certificates or other certificates of certain trusts and, in certain cases, securities retained for the purpose of complying with risk retention requirements under securities laws. • Lending to certain trusts, under a revolving credit, amounts necessary to cover temporary cash flow needs of the trust. These amounts are repaid to us on subordinated basis with interest at a market rate. • The servicing of the education loan assets within the securitization trusts, on both a pre- and post-default basis. • Our acting as administrator for the securitization transactions we sponsored, which includes remarketing certain bonds at future dates. • Our responsibilities relative to representation and warranty violations. • Temporarily advancing to the trust certain borrower benefits afforded the borrowers of education loans that have been securitized. These advances subsequently are returned to us in the next quarter. • Certain back-to-back derivatives entered into by us contemporaneously with the execution of derivatives by certain Private Education Loan securitization trusts. • The option held by us to buy certain delinquent loans from certain Private Education Loan securitization trusts. • The option to exercise the clean-up call and purchase the education loans from the trust when the asset balance is 10 percent or less of the original loan balance. • The option, on some trusts, to purchase education loans aggregating up to 10 percent of the trust’s initial pool balance. • The option (in certain trusts) to call rate reset notes in instances where the remarketing process has failed. The investors of the securitization trusts have no recourse to our other assets should there be a failure of the trusts to pay when due. Generally, the only arrangements under which we have to provide financial support to the trusts are representation and warranty violations requiring the buyback of loans. Under the terms of the transaction documents of certain trusts, we have, from time to time, exercised our options to purchase delinquent loans from Private Education Loan trusts, to purchase the remaining loans from trusts once the loan balance falls below 10 percent of the original amount, to purchase education loans up to 10 percent of the trust’s initial balance, or to call rate reset notes. Certain trusts maintain financial arrangements with third parties also typical of securitization transactions, such as derivative contracts (swaps) and bond insurance policies that, in the case of a counterparty failure, could adversely impact the value of any Residual Interest. 2. We do not record servicing assets or servicing liabilities when our securitization trusts are accounted for as on-balance sheet secured financings. As of December 31, 2018, we have $19 million of servicing assets on our balance sheet, of which $9 million is related to Residual Interests in FFELP Loan securitization trusts we sold in 2013 and $10 million is related to the acquisition of Earnest in 2017.
Education Loan Interest Income	Education Loan Interest Income For loans classified as held-for-investment, we recognize education loan interest income as earned, adjusted for the amortization of premiums (which includes purchased premiums and capitalized direct origination costs), discounts and Repayment Borrower Benefits. These adjustments result in income being recognized based upon the expected yield of the loan over its life after giving effect to expected prepayments. We amortize premium and discount on education loans using a Constant Prepayment Rate (“CPR”) which measures the rate at which loans in the portfolio pay down principal compared to their stated terms. In determining the CPR, we only consider payments made in excess of contractually required payments. This would include loan consolidation and other early payoff activity. For Repayment Borrower Benefits, the estimates of their effect on education loan yield are based on analyses of historical payment behavior of customers who are eligible for the incentives and its effect on the ultimate qualification rate for these incentives. We regularly evaluate the assumptions used to estimate the prepayment speeds and the qualification rates used for Repayment Borrower Benefits. In instances where there are changes to the assumptions, amortization is adjusted on a cumulative basis to reflect the change since the acquisition of the loan. Additionally, interest earned on education loans reflects potential non-payment adjustments in accordance with our uncollectible interest recognition policy. We do not amortize any premiums, discounts or other adjustments to the basis of education loans when they are classified as held-for-sale. See “Allowance for Loan Losses – Purchased Credit Impaired (‘PCI’) Loans” and “–Purchased Non-Credit Impaired Loans” of this Note 2 for discussion of the interest income methodology related to those portfolios.
Interest Expense	Interest Expense Interest expense is based upon contractual interest rates adjusted for the amortization of debt issuance costs, premiums and discounts. Our interest expense may also be adjusted for net payments/receipts related to interest rate and foreign currency swap agreements that qualify and are designated as hedges. Interest expense also includes the amortization of deferred gains and losses on closed hedge transactions that qualified as hedges. Amortization of debt issuance costs, premiums, discounts and terminated hedge-basis adjustments are recognized using the effective interest rate method.
Servicing Revenue	Servicing Revenue We perform loan servicing functions for third-parties in return for a servicing fee. Our compensation is typically based on a per-unit fee arrangement or a percentage of the loans outstanding. We recognize servicing revenues associated with these activities based upon the contractual arrangements as the services are rendered. We recognize late fees on third-party serviced loans as well as on loans in our portfolio according to the contractual provisions of the promissory notes, as well as our expectation of collectability.
Asset Recovery And Business Processing Revenue	Asset Recovery and Business Processing Revenue Asset recovery fees are received for collections or rehabilitation of delinquent or defaulted debt on behalf of clients performed on a contingency basis. Revenue is earned and recognized upon the completion of rehabilitation activities or upon receipt of the delinquent customer funds. Prior to the third quarter of 2018, we received fees from Guarantor agencies for performing default aversion services on delinquent loans prior to default. The fee is received when the loan is initially placed with us and we are obligated to provide such services for the remaining life of the loan for no additional fee. In the event that the loan defaults, in accordance with certain contracts, we are obligated to rebate a portion of the fee to the Guarantor agency in proportion to the principal and interest outstanding when the loan defaults. We defer the fees received, net of an estimate of future rebates owed due to subsequent defaults, and recognize such fees over the service period which is estimated to be the life of the loan. 2. In the third quarter of 2017, $47 million of previously deferred asset recovery revenue, net of a reserve, was recognized as revenue related to loans for which the Company performs these default aversion services. In the third quarter of 2017, the Company was notified that it would no longer perform these services after 2017 due to the termination of the related contract as of December 31, 2017. In accordance with GAAP, we recognized this previously deferred revenue during the third-quarter 2017 to reflect a shortened period over which it is expected to be earned. Business processing fees are received generally based on processing transactions. Revenue is earned and recognized upon the completion of processing the transaction and in some cases also upon the processing of a payment.
Transfer of Financial Assets and Extinguishments of Liabilities	Transfer of Financial Assets and Extinguishments of Liabilities We account for loan sales and debt repurchases in accordance with the applicable accounting guidance. Our securitizations and other secured borrowings are accounted for as on-balance sheet secured borrowings. See “Securitization Accounting” of this Note 2 for further discussion on the criteria assessed to determine whether a transfer of financial assets is a sale or a secured borrowing. If a transfer of loans qualifies as a sale, we derecognize the loan and recognize a gain or loss as the difference between the carrying basis of the loan sold and liabilities retained and the compensation received. We periodically repurchase our outstanding debt in the open market or through public tender offers. We record a gain or loss on the early extinguishment of debt based upon the difference between the carrying cost of the debt and the amount paid to the third party and is net of hedging gains and losses when the debt is in a qualifying hedge relationship. We recognize the results of a transfer of loans and the extinguishment of debt based upon the settlement date of the transaction.
Derivative Accounting	Derivative Accounting The accounting guidance for our derivative instruments, which primarily includes interest rate swaps, cross-currency interest rate swaps and Floor Income Contracts, requires that every derivative instrument, including certain derivative instruments embedded in other contracts, be recorded at fair value on the balance sheet as either an asset or liability. Derivative positions are recorded as net positions by counterparty based on master netting arrangements exclusive of accrued interest and cash collateral held or pledged. Many of our derivatives, mainly fixed to variable or variable to fixed interest rate swaps and cross-currency interest rate swaps, qualify as effective hedges. For these derivatives, the relationship between the hedging instrument and the hedged items (including the hedged risk and method for assessing effectiveness), as well as the risk management objective and strategy for undertaking various hedge transactions at the inception of the hedging relationship, is documented. Each derivative is designated to either a specific (or pool of) asset(s) or liability(ies) on the balance sheet or expected future cash flows and designated as either a “fair value” or a “cash flow” hedge. Fair value hedges are designed to hedge our exposure to changes in fair value of a fixed rate or foreign denominated asset or liability, while cash flow hedges are designed to hedge our exposure to variability of either a floating rate asset’s or liability’s cash flows or an expected fixed rate debt issuance. For effective fair value hedges, both the derivative and the hedged item (for the risk being hedged) are marked-to-market with any difference reflecting ineffectiveness and recorded immediately in the statement of income. For effective cash flow hedges, the change in the fair value of the derivative is recorded in other comprehensive income, net of tax, and recognized in earnings in the same period as the earnings effects of the hedged item. The ineffective portion of a cash flow hedge is recorded immediately through earnings. The assessment of the hedge’s effectiveness is performed at inception and on an ongoing basis, generally using regression testing. For hedges of a pool of assets or liabilities, tests are performed to demonstrate the similarity of individual instruments of the pool. When it is determined that a derivative is not currently an effective hedge, ineffectiveness is recognized for the full change in value of the derivative with no offsetting mark-to-market of the hedged item for the current period. If it is also determined the hedge will not be effective in the future, we discontinue the hedge accounting prospectively, cease recording changes in the fair value of the hedged item, and begin amortization of any basis adjustments that exist related to the hedged item. 2. We also have derivatives, primarily Floor Income Contracts and certain basis swaps, that we believe are effective economic hedges but do not qualify for hedge accounting treatment. These derivatives are classified as “trading” and as a result they are marked-to-market through earnings with no consideration for the fair value fluctuation of the economically hedged item. The “gains (losses) on derivative and hedging activities, net” line item in the consolidated statements of income includes the mark-to-market gains and losses of our derivatives (except effective cash flow hedges which are recorded in other comprehensive income), the unrealized changes in fair value of hedged items in qualifying fair value hedges, as well as the realized changes in fair value related to derivative net settlements and dispositions that do not qualify for hedge accounting. Net settlement income/expense on derivatives that qualify as hedges are included with the income or expense of the hedged item (mainly interest expense).
Accounting for Stock-Based Compensation	Accounting for Stock-Based Compensation We recognize stock-based compensation cost in our consolidated statements of income using the fair value based method. Under this method we determine the fair value of the stock-based compensation at the time of the grant and recognize the resulting compensation expense over the grant’s vesting period. We record stock-based compensation expense net of estimated forfeitures and as such, only those stock-based awards that we expect to vest are recorded. We estimate the forfeiture rate based on historical forfeitures of equity awards and adjust the rate to reflect changes in facts and circumstances, if any. Ultimately, the total expense recognized over the vesting period will equal the fair value of awards that actually vest.
Restructuring and Other Reorganization Expenses	Restructuring and Other Reorganization Expenses From time to time we implement plans to restructure our business. In conjunction with these restructuring plans, involuntary benefit arrangements, disposal costs (including contract termination costs and other exit costs), as well as certain other costs that are incremental and incurred as a direct result of our restructuring plans, are classified as restructuring expenses in the consolidated statements of income. The Company administers the Navient Corporation Employee Severance Plan and the Navient Corporation Executive Severance Plan for Senior Officers (collectively, “the Severance Plan”). The Severance Plan provides severance benefits in the event of termination of the Company’s full-time employees and part-time employees who work at least 24 hours per week. The Severance Plan establishes specified benefits based on base salary, job level immediately preceding termination and years of service upon involuntary termination of employment. The benefits payable under the Severance Plan relate to past service, and they accumulate and vest. Accordingly, we recognize severance expenses to be paid pursuant to the Severance Plan when payment of such benefits is probable and can be reasonably estimated in accordance with ASC 712, “Compensation — Nonretirement Postemployment Benefits.” Such benefits, include severance pay calculated based on the Severance Plan, medical and dental benefits, and outplacement services expenses. Contract termination costs are expensed at the earlier of (1) the contract termination date or (2) the cease use date under the contract. Other exit costs are expensed as incurred and classified as restructuring expenses if (1) the cost is incremental to and incurred as a direct result of planned restructuring activities and (2) the cost is not associated with or incurred to generate revenues subsequent to our consummation of the related restructuring activities. Other reorganization expenses include certain internal costs and third-party costs incurred in connection with our cost reduction initiatives. During 2018 and 2017, the Company incurred $13 million and $29 million, respectively, of restructuring/other reorganization expense in connection with an effort that will reduce costs and improve operating efficiency. These charges were due primarily to severance-related costs.
Income Taxes	Income Taxes We account for income taxes under the asset and liability approach which requires the recognition of deferred tax liabilities and assets for the expected future tax consequences of temporary differences between the carrying amounts and tax basis of our assets and liabilities. To the extent tax laws change, deferred tax assets and liabilities are adjusted in the period that the tax change is enacted. See “Note 14 – Income Taxes” for a description of the impact of the “Tax Cuts and Jobs Act” (“TCJA”) on the net deferred tax asset as of December 31, 2017. “Income tax expense/(benefit)” includes (i) deferred tax expense/(benefit), which represents the net change in the deferred tax asset or liability balance during the year plus any change in a valuation allowance and (ii) current tax expense/(benefit), which represents the amount of tax currently payable to or receivable from a tax authority plus amounts accrued for unrecognized tax benefits. Income tax expense/(benefit) excludes the tax effects related to adjustments recorded in equity. If we have an uncertain tax position, then that tax position is recognized only if it is more likely than not to be sustained upon examination based on the technical merits of the position. The amount of tax benefit recognized in the financial statements is the largest amount of benefit that is more than 50 percent likely of being sustained upon ultimate settlement of the uncertain tax position. We recognize interest related to unrecognized tax benefits in income tax expense/(benefit) and penalties, if any, in operating expenses.
Earnings (Loss) per Common Share	Earnings (Loss) per Common Share We compute earnings (loss) per common share (“EPS”) by dividing net income allocated to common shareholders by the weighted average common shares outstanding. Net income allocated to common shareholders represents net income applicable to common shareholders. Diluted earnings per common share is computed by dividing income allocated to common shareholders by the weighted average common shares outstanding plus amounts representing the dilutive effect of stock options outstanding, restricted stock, restricted stock units, and the outstanding commitment to issue shares under the Employee Stock Purchase Plan. See “Note 10 — Earnings (Loss) per Common Share” for further discussion.
Reclassifications	Reclassifications Certain reclassifications have been made to the balances as of and for the years ended December 31, 2017 and 2016, to be consistent with classifications adopted for 2018, which had no effect on net income, total assets or total liabilities.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements Effective in 2018 Revenue Recognition On January 1, 2018, we adopted Accounting Standard Codification (“ASC”) 606, “Revenue from Contracts with Customers,” which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to its customers. The contract transaction price is allocated to each distinct contractual performance obligation and recognized as revenue at a point in time or over time when or as the good or service is provided to the customer and the performance obligation is satisfied. Generally, our performance obligations are satisfied over time. In conjunction with our implementation plan, we identified revenue streams related to asset recovery and other business processing within our Federal Education Loans and Business Processing segments that are within the scope of the new standard and reviewed related contracts. We determined there was no material change in the timing of our recognition of our asset recovery and business processing revenue or expenses and we did not record a cumulative adjustment as of January 1, 2018 as a result of the adoption of ASC 606. We recognized $8 million of revenue and $5 million of expenses in 2018 related to a contract in our Business Processing segment that would not have been recognized under the prior accounting standard until 2019. The new guidance does not apply to financial instruments and transfers and servicing that are accounted for under other GAAP. Accordingly, the new revenue recognition guidance does not have an impact on our recognition of revenue and costs associated with our loan portfolios, investments, derivatives and servicing contracts. However, we considered the ASC 606 principal versus agent guidance with respect to certain asset recovery guarantor servicing contracts pursuant to which we serve in a portfolio management role and use third-party collection agencies. We determined that we are required under the new accounting standard to reflect the revenue earned and paid to third-party collection agencies as revenue and operating expense. Under the prior accounting standards, we netted payments to third-party collection agencies against revenue. We adopted the new accounting standard using the “cumulative effect transition adjustment” which results in prospectively making this change in 2018. This change in accounting policy resulted in both asset recovery revenue and operating expense in the Federal Education Loan segment being $46 million higher for the year ended December 31, 2018, with no impact on net income. See “Note 15 – Revenue from Contracts with Customers Accounted in Accordance with ASC 606” for the new required disclosures. Classification and Measurement On January 5, 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Updates (“ASU”) No. 2016-01, “Recognition and Measurement of Financial Assets and Financial Liabilities,” which reconsiders the classification and measurement of financial instruments. The new standard requires certain equity instruments be measured at fair value, with fair value changes recognized in earnings. In addition, the standard requires a cumulative-effect adjustment to retained earnings as of the beginning of the reporting period of adoption. It was effective for the Company as of January 1, 2018. The adoption of this new accounting standard is immaterial to our consolidated financial statements and footnote disclosures. Intra-Entity Transfer of Assets On October 24, 2016, the FASB issued ASU No. 2016-16, “Income Taxes — Intra-Entity Transfer of Assets Other and Inventory,” which requires recognition of the income tax consequences of an intra-entity transfer of non-inventory assets when the transfer occurs. The new standard was effective for the Company as of January 1, 2018. The adoption of this new accounting standard is immaterial to our consolidated financial statements and footnote disclosures. Income Taxes On February 14, 2018, the FASB issued ASU No. 2018-02, “Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income,” which allows reclassification from Accumulated Other Comprehensive Income (Loss) (“AOCI”), as required by ASC No. 740, “Income Taxes,” to retained earnings for the residual tax effects resulting from the Tax Cuts and Jobs Act (“TCJA”) enacted on December 22, 2017. The new standard is effective for the Company as of January 1, 2019. However, early adoption is permitted and the Company adopted the standard on January 1, 2018, resulting in a decrease of $13 million to retained earnings due to the reclassification of AOCI to retained earnings. Effective in 2019 Leases On February 25, 2016, the FASB issued ASU No. 2016-02, “Leases,” which requires the identification of arrangements that should be accounted for as leases by lessees. In general, for lease arrangements exceeding a twelve-month term, these arrangements must be recognized as assets and liabilities on the balance sheet of the lessee. Under previous GAAP, all operating leases were off-balance sheet, regardless of the term. A right-of-use asset and lease obligation will be recorded for all leases with a term exceeding twelve months, whether operating or financing, while the income statement will reflect lease expense for operating leases and amortization/interest expense for financing leases. The balance sheet amount recorded for existing leases at the date of adoption must be calculated using the applicable incremental borrowing rate at the date of adoption. The standard allows the option to apply the new guidance prospectively at the effective date, without adjustment to comparative periods presented with certain practical expedients available. It is effective for the Company on January 1, 2019. The Company has assessed the impact that adopting this new accounting standard will have on our consolidated financial statements and footnote disclosures and has concluded it will be immaterial. There will be an immaterial increase to assets and liabilities in equal and offsetting amounts with no change to the income statement presentation. Hedging Activities On August 28, 2017, the FASB issued ASU No. 2017-12, “Derivatives and Hedging,” which is intended to better align risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results. The amendments expand and refine hedge accounting for both nonfinancial and financial risk components and are intended to better align the recognition and presentation of the effects of the hedging instrument and the hedged item in the financial statements. The new standard is effective for the Company on January 1, 2019. The Company has assessed the impact this new standard will have on our consolidated financial statements and footnote disclosures and has concluded it will be immaterial. Effective in 2020 Allowance for Loan Losses On June 16, 2016, the FASB issued ASU No. 2016-13, “Financial Instruments — Credit Losses,” which requires measurement and recognition of an allowance for loan loss that estimates remaining expected credit losses for financial assets held at the reporting date. Our current allowance for loan loss is an incurred loss model. As a result, we expect the new guidance will result in an increase to our allowance for loan losses. The standard is to be applied through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. The standard is effective for the Company as of January 1, 2020 and will primarily impact the allowance for loan losses related to our Private Education Loans and FFELP Loans. This standard represents a significant change from existing GAAP and may result in material changes to the Company’s accounting for the allowance for loan losses. We are currently evaluating the impact of adopting this accounting standard on our consolidated financial statements and footnote disclosures.

Education Loans (Table)

Education Loans (Table)	12 Months Ended
	Dec. 31, 2018
Receivables [Abstract]
Education Loan Portfolio by Program	The estimated weighted average life of education loans in our portfolio was approximately 6 years and 7 years at December 31, 2018 and 2017, respectively. The following table reflects the distribution of our education loan portfolio by program. December 31, 2018 Year Ended December 31, 2018 (Dollars in millions) Ending Balance % of Balance Average Balance Average Effective Interest Rate FFELP Stafford and Other Education Loans, net (1) $ 24,641 26 % $ 26,612 3.98 % FFELP Consolidation Loans, net 47,612 50 50,359 3.91 Private Education Loans, net 22,245 24 23,281 7.64 Total education loans, net $ 94,498 100 % $ 100,252 4.79 % December 31, 2017 Year Ended December 31, 2017 (Dollars in millions) Ending Balance % of Balance Average Balance Average Effective Interest Rate FFELP Stafford and Other Education Loans, net (1) $ 28,409 27 % $ 30,462 2.94 % FFELP Consolidation Loans, net 53,294 51 54,527 3.30 Private Education Loans, net 23,419 22 23,762 6.88 Total education loans, net $ 105,122 100 % $ 108,751 3.98 % (1) Primarily Stafford Loans, but also includes federally guaranteed PLUS and HEAL Loans.

Allowance for Loan Losses (Tabl

Allowance for Loan Losses (Tables)	12 Months Ended
	Dec. 31, 2018
Allowance for Credit Losses and Recorded Investments in Loans	4. Allowance for Loan Losses Metrics Year Ended December 31, 2018 (Dollars in millions) FFELP Loans Private Education Loans Other Loans Total Allowance for Loan Losses Beginning balance $ 60 $ 1,297 $ 10 $ 1,367 Total provision 70 299 1 370 Net adjustment resulting from the change in the charge- off rate (1) — (32 ) — (32 ) Net charge-offs remaining (2) (54 ) (371 ) (2 ) (427 ) Total net charge-offs (54 ) (403 ) (2 ) (459 ) Reclassification of interest reserve (3) — 8 — 8 Ending balance $ 76 $ 1,201 $ 9 $ 1,286 Allowance Ending Balance: Individually evaluated for impairment — TDR $ — $ 1,100 $ 8 $ 1,108 Collectively evaluated for impairment: Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans 76 101 1 178 Purchased Non-Credit Impaired Loans acquired at a discount (4) — — — — Purchased Credit Impaired Loans (4) — — — — Ending total allowance $ 76 $ 1,201 $ 9 $ 1,286 Loans Ending Balance: Individually evaluated for impairment — TDR $ — $ 10,336 $ 28 $ 10,364 Collectively evaluated for impairment: Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans 68,880 11,464 51 80,395 Purchased Non-Credit Impaired Loans acquired at a discount (4) 2,850 2,180 — 5,030 Purchased Credit Impaired Loans (4) — 225 — 225 Ending total loans (5) $ 71,730 $ 24,205 $ 79 $ 96,014 Net charge-offs as a percentage of average loans in repayment, excluding the net adjustment resulting from the change in the charge-off rate (1) .09 % 1.66 % — % Net adjustment resulting from the change in charge-off rate as a percentage of average loans in repayment (1) — % .14 % — % Allowance coverage of charge-offs 1.4 3.0 — Allowance as a percentage of the ending total loan balance .11 % 4.96 % 11.52 % Allowance as a percentage of the ending loans in repayment .13 % 5.45 % 11.52 % Ending total loans (5) $ 71,730 $ 24,205 $ 79 Average loans in repayment $ 62,927 $ 22,312 $ 75 Ending loans in repayment $ 59,551 $ 22,037 $ 79 (1) In third-quarter 2018, the portion of the loan amount charged off at default on Private Education Loans increased from 79 percent to 80.5 percent. This charge resulted in a $32 million reduction to the balance of the receivable for partially charged-off loan balance. (2) Charge-offs are reported net of expected recoveries. For Private Education Loans, the expected recovery amount is transferred to the receivable for partially charged-off loan balance. Charge-offs include charge-offs against the receivable for partially charged-off loans which represents the difference between what was expected to be recovered and any shortfalls in what was actually recovered in the period. See “Receivable for Partially Charged-Off Private Education Loans” for further discussion. (3) Represents the additional allowance related to the amount of uncollectible interest reserved within interest income that is transferred in the period to the allowance for loan losses when interest is capitalized to a loan’s principal balance. (4) The Purchased Credit Impaired Loans’ losses are not provided for by the allowance for loan losses in the above table as these loans are separately reserved for, if needed. No allowance for loan losses has been established for these loans as of December 31, 2018. The losses of the Purchased Non-Credit Impaired Loans acquired at a discount are not provided for by the allowance for loan losses in the above table as the remaining purchased discount associated with the FFELP and Private Education Loans of $37 million and $326 million, respectively, as of December 31, 2018 is greater than the incurred losses and as a result no allowance for loan losses has been established for these loans as of December 31, 2018. (5) Ending total loans for Private Education Loans includes the receivable for partially charged-off loans. Year Ended December 31, 2017 (Dollars in millions) FFELP Loans Private Education Loans Other Loans Total Allowance for Loan Losses Beginning balance $ 67 $ 1,351 $ 15 $ 1,433 Total provision 42 382 2 426 Charge-offs (1) (49 ) (443 ) (7 ) (499 ) Reclassification of interest reserve (2) — 7 — 7 Ending balance $ 60 $ 1,297 $ 10 $ 1,367 Allowance Ending Balance: Individually evaluated for impairment - TDR $ — $ 1,171 $ 9 $ 1,180 Collectively evaluated for impairment: Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans 60 126 1 187 Purchased Non-Credit Impaired Loans acquired at a discount (3) — — — — Purchased Credit Impaired Loans (3) — — — — Ending total allowance $ 60 $ 1,297 $ 10 $ 1,367 Loans Ending Balance: Individually evaluated for impairment - TDR $ — $ 10,921 $ 30 $ 10,951 Collectively evaluated for impairment: Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans 77,860 11,861 40 89,761 Purchased Non-Credit Impaired Loans acquired at a discount (3) 3,237 2,610 — 5,847 Purchased Credit Impaired Loans (3) — 248 — 248 Ending total loans (4) $ 81,097 $ 25,640 $ 70 $ 106,807 Charge-offs as a percentage of average loans in repayment .07 % 1.98 % 5.39 % Allowance coverage of charge-offs 1.2 2.9 1.5 Allowance as a percentage of the ending total loan balance .07 % 5.06 % 14.32 % Allowance as a percentage of the ending loans in repayment .09 % 5.66 % 14.32 % Ending total loans (4) $ 81,097 $ 25,640 $ 70 Average loans in repayment $ 68,318 $ 22,342 $ 130 Ending loans in repayment $ 67,853 $ 22,924 $ 70 (1) Charge-offs are reported net of expected recoveries. For Private Education Loans, the expected recovery amount is transferred to the receivable for partially charged-off loan balance. Charge-offs include charge-offs against the receivable for partially charged-off loans which represents the difference between what was expected to be recovered and any shortfalls in what was actually recovered in the period. See “Receivable for Partially Charged-Off Private Education Loans” for further discussion. (2) Represents the additional allowance related to the amount of uncollectible interest reserved within interest income that is transferred in the period to the allowance for loan losses when interest is capitalized to a loan’s principal balance. (3) The Purchased Credit Impaired Loans’ losses are not provided for by the allowance for loan losses in the above table as these loans are separately reserved for, if needed. No allowance for loan losses has been established for these loans as of December 31, 2017. The losses of the Purchased Non-Credit Impaired Loans acquired at a discount are not provided for by the allowance for loan losses in the above table as the remaining purchased discount associated with the FFELP and Private Education Loans of $43 million and $392 million, respectively, as of December 31, 2017 is greater than the incurred losses and as a result no allowance for loan losses has been established for these loans as of December 31, 2017. (4) Ending total loans for Private Education Loans includes the receivable for partially charged-off loans. Year Ended December 31, 2016 (Dollars in millions) FFELP Loans Private Education Loans Other Loans Total Allowance for Loan Losses Beginning balance $ 78 $ 1,471 $ 15 $ 1,564 Total provision 43 383 3 429 Charge-offs (1) (54 ) (513 ) (3 ) (570 ) Reclassification of interest reserve (2) — 10 — 10 Ending balance $ 67 $ 1,351 $ 15 $ 1,433 Allowance Ending Balance: Individually evaluated for impairment - TDR $ — $ 1,190 $ 11 $ 1,201 Collectively evaluated for impairment 67 161 4 232 Ending total allowance $ 67 $ 1,351 $ 15 $ 1,433 Loans Ending Balance: Individually evaluated for impairment - TDR $ — $ 11,165 $ 32 $ 11,197 Collectively evaluated for impairment 86,918 13,983 132 101,033 Ending total loans (3) $ 86,918 $ 25,148 $ 164 $ 112,230 Charge-offs as a percentage of average loans in repayment .07 % 2.20 % 2.10 % Allowance coverage of charge-offs 1.2 2.6 7.0 Allowance as a percentage of the ending total loan balance .08 % 5.37 % 9.35 % Allowance as a percentage of the ending loans in repayment .09 % 6.10 % 9.35 % Ending total loans (3) $ 86,918 $ 25,148 $ 164 Average loans in repayment $ 72,714 $ 23,275 $ 104 Ending loans in repayment $ 70,557 $ 22,150 $ 164 (1) Charge-offs are reported net of expected recoveries. For Private Education Loans, the expected recovery amount is transferred to the receivable for partially charged-off loan balance. Charge-offs include charge-offs against the receivable for partially charged-off loans which represents the difference between what was expected to be recovered and any shortfalls in what was actually recovered in the period. See “Receivable for Partially Charged-Off Private Education Loans” for further discussion. (2) Represents the additional allowance related to the amount of uncollectible interest reserved within interest income that is transferred in the period to the allowance for loan losses when interest is capitalized to a loan’s principal balance. (3) Ending total loans for Private Education Loans includes the receivable for partially charged-off loans.
Age Analysis of Past Due Loans Delinquencies	FFELP Loan Delinquencies December 31, 2018 December 31, 2017 December 31, 2016 (Dollars in millions) Balance % Balance % Balance % Loans in-school/grace/deferment (1) $ 3,793 $ 4,711 $ 5,871 Loans in forbearance (2) 8,386 8,533 10,490 Loans in repayment and percentage of each status: Loans current 53,500 89.8 % 59,264 87.3 % 61,977 87.8 % Loans delinquent 31-60 days (3) 1,964 3.4 2,638 3.9 2,820 4.0 Loans delinquent 61-90 days (3) 910 1.5 1,763 2.6 1,325 1.9 Loans delinquent greater than 90 days (3) 3,177 5.3 4,188 6.2 4,435 6.3 Total FFELP Loans in repayment 59,551 100 % 67,853 100 % 70,557 100 % Total FFELP Loans, gross 71,730 81,097 86,918 FFELP Loan unamortized premium 599 666 879 Total FFELP Loans 72,329 81,763 87,797 FFELP Loan allowance for losses (76 ) (60 ) (67 ) FFELP Loans, net $ 72,253 $ 81,703 $ 87,730 Percentage of FFELP Loans in repayment 83.0 % 83.7 % 81.2 % Delinquencies as a percentage of FFELP Loans in repayment 10.2 % 12.7 % 12.2 % FFELP Loans in forbearance as a percentage of loans in repayment and forbearance 12.3 % 11.2 % 12.9 % (1) Loans for customers who may still be attending school or engaging in other permitted educational activities and are not yet required to make payments on their loans, e.g., residency periods for medical students or a grace period for bar exam preparation, as well as loans for customers who have requested and qualify for other permitted program deferments such as military, unemployment, or economic hardships. (2) Loans for customers who have used their allowable deferment time or do not qualify for deferment, that need additional time to obtain employment or who have temporarily ceased making full payments due to hardship or other factors such as disaster relief. (3) The period of delinquency is based on the number of days scheduled payments are contractually past due. Private Education Loan Delinquencies TDRs December 31, 2018 December 31, 2017 December 31, 2016 (Dollars in millions) Balance % Balance % Balance % Loans in-school/grace/deferment (1) $ 426 $ 477 $ 579 Loans in forbearance (2) 518 681 588 Loans in repayment and percentage of each status: Loans current 7,890 87.4 % 8,333 88.9 % 8,273 85.8 % Loans delinquent 31-60 days (3) 344 3.8 351 3.7 412 4.3 Loans delinquent 61-90 days (3) 235 2.6 207 2.2 267 2.8 Loans delinquent greater than 90 days (3) 556 6.2 487 5.2 686 7.1 Total TDR loans in repayment 9,025 100 % 9,378 100 % 9,638 100 % Total TDR loans, gross 9,969 10,536 10,805 TDR loans unamortized discount (212 ) (225 ) (237 ) Total TDR loans 9,757 10,311 10,568 TDR loans receivable for partially charged-off loans 367 385 360 TDR loans allowance for losses (1,100 ) (1,171 ) (1,190 ) TDR loans, net $ 9,024 $ 9,525 $ 9,738 Percentage of TDR loans in repayment 90.5 % 89.0 % 89.2 % Delinquencies as a percentage of TDR loans in repayment 12.6 % 11.1 % 14.2 % Loans in forbearance as a percentage of TDR loans in repayment and forbearance 5.4 % 6.8 % 5.7 % (1) Deferment includes customers who have returned to school or are engaged in other permitted educational activities and are not yet required to make payments on their loans, e.g., residency periods for medical students or a grace period for bar exam preparation. (2) Loans for customers who have requested extension of grace period generally during employment transition or who have temporarily ceased making full payments due to hardship or other factors such as disaster relief, consistent with established loan program servicing policies and procedures. (3) The period of delinquency is based on the number of days scheduled payments are contractually past due. Private Education Loan Delinquencies Non-TDRs December 31, 2018 December 31, 2017 December 31, 2016 (Dollars in millions) Balance % Balance % Balance % Loans in-school/grace/deferment (1) $ 392 $ 584 $ 814 Loans in forbearance (2) 158 214 202 Loans in repayment and percentage of each status: Loans current 12,851 98.8 % 13,257 97.9 % 12,233 97.8 % Loans delinquent 31-60 days (3) 71 .5 120 .9 110 .9 Loans delinquent 61-90 days (3) 32 .3 59 .4 54 .4 Loans delinquent greater than 90 days (3) 58 .4 110 .8 115 .9 Total non-TDR loans in repayment 13,012 100 % 13,546 100 % 12,512 100 % Total non-TDR loans, gross 13,562 14,344 13,528 Non-TDR loans unamortized discount (547 ) (699 ) (220 ) Total non-TDR loans 13,015 13,645 13,308 Non-TDR loans receivable for partially charged-off loans 307 375 455 Non-TDR loans allowance for losses (101 ) (126 ) (161 ) Non-TDR loans, net $ 13,221 $ 13,894 $ 13,602 Percentage of non-TDR loans in repayment 95.9 % 94.4 % 92.5 % Delinquencies as a percentage of non-TDR loans in repayment 1.2 % 2.1 % 2.2 % Loans in forbearance as a percentage of non- TDR loans in repayment and forbearance 1.2 % 1.6 % 1.6 % (1) Deferment includes customers who have returned to school or are engaged in other permitted educational activities and are not yet required to make payments on their loans, e.g., residency periods for medical students or a grace period for bar exam preparation. (2) Loans for customers who have requested extension of grace period generally during employment transition or who have temporarily ceased making full payments due to hardship or other factors such as disaster relief, consistent with established loan program servicing policies and procedures. (3) The period of delinquency is based on the number of days scheduled payments are contractually past due.
Loans Modified Accounts for TDR	The following table provides the recorded investment, unpaid principal balance and related allowance for our TDR loans. TDRs (Dollars in millions) December 31, 2018 December 31, 2017 Recorded investment (1) $ 10,326 $ 10,890 Total ending loans (2) $ 10,336 $ 10,921 Related allowance $ 1,100 $ 1,171 (1) Recorded investment is equal to the unpaid principal balance (which includes the receivable for partially charged-off loans), accrued interest and unamortized discount. (2) Total ending loans includes the receivable for partially charged-off loans.
Entity Loan Modification Program [Member]
Loans Modified Accounts for TDR	The following table provides the amount of loans modified in the periods presented that resulted in a TDR. Additionally, the table summarizes charge-offs occurring in the TDR portfolio, as well as TDRs for which a payment default occurred in the current period within 12 months of the loan first being designated as a TDR. We define payment default as 60 days past due for this disclosure. Years Ended December 31, (Dollars in millions) 2018 2017 2016 Modified loans (1) $ 596 $ 816 $ 1,169 Charge-offs (2) $ 343 $ 346 $ 382 Payment-default $ 142 $ 181 $ 265 (1) Represents period ending balance of loans that have been modified during the period and resulted in a TDR. (2) Represents loans that charged off that were classified as TDRs.
Troubled Debt Restructuring Loans [Member]
Average Recorded Investment and Interest Income Recognized for TDR	4. The following table provides the average recorded investment and interest income recognized for our TDR loans. Years Ended December 31, (Dollars in millions) 2018 2017 2016 Average recorded investment $ 10,637 $ 10,989 $ 11,078 Interest income recognized $ 764 $ 708 $ 667
Private Education Loans [Member]
Private Education Loan Portfolio Stratified by Key Credit Quality Indicators	The following table highlights the principal balance (excluding the receivable for partially charged-off loans) of our Private Education Loan portfolio stratified by the key credit quality indicators. Private Education Loans Credit Quality Indicators TDRs December 31, 2018 December 31, 2017 (Dollars in millions) Balance (2) % of Balance Balance (2) % of Balance Credit Quality Indicators Original Winning FICO Scores: FICO 640 and above $ 9,133 92 % $ 9,647 92 % FICO below 640 836 8 889 8 Total $ 9,969 100 % $ 10,536 100 % School Type: Not-for-profit $ 7,888 79 % $ 8,247 78 % For-profit 2,081 21 2,289 22 Total $ 9,969 100 % $ 10,536 100 % Cosigners: With cosigner $ 6,172 62 % $ 6,441 61 % Without cosigner 3,797 38 4,095 39 Total $ 9,969 100 % $ 10,536 100 % Seasoning (1) 1-12 payments $ 335 3 % $ 506 5 % 13-24 payments 436 4 644 6 25-36 payments 660 7 947 9 37-48 payments 934 10 1,271 12 More than 48 payments 7,178 72 6,691 63 Not yet in repayment 426 4 477 5 Total $ 9,969 100 % $ 10,536 100 % (1) Number of months in active repayment for which a scheduled payment was received. (2) Balance equals the gross Private Education Loans. Private Education Loans Credit Quality Indicators Non-TDRs December 31, 2018 December 31, 2017 (Dollars in millions) Balance (2) % of Balance Balance (2) % of Balance Credit Quality Indicators Original Winning FICO Scores: FICO 640 and above $ 13,087 96 % $ 13,752 96 % FICO below 640 475 4 592 4 Total $ 13,562 100 % $ 14,344 100 % School Type: Not-for-profit $ 11,953 88 % $ 12,431 87 % For-profit 1,609 12 1,913 13 Total $ 13,562 100 % $ 14,344 100 % Cosigners: With cosigner $ 6,961 51 % $ 9,193 64 % Without cosigner 6,601 49 5,151 36 Total $ 13,562 100 % $ 14,344 100 % Seasoning (1) 1-12 payments $ 3,353 25 % $ 1,424 10 % 13-24 payments 486 3 437 3 25-36 payments 322 2 466 3 37-48 payments 383 3 867 6 More than 48 payments 8,626 64 10,566 74 Not yet in repayment 392 3 584 4 Total $ 13,562 100 % $ 14,344 100 % (1) Number of months in active repayment for which a scheduled payment was received. (2)
Receivable For Partially Charged Off Loans	4. The following table summarizes the activity in the receivable for partially charged-off loans. Years Ended December 31, (Dollars in millions) 2018 2017 2016 Receivable at beginning of period $ 760 $ 815 $ 881 Expected future recoveries of current period defaults (1) 89 110 128 Recoveries (2) (139 ) (155 ) (181 ) Charge-offs (3) (36 ) (10 ) (13 ) Receivable at end of period $ 674 $ 760 $ 815 (1) Represents our estimate of the amount to be collected in the future. (2) Current period cash collections. (3) Represents the current period recovery shortfall — the difference between what was expected to be collected and what was actually collected. Additionally, in third-quarter 2018, the portion of the loan amount charged off at default increased from 79 percent to 80.5 percent. This change resulted in a $32 million reduction to the balance of the receivable for partially charged-off loans. These amounts are included in total charge-offs as reported in the “Allowance for Private Education Loan Losses” table.
Accrued Interest Receivable	The following table provides information regarding accrued interest receivable on our Private Education Loans. (Dollars in millions) Total Greater Than 90 Days Past Due Allowance for Uncollectible Interest December 31, 2018 TDR $ 205 $ 26 $ 23 Non-TDR 149 3 4 Total $ 354 $ 29 $ 27 December 31, 2017 TDR $ 196 $ 20 $ 20 Non-TDR 187 4 6 Total $ 383 $ 24 $ 26 December 31, 2016 TDR $ 192 $ 28 $ 23 Non-TDR 199 5 7 Total $ 391 $ 33 $ 30

Business Combinations, Goodwi_2

Business Combinations, Goodwill and Acquired Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Schedule of Carrying Value of Equity and Percentage of Fair Value in Excess of Carrying Value	The following table summarizes our goodwill, accumulated impairments and net goodwill for our reporting units and reportable segments as of December 31, 2018. 5. As of December 31, 2018 (Dollars in millions) Gross Accumulated Impairments and Other Adjustments Net Federal Education Loans reportable segment: FFELP Loans $ 231 $ (4 ) $ 227 Federal Education Loan Servicing 13 — 13 Total Federal Education Loans reportable segment 244 (4 ) 240 Consumer Lending reportable segment: Private Education Loans (1) 147 (41 ) 106 Private Education Refinance Loans 77 — 77 Total Consumer Lending reportable segment 224 (41 ) 183 Business Processing reportable segment: Government Services 272 (136 ) 136 Healthcare Services 106 — 106 Total Business Processing reportable segment 378 (136 ) 242 Total $ 846 $ (181 ) $ 665 As of December 31, 2017 (Dollars in millions) Gross Accumulated Impairments and Other Adjustments Net FFELP Loans reportable segment 194 (4 ) 190 Private Education Loans reportable segment: Private Education Loans (1) 147 (41 ) 106 Earnest 87 — 87 Total Private Education Loans reportable segment 234 (41 ) 193 Business Services reportable segment: Servicing 50 — 50 Asset Recovery - Contingency 136 (136 ) — Asset Recovery - Gila 160 — 160 Asset Recovery - Xtend Healthcare 108 — 108 Total Business Services reportable segment 454 (136 ) 318 Total $ 882 $ (181 ) $ 701 (1) In conjunction with our Separation from SLM BankCo in 2014, we removed $41 million of goodwill from our balance sheet as required under ASC 350, “Intangibles — Goodwill and Other.” This goodwill was allocated to the consumer banking business retained by SLM BankCo based on relative fair value.
Acquired Intangible Assets	Acquired intangible assets include the following: As of December 31, 2018 As of December 31, 2017 (Dollars in millions) Cost Basis (1) Accumulated Impairment and Amortization (1) Net Cost Basis (1) Accumulated Impairment and Amortization (1) Net Customer, services and lending relationships $ 284 $ (226 ) $ 58 $ 292 $ (234 ) $ 58 Favorable lease 1 — 1 1 — 1 Non-competes 3 (3 ) — 2 (2 ) — Software and technology 115 (90 ) 25 104 (85 ) 19 Trade names and trademarks (2) 61 (24 ) 37 48 (18 ) 30 Total acquired intangible assets $ 464 $ (343 ) $ 121 $ 447 $ (339 ) $ 108 (1) Accumulated impairment and amortization include impairment amounts only if the acquired intangible asset has been deemed partially impaired. When an acquired intangible asset is considered fully impaired and no longer in use, the cost basis and any accumulated amortization related to the asset is written off. (2) During 2016 we reclassified certain trade names from indefinite life to definite life intangible assets and began to amortize these assets over their expected benefit period.

Borrowings (Tables)

Borrowings (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Company's Borrowings	6. The following table summarizes our borrowings. December 31, 2018 December 31, 2017 (Dollars in millions) Short Term Long Term Total Short Term Long Term Total Unsecured borrowings: Senior unsecured debt (1) $ 817 $ 10,674 $ 11,491 $ 1,306 $ 12,624 $ 13,930 Total unsecured borrowings 817 10,674 11,491 1,306 12,624 13,930 Secured borrowings: FFELP Loan securitizations (2) — 66,318 66,318 — 71,208 71,208 Private Education Loan securitizations (3) 300 12,985 13,285 686 12,646 13,332 FFELP Loan — other facilities 2,927 2,625 5,552 1,536 6,830 8,366 Private Education Loan — other facilities 1,114 1,266 2,380 684 1,710 2,394 Other (4) 267 — 267 538 — 538 Total secured borrowings 4,608 83,194 87,802 3,444 92,394 95,838 Total before hedge accounting adjustments 5,425 93,868 99,293 4,750 105,018 109,768 Hedge accounting adjustments (3 ) (349 ) (352 ) 21 (6 ) 15 Total $ 5,422 $ 93,519 $ 98,941 $ 4,771 $ 105,012 $ 109,783 (1) Includes principal amount of $817 million and $1.3 billion of short-term debt as of December 31, 2018 and 2017, respectively. Includes principal amount of $10.8 billion and $12.7 billion of long-term debt as of December 31, 2018 and 2017, respectively. (2) Includes $244 million of long-term debt related to the FFELP Loan asset-backed securitization repurchase facilities (“FFELP Loan Repurchase Facilities”) as of December 31, 2018. (3) Includes $300 million and $686 million of short-term debt related to the Private Education Loan asset-backed securitization repurchase facilities (“Private Education Loan Repurchase Facilities”) as of December 31, 2018 and 2017, respectively. Includes $2.0 billion and $1.3 billion of long-term debt related to the Private Education Loan Repurchase Facilities as of December 31, 2018 and 2017, respectively. (4) “Other” primarily includes the obligation to return cash collateral held related to derivative exposures.
Outstanding Short-Term Borrowings	The following tables summarize outstanding short-term borrowings (secured and unsecured), the weighted average interest rates at the end of each period, and the related average balances and weighted average interest rates during the periods. December 31, 2018 Year Ended December 31, 2018 (Dollars in millions) Ending Balance Weighted Average Interest Rate Average Balance Weighted Average Interest Rate Private Education Loan securitizations (1) $ 300 5.23 % $ 536 4.72 % FFELP Loan — other facilities 2,927 3.10 1,137 2.79 Private Education Loan — other facilities 1,114 3.63 847 3.40 Senior unsecured debt 814 4.92 2,021 5.90 Other interest-bearing liabilities 267 2.39 292 1.73 Total short-term borrowings $ 5,422 3.56 % $ 4,833 4.35 % Maximum outstanding at any month end $ 6,363 December 31, 2017 Year Ended December 31, 2017 (Dollars in millions) Ending Balance Weighted Average Interest Rate Average Balance Weighted Average Interest Rate Private Education Loan securitizations (1) $ 686 4.65 % $ 706 4.32 % FFELP Loan — other facilities 1,536 2.11 261 1.26 Private Education Loan —other facilities 684 2.92 572 2.42 Senior unsecured debt 1,327 8.06 1,197 6.80 Other interest-bearing liabilities 538 1.33 458 1.27 Total short-term borrowings $ 4,771 4.16 % $ 3,194 4.22 % Maximum outstanding at any month end $ 4,771
Long-Term Borrowings	The following tables summarize outstanding long-term borrowings, the weighted average interest rates at the end of the periods, and the related average balances during the periods. December 31, 2018 Weighted Average Year Ended December 31, 2018 (Dollars in millions) Ending Balance (1) Interest Rate (2) Average Balance Floating rate notes: U.S. dollar-denominated: Interest bearing, due 2019-2083 $ 74,842 3.38 % $ 80,189 Non-U.S. dollar-denominated: Interest bearing, due 2023-2040 4,064 .66 4,919 Total floating rate notes 78,906 3.24 85,108 Fixed rate notes: U.S. dollar-denominated: Interest bearing, due 2020-2059 14,431 5.57 13,814 Non-U.S.-dollar denominated: Interest bearing, due 2034 182 2.49 273 Total fixed rate notes 14,613 5.53 14,087 Total long-term borrowings $ 93,519 3.60 % $ 99,195 December 31, 2017 Weighted Average Year Ended December 31, 2017 (Dollars in millions) Ending Balance (1) Interest Rate (2) Average Balance Floating rate notes: U.S. dollar-denominated: Interest bearing, due 2018-2083 $ 83,209 2.31 % $ 86,186 Non-U.S. dollar-denominated: Interest bearing, due 2023-2041 6,423 .37 7,355 Total floating rate notes 89,632 2.17 93,541 Fixed rate notes: U.S. dollar-denominated: Interest bearing, due 2019-2058 15,114 5.60 15,266 Non-U.S.-dollar denominated: Interest bearing, due 2034-2035 266 2.72 281 Total fixed rate notes 15,380 5.55 15,547 Total long-term borrowings $ 105,012 2.67 % $ 109,088 (1) Ending balance is expressed in U.S. dollars using the spot currency exchange rate. Includes fair value adjustments under hedge accounting for notes designated as the hedged item in a fair value hedge. (2) Weighted average interest rate is stated rate relative to currency denomination of debt.
Expected Maturities of Long-term Borrowings	As of December 31, 2018, the expected maturities of our long-term borrowings are shown in the following table. Expected Maturity (Dollars in millions) Senior Unsecured Debt Secured Borrowings (1) Total (2) Year of Maturity 2019 $ — $ 10,274 $ 10,274 2020 2,046 9,814 11,860 2021 1,434 6,357 7,791 2022 1,736 6,215 7,951 2023 1,496 6,110 7,606 2024-2043 3,962 44,424 48,386 10,674 83,194 93,868 Hedge accounting adjustments 107 (456 ) (349 ) Total $ 10,781 $ 82,738 $ 93,519 (1) We view our securitization trust debt as long-term based on the contractual maturity dates which range from 2019 to 2083. However, we have projected the expected principal paydowns based on our current estimates regarding the securitized loans’ prepayment speeds for purposes of this disclosure to better reflect how we expect this debt to be paid down over time. The projected principal paydowns in year 2019 include $10.3 billion related to the securitization trust debt. (2) The aggregate principal amount of debt that matures in each period is $10.3 billion in 2019, $11.9 billion in 2020, $7.9 billion in 2021, $8.0 billion in 2022, $7.7 billion in 2023 and $48.8 billion in 2024-2043.
Financing VIEs	We consolidate the following financing VIEs as of December 31, 2018 and 2017, as we are the primary beneficiary. As a result, these VIEs are accounted for as secured borrowings. December 31, 2018 Debt Outstanding Carrying Amount of Assets Securing Debt Outstanding (Dollars in millions) Short Term Long Term Total Loans Cash Other Assets, Net Total Secured Borrowings — VIEs: FFELP Loan securitizations (1) $ — $ 66,318 $ 66,318 $ 66,266 $ 3,181 $ 1,211 $ 70,658 Private Education Loan securitizations (2) 300 12,985 13,285 16,336 536 198 17,070 FFELP Loan — other facilities 2,927 2,625 5,552 5,656 132 162 5,950 Private Education Loan — other facilities 1,114 1,266 2,380 3,361 79 27 3,467 Total before hedge accounting adjustments 4,341 83,194 87,535 91,619 3,928 1,598 97,145 Hedge accounting adjustments — (456 ) (456 ) — — (642 ) (642 ) Total $ 4,341 $ 82,738 $ 87,079 $ 91,619 $ 3,928 $ 956 $ 96,503 December 31, 2017 Debt Outstanding Carrying Amount of Assets Securing Debt Outstanding (Dollars in millions) Short Term Long Term Total Loans Cash Other Assets, Net Total Secured Borrowings — VIEs: FFELP Loan securitizations (1) $ — $ 71,208 $ 71,208 $ 72,145 $ 2,335 $ 1,078 $ 75,558 Private Education Loan securitizations (2) 686 12,646 13,332 17,739 484 237 18,460 FFELP Loan — other facilities 1,536 3,999 5,535 5,565 204 156 5,925 Private Education Loan — other facilities 684 1,710 2,394 3,147 68 31 3,246 Total before hedge accounting adjustments 2,906 89,563 92,469 98,596 3,091 1,502 103,189 Hedge accounting adjustments — (246 ) (246 ) — — (342 ) (342 ) Total $ 2,906 $ 89,317 $ 92,223 $ 98,596 $ 3,091 $ 1,160 $ 102,847 (1) Includes $244 (2) Includes $300 million of short-term debt, $2.0 billion of long-term debt and $115 million of restricted cash related to the Private Education Loan Repurchase Facilities as of December 31, 2018. Includes $686 million of short-term debt, $1.3 billion of long-term debt and $96 million of restricted cash related to the Private Education Loan Repurchase Facilities as of December 31, 2017.
Gains (Losses) on Debt Repurchases	The following table summarizes activity related to our senior unsecured debt and ABS repurchases. “Gains (losses) on debt repurchases” is shown net of hedging-related gains and losses. Years Ended December 31, (Dollars in millions) 2018 2017 2016 Debt principal repurchased $ 2,809 $ 513 $ 1,467 Gains (losses) on debt repurchases 19 (3 ) 1

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Impact of Derivatives on Consolidated Balance Sheet	The following tables summarize the fair values and notional amounts or number of contracts of all derivative instruments at December 31, 2018 and 2017, and their impact on other comprehensive income and earnings for 2018, 2017 and 2016. Impact of Derivatives on Consolidated Balance Sheet Cash Flow Fair Value Trading Total (Dollars in millions) Hedged Risk Exposure Dec. 31, 2018 Dec. 31, 2017 Dec. 31, 2018 Dec. 31, 2017 Dec. 31, 2018 Dec. 31, 2017 Dec. 31, 2018 Dec. 31, 2017 Fair Values (1) Derivative Assets: Interest rate swaps Interest rate $ — $ 95 $ 170 $ 290 $ 3 $ 7 $ 173 $ 392 Cross-currency interest rate swaps Foreign currency and interest rate — — 6 88 — — 6 88 Total derivative assets (2) — 95 176 378 3 7 179 480 Derivative Liabilities: Interest rate swaps Interest rate — (16 ) (34 ) (102 ) (45 ) (71 ) (79 ) (189 ) Floor Income Contracts Interest rate — — — — (53 ) (74 ) (53 ) (74 ) Cross-currency interest rate swaps Foreign currency and interest rate — — (639 ) (410 ) (26 ) (44 ) (665 ) (454 ) Other (3) Interest rate — — — — (4 ) (18 ) (4 ) (18 ) Total derivative liabilities (2) — (16 ) (673 ) (512 ) (128 ) (207 ) (801 ) (735 ) Net total derivatives $ — $ 79 $ (497 ) $ (134 ) $ (125 ) $ (200 ) $ (622 ) $ (255 ) (1) Fair values reported are exclusive of collateral held and pledged and accrued interest. Assets and liabilities are presented without consideration of master netting agreements. Derivatives are carried on the balance sheet based on net position by counterparty under master netting agreements, and classified in other assets or other liabilities depending on whether in a net positive or negative position. (2) The following table reconciles gross positions without the impact of master netting agreements to the balance sheet classification:
Gross Positions with Impact of Master Netting Agreements	The following table reconciles gross positions without the impact of master netting agreements to the balance sheet classification: Other Assets Other Liabilities (Dollar in millions) December 31, 2018 December 31, 2017 December 31, 2018 December 31, 2017 Gross position $ 179 $ 480 $ (801 ) $ (735 ) Impact of master netting agreements (22 ) (42 ) 22 42 Derivative values with impact of master netting agreements (as carried on balance sheet) 157 438 (779 ) (693 ) Cash collateral (held) pledged (266 ) (536 ) 188 235 Net position $ (109 ) $ (98 ) $ (591 ) $ (458 ) (3)
Derivative Notional Values	Cash Flow Fair Value Trading Total (Dollars in billions) Dec. 31, 2018 Dec. 31, 2017 Dec. 31, 2018 Dec. 31, 2017 Dec. 31, 2018 Dec. 31, 2017 Dec. 31, 2018 Dec. 31, 2017 Notional Values: Interest rate swaps $ 21.4 $ 24.1 $ 10.3 $ 12.4 $ 66.9 $ 72.0 $ 98.6 $ 108.5 Floor Income Contracts — — — — 27.9 21.9 27.9 21.9 Cross-currency interest rate swaps — — 4.5 6.7 .2 .3 4.7 7.0 Other (1) — — — — .2 .5 .2 .5 Total derivatives $ 21.4 $ 24.1 $ 14.8 $ 19.1 $ 95.2 $ 94.7 $ 131.4 $ 137.9 (1) “Other” includes derivatives related to our Total Return Swap Facility.
Impact of Derivatives on Consolidated Statements of Income	Impact of Derivatives on Consolidated Statements of Income Total Gains (Losses) (1) Years Ended December 31, (Dollars in millions) 2018 2017 2016 Fair Value Hedges (2) Interest Rate Swaps Gains (losses) recognized in net income on derivatives $ (137 ) $ (214 ) $ (288 ) Gains (losses) recognized in net income on hedged items 162 193 302 Net fair value hedge ineffectiveness gains (losses) 25 (21 ) 14 Cross currency interest rate swaps Gains (losses) recognized in net income on derivatives (311 ) 921 (319 ) Gains (losses) recognized in net income on hedged items 210 (954 ) 350 Net fair value hedge ineffectiveness gains (losses) (101 ) (33 ) 31 Total fair value hedges (76 ) (54 ) 45 Cash Flow Hedges (2) Interest rate swaps (3) — — — Total cash flow hedges — — — Trading Interest rate swaps 22 8 29 Floor income contracts 15 81 51 Cross currency interest rate swaps (3 ) 2 5 Other 4 (15 ) (13 ) Total trading derivatives 38 76 72 Gains (losses) on derivative and hedging activities, net $ (38 ) $ 22 $ 117 (1) Recorded in “Gains (losses) on derivative and hedging activities, net” in the consolidated statements of income. (2) The accrued interest income (expense) on fair value hedges and cash flow hedges is recorded in net interest income (expense) and is excluded from this table. (3) Represents ineffectiveness related to cash flow hedges.
Impact of Derivatives on Consolidated Statements of Changes in Stockholders' Equity	Impact of Derivatives on Consolidated Statements of Changes in Stockholders’ Equity (net of tax) Years Ended December 31, (Dollars in millions) 2018 2017 2016 Total gains (losses) on cash flow hedges $ 50 $ 25 $ 26 Reclassification adjustments for derivative (gains) losses included in net income (interest expense) (1)(2) (11 ) 30 31 Total change in stockholders’ equity for unrealized gains (losses) on derivatives $ 39 $ 55 $ 57 (1) Includes net settlement income/expense. (2) We expect to reclassify $3 million of after-tax net losses from accumulated other comprehensive income to earnings during the next 12 months related to amortization of terminated hedge relationships.
Collateral Held and Pledged	The following table details collateral held and pledged related to derivative exposure between us and our derivative counterparties. (Dollars in millions) December 31, 2018 December 31, 2017 Collateral held: Cash (obligation to return cash collateral is recorded in short-term borrowings) $ 266 $ 536 Securities at fair value — corporate derivatives (not recorded in financial statements) (1) — — Securities at fair value — on-balance sheet securitization derivatives (not recorded in financial statements) (2) 90 297 Total collateral held $ 356 $ 833 Derivative asset at fair value including accrued interest $ 210 $ 618 Collateral pledged to others: Cash (right to receive return of cash collateral is recorded in investments) $ 188 $ 235 Total collateral pledged $ 188 $ 235 Derivative liability at fair value including accrued interest and premium receivable $ 752 $ 659 (1) The Company has the ability to sell or re-pledge securities it holds as collateral. (2) The trusts do not have the ability to sell or re-pledge securities they hold as collateral.

Other Assets (Tables)

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Schedule of Other Assets	The following table provides the detail of our other assets. (Dollars in millions) December 31, 2018 December 31, 2017 Accrued interest receivable $ 1,999 $ 1,965 Benefit and insurance-related investments 470 481 Income tax asset, net (current and deferred) 271 380 Derivatives at fair value 157 438 Fixed assets, net 136 156 Accounts receivable 95 108 Other loans, net 69 59 Other 207 438 Total $ 3,404 $ 4,025

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Common Share Repurchases and Issuances	The following table summarizes our common share repurchases and issuances. Years Ended December 31, 2018 2017 2016 Common stock repurchased (1) 17,443,351 29,646,374 59,625,325 Average purchase price per share $ 12.64 $ 14.85 $ 12.68 Shares repurchased related to employee stock-based compensation plans (2) 3,829,629 1,847,651 3,197,355 Average purchase price per share $ 13.71 $ 15.40 $ 13.21 Common shares issued (3) 5,659,681 3,680,479 5,476,010 (1) Common shares purchased under our share repurchase program. (2) Comprises shares withheld from stock option exercises and vesting of restricted stock for employees’ tax withholding obligations and shares tendered by employees to satisfy option exercise costs. (3) Common shares issued under our various compensation and benefit plans.

Earnings (Loss) per Common Sh_2

Earnings (Loss) per Common Share (Tables)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Schedule of Earnings (Loss) per Common Share	Basic earnings (loss) per common share (“EPS”) are calculated using the weighted average number of shares of common stock outstanding during each period. A reconciliation of the numerators and denominators of the basic and diluted EPS calculations follows. Years Ended December 31, (In millions, except per share data) 2018 2017 2016 Numerator: Net income $ 395 $ 292 $ 681 Denominator: Weighted average shares used to compute basic EPS 260 275 316 Effect of dilutive securities: Dilutive effect of stock options, restricted stock, restricted stock units, performance stock units and Employee Stock Purchase Plan (“ESPP”) (1) 4 6 6 Dilutive potential common shares (2) 4 6 6 Weighted average shares used to compute diluted EPS 264 281 322 Basic earnings per common share $ 1.52 $ 1.06 $ 2.15 Diluted earnings per common share $ 1.49 $ 1.04 $ 2.12 (1) Includes the potential dilutive effect of additional common shares that are issuable upon exercise of outstanding stock options, restricted stock, restricted stock units, performance stock units and the outstanding commitment to issue shares under applicable ESPPs, determined by the treasury stock method. (2) For the years ended December 31, 2018, 2017 and 2016, stock options covering approximately 6 million, 5 million and 4 million shares, respectively, were outstanding but not included in the computation of diluted earnings per share because they were anti-dilutive.

Stock-Based Compensation Plan_2

Stock-Based Compensation Plans and Arrangements (Tables)	12 Months Ended
	Dec. 31, 2018
Postemployment Benefits [Abstract]
Black-Scholes Model Assumptions for Calculating Stock Option Fair Values	The fair values of the options granted in 2018, 2017 and 2016 were estimated as of the grant date using a Black-Scholes option pricing model with the following weighted average assumptions: Years Ended December 31, 2018 2017 2016 Expected life of the option 3.2 years 3.0 years 3.0 years Expected volatility 36 % 34 % 30 % Risk-free interest rate 2.27 % 1.44 % .90 % Expected dividend rate 4.70 % 4.13 % 6.97 % Weighted average fair value of options granted $ 2.59 $ 2.69 $ 1.01
Stock Option Activity	The following table summarizes Navient’s stock option activity in 2018. (Dollars in millions, except per share data) Number of Options Weighted Average Exercise Price per Share Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (1) Outstanding at December 31, 2017 14,183,726 $ 12.48 Granted 1,551,307 13.63 Exercised (2) (3,715,212 ) 10.53 Canceled (844,931 ) 16.69 Outstanding at December 31, 2018 (3) 11,174,890 $ 12.97 1.8 yrs. $ 4 Exercisable at December 31, 2018 7,500,940 $ 13.24 1.2 yrs. $ 4 (1) The aggregate intrinsic value represents the total intrinsic value (the aggregate difference between our closing stock price on December 31, 2018 and the exercise price of in-the-money options) that would have been received by the option holders if all in-the-money options had been exercised on December 31, 2018. (2) The total intrinsic value of Navient stock options exercised was $12 million, $9 million and $13 million for 2018, 2017 and 2016, respectively. (3) As of December 31, 2018, there was $1 million of unrecognized compensation cost related to stock options, which is expected to be recognized over a weighted average period of 1.9 years.
Restricted Stock Activity	11. The following table summarizes Navient’s restricted stock activity in 2018. Number of Shares Weighted Average Grant Date Fair Value Non-vested at December 31, 2017 — $ — Granted 55,503 13.56 Vested (1) (36,429 ) 13.52 Canceled (19,074 ) 13.63 Non-vested at December 31, 2018 (2) — $ — (1) The total fair value of Navient shares that vested was $1 million, $1 million and $1 million for 2018, 2017 and 2016, respectively. (2) As of December 31, 2018, there was no unrecognized compensation cost related to restricted stock.
Restricted Stock Unit and Performance Stock Unit Activity	The following table summarizes Navient’s RSU and PSU activity in 2018. Number of RSUs/PSUs Weighted Average Grant Date Fair Value Outstanding at December 31, 2017 4,428,305 $ 13.33 Granted 1,884,580 12.97 Vested and converted to common stock (1) (1,598,227 ) 13.87 Forfeited (226,323 ) 21.65 Canceled (228,564 ) 12.89 Outstanding at December 31, 2018 (2) 4,259,771 $ 12.55 (1) The total fair value of Navient RSUs and PSUs that vested and converted to common stock was $22 million, $23 million and $30 million for 2018, 2017 and 2016, respectively. (2) As of December 31, 2018, there was $11 million of unrecognized compensation cost related to RSUs and PSUs, which is expected to be recognized over a weighted average period of 1.8 years.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Valuation of Financial Instruments that are Marked-to-Market on Recurring Basis	12. The following table summarizes the valuation of our financial instruments that are marked-to-market on a recurring basis. During 2018 and 2017, there were no significant transfers of financial instruments between levels. Fair Value Measurements on a Recurring Basis December 31, 2018 December 31, 2017 (Dollars in millions) Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets Available-for-sale investments: Other $ — $ — $ — $ — $ — $ 2 $ — $ 2 Total available-for-sale investments — — — — — 2 — 2 Derivative instruments: (1) Interest rate swaps — 171 2 173 — 388 4 392 Cross-currency interest rate swaps — — 6 6 — — 88 88 Total derivative assets (2) — 171 8 179 — 388 92 480 Total $ — $ 171 $ 8 $ 179 $ — $ 390 $ 92 $ 482 Liabilities (3) Derivative instruments (1) Interest rate swaps $ — $ (50 ) $ (29 ) $ (79 ) $ — $ (144 ) $ (45 ) $ (189 ) Floor Income Contracts — (53 ) — (53 ) — (74 ) — (74 ) Cross-currency interest rate swaps — (26 ) (639 ) (665 ) — (44 ) (410 ) (454 ) Other — — (4 ) (4 ) — — (18 ) (18 ) Total derivative liabilities (2) — (129 ) (672 ) (801 ) — (262 ) (473 ) (735 ) Total $ — $ (129 ) $ (672 ) $ (801 ) $ — $ (262 ) $ (473 ) $ (735 ) (1) Fair value of derivative instruments excludes accrued interest and the value of collateral. (2) See “Note 7 — Derivative Financial Instruments” for a reconciliation of gross positions without the impact of master netting agreements to the balance sheet classification. (3) Borrowings which are the hedged items in a fair value hedge relationship and which are adjusted for changes in value due to benchmark interest rates only are not carried at full fair value and are not reflected in this table.
Change in Balance Sheet Carrying Value Associated with Level 3 Financial Instruments Carried at Fair Value on Recurring Basis	12. The following tables summarize the change in balance sheet carrying value associated with level 3 financial instruments carried at fair value on a recurring basis. Year Ended December 31, 2018 Derivative Instruments (Dollars in millions) Interest Rate Swaps Cross Currency Interest Rate Swaps Other Total Derivative Instruments Balance, beginning of period $ (41 ) $ (322 ) $ (18 ) $ (381 ) Total gains/(losses): Included in earnings (1) 11 (433 ) 8 (414 ) Included in other comprehensive income — — — — Settlements 3 122 6 131 Transfers in and/or out of level 3 — — — — Balance, end of period $ (27 ) $ (633 ) $ (4 ) $ (664 ) Change in mark-to-market gains/(losses) relating to instruments still held at the reporting date (2) $ 13 $ (284 ) $ 14 $ (257 ) Year Ended December 31, 2017 Derivative Instruments (Dollars in millions) Interest Rate Swaps Cross Currency Interest Rate Swaps Other Total Derivative Instruments Balance, beginning of period $ (46 ) $ (1,243 ) $ (13 ) $ (1,302 ) Total gains/(losses): Included in earnings (1) — 803 (15 ) 788 Included in other comprehensive income — — — — Settlements 5 118 10 133 Transfers in and/or out of level 3 — — — — Balance, end of period $ (41 ) $ (322 ) $ (18 ) $ (381 ) Change in mark-to-market gains/(losses) relating to instruments still held at the reporting date (2) $ 5 $ 795 $ (5 ) $ 795 Year Ended December 31, 2016 Derivative Instruments (Dollars in millions) Interest Rate Swaps Cross Currency Interest Rate Swaps Other Total Derivative Instruments Balance, beginning of period $ (44 ) $ (903 ) $ (2 ) $ (949 ) Total gains/(losses): Included in earnings (1) 3 (428 ) (14 ) (439 ) Included in other comprehensive income — — — — Settlements 3 88 3 94 Transfers in and/or out of level 3 (3) (8 ) — — (8 ) Balance, end of period $ (46 ) $ (1,243 ) $ (13 ) $ (1,302 ) Change in mark-to-market gains/(losses) relating to instruments still held at the reporting date (2) $ 7 $ (340 ) $ (11 ) $ (344 ) (1) “Included in earnings” is comprised of the following amounts recorded in the specified line item in the consolidated statements of income:
Included in Earnings	Years Ended December 31, (Dollars in millions) 2018 2017 2016 Gains (losses) on derivative and hedging activities, net $ (292 ) $ 906 $ (351 ) Interest expense (122 ) (118 ) (88 ) Total $ (414 ) $ 788 $ (439 ) (2) Recorded in “gains (losses) on derivative and hedging activities, net” in the consolidated statements of income. (3) Consumer Price Index/LIBOR basis swaps were transferred from level 3 to level 2 in the fourth quarter of 2016 due to the conclusion that these swaps now trade in an active market.
Unobservable Data Used in Recurring Valuations of Level 3	12. The following table presents the significant inputs that are unobservable or from inactive markets used in the recurring valuations of the level 3 financial instruments detailed above. (Dollars in millions) Fair Value at December 31, 2018 Valuation Technique Input Range (Weighted Average) Derivatives Prime/LIBOR basis swaps $ (27 ) Discounted cash flow Constant Prepayment Rate 7% Bid/ask adjustment to discount rate .08% — .08% (.08%) Cross-currency interest rate swaps (633 ) Discounted cash flow Constant Prepayment Rate 4% Other (4 ) Total $ (664 )
Fair Values of Financial Assets and Liabilities, Including Derivative Financial Instruments	12. The following table summarizes the fair values of our financial assets and liabilities, including derivative financial instruments. December 31, 2018 December 31, 2017 (Dollars in millions) Fair Value Carrying Value Difference Fair Value Carrying Value Difference Earning assets FFELP Loans $ 72,074 $ 72,253 $ (179 ) $ 82,271 $ 81,703 $ 568 Private Education Loans 22,958 22,245 713 24,421 23,419 1,002 Cash and investments (1) 5,488 5,488 — 5,034 5,034 — Total earning assets 100,520 99,986 534 111,726 110,156 1,570 Interest-bearing liabilities Short-term borrowings 5,418 5,422 4 4,783 4,771 (12 ) Long-term borrowings 92,173 93,519 1,346 104,921 105,012 91 Total interest-bearing liabilities 97,591 98,941 1,350 109,704 109,783 79 Derivative financial instruments Floor Income Contracts (53 ) (53 ) — (74 ) (74 ) — Interest rate swaps 94 94 — 203 203 — Cross-currency interest rate swaps (659 ) (659 ) — (366 ) (366 ) — Other (4 ) (4 ) — (18 ) (18 ) — Excess of net asset fair value over carrying value $ 1,884 $ 1,649 (1) “Cash and investments” includes available-for-sale investments whose cost basis is $0 million and $2 million at December 31, 2018 and 2017, respectively, versus a fair value of $0 million and $2 million at December 31, 2018 and 2017, respectively.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Reconciliations of Statutory U.S. Federal Income Tax Rates to Our Effective Tax Rate for Continuing Operations	Reconciliations of the statutory U.S. federal income tax rates to our effective tax rate for continuing operations follow: Years Ended December 31, 2018 2017 2016 Statutory rate 21.0 % 35.0 % 35.0 % DTA Remeasurement Loss (1) — 27.2 — State tax, net of federal benefit 3.9 .7 3.8 Other, net .3 (1.1 ) (.3 ) Effective tax rate 25.2 % 61.8 % 38.5 % (1) The TCJA, enacted on December 22, 2017, made significant changes to all aspects of income taxation, including a reduction to the corporate federal statutory tax rate. GAAP requires the effects of the TCJA to be recognized in the period the law is enacted, even though the effective date of the law for most provisions is January 1, 2018. The primary impact to us is the reduction to the corporate federal statutory tax rate from 35 percent to 21 percent as of January 1, 2018. This rate reduction required us to remeasure our deferred tax asset at December 31, 2017, at the 21 percent corporate federal statutory tax rate and resulted in a DTA Remeasurement Loss of $208 million for GAAP, which is reflected as incremental income tax expense in the fourth quarter of 2017.
Components of Provision for Income Tax Expense (Benefit)	Income tax expense consists of: December 31, (Dollars in millions) 2018 2017 2016 Current provision/(benefit): Federal $ 71 $ 77 $ 246 State 13 (3 ) 47 Foreign 3 3 1 Total current provision/(benefit) 87 77 294 Deferred provision/(benefit): Federal 33 385 115 State 13 11 18 Foreign — (1 ) — Total deferred provision/(benefit) 46 395 133 Provision for income tax expense/(benefit) $ 133 $ 472 $ 427
Schedule of Deferred Tax Assets and Liabilities	The tax effect of temporary differences that give rise to deferred tax assets and liabilities include the following: December 31, (Dollars in millions) 2018 2017 Deferred tax assets: Loan reserves $ 292 $ 317 Education loan premiums and discounts, net 48 52 Operating loss and credit carryovers 18 22 Stock-based compensation plans 16 18 Accrued expenses not currently deductible 14 24 Other 18 14 Total deferred tax assets 406 447 Deferred tax liabilities: Market value adjustments on education loans, investments and derivatives 46 14 Acquired intangible assets 12 3 Original issue discount on borrowings 7 11 Debt repurchases 6 8 Other 13 19 Total deferred tax liabilities 84 55 Net deferred tax assets $ 322 $ 392
Summary of Changes in Unrecognized Tax Benefits	The following table summarizes changes in unrecognized tax benefits: December 31, (Dollars in millions) 2018 2017 2016 Unrecognized tax benefits at beginning of year $ 57.4 $ 73.0 $ 56.3 Increases resulting from tax positions taken during a prior period 8.0 .7 19.9 Decreases resulting from tax positions taken during a prior period (.3 ) (1.8 ) (5.6 ) Increases resulting from tax positions taken during the current period 3.8 4.4 4.4 Decreases related to settlements with taxing authorities (1.4 ) (5.1 ) (.1 ) Increases related to settlements with taxing authorities — — — Reductions related to the lapse of statute of limitations (1.8 ) (13.8 ) (1.9 ) Unrecognized tax benefits at end of year $ 65.7 $ 57.4 $ 73.0

Revenue from Contract with Cu_2

Revenue from Contract with Customers Accounted in Accordance with ASC 606 (Tables)	12 Months Ended
	Dec. 31, 2018
Revenue From Contract With Customer [Abstract]
Summary of Disaggregation of Revenue from Contracts Accounted Under ASC 606 with Customers	15. Revenue from Contracts with Customers Accounted in Accordance with ASC 606 (Continued) The following tables illustrate the disaggregation of revenue from contracts accounted for under ASC 606 with customers according to service type and client type by reportable operating segment. Revenue by Service Type Year Ended December 31, 2018 (Dollars in millions) Federal Education Loans Business Processing Total Revenue Federal Education Loan asset recovery services $ 91 $ — $ 91 Government services — 175 175 Healthcare services — 93 93 Total $ 91 $ 268 $ 359 Revenue by Client Type Year Ended December 31, 2018 (Dollars in millions) Federal Education Loans Business Processing Total Revenue Federal government $ 21 $ 7 $ 28 Guarantor agencies 58 — 58 Other institutions 12 — 12 State and local government — 92 92 Tolling authorities — 76 76 Hospitals and other healthcare providers — 93 93 Total $ 91 $ 268 $ 359

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Results and Reconciliations to GAAP	Year Ended December 31, 2018 Adjustments (Dollars in millions) Federal Education Loans Consumer Lending Business Processing Other Total Core Earnings Reclassi- fications Additions/ (Subtractions) Total Adjustments (1) Total GAAP Interest income: Education loans $ 3,080 $ 1,778 $ — $ — $ 4,858 $ 17 $ (70 ) $ (53 ) $ 4,805 Other loans 4 2 — — 6 — — — 6 Cash and investments 46 13 — 38 97 — — — 97 Total interest income 3,130 1,793 — 38 4,961 17 (70 ) (53 ) 4,908 Total interest expense 2,467 1,013 — 192 3,672 8 (12 ) (4 ) 3,668 Net interest income (loss) 663 780 — (154 ) 1,289 9 (58 ) (49 ) 1,240 Less: provisions for loan losses 70 300 — — 370 — — — 370 Net interest income (loss) after provisions for loan losses 593 480 — (154 ) 919 9 (58 ) (49 ) 870 Other income (loss): Servicing revenue 262 12 — — 274 — — — 274 Asset recovery and business processing revenue 163 — 267 — 430 — — — 430 Other income (loss) 24 — — 6 30 (22 ) (29 ) (51 ) (21 ) Gains on debt repurchases — — — 9 9 13 (3 ) 10 19 Total other income (loss) 449 12 267 15 743 (9 ) (32 ) (41 ) 702 Expenses: Direct operating expenses 298 169 229 — 696 — — — 696 Unallocated shared services expenses — — — 288 288 — — — 288 Operating expenses 298 169 229 288 984 — — — 984 Goodwill and acquired intangible asset impairment and amortization — — — — — — 47 47 47 Restructuring/other reorganization expenses — — — 13 13 — — — 13 Total expenses 298 169 229 301 997 — 47 47 1,044 Income (loss) before income tax expense (benefit) 744 323 38 (440 ) 665 — (137 ) (137 ) 528 Income tax expense (benefit) (2) 164 71 8 (97 ) 146 — (13 ) (13 ) 133 Net income (loss) $ 580 $ 252 $ 30 $ (343 ) $ 519 $ — $ (124 ) $ (124 ) $ 395 (1) Core Earnings adjustments to GAAP: Year Ended December 31, 2018 (Dollars in millions) Net Impact of Derivative Accounting Net Impact of Acquired Intangibles Total Net interest income (loss) after provisions for loan losses $ (49 ) $ — $ (49 ) Total other income (loss) (41 ) — (41 ) Goodwill and acquired intangible asset impairment and amortization — 47 47 Total Core Earnings adjustments to GAAP $ (90 ) $ (47 ) (137 ) Income tax expense (benefit) (13 ) Net income (loss) $ (124 ) (2) Income taxes are based on a percentage of net income before tax for the individual reportable segment. Year Ended December 31, 2017 Adjustments (Dollars in millions) Federal Education Loans Consumer Lending Business Processing Other Total Core Earnings Reclassi- fications Additions/ (Subtractions) Total Adjustments (1) Total GAAP Interest income: Education loans $ 2,679 $ 1,634 $ — $ — $ 4,313 $ 69 $ (55 ) $ 14 $ 4,327 Other loans 13 — — — 13 — — — 13 Cash and investments 29 5 — 9 43 — — — 43 Total interest income 2,721 1,639 — 9 4,369 69 (55 ) 14 4,383 Total interest expense 2,022 825 — 143 2,990 (8 ) (11 ) (19 ) 2,971 Net interest income (loss) 699 814 — (134 ) 1,379 77 (44 ) 33 1,412 Less: provisions for loan losses 44 382 — — 426 — — — 426 Net interest income (loss) after provisions for loan losses 655 432 — (134 ) 953 77 (44 ) 33 986 Other income (loss): Servicing revenue 280 10 — — 290 — — — 290 Asset recovery and business processing revenue 263 — 212 — 475 — — — 475 Other income (loss) 3 — — 16 19 (77 ) 89 12 31 Gains on sales of loans and investments 3 — — — 3 — — — 3 Losses on debt repurchases — — — (3 ) (3 ) — — — (3 ) Total other income (loss) 549 10 212 13 784 (77 ) 89 12 796 Expenses: Direct operating expenses 316 156 187 — 659 — — — 659 Unallocated shared services expenses — — — 307 307 — — — 307 Operating expenses 316 156 187 307 966 — — — 966 Goodwill and acquired intangible asset impairment and amortization — — — — — — 23 23 23 Restructuring/other reorganization expenses — — — 29 29 — — — 29 Total expenses 316 156 187 336 995 — 23 23 1,018 Income (loss) before income tax expense (benefit) 888 286 25 (457 ) 742 — 22 22 764 Income tax expense (benefit) (2) 321 103 9 58 491 — (19 ) (19 ) 472 Net income (loss) $ 567 $ 183 $ 16 $ (515 ) $ 251 $ — $ 41 $ 41 $ 292 (1) Core Earnings adjustments to GAAP: Year Ended December 31, 2017 (Dollars in millions) Net Impact of Derivative Accounting Net Impact of Acquired Intangibles Total Net interest income after provisions for loan losses $ 33 $ — $ 33 Total other income (loss) 12 — 12 Goodwill and acquired intangible asset impairment and amortization — 23 23 Total Core Earnings adjustments to GAAP $ 45 $ (23 ) 22 Income tax expense (benefit) (19 ) Net income (loss) $ 41 (2) Income taxes are based on a percentage of net income before tax for the individual reportable segment with the impact of the DTA Remeasurement Loss included in the Other segment Year Ended December 31, 2016 Adjustments (Dollars in millions) Federal Education Loans Consumer Lending Business Processing Other Total Core Earnings Reclassi- fications Additions/ (Subtractions) Total Adjustments (1) Total GAAP Interest income: Education loans $ 2,395 $ 1,587 $ — $ — $ 3,982 $ 247 $ (114 ) $ 133 $ 4,115 Other loans 9 — — — 9 — — — 9 Cash and investments 16 2 — 4 22 — — — 22 Total interest income 2,420 1,589 — 4 4,013 247 (114 ) 133 4,146 Total interest expense 1,597 704 — 109 2,410 31 — 31 2,441 Net interest income (loss) 823 885 — (105 ) 1,603 216 (114 ) 102 1,705 Less: provisions for loan losses 46 383 — — 429 — — — 429 Net interest income (loss) after provisions for loan losses 777 502 — (105 ) 1,174 216 (114 ) 102 1,276 Other income (loss): Servicing revenue 289 15 — — 304 — — — 304 Asset recovery and business processing revenue 216 — 174 — 390 — — — 390 Other income (loss) — — — 14 14 (216 ) 326 110 124 Gains on debt repurchases — — — 1 1 — — — 1 Total other income (loss) 505 15 174 15 709 (216 ) 326 110 819 Expenses: Direct operating expenses 366 149 149 — 664 — — — 664 Unallocated shared services expenses — — — 287 287 — — — 287 Operating expenses 366 149 149 287 951 — — — 951 Goodwill and acquired intangible asset impairment and amortization — — — — — — 36 36 36 Restructuring/other reorganization expenses — — — — — — — — — Total expenses 366 149 149 287 951 — 36 36 987 Income (loss) before income tax expense (benefit) 916 368 25 (377 ) 932 — 176 176 1,108 Income tax expense (benefit) (2) 338 137 9 (139 ) 345 — 82 82 427 Net income (loss) $ 578 $ 231 $ 16 $ (238 ) $ 587 $ — $ 94 $ 94 $ 681 (1) Core Earnings adjustments to GAAP: Year Ended December 31, 2016 (Dollars in millions) Net Impact of Derivative Accounting Net Impact of Acquired Intangibles Total Net interest income after provisions for loan losses $ 102 $ — $ 102 Total other income (loss) 110 — 110 Goodwill and acquired intangible asset impairment and amortization — 36 36 Total Core Earnings adjustments to GAAP $ 212 $ (36 ) 176 Income tax expense (benefit) 82 Net income (loss) $ 94 (2) Income taxes are based on a percentage of net income before tax for the individual reportable segment.
Core Earnings Adjustments to GAAP	Summary of Core Earnings Adjustments to GAAP Years Ended December 31, (Dollars in millions) 2018 2017 2016 Core Earnings net income $ 519 $ 251 $ 587 Core Earnings adjustments to GAAP: Net impact of derivative accounting (1) (90 ) 45 212 Net impact of goodwill and acquired intangible assets (2) (47 ) (23 ) (36 ) Net income tax effect (3) 13 19 (82 ) Total Core Earnings adjustments to GAAP (124 ) 41 94 GAAP net income $ 395 $ 292 $ 681 (1) Derivative accounting: (2) Goodwill and acquired intangible assets: (3) Net tax effect:
Federal Education Loans [Member]
Asset Information for Loans Segment	The following table includes GAAP-basis asset information for our Federal Education Loans segment. December 31, (Dollars in millions) 2018 2017 FFELP Loans, net $ 72,253 $ 81,703 Cash and investments (1) 3,368 2,821 Other 2,100 2,601 Total assets $ 77,721 $ 87,125 (1) Includes restricted cash and investments.
Consumer Lending [Member]
Asset Information for Loans Segment	The following table includes GAAP-basis asset information for our Consumer Lending segment. December 31, (Dollars in millions) 2018 2017 Private Education Loans, net $ 22,245 $ 23,419 Cash and investments (1) 732 706 Other 1,076 1,143 Total assets $ 24,053 $ 25,268 (1) Includes restricted cash and investments.

Quarterly Financial Informati_2

Quarterly Financial Information (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	2018 (Dollars in millions, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Net interest income $ 329 $ 298 $ 306 $ 307 Less: provisions for loan losses 87 112 85 85 Net interest income after provisions for loan losses 242 186 221 222 Other income 163 176 203 196 Gains (losses) on derivative and hedging activities, net 48 (40 ) 2 (48 ) Operating expenses 275 201 255 252 Goodwill and acquired intangible asset impairment and amortization expense 9 6 23 8 Restructuring/other reorganization expenses 7 2 1 4 Income tax expense 36 30 33 34 Net income $ 126 $ 83 $ 114 $ 72 Basic earnings per common share $ .48 $ .31 $ .44 $ .28 Diluted earnings per common share $ .47 $ .31 $ .43 $ .28 2017 (Dollars in millions, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Net interest income $ 340 $ 351 $ 355 $ 366 Less: provisions for loan losses 107 105 105 109 Net interest income after provisions for loan losses 233 246 250 257 Other income 168 187 238 181 Gains (losses) on derivative and hedging activities, net (16 ) (25 ) 25 38 Operating expenses 238 230 238 260 Goodwill and acquired intangible asset impairment and amortization expense 6 6 6 5 Restructuring/other reorganization expenses — — — 29 Income tax expense 53 60 93 266 Net income (loss) $ 88 $ 112 $ 176 $ (84 ) Basic earnings (loss) per common share $ .31 $ .40 $ .65 $ (.32 ) Diluted earnings (loss) per common share $ .30 $ .39 $ .64 $ (.32 )

Organization and Business - Add

Organization and Business - Additional Information (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Loans, net	$ 94,498	$ 105,122

Significant Accounting Polici_3

Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended						12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Jun. 01, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Loans, net	$ 94,498,000,000				$ 105,122,000,000		$ 94,498,000,000	$ 105,122,000,000
Percentage of threshold							50.00%
Goodwill impaired method for fair value determination							We complete a goodwill impairment analysis which may be a qualitative or a quantitative two-step analysis depending on the facts and circumstances associated with the reporting unit. In conjunction with a qualitative impairment analysis, we assess relevant qualitative factors to determine whether it is “more-likely-than-not” that the fair value of a reporting unit is less than its carrying amount. The “more-likely-than-not” threshold is defined as having a likelihood of more than 50 percent. In conjunction with a quantitative impairment analysis, we complete Step 1 of the goodwill impairment analysis. Step 1 consists of a comparison of the fair value of the reporting unit to the reporting unit’s carrying value, including goodwill. If the carrying value of the reporting unit exceeds the fair value, Step 2 in the goodwill impairment analysis is performed to measure the amount of impairment loss, if any. Step 2 of the goodwill impairment analysis compares the implied fair value of the reporting unit’s goodwill to the carrying value of the reporting unit’s goodwill. The implied fair value of goodwill is determined in a manner consistent with determining goodwill in a business combination. If the carrying amount of the reporting unit’s goodwill exceeds the implied fair value of the goodwill, an impairment loss is recognized in an amount equal to that excess. If, based on first assessing impairment utilizing a qualitative approach, we determine it is “more-likely-than-not” that the fair value of the reporting unit is less than its carrying amount, we will also complete a quantitative impairment analysis.
Option to exercise clean-up call and purchase education loans from trust of original loan balance							10 percent or less of the original loan balance
Percentage of trust's asset balance needed to trigger clean-up call							10.00%
Option to purchase education loan of the trust's initial pool balance							up to 10 percent of the trust’s initial pool balance
Description of post employment benefits							The Company administers the Navient Corporation Employee Severance Plan and the Navient Corporation Executive Severance Plan for Senior Officers (collectively, “the Severance Plan”). The Severance Plan provides severance benefits in the event of termination of the Company’s full-time employees and part-time employees who work at least 24 hours per week.
Restructuring/other reorganization expenses	4,000,000	$ 1,000,000	$ 2,000,000	$ 7,000,000	29,000,000		$ 13,000,000	29,000,000
Contract with customer, revenue recognized							359,000,000
Tax Cuts and Jobs Act, Reclassification from AOCI to Retained Earnings, Tax Effect							(13,000,000)
Business Processing [Member]
Summary Of Significant Accounting Policies [Line Items]
Contract with customer, revenue recognized							268,000,000
Business Processing [Member] | ASU 2014-09 [Member]
Summary Of Significant Accounting Policies [Line Items]
Contract with customer, revenue recognized							8,000,000
Expenses recognized from contract with customer							5,000,000
Federal Education Loans [Member]
Summary Of Significant Accounting Policies [Line Items]
Loans, net	72,253,000,000				81,703,000,000		72,253,000,000	81,703,000,000
Contract with customer, revenue recognized							91,000,000
Federal Education Loans [Member] | ASU 2014-09 [Member] | Difference Before and After Topic 606 [Member]
Summary Of Significant Accounting Policies [Line Items]
Effect of change in accounting policy on asset recovery							46,000,000
Effect of change in accounting policy on operating expense							46,000,000
Effect of change in accounting policy on net income							0
Default Aversion Service [Member]
Summary Of Significant Accounting Policies [Line Items]
Deferred asset recovery revenue recognized						$ 47,000,000
Securitization Trust [Member]
Summary Of Significant Accounting Policies [Line Items]
Assets	19,000,000						19,000,000
Residual interests							9,000,000
Securitization Trust [Member] | Earnest [Member]
Summary Of Significant Accounting Policies [Line Items]
Assets	10,000,000						$ 10,000,000
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Delinquency period (in days)							212 days
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of aggregate education loan to purchase							10.00%
FFELP Loans [Member]
Summary Of Significant Accounting Policies [Line Items]
Loans receivable, Fair Value	72,074,000,000				82,271,000,000		$ 72,074,000,000	82,271,000,000
Uncollected contractual principal and interest payments	59,551,000,000				67,853,000,000		59,551,000,000	67,853,000,000		$ 70,557,000,000
Loans, net	72,253,000,000				81,703,000,000		72,253,000,000	81,703,000,000
Loans receivable, discount	$ 37,000,000				43,000,000		37,000,000	43,000,000	$ 47,000,000
Allowance for loans acquired							$ 0	0
FFELP Loans [Member] | After October 1 1993 and before July 1 2006 [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage reimbursement on all qualifying default claims period	98.00%						98.00%
FFELP Loans [Member] | On or After July 1 2006 [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage reimbursement on all qualifying default claims period	97.00%						97.00%
FFELP Loans [Member] | Prior to October 1 1993 [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage reimbursement on all qualifying default claims period	100.00%						100.00%
Loans Acquired With Non-Deteriorated Credit Quality [Member] | FFELP Loans [Member]
Summary Of Significant Accounting Policies [Line Items]
Loans receivable, principal amount					3,500,000,000			3,500,000,000
Private Education Loans [Member]
Summary Of Significant Accounting Policies [Line Items]
Loans receivable, Fair Value	$ 22,958,000,000				24,421,000,000		$ 22,958,000,000	24,421,000,000
Uncollected contractual principal and interest payments	22,037,000,000				22,924,000,000		22,037,000,000	22,924,000,000		$ 22,150,000,000
Estimated accretable yield									108,000,000
Loans, net	22,245,000,000				23,419,000,000		22,245,000,000	23,419,000,000
Valuation allowance	0						0
Loans receivable, discount	326,000,000				392,000,000		326,000,000	392,000,000	424,000,000
Allowance for loans acquired							$ 0	0
Allowance for credit losses factors influenced managements judgment							Our model is based upon the most recent twelve months of actual collection experience as the starting point for the non-TDR portfolio and the most recent approximate 15 years for the TDR portfolio and applies expected macroeconomic changes and collection procedure changes to estimate expected losses caused by loss events incurred as of the balance sheet date. Our model for the non-TDR portfolio places a greater emphasis on the more recent default experience rather than the default experience for older historical periods, as we believe the more recent default experience is more indicative of the probable losses incurred in the loan portfolio today that will default over the next two years. The TDR portfolio uses a longer historical default experience since we are projecting life of loan remaining losses. Similar to estimating defaults, we use historical customer payment behavior to estimate the timing and amount of future recoveries on charged-off loans. We use judgment in determining whether historical performance is representative of what we expect to collect in the future. We then apply the default and collection rate projections to each category of loans. Once the quantitative calculation is performed, we review the adequacy of the allowance for loan losses and determine if qualitative adjustments need to be considered. Additionally, we consider changes in laws and regulations that could potentially impact the allowance for loan losses.
Private Education Loans [Member] | Loans With Deteriorated Credit Quality [Member]
Summary Of Significant Accounting Policies [Line Items]
Loans receivable, principal amount									261,000,000
Loans receivable, Fair Value									101,000,000
Uncollected contractual principal and interest payments									$ 411,000,000
Loans, net	$ 82,000,000						$ 82,000,000
Private Education Loans [Member] | Loans Acquired With Non-Deteriorated Credit Quality [Member]
Summary Of Significant Accounting Policies [Line Items]
Loans receivable, principal amount					$ 2,800,000,000			$ 2,800,000,000

Education Loans - Additional In

Education Loans - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Percentage of education loan portfolio in repayment	86.00%	86.00%
After October 1 1993 and before July 1 2006 [Member] | FFELP Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Percentage reimbursement on all qualifying default claims period	98.00%
On or After July 1 2006 [Member] | FFELP Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Percentage reimbursement on all qualifying default claims period	97.00%
Weighted Average [Member]
Accounts Notes And Loans Receivable [Line Items]
Estimated weighted average life of education loans	6 years	7 years
Stafford Loans [Member] | Minimum [Member] | FFELP Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Repayment term	5 years
Stafford Loans [Member] | Maximum [Member] | FFELP Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Repayment term	10 years
Plus Loans [Member] | Minimum [Member] | FFELP Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Repayment term	5 years
Plus Loans [Member] | Maximum [Member] | FFELP Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Repayment term	10 years
Consolidation Loans [Member] | Minimum [Member] | FFELP Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Repayment term	12 years
Consolidation Loans [Member] | Maximum [Member] | FFELP Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Repayment term	30 years
Private Education Loans [Member] | Minimum [Member]
Accounts Notes And Loans Receivable [Line Items]
Repayment term	10 years
Private Education Loans [Member] | Maximum [Member]
Accounts Notes And Loans Receivable [Line Items]
Repayment term	15 years

Education Loans - Education Loa

Education Loans - Education Loan Portfolio by Program (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Loans, net	$ 94,498	$ 105,122
Percentage to total education loans	100.00%	100.00%
Average Balance education loans	$ 100,252	$ 108,751
Average Effective Interest Rate of education loans	4.79%	3.98%
FFELP Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans, net	$ 72,253	$ 81,703
Stafford And Other Education Loans [Member] | FFELP Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans, net	$ 24,641	$ 28,409
Percentage to total education loans	26.00%	27.00%
Average Balance education loans	$ 26,612	$ 30,462
Average Effective Interest Rate of education loans	3.98%	2.94%
Consolidation Loans Member | FFELP Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans, net	$ 47,612	$ 53,294
Percentage to total education loans	50.00%	51.00%
Average Balance education loans	$ 50,359	$ 54,527
Average Effective Interest Rate of education loans	3.91%	3.30%
Private Education Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans, net	$ 22,245	$ 23,419
Percentage to total education loans	24.00%	22.00%
Average Balance education loans	$ 23,281	$ 23,762
Average Effective Interest Rate of education loans	7.64%	6.88%

Allowance for Loan Losses - Add

Allowance for Loan Losses - Additional Information (Detail) $ in Billions	12 Months Ended
	Dec. 31, 2018USD ($)Loan	Dec. 31, 2017USD ($)
Financing Receivable, Allowance for Credit Losses [Line Items]
Percentage of loans granted forbearance that migrated to TDR classification	65.00%	61.00%
Payment default period for TDRs	60 days past due
Interest Rate Reduction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
TDR loans, Unpaid Principal Balance | $	$ 1.8	$ 2.7
Minimum [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Delinquency period (in days)	212 days
Private Education Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Number of classes of loans | Loan	2

Allowance for Loan Losses - All

Allowance for Loan Losses - Allowance for Credit Losses and Recorded Investments in Loans (Detail) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2018USD ($)SecurityLoan	Dec. 31, 2017USD ($)SecurityLoan	Dec. 31, 2016USD ($)SecurityLoan
Allowance for Loan Losses
Beginning balance				$ 1,367				$ 1,433	$ 1,367	$ 1,433	$ 1,564
Total provision	$ 85	$ 85	$ 112	87	$ 109	$ 105	$ 105	107	370	426	429
Net adjustment resulting from the change in the charge-off rate									(32)
Net charge-offs remaining									(427)
Total net charge-offs									(459)	(499)	(570)
Reclassification of interest reserve									8	7	10
Ending balance	1,286				1,367				1,286	1,367	1,433
Allowance Ending Balance:
Ending balance: individually evaluated for impairment - TDR	1,108				1,180				1,108	1,180	1,201
Ending balance: collectively evaluated for impairment											232
Collectively evaluated for impairment:
Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans	178				187				178	187
Ending balance	1,286				1,367				1,286	1,367	1,433
Loans Ending Balance:
Ending balance: individually evaluated for impairment - TDR	10,364				10,951				10,364	10,951	11,197
Collectively evaluated for impairment:
Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans	80,395				89,761				80,395	89,761
Purchased Non-Credit Impaired Loans acquired at a discount	5,030				5,847				5,030	5,847
Purchased Credit Impaired Loans	225				248				225	248
Collectively evaluated for impairment:											101,033
Ending total loans	96,014				106,807				96,014	106,807	112,230
Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans	178				187				178	187
Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans	80,395				89,761				80,395	89,761
Purchased Non-Credit Impaired Loans acquired at a discount(3)	5,030				5,847				5,030	5,847
Purchased Credit Impaired Loans(3)	225				248				225	248
Ending balance	1,286				1,367				1,286	1,367	1,433
FFELP Loans [Member]
Allowance for Loan Losses
Beginning balance				60				67	60	67	78
Total provision									70	42	43
Net charge-offs remaining									(54)
Total net charge-offs									(54)	(49)	(54)
Ending balance	76				60				76	60	67
Allowance Ending Balance:
Ending balance: collectively evaluated for impairment											67
Collectively evaluated for impairment:
Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans	76				60				76	60
Ending balance	76				60				76	60	67
Collectively evaluated for impairment:
Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans	68,880				77,860				68,880	77,860
Purchased Non-Credit Impaired Loans acquired at a discount	2,850				3,237				2,850	3,237
Collectively evaluated for impairment:											86,918
Ending total loans	71,730				81,097				$ 71,730	$ 81,097	$ 86,918
Net charge-offs as a percentage of average loans in repayment, excluding the net adjustment resulting from the change in the charge-off rate (annualized)									0.09%
Allowance coverage of charge-offs | SecurityLoan									1.4	1.2	1.2
Allowance as a percentage of the ending total loan balance									0.11%	0.07%	0.08%
Allowance as a percentage of the ending loans in repayment									0.13%	0.09%	0.09%
Average loans in repayment									$ 62,927	$ 68,318	$ 72,714
Ending loans in repayment	59,551				67,853				59,551	67,853	$ 70,557
Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans	76				60				76	60
Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans	68,880				77,860				68,880	77,860
Purchased Non-Credit Impaired Loans acquired at a discount(3)	2,850				3,237				2,850	$ 3,237
Charge-offs as a percentage of average loans in repayment										0.07%	0.07%
Ending balance	76				60				76	$ 60	$ 67
Private Education Loans [Member]
Allowance for Loan Losses
Beginning balance				1,297				1,351	1,297	1,351	1,471
Total provision									299	382	383
Net adjustment resulting from the change in the charge-off rate									(32)
Net charge-offs remaining									(371)
Total net charge-offs									(403)	(443)	(513)
Reclassification of interest reserve									8	7	10
Ending balance	1,201				1,297				1,201	1,297	1,351
Allowance Ending Balance:
Ending balance: individually evaluated for impairment - TDR	1,100				1,171				1,100	1,171	1,190
Ending balance: collectively evaluated for impairment											161
Collectively evaluated for impairment:
Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans	101				126				101	126
Ending balance	1,201				1,297				1,201	1,297	1,351
Loans Ending Balance:
Ending balance: individually evaluated for impairment - TDR	10,336				10,921				10,336	10,921	11,165
Collectively evaluated for impairment:
Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans	11,464				11,861				11,464	11,861
Purchased Non-Credit Impaired Loans acquired at a discount	2,180				2,610				2,180	2,610
Purchased Credit Impaired Loans	225				248				225	248
Collectively evaluated for impairment:											13,983
Ending total loans	24,205				25,640				$ 24,205	$ 25,640	$ 25,148
Net charge-offs as a percentage of average loans in repayment, excluding the net adjustment resulting from the change in the charge-off rate (annualized)									1.66%
Net adjustment resulting from the change in the charge-off rate as a percentage of average loans in repayment (annualized)									0.14%
Allowance coverage of charge-offs | SecurityLoan									3	2.9	2.6
Allowance as a percentage of the ending total loan balance									4.96%	5.06%	5.37%
Allowance as a percentage of the ending loans in repayment									5.45%	5.66%	6.10%
Average loans in repayment									$ 22,312	$ 22,342	$ 23,275
Ending loans in repayment	22,037				22,924				22,037	22,924	$ 22,150
Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans	101				126				101	126
Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans	11,464				11,861				11,464	11,861
Purchased Non-Credit Impaired Loans acquired at a discount(3)	2,180				2,610				2,180	2,610
Purchased Credit Impaired Loans(3)	225				248				225	$ 248
Charge-offs as a percentage of average loans in repayment										1.98%	2.20%
Ending balance	1,201				1,297				1,201	$ 1,297	$ 1,351
Other Loans [Member]
Allowance for Loan Losses
Beginning balance				$ 10				$ 15	10	15	15
Total provision									1	2	3
Net charge-offs remaining									(2)
Total net charge-offs									(2)	(7)	(3)
Ending balance	9				10				9	10	15
Allowance Ending Balance:
Ending balance: individually evaluated for impairment - TDR	8				9				8	9	11
Ending balance: collectively evaluated for impairment											4
Collectively evaluated for impairment:
Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans	1				1				1	1
Ending balance	9				10				9	10	15
Loans Ending Balance:
Ending balance: individually evaluated for impairment - TDR	28				30				28	30	32
Collectively evaluated for impairment:
Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans	51				40				51	40
Collectively evaluated for impairment:											132
Ending total loans	79				70				$ 79	$ 70	$ 164
Allowance coverage of charge-offs | SecurityLoan										1.5	7
Allowance as a percentage of the ending total loan balance									11.52%	14.32%	9.35%
Allowance as a percentage of the ending loans in repayment									11.52%	14.32%	9.35%
Average loans in repayment									$ 75	$ 130	$ 104
Ending loans in repayment	79				70				79	70	$ 164
Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans	1				1				1	1
Excluding Purchased Non-Credit Impaired Loans acquired at a discount and Purchased Credit Impaired Loans	51				40				51	$ 40
Charge-offs as a percentage of average loans in repayment										5.39%	2.10%
Ending balance	$ 9				$ 10				$ 9	$ 10	$ 15

Allowance for Loan Losses - A_2

Allowance for Loan Losses - Allowance for Credit Losses and Recorded Investments in Loans (Parenthetical) (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Jun. 01, 2017
Accounts Notes And Loans Receivable [Line Items]
Net adjustment resulting from the change in the charge-off rate		$ 32,000,000
FFELP Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance for loans acquired		0	$ 0
Loans receivable, discount		37,000,000	43,000,000	$ 47,000,000
Private Education Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Net adjustment resulting from the change in the charge-off rate		32,000,000
Allowance for loans acquired		0	0
Loans receivable, discount		$ 326,000,000	$ 392,000,000	$ 424,000,000
Private Education Loans [Member] | Loans Receivable For Partially Charged Off Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Net adjustment resulting from the change in the charge-off rate	$ 32,000,000
Private Education Loans [Member] | Minimum [Member]
Accounts Notes And Loans Receivable [Line Items]
Portion of loan amount charged off at default	79.00%
Private Education Loans [Member] | Maximum [Member]
Accounts Notes And Loans Receivable [Line Items]
Portion of loan amount charged off at default	80.50%

Allowance for Loan Losses - Age

Allowance for Loan Losses - Age Analysis of Past Due Loans Delinquencies (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loans in repayment and percentage of each status:
Loans allowance for losses	$ (1,286)	$ (1,367)	$ (1,433)	$ (1,564)
Loans, net	94,498	105,122
FFELP Loans [Member]
Loans in repayment and percentage of each status:
Total loans in repayment	59,551	67,853	70,557
Loans allowance for losses	(76)	(60)	(67)	$ (78)
Loans, net	72,253	81,703
Credit Concentration Risk [Member] | Private Education Loans - TDRs [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans, gross	9,969	10,536	10,805
Loans in repayment and percentage of each status:
Loans current	7,890	8,333	8,273
Total loans in repayment	9,025	9,378	9,638
Loans unamortized premium (discount)	(212)	(225)	(237)
Total loans	9,757	10,311	10,568
Loans receivable for partially charged-off loans	367	385	360
Loans allowance for losses	(1,100)	(1,171)	(1,190)
Loans, net	9,024	9,525	9,738
Credit Concentration Risk [Member] | Private Education Loans - Non-TDRs [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans, gross	13,562	14,344	13,528
Loans in repayment and percentage of each status:
Total loans in repayment	13,012	13,546	12,512
Loans unamortized premium (discount)	(547)	(699)	(220)
Total loans	13,015	13,645	13,308
Loans receivable for partially charged-off loans	307	375	455
Loans allowance for losses	(101)	(126)	(161)
Loans, net	$ 13,221	$ 13,894	$ 13,602
Credit Concentration Risk [Member] | Accounts Receivable [Member] | Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	100.00%	100.00%	100.00%
Credit Concentration Risk [Member] | Accounts Receivable [Member] | Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	100.00%	100.00%	100.00%
Credit Concentration Risk [Member] | Financing Receivables, 31 to 60 Days Past Due [Member] | Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent	$ 344	$ 351	$ 412
Credit Concentration Risk [Member] | Financing Receivables, 31 to 60 Days Past Due [Member] | Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent	$ 71	$ 120	$ 110
Credit Concentration Risk [Member] | Financing Receivables, 31 to 60 Days Past Due [Member] | Accounts Receivable [Member] | Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	3.80%	3.70%	4.30%
Credit Concentration Risk [Member] | Financing Receivables, 31 to 60 Days Past Due [Member] | Accounts Receivable [Member] | Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	0.50%	0.90%	0.90%
Credit Concentration Risk [Member] | Financing Receivables, 61 to 90 Days Past Due [Member] | Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent	$ 235	$ 207	$ 267
Credit Concentration Risk [Member] | Financing Receivables, 61 to 90 Days Past Due [Member] | Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent	$ 32	$ 59	$ 54
Credit Concentration Risk [Member] | Financing Receivables, 61 to 90 Days Past Due [Member] | Accounts Receivable [Member] | Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	2.60%	2.20%	2.80%
Credit Concentration Risk [Member] | Financing Receivables, 61 to 90 Days Past Due [Member] | Accounts Receivable [Member] | Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	0.30%	0.40%	0.40%
Credit Concentration Risk [Member] | Financing Receivables, 90 Days Past Due [Member] | Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent	$ 556	$ 487	$ 686
Credit Concentration Risk [Member] | Financing Receivables, 90 Days Past Due [Member] | Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent	$ 58	$ 110	$ 115
Credit Concentration Risk [Member] | Financing Receivables, 90 Days Past Due [Member] | Accounts Receivable [Member] | Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	6.20%	5.20%	7.10%
Credit Concentration Risk [Member] | Financing Receivables, 90 Days Past Due [Member] | Accounts Receivable [Member] | Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	0.40%	0.80%	0.90%
Credit Concentration Risk [Member] | Financing Receivables, Current [Member] | Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Loans current	$ 12,851	$ 13,257	$ 12,233
Credit Concentration Risk [Member] | Financing Receivables, Current [Member] | Accounts Receivable [Member] | Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	87.40%	88.90%	85.80%
Credit Concentration Risk [Member] | Financing Receivables, Current [Member] | Accounts Receivable [Member] | Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	98.80%	97.90%	97.80%
Credit Concentration Risk [Member] | Financing Receivables, Loans In Repayment [Member] | Accounts Receivable [Member] | Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	90.50%	89.00%	89.20%
Credit Concentration Risk [Member] | Financing Receivables, Loans In Repayment [Member] | Accounts Receivable [Member] | Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	95.90%	94.40%	92.50%
Credit Concentration Risk [Member] | Financing Receivables, Delinquent Loans in Repayment [Member] | Accounts Receivable [Member] | Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	12.60%	11.10%	14.20%
Credit Concentration Risk [Member] | Financing Receivables, Delinquent Loans in Repayment [Member] | Accounts Receivable [Member] | Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	1.20%	2.10%	2.20%
Credit Concentration Risk [Member] | Financing Receivables, Forbearance, Loans In Repayment [Member] | Accounts Receivable [Member] | Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	5.40%	6.80%	5.70%
Credit Concentration Risk [Member] | Financing Receivables, Forbearance, Loans In Repayment [Member] | Accounts Receivable [Member] | Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	1.20%	1.60%	1.60%
Credit Concentration Risk [Member] | School/Grace/Deferment [Member] | Private Education Loans - TDRs [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans, gross	$ 426	$ 477	$ 579
Credit Concentration Risk [Member] | School/Grace/Deferment [Member] | Private Education Loans - Non-TDRs [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans, gross	392	584	814
Credit Concentration Risk [Member] | Forbearance [Member] | Private Education Loans - TDRs [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans, gross	518	681	588
Credit Concentration Risk [Member] | Forbearance [Member] | Private Education Loans - Non-TDRs [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans, gross	158	214	202
Credit Concentration Risk [Member] | FFELP Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans, gross	71,730	81,097	86,918
Loans in repayment and percentage of each status:
Loans current	53,500	59,264	61,977
Total loans in repayment	59,551	67,853	70,557
Loans unamortized premium (discount)	599	666	879
Total loans	72,329	81,763	87,797
Loans allowance for losses	(76)	(60)	(67)
Loans, net	$ 72,253	$ 81,703	$ 87,730
Credit Concentration Risk [Member] | FFELP Loans [Member] | Accounts Receivable [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	100.00%	100.00%	100.00%
Credit Concentration Risk [Member] | FFELP Loans [Member] | Financing Receivables, 31 to 60 Days Past Due [Member]
Loans in repayment and percentage of each status:
Loans delinquent	$ 1,964	$ 2,638	$ 2,820
Credit Concentration Risk [Member] | FFELP Loans [Member] | Financing Receivables, 31 to 60 Days Past Due [Member] | Accounts Receivable [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	3.40%	3.90%	4.00%
Credit Concentration Risk [Member] | FFELP Loans [Member] | Financing Receivables, 61 to 90 Days Past Due [Member]
Loans in repayment and percentage of each status:
Loans delinquent	$ 910	$ 1,763	$ 1,325
Credit Concentration Risk [Member] | FFELP Loans [Member] | Financing Receivables, 61 to 90 Days Past Due [Member] | Accounts Receivable [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	1.50%	2.60%	1.90%
Credit Concentration Risk [Member] | FFELP Loans [Member] | Financing Receivables, 90 Days Past Due [Member]
Loans in repayment and percentage of each status:
Loans delinquent	$ 3,177	$ 4,188	$ 4,435
Credit Concentration Risk [Member] | FFELP Loans [Member] | Financing Receivables, 90 Days Past Due [Member] | Accounts Receivable [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	5.30%	6.20%	6.30%
Credit Concentration Risk [Member] | FFELP Loans [Member] | Financing Receivables, Current [Member] | Accounts Receivable [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	89.80%	87.30%	87.80%
Credit Concentration Risk [Member] | FFELP Loans [Member] | Financing Receivables, Loans In Repayment [Member] | Accounts Receivable [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	83.00%	83.70%	81.20%
Credit Concentration Risk [Member] | FFELP Loans [Member] | Financing Receivables, Delinquent Loans in Repayment [Member] | Accounts Receivable [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	10.20%	12.70%	12.20%
Credit Concentration Risk [Member] | FFELP Loans [Member] | Financing Receivables, Forbearance, Loans In Repayment [Member] | Accounts Receivable [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	12.30%	11.20%	12.90%
Credit Concentration Risk [Member] | FFELP Loans [Member] | School/Grace/Deferment [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans, gross	$ 3,793	$ 4,711	$ 5,871
Credit Concentration Risk [Member] | FFELP Loans [Member] | Forbearance [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans, gross	$ 8,386	$ 8,533	$ 10,490

Allowance for Loan Losses - Pri

Allowance for Loan Losses - Private Education Loan Portfolio Stratified by Key Credit Quality Indicators (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Private Education Loans - TDRs [Member] | Original Winning FICO Scores [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 9,969	$ 10,536
Total Private Education Loans Credit Quality Indicators, Percent	100.00%	100.00%
Private Education Loans - TDRs [Member] | Original Winning FICO Scores [Member] | FICO 640 and Above [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 9,133	$ 9,647
Total Private Education Loans Credit Quality Indicators, Percent	92.00%	92.00%
Private Education Loans - TDRs [Member] | Original Winning FICO Scores [Member] | FICO Below 640 [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 836	$ 889
Total Private Education Loans Credit Quality Indicators, Percent	8.00%	8.00%
Private Education Loans - TDRs [Member] | School Type [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 9,969	$ 10,536
Total Private Education Loans Credit Quality Indicators, Percent	100.00%	100.00%
Private Education Loans - TDRs [Member] | School Type [Member] | Not For Profit [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 7,888	$ 8,247
Total Private Education Loans Credit Quality Indicators, Percent	79.00%	78.00%
Private Education Loans - TDRs [Member] | School Type [Member] | For Profit [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 2,081	$ 2,289
Total Private Education Loans Credit Quality Indicators, Percent	21.00%	22.00%
Private Education Loans - TDRs [Member] | Cosigners [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 9,969	$ 10,536
Total Private Education Loans Credit Quality Indicators, Percent	100.00%	100.00%
Private Education Loans - TDRs [Member] | Cosigners [Member] | With Consigner [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 6,172	$ 6,441
Total Private Education Loans Credit Quality Indicators, Percent	62.00%	61.00%
Private Education Loans - TDRs [Member] | Cosigners [Member] | Without Consigner [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 3,797	$ 4,095
Total Private Education Loans Credit Quality Indicators, Percent	38.00%	39.00%
Private Education Loans - TDRs [Member] | Seasoning [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 9,969	$ 10,536
Total Private Education Loans Credit Quality Indicators, Percent	100.00%	100.00%
Private Education Loans - TDRs [Member] | Seasoning [Member] | 1-12 Payments [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 335	$ 506
Total Private Education Loans Credit Quality Indicators, Percent	3.00%	5.00%
Private Education Loans - TDRs [Member] | Seasoning [Member] | 13-24 Payments [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 436	$ 644
Total Private Education Loans Credit Quality Indicators, Percent	4.00%	6.00%
Private Education Loans - TDRs [Member] | Seasoning [Member] | 25-36 Payments [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 660	$ 947
Total Private Education Loans Credit Quality Indicators, Percent	7.00%	9.00%
Private Education Loans - TDRs [Member] | Seasoning [Member] | 37-48 Payments [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 934	$ 1,271
Total Private Education Loans Credit Quality Indicators, Percent	10.00%	12.00%
Private Education Loans - TDRs [Member] | Seasoning [Member] | More than 48 Payments [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 7,178	$ 6,691
Total Private Education Loans Credit Quality Indicators, Percent	72.00%	63.00%
Private Education Loans - TDRs [Member] | Seasoning [Member] | Not Yet in Repayment [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 426	$ 477
Total Private Education Loans Credit Quality Indicators, Percent	4.00%	5.00%
Private Education Loans - Non-TDRs [Member] | Original Winning FICO Scores [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 13,562	$ 14,344
Total Private Education Loans Credit Quality Indicators, Percent	100.00%	100.00%
Private Education Loans - Non-TDRs [Member] | Original Winning FICO Scores [Member] | FICO 640 and Above [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 13,087	$ 13,752
Total Private Education Loans Credit Quality Indicators, Percent	96.00%	96.00%
Private Education Loans - Non-TDRs [Member] | Original Winning FICO Scores [Member] | FICO Below 640 [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 475	$ 592
Total Private Education Loans Credit Quality Indicators, Percent	4.00%	4.00%
Private Education Loans - Non-TDRs [Member] | School Type [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 13,562	$ 14,344
Total Private Education Loans Credit Quality Indicators, Percent	100.00%	100.00%
Private Education Loans - Non-TDRs [Member] | School Type [Member] | Not For Profit [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 11,953	$ 12,431
Total Private Education Loans Credit Quality Indicators, Percent	88.00%	87.00%
Private Education Loans - Non-TDRs [Member] | School Type [Member] | For Profit [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 1,609	$ 1,913
Total Private Education Loans Credit Quality Indicators, Percent	12.00%	13.00%
Private Education Loans - Non-TDRs [Member] | Cosigners [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 13,562	$ 14,344
Total Private Education Loans Credit Quality Indicators, Percent	100.00%	100.00%
Private Education Loans - Non-TDRs [Member] | Cosigners [Member] | With Consigner [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 6,961	$ 9,193
Total Private Education Loans Credit Quality Indicators, Percent	51.00%	64.00%
Private Education Loans - Non-TDRs [Member] | Cosigners [Member] | Without Consigner [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 6,601	$ 5,151
Total Private Education Loans Credit Quality Indicators, Percent	49.00%	36.00%
Private Education Loans - Non-TDRs [Member] | Seasoning [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 13,562	$ 14,344
Total Private Education Loans Credit Quality Indicators, Percent	100.00%	100.00%
Private Education Loans - Non-TDRs [Member] | Seasoning [Member] | 1-12 Payments [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 3,353	$ 1,424
Total Private Education Loans Credit Quality Indicators, Percent	25.00%	10.00%
Private Education Loans - Non-TDRs [Member] | Seasoning [Member] | 13-24 Payments [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 486	$ 437
Total Private Education Loans Credit Quality Indicators, Percent	3.00%	3.00%
Private Education Loans - Non-TDRs [Member] | Seasoning [Member] | 25-36 Payments [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 322	$ 466
Total Private Education Loans Credit Quality Indicators, Percent	2.00%	3.00%
Private Education Loans - Non-TDRs [Member] | Seasoning [Member] | 37-48 Payments [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 383	$ 867
Total Private Education Loans Credit Quality Indicators, Percent	3.00%	6.00%
Private Education Loans - Non-TDRs [Member] | Seasoning [Member] | More than 48 Payments [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 8,626	$ 10,566
Total Private Education Loans Credit Quality Indicators, Percent	64.00%	74.00%
Private Education Loans - Non-TDRs [Member] | Seasoning [Member] | Not Yet in Repayment [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Private Education Loans Credit Quality Indicators	$ 392	$ 584
Total Private Education Loans Credit Quality Indicators, Percent	3.00%	4.00%

Allowance for Loan Losses - Rec

Allowance for Loan Losses - Receivable for Partially Charged-Off Private Education Loans (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Receivable at beginning of period	$ 105,122
Charge-offs	(459)	$ (499)	$ (570)
Receivable at end of period	94,498	105,122
Private Education Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Receivable at beginning of period	23,419
Charge-offs	(403)	(443)	(513)
Receivable at end of period	22,245	23,419
Private Education Loans [Member] | Loans Receivable For Partially Charged Off Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Receivable at beginning of period	760	815	881
Expected future recoveries of current period defaults	89	110	128
Recoveries	(139)	(155)	(181)
Charge-offs	(36)	(10)	(13)
Receivable at end of period	$ 674	$ 760	$ 815

Allowance for Loan Losses - R_2

Allowance for Loan Losses - Receivable for Partially Charged-Off Private Education Loans (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2018
Financing Receivable, Allowance for Credit Losses [Line Items]
Net adjustment resulting from the change in the charge-off rate		$ 32
Private Education Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Net adjustment resulting from the change in the charge-off rate		$ 32
Private Education Loans [Member] | Minimum [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Portion of loan amount charged off at default	79.00%
Private Education Loans [Member] | Maximum [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Portion of loan amount charged off at default	80.50%
Private Education Loans [Member] | Loans Receivable For Partially Charged Off Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Net adjustment resulting from the change in the charge-off rate	$ 32

Allowance for Loan Losses - R_3

Allowance for Loan Losses - Recorded Investment, Unpaid Principal Balance and Related Allowance for TDR Loans (Detail) - TDR [Member] - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable Impaired [Line Items]
Recorded investment	$ 10,326	$ 10,890
Total ending loans	10,336	10,921
Related allowance	$ 1,100	$ 1,171

Allowance for Loan Losses - Ave

Allowance for Loan Losses - Average Recorded Investment and Interest Income Recognized for TDR (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Impaired financing receivable, Average recorded investment	$ 10,637	$ 10,989	$ 11,078
Impaired financing receivable, Interest income recognized	$ 764	$ 708	$ 667

Allowance for Loan Losses - Loa

Allowance for Loan Losses - Loans Modified Accounts for TDR (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Modified loans	$ 596	$ 816	$ 1,169
Charge-offs	343	346	382
Payment-default	$ 142	$ 181	$ 265

Allowance for Loan Losses - Acc

Allowance for Loan Losses - Accrued Interest Receivable (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounts Notes And Loans Receivable [Line Items]
Accrued Interest Receivable	$ 1,999	$ 1,965
Private Education Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Accrued Interest Receivable	354	383	$ 391
Accrued Interest Receivable, Allowance for Uncollectible Interest	27	26	30
Private Education Loans [Member] | TDR [Member]
Accounts Notes And Loans Receivable [Line Items]
Accrued Interest Receivable	205	196	192
Accrued Interest Receivable, Allowance for Uncollectible Interest	23	20	23
Private Education Loans [Member] | Non-TDR [Member]
Accounts Notes And Loans Receivable [Line Items]
Accrued Interest Receivable	149	187	199
Accrued Interest Receivable, Allowance for Uncollectible Interest	4	6	7
Accrued Interest Receivable, Greater Than 90 Days Past Due [Member] | Private Education Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Accrued Interest Receivable	29	24	33
Accrued Interest Receivable, Greater Than 90 Days Past Due [Member] | Private Education Loans [Member] | TDR [Member]
Accounts Notes And Loans Receivable [Line Items]
Accrued Interest Receivable	26	20	28
Accrued Interest Receivable, Greater Than 90 Days Past Due [Member] | Private Education Loans [Member] | Non-TDR [Member]
Accounts Notes And Loans Receivable [Line Items]
Accrued Interest Receivable	$ 3	$ 4	$ 5

Business Combinations, Goodwi_3

Business Combinations, Goodwill and Acquired Intangible Assets - Additional Information (Detail) - USD ($)	Oct. 01, 2018	Nov. 30, 2017	Jul. 31, 2017	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Nov. 30, 2018	Jul. 31, 2018
Business Acquisition [Line Items]
Goodwill					$ 665,000,000	$ 701,000,000
Goodwill impairment loss					0
Amortization of acquired intangible assets					31,000,000	$ 23,000,000	$ 29,000,000
2,019					26,000,000
2,020					22,000,000
2,021					19,000,000
2,022					16,000,000
After 2,022					38,000,000
FFELP Loans [Member]
Business Acquisition [Line Items]
Goodwill impairment loss	$ 0
Federal Education Loan Servicing [Member]
Business Acquisition [Line Items]
Goodwill impairment loss	0
Government Services [Member]
Business Acquisition [Line Items]
Goodwill				$ 136,000,000
Goodwill impairment loss				$ 0
Reporting unit, percentage of fair value is greater than book value				56.00%
Government Services [Member] | Toll Services [Member]
Business Acquisition [Line Items]
Impairment of intangible assets				$ 16,000,000	16,000,000
Private Education Refinance Loans [Member]
Business Acquisition [Line Items]
Goodwill impairment loss	0
Healthcare Services [Member]
Business Acquisition [Line Items]
Goodwill	106,000,000
Goodwill impairment loss	$ 0
Reporting unit, percentage of fair value is greater than book value	28.00%
Business Processing [Member]
Business Acquisition [Line Items]
Goodwill					242,000,000
Business Processing [Member] | Servicing [Member]
Business Acquisition [Line Items]
Change in reallocation of goodwill					50,000,000
Business Processing [Member] | Government Services [Member]
Business Acquisition [Line Items]
Goodwill					136,000,000
Business Processing [Member] | Healthcare Services [Member]
Business Acquisition [Line Items]
Goodwill					106,000,000
Federal Education Loans [Member]
Business Acquisition [Line Items]
Goodwill					240,000,000
Federal Education Loans [Member] | FFELP Loans [Member]
Business Acquisition [Line Items]
Goodwill					227,000,000
Change in reallocation of goodwill					37,000,000
Federal Education Loans [Member] | Federal Education Loan Servicing [Member]
Business Acquisition [Line Items]
Goodwill					13,000,000
Change in reallocation of goodwill					13,000,000
Federal Education Loans [Member] | Federal Education Loan Asset Recovery Services [Member]
Business Acquisition [Line Items]
Goodwill					$ 0
Earnest [Member]
Business Acquisition [Line Items]
Controlling interest percentage		95.00%
Payments to acquire business, cash		$ 149,000,000
Business acquisition, effective date of acquisition					Nov. 30, 2017
Goodwill								$ 77,000,000
Business acquisition, definite life intangible assets		$ 20,000,000
Earnest [Member] | Minimum [Member]
Business Acquisition [Line Items]
Definite life intangible assets, amortization period					5 years
Earnest [Member] | Maximum [Member]
Business Acquisition [Line Items]
Definite life intangible assets, amortization period					10 years
Duncan Solutions [Member]
Business Acquisition [Line Items]
Controlling interest percentage			100.00%
Payments to acquire business, cash			$ 86,000,000
Business acquisition, effective date of acquisition					Jul. 31, 2017
Goodwill									$ 39,000,000
Business acquisition, definite life intangible assets			$ 33,000,000
Duncan Solutions [Member] | Minimum [Member]
Business Acquisition [Line Items]
Definite life intangible assets, amortization period					2 years
Duncan Solutions [Member] | Maximum [Member]
Business Acquisition [Line Items]
Definite life intangible assets, amortization period					10 years

Business Combinations, Goodwi_4

Business Combinations, Goodwill and Acquired Intangible Assets - Summary of Goodwill, Accumulated Impairments and Net Goodwill for Each Reporting Units and Reportable Segments (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Nov. 30, 2018	Oct. 01, 2018	Sep. 30, 2018	Dec. 31, 2017
Goodwill [Line Items]
Gross	$ 846				$ 882
Accumulated Impairments and Other Adjustments	(181)				(181)
Net	665				701
Earnest [Member]
Goodwill [Line Items]
Net		$ 77
Government Services [Member]
Goodwill [Line Items]
Net				$ 136
Healthcare Services [Member]
Goodwill [Line Items]
Net			$ 106
Federal Education Loans [Member]
Goodwill [Line Items]
Gross	244
Accumulated Impairments and Other Adjustments	(4)
Net	240
Federal Education Loans [Member] | FFELP Loans [Member]
Goodwill [Line Items]
Gross	231
Accumulated Impairments and Other Adjustments	(4)
Net	227
Federal Education Loans [Member] | Federal Education Loan Servicing [Member]
Goodwill [Line Items]
Gross	13
Net	13
Consumer Lending Segment [Member]
Goodwill [Line Items]
Gross	224
Accumulated Impairments and Other Adjustments	(41)
Net	183
Consumer Lending Segment [Member] | Private Education Loans [Member]
Goodwill [Line Items]
Gross	147
Accumulated Impairments and Other Adjustments	(41)
Net	106
Consumer Lending Segment [Member] | Private Education Refinance Loans [Member]
Goodwill [Line Items]
Gross	77
Net	77
Business Processing [Member]
Goodwill [Line Items]
Gross	378
Accumulated Impairments and Other Adjustments	(136)
Net	242
Business Processing [Member] | Government Services [Member]
Goodwill [Line Items]
Gross	272
Accumulated Impairments and Other Adjustments	(136)
Net	136
Business Processing [Member] | Healthcare Services [Member]
Goodwill [Line Items]
Gross	106
Net	$ 106
FFELP Loans Segment [Member]
Goodwill [Line Items]
Gross					194
Accumulated Impairments and Other Adjustments					(4)
Net					190
Private Education Loans Segment
Goodwill [Line Items]
Gross					234
Accumulated Impairments and Other Adjustments					(41)
Net					193
Private Education Loans Segment | Earnest [Member]
Goodwill [Line Items]
Gross					87
Net					87
Private Education Loans Segment | Private Education Loans [Member]
Goodwill [Line Items]
Gross					147
Accumulated Impairments and Other Adjustments					(41)
Net					106
Business Services Segment [Member]
Goodwill [Line Items]
Gross					454
Accumulated Impairments and Other Adjustments					(136)
Net					318
Business Services Segment [Member] | Asset Recovery - Contingency [Member]
Goodwill [Line Items]
Gross					136
Accumulated Impairments and Other Adjustments					(136)
Business Services Segment [Member] | Asset Recovery - Gila [Member]
Goodwill [Line Items]
Gross					160
Net					160
Business Services Segment [Member] | Asset Recovery - Xtend Healthcare [Member]
Goodwill [Line Items]
Gross					108
Net					108
Business Services Segment [Member] | Servicing [Member]
Goodwill [Line Items]
Gross					50
Net					$ 50

Business Combinations, Goodwi_5

Business Combinations, Goodwill and Acquired Intangible Assets - Summary of Goodwill, Accumulated Impairments and Net Goodwill for Each Reporting Units and Reportable Segments (Parenthetical) (Detail) $ in Millions	Apr. 30, 2014USD ($)
SLM BankCo [Member]
Goodwill [Line Items]
Goodwill allocated to consumer banking business	$ 41

Business Combinations, Goodwi_6

Business Combinations, Goodwill and Acquired Intangible Assets - Acquired Intangible Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Acquired Finite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Cost Basis	$ 464	$ 447
Intangible assets subject to amortization, Accumulated Impairment and Amortization	(343)	(339)
Intangible assets subject to amortization, Net	121	108
Customer, Services and Lending Relationships [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Cost Basis	284	292
Intangible assets subject to amortization, Accumulated Impairment and Amortization	(226)	(234)
Intangible assets subject to amortization, Net	58	58
Favorable Lease [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Cost Basis	1	1
Intangible assets subject to amortization, Net	1	1
Non-competes [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Cost Basis	3	2
Intangible assets subject to amortization, Accumulated Impairment and Amortization	(3)	(2)
Software and Technology [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Cost Basis	115	104
Intangible assets subject to amortization, Accumulated Impairment and Amortization	(90)	(85)
Intangible assets subject to amortization, Net	25	19
Trade Names and Trademarks [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Cost Basis	61	48
Intangible assets subject to amortization, Accumulated Impairment and Amortization	(24)	(18)
Intangible assets subject to amortization, Net	$ 37	$ 30

Borrowings - Company's Borrowin

Borrowings - Company's Borrowings (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Short-term borrowings	$ 5,422	$ 4,771
Long-term borrowings	93,519	105,012
Total	98,941	109,783
Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Short-term borrowings	814	1,327
FFELP Loan - Other Facilities [Member]
Debt Instrument [Line Items]
Short-term borrowings	2,927	1,536
Long-term borrowings	5,600
Private Education Loan - Other Facilities [Member]
Debt Instrument [Line Items]
Short-term borrowings	1,114	684
Total Before Hedge Accounting Adjustments [Member]
Debt Instrument [Line Items]
Short-term borrowings	5,425	4,750
Long-term borrowings	93,868	105,018
Total	99,293	109,768
Total Before Hedge Accounting Adjustments [Member] | Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Short-term borrowings	817	1,306
Long-term borrowings	10,674	12,624
Total	11,491	13,930
Total Before Hedge Accounting Adjustments [Member] | Total Unsecured Borrowings [Member]
Debt Instrument [Line Items]
Short-term borrowings	817	1,306
Long-term borrowings	10,674	12,624
Total	11,491	13,930
Total Before Hedge Accounting Adjustments [Member] | FFELP Loan Securitizations [Member]
Debt Instrument [Line Items]
Long-term borrowings	66,318	71,208
Total	66,318	71,208
Total Before Hedge Accounting Adjustments [Member] | Private Education Loan Securitizations [Member]
Debt Instrument [Line Items]
Short-term borrowings	300	686
Long-term borrowings	12,985	12,646
Total	13,285	13,332
Total Before Hedge Accounting Adjustments [Member] | FFELP Loan - Other Facilities [Member]
Debt Instrument [Line Items]
Short-term borrowings	2,927	1,536
Long-term borrowings	2,625	6,830
Total	5,552	8,366
Total Before Hedge Accounting Adjustments [Member] | Private Education Loan - Other Facilities [Member]
Debt Instrument [Line Items]
Short-term borrowings	1,114	684
Long-term borrowings	1,266	1,710
Total	2,380	2,394
Total Before Hedge Accounting Adjustments [Member] | Other [Member]
Debt Instrument [Line Items]
Short-term borrowings	267	538
Total	267	538
Total Before Hedge Accounting Adjustments [Member] | Secured Borrowings [Member]
Debt Instrument [Line Items]
Short-term borrowings	4,608	3,444
Long-term borrowings	83,194	92,394
Total	87,802	95,838
Hedge Accounting Adjustments [Member]
Debt Instrument [Line Items]
Short-term borrowings	(3)	21
Long-term borrowings	(349)	(6)
Total	$ (352)	$ 15

Borrowings - Company's Borrow_2

Borrowings - Company's Borrowings (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term debt	$ 93,519	$ 105,012
Short-term Debt	5,422	4,771
Private Education Loan Securitizations Repurchase Facilities [Member]
Debt Instrument [Line Items]
Short-term Debt	300	686
Total Before Hedge Accounting Adjustments [Member]
Debt Instrument [Line Items]
Long-term debt	93,868	105,018
Short-term Debt	5,425	4,750
Total Before Hedge Accounting Adjustments [Member] | FFELP Loan Securitizations Asset-backed Repurchase Facilities [Member]
Debt Instrument [Line Items]
Long-term debt	244
Total Before Hedge Accounting Adjustments [Member] | Private Education Loan Securitizations Repurchase Facilities [Member]
Debt Instrument [Line Items]
Long-term debt	2,000	1,300
Short-term Debt	300	686
Total Before Hedge Accounting Adjustments [Member] | Short Term Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt principal amount	817	1,300
Total Before Hedge Accounting Adjustments [Member] | Long Term Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt principal amount	$ 10,800	$ 12,700

Borrowings - Outstanding Short-

Borrowings - Outstanding Short-Term Borrowings (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Short-term Debt [Line Items]
Short-term borrowings, Ending Balance	$ 5,422	$ 4,771
Weighted Average Interest Rate	3.56%	4.16%
Short-term borrowings, Average Balance	$ 4,833	$ 3,194
Weighted Average Interest Rate, Average Balance	4.35%	4.22%
Maximum outstanding at any month end	$ 6,363	$ 4,771
Private Education Loan Securitizations Repurchase Facilities [Member]
Short-term Debt [Line Items]
Short-term borrowings, Ending Balance	$ 300	$ 686
Weighted Average Interest Rate	5.23%	4.65%
Short-term borrowings, Average Balance	$ 536	$ 706
Weighted Average Interest Rate, Average Balance	4.72%	4.32%
FFELP Loan - Other Facilities [Member]
Short-term Debt [Line Items]
Short-term borrowings, Ending Balance	$ 2,927	$ 1,536
Weighted Average Interest Rate	3.10%	2.11%
Short-term borrowings, Average Balance	$ 1,137	$ 261
Weighted Average Interest Rate, Average Balance	2.79%	1.26%
Private Education Loan - Other Facilities [Member]
Short-term Debt [Line Items]
Short-term borrowings, Ending Balance	$ 1,114	$ 684
Weighted Average Interest Rate	3.63%	2.92%
Short-term borrowings, Average Balance	$ 847	$ 572
Weighted Average Interest Rate, Average Balance	3.40%	2.42%
Senior Unsecured Debt [Member]
Short-term Debt [Line Items]
Short-term borrowings, Ending Balance	$ 814	$ 1,327
Weighted Average Interest Rate	4.92%	8.06%
Short-term borrowings, Average Balance	$ 2,021	$ 1,197
Weighted Average Interest Rate, Average Balance	5.90%	6.80%
Other Interest Bearing Liabilities [Member]
Short-term Debt [Line Items]
Short-term borrowings, Ending Balance	$ 267	$ 538
Weighted Average Interest Rate	2.39%	1.33%
Short-term borrowings, Average Balance	$ 292	$ 458
Weighted Average Interest Rate, Average Balance	1.73%	1.27%

Borrowings - Long-Term Borrowin

Borrowings - Long-Term Borrowings (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term borrowings	$ 93,519	$ 105,012
Weighted Average Interest Rate	3.60%	2.67%
Long-term borrowings, Average Balance	$ 99,195	$ 109,088
U.S Dollar Denominated Interest Bearing, Due 2019-2083 [Member]
Debt Instrument [Line Items]
Long-term borrowings	$ 74,842
Weighted Average Interest Rate	3.38%
Long-term borrowings, Average Balance	$ 80,189
Non-U. S Dollar-Denominated Interest Bearing, Due 2023-2040 [Member]
Debt Instrument [Line Items]
Long-term borrowings	$ 4,064
Weighted Average Interest Rate	0.66%
Long-term borrowings, Average Balance	$ 4,919
Floating Rate Notes [Member]
Debt Instrument [Line Items]
Long-term borrowings	$ 78,906	$ 89,632
Weighted Average Interest Rate	3.24%	2.17%
Long-term borrowings, Average Balance	$ 85,108	$ 93,541
U.S Dollar Denominated Interest Bearing, Due 2020-2059 [Member]
Debt Instrument [Line Items]
Long-term borrowings	$ 14,431
Weighted Average Interest Rate	5.57%
Long-term borrowings, Average Balance	$ 13,814
Non-U. S Dollar Denominated Interest Bearing, Due 2034 [Member]
Debt Instrument [Line Items]
Long-term borrowings	$ 182
Weighted Average Interest Rate	2.49%
Long-term borrowings, Average Balance	$ 273
Fixed Rate Notes [Member]
Debt Instrument [Line Items]
Long-term borrowings	$ 14,613	$ 15,380
Weighted Average Interest Rate	5.53%	5.55%
Long-term borrowings, Average Balance	$ 14,087	$ 15,547
U.S Dollar Denominated Interest Bearing, Due 2018-2083 [Member]
Debt Instrument [Line Items]
Long-term borrowings		$ 83,209
Weighted Average Interest Rate		2.31%
Long-term borrowings, Average Balance		$ 86,186
Non-U. S Dollar-Denominated Interest Bearing, Due 2023-2041 [Member]
Debt Instrument [Line Items]
Long-term borrowings		$ 6,423
Weighted Average Interest Rate		0.37%
Long-term borrowings, Average Balance		$ 7,355
U.S Dollar Denominated Interest Bearing, Due 2019-2058 [Member]
Debt Instrument [Line Items]
Long-term borrowings		$ 15,114
Weighted Average Interest Rate		5.60%
Long-term borrowings, Average Balance		$ 15,266
Non-U. S Dollar Denominated Interest Bearing, Due 2034-2035 [Member]
Debt Instrument [Line Items]
Long-term borrowings		$ 266
Weighted Average Interest Rate		2.72%
Long-term borrowings, Average Balance		$ 281

Borrowings - Expected Maturitie

Borrowings - Expected Maturities of Long-term Borrowings (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
2,019	$ 10,300
2,020	11,900
2,021	7,900
2,022	8,000
2,023	7,700
2024-2043	48,800
Total	93,519	$ 105,012
Fixed Maturities [Member]
Debt Instrument [Line Items]
2,019	10,274
2,020	11,860
2,021	7,791
2,022	7,951
2,023	7,606
2024-2043	48,386
Long term debt maturities total	93,868
Hedge accounting adjustments	(349)
Total	93,519
Fixed Maturities [Member] | Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
2,020	2,046
2,021	1,434
2,022	1,736
2,023	1,496
2024-2043	3,962
Long term debt maturities total	10,674
Hedge accounting adjustments	107
Total	10,781
Fixed Maturities [Member] | Secured Borrowings [Member]
Debt Instrument [Line Items]
2,019	10,274
2,020	9,814
2,021	6,357
2,022	6,215
2,023	6,110
2024-2043	44,424
Long term debt maturities total	83,194
Hedge accounting adjustments	(456)
Total	$ 82,738

Borrowings - Expected Maturit_2

Borrowings - Expected Maturities of Long-term Borrowings (Parenthetical) (Detail) $ in Billions	Dec. 31, 2018USD ($)
Debt Disclosure [Abstract]
On-balance sheet securitization trust debt included in projected principal paydowns in 2019	$ 10.3
Aggregate principal amount of debt maturing in 2019	10.3
Aggregate principal amount of debt maturing in 2020	11.9
Aggregate principal amount of debt maturing in 2021	7.9
Aggregate principal amount of debt maturing in 2022	8
Aggregate principal amount of debt maturing in 2023	7.7
Aggregate principal amount of debt maturing in 2024-2043	$ 48.8

Borrowings - Financing VIEs (De

Borrowings - Financing VIEs (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Securities Financing Transaction [Line Items]
Short-term borrowings	$ 5,422	$ 4,771
Long-term borrowings	93,519	105,012
Total	98,941	109,783
Loans	94,498	105,122
Total Before Hedge Accounting Adjustments [Member]
Securities Financing Transaction [Line Items]
Short-term borrowings	5,425	4,750
Long-term borrowings	93,868	105,018
Total	99,293	109,768
Hedge Accounting Adjustments [Member]
Securities Financing Transaction [Line Items]
Short-term borrowings	(3)	21
Long-term borrowings	(349)	(6)
Total	(352)	15
Assets and Liabilities of Consolidated Variable Interest Entities [Member]
Securities Financing Transaction [Line Items]
Short-term borrowings	4,341	2,906
Long-term borrowings	82,738	89,317
Total	87,079	92,223
Loans	91,619	98,596
Cash	3,928	3,091
Other assets, Net	956	1,160
Total Carrying Amount of Assets Securing Debt Outstanding	96,503	102,847
Assets and Liabilities of Consolidated Variable Interest Entities [Member] | FFELP Loan Securitizations [Member]
Securities Financing Transaction [Line Items]
Long-term borrowings	66,318	71,208
Total	66,318	71,208
Loans	66,266	72,145
Cash	3,181	2,335
Other assets, Net	1,211	1,078
Total Carrying Amount of Assets Securing Debt Outstanding	70,658	75,558
Assets and Liabilities of Consolidated Variable Interest Entities [Member] | Private Education Loan Securitizations [Member]
Securities Financing Transaction [Line Items]
Short-term borrowings	300	686
Long-term borrowings	12,985	12,646
Total	13,285	13,332
Loans	16,336	17,739
Cash	536	484
Other assets, Net	198	237
Total Carrying Amount of Assets Securing Debt Outstanding	17,070	18,460
Assets and Liabilities of Consolidated Variable Interest Entities [Member] | FFELP Loan - Other Facilities [Member]
Securities Financing Transaction [Line Items]
Short-term borrowings	2,927	1,536
Long-term borrowings	2,625	3,999
Total	5,552	5,535
Loans	5,656	5,565
Cash	132	204
Other assets, Net	162	156
Total Carrying Amount of Assets Securing Debt Outstanding	5,950	5,925
Assets and Liabilities of Consolidated Variable Interest Entities [Member] | Private Education Loan - Other Facilities [Member]
Securities Financing Transaction [Line Items]
Short-term borrowings	1,114	684
Long-term borrowings	1,266	1,710
Total	2,380	2,394
Loans	3,361	3,147
Cash	79	68
Other assets, Net	27	31
Total Carrying Amount of Assets Securing Debt Outstanding	3,467	3,246
Assets and Liabilities of Consolidated Variable Interest Entities [Member] | Total Before Hedge Accounting Adjustments [Member]
Securities Financing Transaction [Line Items]
Short-term borrowings	4,341	2,906
Long-term borrowings	83,194	89,563
Total	87,535	92,469
Loans	91,619	98,596
Cash	3,928	3,091
Other assets, Net	1,598	1,502
Total Carrying Amount of Assets Securing Debt Outstanding	97,145	103,189
Assets and Liabilities of Consolidated Variable Interest Entities [Member] | Hedge Accounting Adjustments [Member]
Securities Financing Transaction [Line Items]
Long-term borrowings	(456)	(246)
Total	(456)	(246)
Other assets, Net	(642)	(342)
Total Carrying Amount of Assets Securing Debt Outstanding	$ (642)	$ (342)

Borrowings - Financing VIEs (Pa

Borrowings - Financing VIEs (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Securities Financing Transaction [Line Items]
Long-term debt	$ 93,519	$ 105,012
Short-term Debt	5,422	4,771
Assets and Liabilities of Consolidated Variable Interest Entities [Member]
Securities Financing Transaction [Line Items]
Long-term debt	82,738	89,317
Restricted cash	3,928	3,091
Short-term Debt	4,341	2,906
FFELP Loan Securitizations Repurchase Facilities [Member] | Assets and Liabilities of Consolidated Variable Interest Entities [Member]
Securities Financing Transaction [Line Items]
Long-term debt	244
Restricted cash	9
Private Education Loan Securitizations Repurchase Facilities [Member]
Securities Financing Transaction [Line Items]
Short-term Debt	300	686
Private Education Loan Securitizations Repurchase Facilities [Member] | Assets and Liabilities of Consolidated Variable Interest Entities [Member]
Securities Financing Transaction [Line Items]
Long-term debt	2,000	1,300
Restricted cash	115	96
Short-term Debt	$ 300	$ 686

Borrowings - Additional Informa

Borrowings - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Outstanding borrowings under facility	$ 93,519,000,000	$ 105,012,000,000
Issuance of unsecured debt	500,000,000	$ 1,600,000,000	$ 1,300,000,000
FFELP Loan - Other Facilities [Member]
Debt Instrument [Line Items]
Outstanding borrowings under facility	5,600,000,000
Assets securing facility	6,000,000,000
Maximum unused capacity	752,000,000
Unencumbered Loans	$ 332,000,000
FFELP Loan - Other Facilities [Member] | Minimum [Member]
Debt Instrument [Line Items]
Facility maturity date	2019-11
FFELP Loan - Other Facilities [Member] | Maximum [Member]
Debt Instrument [Line Items]
Facility maturity date	2020-04
FFELP Loan Securitizations Asset-backed Repurchase Facilities [Member] | Asset-backed Securities, Securitized Loans and Receivables [Member]
Debt Instrument [Line Items]
Outstanding borrowings under facility	$ 200,000,000
Amount of asset-backed securitization repurchase facility	900,000,000
Private Education Loan Abcp Borrowings [Member]
Debt Instrument [Line Items]
Outstanding borrowings under facility	2,400,000,000
Assets securing facility	3,500,000,000
Maximum unused capacity	635,000,000
Unencumbered Loans	$ 2,600,000,000
Private Education Loan Abcp Borrowings [Member] | Minimum [Member]
Debt Instrument [Line Items]
Facility maturity date	2019-06
Private Education Loan Abcp Borrowings [Member] | Maximum [Member]
Debt Instrument [Line Items]
Facility maturity date	2020-06
Private Education Loan Securitizations Asset-backed Repurchase Facilities [Member] | Asset-backed Securities, Securitized Loans and Receivables [Member]
Debt Instrument [Line Items]
Outstanding borrowings under facility	$ 2,300,000,000
Amount of asset-backed securitization repurchase facility				$ 3,200,000,000

Borrowings - Gains (Losses) on

Borrowings - Gains (Losses) on Debt Repurchases (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Debt principal repurchased	$ 2,809	$ 513	$ 1,467
Gains (losses) on debt repurchases	$ 19	$ (3)	$ 1

Derivative Financial Instrume_3

Derivative Financial Instruments - Additional Information (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Net positive exposure related to corporate derivatives	$ 19,000,000	$ 24,000,000
Euro and British Pound Sterling denominated bonds outstanding in securitization trusts	4,500,000,000
Notional of interest rate swaps entered into by the trusts to swap Prime to LIBOR	131,400,000,000	137,900,000,000
Net positive exposure on foreign currency swaps	7,000,000	64,000,000
Reduction of derivative assets	183,000,000
Reduction of derivative liabilities	159,000,000
Decrease in valuation due to net credit risk adjustments	26,000,000	6,000,000
Decrease in valuation due to liquidity adjustments	19,000,000	30,000,000
Derivative liability at fair value including accrued interest and premium receivable	752,000,000	659,000,000
Counterparty [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liability at fair value including accrued interest and premium receivable	87,000,000
Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional of interest rate swaps entered into by the trusts to swap Prime to LIBOR	98,600,000,000	$ 108,500,000,000
Interest Rate Swaps [Member] | Assets and Liabilities of Consolidated Variable Interest Entities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional of interest rate swaps entered into by the trusts to swap Prime to LIBOR	$ 5,100,000,000

Derivative Financial Instrume_4

Derivative Financial Instruments - Impact of Derivatives on Consolidated Balance Sheet (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Derivative Assets:
Derivative assets	$ 179	$ 480
Derivative Liabilities:
Derivative liabilities	(801)	(735)
Net total derivatives	(622)	(255)
Designated as Hedging Instrument [Member] | Cash Flow [Member]
Derivative Assets:
Derivative assets		95
Derivative Liabilities:
Derivative liabilities		(16)
Net total derivatives		79
Designated as Hedging Instrument [Member] | Fair Value [Member]
Derivative Assets:
Derivative assets	176	378
Derivative Liabilities:
Derivative liabilities	(673)	(512)
Net total derivatives	(497)	(134)
Trading [Member]
Derivative Assets:
Derivative assets	3	7
Derivative Liabilities:
Derivative liabilities	(128)	(207)
Net total derivatives	(125)	(200)
Interest Rate Swaps [Member]
Derivative Assets:
Derivative assets	173	392
Derivative Liabilities:
Derivative liabilities	(79)	(189)
Interest Rate Swaps [Member] | Designated as Hedging Instrument [Member] | Cash Flow [Member]
Derivative Assets:
Derivative assets		95
Derivative Liabilities:
Derivative liabilities		(16)
Interest Rate Swaps [Member] | Designated as Hedging Instrument [Member] | Fair Value [Member]
Derivative Assets:
Derivative assets	170	290
Derivative Liabilities:
Derivative liabilities	(34)	(102)
Interest Rate Swaps [Member] | Trading [Member]
Derivative Assets:
Derivative assets	3	7
Derivative Liabilities:
Derivative liabilities	(45)	(71)
Cross-Currency Interest Rate Swaps [Member]
Derivative Assets:
Derivative assets	6	88
Derivative Liabilities:
Derivative liabilities	(665)	(454)
Cross-Currency Interest Rate Swaps [Member] | Designated as Hedging Instrument [Member] | Fair Value [Member]
Derivative Assets:
Derivative assets	6	88
Derivative Liabilities:
Derivative liabilities	(639)	(410)
Cross-Currency Interest Rate Swaps [Member] | Trading [Member]
Derivative Liabilities:
Derivative liabilities	(26)	(44)
Floor Income Contracts [Member]
Derivative Liabilities:
Derivative liabilities	(53)	(74)
Floor Income Contracts [Member] | Trading [Member]
Derivative Liabilities:
Derivative liabilities	(53)	(74)
Other [Member]
Derivative Liabilities:
Derivative liabilities	(4)	(18)
Other [Member] | Trading [Member]
Derivative Liabilities:
Derivative liabilities	$ (4)	$ (18)

Derivative Financial Instrume_5

Derivative Financial Instruments - Gross Positions without Impact of Master Netting Agreements (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Derivatives Fair Value [Line Items]
Derivative assets	$ 179	$ 480
Derivative values with impact of master netting agreements (as carried on balance sheet), Assets	157	438
Cash collateral (held) pledged, Assets	(266)	(536)
Derivative liabilities	(801)	(735)
Cash collateral (held) pledged, Liabilities	188	235
Other Assets [Member]
Derivatives Fair Value [Line Items]
Derivative assets	179	480
Impact of master netting agreements, Assets	(22)	(42)
Derivative values with impact of master netting agreements (as carried on balance sheet), Assets	157	438
Cash collateral (held) pledged, Assets	(266)	(536)
Net position, Assets	(109)	(98)
Other Liabilities [Member]
Derivatives Fair Value [Line Items]
Derivative liabilities	(801)	(735)
Impact of master netting agreements, Liabilities	22	42
Derivative values with impact of master netting agreements (as carried on balance sheet), Liabilities	(779)	(693)
Cash collateral (held) pledged, Liabilities	188	235
Net position, Liabilities	$ (591)	$ (458)

Derivative Financial Instrume_6

Derivative Financial Instruments - Derivative Notional Values (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Total Derivative Notional Values	$ 131,400,000,000	$ 137,900,000,000
Designated as Hedging Instrument [Member] | Cash Flow [Member]
Derivative [Line Items]
Total Derivative Notional Values	21,400,000,000	24,100,000,000
Designated as Hedging Instrument [Member] | Fair Value [Member]
Derivative [Line Items]
Total Derivative Notional Values	14,800,000,000	19,100,000,000
Trading [Member]
Derivative [Line Items]
Total Derivative Notional Values	95,200,000,000	94,700,000,000
Interest Rate Swaps [Member]
Derivative [Line Items]
Total Derivative Notional Values	98,600,000,000	108,500,000,000
Interest Rate Swaps [Member] | Designated as Hedging Instrument [Member] | Cash Flow [Member]
Derivative [Line Items]
Total Derivative Notional Values	21,400,000,000	24,100,000,000
Interest Rate Swaps [Member] | Designated as Hedging Instrument [Member] | Fair Value [Member]
Derivative [Line Items]
Total Derivative Notional Values	10,300,000,000	12,400,000,000
Interest Rate Swaps [Member] | Trading [Member]
Derivative [Line Items]
Total Derivative Notional Values	66,900,000,000	72,000,000,000
Floor Income Contracts [Member]
Derivative [Line Items]
Total Derivative Notional Values	27,900,000,000	21,900,000,000
Floor Income Contracts [Member] | Trading [Member]
Derivative [Line Items]
Total Derivative Notional Values	27,900,000,000	21,900,000,000
Cross-Currency Interest Rate Swaps [Member]
Derivative [Line Items]
Total Derivative Notional Values	4,700,000,000	7,000,000,000
Cross-Currency Interest Rate Swaps [Member] | Designated as Hedging Instrument [Member] | Fair Value [Member]
Derivative [Line Items]
Total Derivative Notional Values	4,500,000,000	6,700,000,000
Cross-Currency Interest Rate Swaps [Member] | Trading [Member]
Derivative [Line Items]
Total Derivative Notional Values	200,000,000	300,000,000
Other [Member]
Derivative [Line Items]
Total Derivative Notional Values	200,000,000	500,000,000
Other [Member] | Trading [Member]
Derivative [Line Items]
Total Derivative Notional Values	$ 200,000,000	$ 500,000,000

Derivative Financial Instrume_7

Derivative Financial Instruments - Impact of Derivatives on Consolidated Statements of Income (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative and hedging activities, net	$ (48)	$ 2	$ (40)	$ 48	$ 38	$ 25	$ (25)	$ (16)	$ (38)	$ 22	$ 117
Designated as Hedging Instrument [Member] | Fair Value [Member] | Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in net income on derivatives									(137)	(214)	(288)
Gains (losses) recognized in net income on hedged items									162	193	302
Net fair value hedge ineffectiveness gains (losses)									25	(21)	14
Designated as Hedging Instrument [Member] | Fair Value [Member] | Cross-Currency Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in net income on derivatives									(311)	921	(319)
Gains (losses) recognized in net income on hedged items									210	(954)	350
Net fair value hedge ineffectiveness gains (losses)									(101)	(33)	31
Gains (losses) on derivative and hedging activities, net									(76)	(54)	45
Trading [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative and hedging activities, net									38	76	72
Trading [Member] | Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative and hedging activities, net									22	8	29
Trading [Member] | Cross-Currency Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative and hedging activities, net									(3)	2	5
Trading [Member] | Floor Income Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative and hedging activities, net									15	81	51
Trading [Member] | Other [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative and hedging activities, net									$ 4	$ (15)	$ (13)

Derivative Financial Instrume_8

Derivative Financial Instruments - Impact of Derivatives on Consolidated Statements of Changes in Stockholders' Equity (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) on cash flow hedges	$ 50	$ 25	$ 26
Total change in stockholders’ equity for unrealized gains (losses) on derivatives	39	55	57
Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification adjustments for derivative (gains) losses included in net income (interest expense)	$ (11)	$ 30	$ 31

Derivative Financial Instrume_9

Derivative Financial Instruments - Impact of Derivatives on Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Derivative Gain Loss On Derivative Net [Abstract]
Amount of after-tax net losses to be reclassified from accumulated other comprehensive income to earnings in the next 12 months	$ 3

Derivative Financial Instrum_10

Derivative Financial Instruments - Collateral Held and Pledged (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Collateral held:
Cash (obligation to return cash collateral is recorded in short-term borrowings)	$ 266	$ 536
Securities at fair value — on-balance sheet securitization derivatives (not recorded in financial statements)	90	297
Total collateral held	356	833
Derivative asset at fair value including accrued interest	210	618
Collateral pledged to others:
Cash (right to receive return of cash collateral is recorded in investments)	188	235
Total collateral pledged	188	235
Derivative liability at fair value including accrued interest and premium receivable	$ 752	$ 659

Other Assets - Schedule of Othe

Other Assets - Schedule of Other Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Offsetting [Abstract]
Accrued interest receivable	$ 1,999	$ 1,965
Benefit and insurance-related investments	470	481
Income tax asset, net (current and deferred)	271	380
Derivatives at fair value	157	438
Fixed assets, net	136	156
Accounts receivable	95	108
Other loans, net	69	59
Other	207	438
Total	$ 3,404	$ 4,025

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Common stock, shares authorized	1,125,000,000	1,125,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares issued	445,000,000	440,000,000
Common shares unissued but encumbered	22,000,000
Common stock dividend paid	$ 0.64	$ 0.64	$ 0.64
Purchase price of common stock repurchased on open market		$ 440,000,000
Authorized share repurchased program amount	$ 500,000,000
Common Stock Shares Outstanding [Member]
Class of Stock [Line Items]
Common stock, shares issued	247,000,000
Common stock repurchased	17,443,351	29,646,374	59,625,325
Purchase price of common stock repurchased on open market	$ 220,000,000	$ 440,000,000	$ 755,000,000
Common Stock [Member]
Class of Stock [Line Items]
Authorized common share repurchased program remaining available amount	$ 440,000,000
Closing price of common stock	$ 8.81

Stockholders' Equity - Common S

Stockholders' Equity - Common Share Repurchases and Issuances (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity, Class of Treasury Stock [Line Items]
Average purchase price per share	$ 12.64	$ 14.85	$ 12.68
Shares repurchased related to employee stock-based compensation plans	3,829,629	1,847,651	3,197,355
Average purchase price per share	$ 13.71	$ 15.40	$ 13.21
Common shares issued	5,659,681	3,680,479	5,476,010
Common Stock Shares Outstanding [Member]
Equity, Class of Treasury Stock [Line Items]
Common stock repurchased	17,443,351	29,646,374	59,625,325
Shares repurchased related to employee stock-based compensation plans	3,829,629	1,847,651	3,197,355
Common shares issued	5,659,681	3,680,479	5,476,010

Earnings (Loss) per Common Sh_3

Earnings (Loss) per Common Share - Schedule of Earnings (Loss) per Common Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Numerator:
Net income	$ 72	$ 114	$ 83	$ 126	$ (84)	$ 176	$ 112	$ 88	$ 395	$ 292	$ 681
Denominator:
Weighted average shares used to compute basic EPS									260	275	316
Effect of dilutive securities:
Dilutive effect of stock options, restricted stock, restricted stock units, performance stock units and Employee Stock Purchase Plan (“ESPP”)									4	6	6
Dilutive potential common shares									4	6	6
Weighted average shares used to compute diluted EPS									264	281	322
Basic earnings per common share	$ 0.28	$ 0.44	$ 0.31	$ 0.48	$ (0.32)	$ 0.65	$ 0.40	$ 0.31	$ 1.52	$ 1.06	$ 2.15
Diluted earnings per common share	$ 0.28	$ 0.43	$ 0.31	$ 0.47	$ (0.32)	$ 0.64	$ 0.39	$ 0.30	$ 1.49	$ 1.04	$ 2.12

Earnings (Loss) per Common Sh_4

Earnings (Loss) per Common Share - Schedule of Earnings (Loss) per Common Share (Parenthetical) (Detail) - shares shares in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Employee Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock awards not included in the computation of diluted earnings per share	6	5	4

Stock-Based Compensation Plan_3

Stock-Based Compensation Plans and Arrangements - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 25	$ 35	$ 26
Unrecognized compensation cost	$ 12
Weighted average period for total unrecognized compensation cost	1 year 9 months 18 days
Time Vested Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	Most stock options are time-vested, with one-third vesting per year beginning with the first anniversary of the grant date.
Restricted Stock Units, RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	RSUs generally are time-vested, with one-third vesting per year beginning with the first anniversary of the grant date
Performance Stock Units, PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	PSUs vest based on achieving certain corporate performance goals over a three-year performance period
Navient Corporation 2014 Omnibus Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Effective date	Apr. 7, 2014
Shares authorized to be issued under plan	55,000,000
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Effective date	May 1, 2014
Shares authorized to be issued under plan	1,000,000
Grants Made since 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term for stock options (in years)	5 years
Grants Made Prior to 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term for stock options (in years)	10 years

Stock-Based Compensation Plan_4

Stock-Based Compensation Plans and Arrangements - Black-Scholes Model Assumptions for Calculating Stock Option and ESPP Fair Values (Detail) - Employee Stock Option [Member] - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life of the option	3 years 2 months 12 days	3 years	3 years
Expected volatility	36.00%	34.00%	30.00%
Risk-free interest rate	2.27%	1.44%	0.90%
Expected dividend rate	4.70%	4.13%	6.97%
Weighted average fair value of options granted and stock purchase rights	$ 2.59	$ 2.69	$ 1.01

Stock-Based Compensation Plan_5

Stock-Based Compensation Plans and Arrangements - Stock Option Activity (Detail) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options, Outstanding, beginning balance | shares	14,183,726
Granted, Options | shares	1,551,307
Exercised, Options | shares	(3,715,212)
Canceled, Options | shares	(844,931)
Number of Options, Outstanding, ending balance | shares	11,174,890
Number of Options, Exercisable, ending balance | shares	7,500,940
Weighted Average Exercise Price per Share, Outstanding, beginning balance | $ / shares	$ 12.48
Granted, Weighted Average Exercise Price per Share | $ / shares	13.63
Exercised, Weighted Average Exercise Price per Share | $ / shares	10.53
Canceled, Weighted Average Exercise Price per Share | $ / shares	16.69
Weighted Average Exercise Price per Share, Outstanding, ending balance | $ / shares	12.97
Weighted Average Exercise Price per Share, Exercisable, ending balance | $ / shares	$ 13.24
Weighted Average Remaining Contractual Term, Outstanding, ending balance	1 year 9 months 18 days
Weighted Average Remaining Contractual Term, Exercisable, ending balance	1 year 2 months 12 days
Aggregate Intrinsic Value, Outstanding, ending balance | $	$ 4
Aggregate Intrinsic Value, Exercisable, ending balance | $	$ 4

Stock-Based Compensation Plan_6

Stock-Based Compensation Plans and Arrangements - Stock Option Activity (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 12
Weighted average period for total unrecognized compensation cost	1 year 9 months 18 days
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of options exercised	$ 12	$ 9	$ 13
Unrecognized compensation cost		$ 1
Weighted average period for total unrecognized compensation cost	1 year 10 months 24 days

Stock-Based Compensation Plan_7

Stock-Based Compensation Plans and Arrangements - Restricted Stock and Performance Stock Unit Activity (Detail)	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Restricted Stock Units and Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Non-vested, beginning balance | shares	4,428,305
Granted, Shares | shares	1,884,580
Vested, Shares | shares	(1,598,227)
Forfeited, Shares | shares	(226,323)
Canceled, Shares | shares	(228,564)
Number of Shares, Non-vested, ending balance | shares	4,259,771
Weighted Average Grant Date Fair Value, Non-vested, beginning balance | $ / shares	$ 13.33
Granted, Weighted Average Grant Date Fair Value | $ / shares	12.97
Vested, Weighted Average Grant Date Fair Value | $ / shares	13.87
Forfeited, Weighted Average Grant Date Fair Value | $ / shares	21.65
Canceled, Weighted Average Grant Date Fair Value | $ / shares	12.89
Weighted Average Grant Date Fair Value, Non-vested, ending balance | $ / shares	$ 12.55
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Shares | shares	55,503
Vested, Shares | shares	(36,429)
Canceled, Shares | shares	(19,074)
Granted, Weighted Average Grant Date Fair Value | $ / shares	$ 13.56
Vested, Weighted Average Grant Date Fair Value | $ / shares	13.52
Canceled, Weighted Average Grant Date Fair Value | $ / shares	$ 13.63

Stock-Based Compensation Plan_8

Stock-Based Compensation Plans and Arrangements - Restricted Stock and Performance Stock Unit Activity (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 12
Weighted average period for total unrecognized compensation cost	1 year 9 months 18 days
Restricted Stock Units and Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total fair value of restricted stock that vested	$ 22	$ 23	$ 30
Unrecognized compensation cost	$ 11
Weighted average period for total unrecognized compensation cost	1 year 9 months 18 days
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total fair value of restricted stock that vested	$ 1	$ 1	$ 1
Unrecognized compensation cost	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Maximum remaining term for investment purchased for estimating at cost	90 days
Decrease in valuation due to net credit risk adjustments	$ 26	$ 6
Decrease in valuation due to liquidity adjustments	$ 19	$ 30

Fair Value Measurements - Valua

Fair Value Measurements - Valuation of Financial Instruments that are Marked-to-Market on Recurring Basis (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Available-for-sale investments:
Available-for-sale investments	$ 0	$ 2
Derivative assets	179	480
Derivative liabilities	(801)	(735)
Interest Rate Swaps [Member]
Available-for-sale investments:
Derivative assets	173	392
Derivative liabilities	(79)	(189)
Cross-Currency Interest Rate Swaps [Member]
Available-for-sale investments:
Derivative assets	6	88
Derivative liabilities	(665)	(454)
Floor Income Contracts [Member]
Available-for-sale investments:
Derivative liabilities	(53)	(74)
Other [Member]
Available-for-sale investments:
Derivative liabilities	(4)	(18)
Fair Value Measurements Recurring [Member]
Available-for-sale investments:
Available-for-sale investments		2
Derivative assets	179	480
Total	179	482
Derivative liabilities	(801)	(735)
Total	(801)	(735)
Fair Value Measurements Recurring [Member] | Interest Rate Swaps [Member]
Available-for-sale investments:
Derivative assets	173	392
Derivative liabilities	(79)	(189)
Fair Value Measurements Recurring [Member] | Cross-Currency Interest Rate Swaps [Member]
Available-for-sale investments:
Derivative assets	6	88
Derivative liabilities	(665)	(454)
Fair Value Measurements Recurring [Member] | Floor Income Contracts [Member]
Available-for-sale investments:
Derivative liabilities	(53)	(74)
Fair Value Measurements Recurring [Member] | Other [Member]
Available-for-sale investments:
Derivative liabilities	(4)	(18)
Fair Value Measurements Recurring [Member] | Other [Member]
Available-for-sale investments:
Available-for-sale investments		2
Fair Value Measurements Recurring [Member] | Level 2 [Member]
Available-for-sale investments:
Available-for-sale investments		2
Derivative assets	171	388
Total	171	390
Derivative liabilities	(129)	(262)
Total	(129)	(262)
Fair Value Measurements Recurring [Member] | Level 2 [Member] | Interest Rate Swaps [Member]
Available-for-sale investments:
Derivative assets	171	388
Derivative liabilities	(50)	(144)
Fair Value Measurements Recurring [Member] | Level 2 [Member] | Cross-Currency Interest Rate Swaps [Member]
Available-for-sale investments:
Derivative liabilities	(26)	(44)
Fair Value Measurements Recurring [Member] | Level 2 [Member] | Floor Income Contracts [Member]
Available-for-sale investments:
Derivative liabilities	(53)	(74)
Fair Value Measurements Recurring [Member] | Level 2 [Member] | Other [Member]
Available-for-sale investments:
Available-for-sale investments		2
Fair Value Measurements Recurring [Member] | Level 3 [Member]
Available-for-sale investments:
Derivative assets	8	92
Total	8	92
Derivative liabilities	(672)	(473)
Total	(672)	(473)
Fair Value Measurements Recurring [Member] | Level 3 [Member] | Interest Rate Swaps [Member]
Available-for-sale investments:
Derivative assets	2	4
Derivative liabilities	(29)	(45)
Fair Value Measurements Recurring [Member] | Level 3 [Member] | Cross-Currency Interest Rate Swaps [Member]
Available-for-sale investments:
Derivative assets	6	88
Derivative liabilities	(639)	(410)
Fair Value Measurements Recurring [Member] | Level 3 [Member] | Other [Member]
Available-for-sale investments:
Derivative liabilities	$ (4)	$ (18)

Fair Value Measurements - Chang

Fair Value Measurements - Change in Balance Sheet Carrying Value Associated with Level 3 Financial Instruments Carried at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	$ (381)	$ (1,302)	$ (949)
Total gains/(losses):
Included in earnings	(414)	788	(439)
Included in other comprehensive income	0	0	0
Settlements	131	133	94
Transfers in and/or out of level 3	0	0	(8)
Balance, end of period	(664)	(381)	(1,302)
Change in mark-to-market gains/(losses) relating to instruments still held at the reporting date	(257)	795	(344)
Interest Rate Swaps [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	(41)	(46)	(44)
Total gains/(losses):
Included in earnings	11	0	3
Included in other comprehensive income	0	0	0
Settlements	3	5	3
Transfers in and/or out of level 3	0	0	(8)
Balance, end of period	(27)	(41)	(46)
Change in mark-to-market gains/(losses) relating to instruments still held at the reporting date	13	5	7
Cross-Currency Interest Rate Swaps [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	(322)	(1,243)	(903)
Total gains/(losses):
Included in earnings	(433)	803	(428)
Included in other comprehensive income	0	0	0
Settlements	122	118	88
Transfers in and/or out of level 3	0	0	0
Balance, end of period	(633)	(322)	(1,243)
Change in mark-to-market gains/(losses) relating to instruments still held at the reporting date	(284)	795	(340)
Other [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	(18)	(13)	(2)
Total gains/(losses):
Included in earnings	8	(15)	(14)
Included in other comprehensive income	0	0	0
Settlements	6	10	3
Transfers in and/or out of level 3	0	0	0
Balance, end of period	(4)	(18)	(13)
Change in mark-to-market gains/(losses) relating to instruments still held at the reporting date	$ 14	$ (5)	$ (11)

Fair Value Measurements - Inclu

Fair Value Measurements - Included in Earnings (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Gains (losses) on derivative and hedging activities, net	$ (414)	$ 788	$ (439)
Gain (Losses) on Derivative Instruments [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Gains (losses) on derivative and hedging activities, net	(292)	906	(351)
Interest Expense [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Gains (losses) on derivative and hedging activities, net	$ (122)	$ (118)	$ (88)

Fair Value Measurements - Unobs

Fair Value Measurements - Unobservable Data Used in Recurring Valuations of Level 3 (Detail) $ in Millions	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Interest Rate Swaps [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative financial instruments, Fair Value	$ 94	$ 203
Cross-Currency Interest Rate Swaps [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative financial instruments, Fair Value	(659)	(366)
Other [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative financial instruments, Fair Value	(4)	$ (18)
Level 3 [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative financial instruments, Fair Value	(664)
Level 3 [Member] | Cross-Currency Interest Rate Swaps [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative financial instruments, Fair Value	$ (633)
Derivative Asset (Liability) Net, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Derivatives	4
Derivative Asset (Liability) Net, Measurement Input [Extensible List]	us-gaap:MeasurementInputConstantPrepaymentRateMember
Level 3 [Member] | Other [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative financial instruments, Fair Value	$ (4)
Level 3 [Member] | Prime/LIBOR Basis Swaps [Member] | Interest Rate Swaps [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative financial instruments, Fair Value	$ (27)
Derivative Asset (Liability) Net, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Level 3 [Member] | Prime/LIBOR Basis Swaps [Member] | Interest Rate Swaps [Member] | Constant Prepayment Rate [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivatives	7
Level 3 [Member] | Prime/LIBOR Basis Swaps [Member] | Interest Rate Swaps [Member] | Bid/ask adjustment to discount rate [Member] | Minimum [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivatives	0.08
Level 3 [Member] | Prime/LIBOR Basis Swaps [Member] | Interest Rate Swaps [Member] | Bid/ask adjustment to discount rate [Member] | Maximum [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivatives	0.08
Level 3 [Member] | Prime/LIBOR Basis Swaps [Member] | Interest Rate Swaps [Member] | Bid/ask adjustment to discount rate [Member] | Weighted Average [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivatives	(0.08)

Fair Value Measurements - Fair

Fair Value Measurements - Fair Values of Financial Assets and Liabilities, Including Derivative Financial Instruments (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, Carrying Value	$ 94,498	$ 105,122
Total earning assets, Carrying Value	99,986	110,156
Short-term borrowings, Carrying Value	5,422	4,771
Long-term borrowings, Carrying Value	93,519	105,012
Total	98,941	109,783
Total earning assets, Fair Value	100,520	111,726
Short-term borrowings, Fair Value	5,418	4,783
Long-term borrowings, Fair Value	92,173	104,921
Total interest-bearing liabilities, Fair Value	97,591	109,704
FFELP Loans [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, Carrying Value	72,253	81,703
Loans receivable, Fair Value	72,074	82,271
Floor Income Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments, Carrying Value	(53)	(74)
Derivative financial instruments, Fair Value	(53)	(74)
Interest Rate Swaps [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments, Carrying Value	94	203
Derivative financial instruments, Fair Value	94	203
Cross-Currency Interest Rate Swaps [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments, Carrying Value	(659)	(366)
Derivative financial instruments, Fair Value	(659)	(366)
Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments, Carrying Value	(4)	(18)
Derivative financial instruments, Fair Value	(4)	(18)
Private Education Loans [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, Carrying Value	22,245	23,419
Loans receivable, Fair Value	22,958	24,421
Difference [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total earning assets, Fair Value	534	1,570
Short-term borrowings, Fair Value	4	(12)
Long-term borrowings, Fair Value	1,346	91
Total interest-bearing liabilities, Fair Value	1,350	79
Excess of net asset fair value over carrying value	1,884	1,649
Difference [Member] | FFELP Loans [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans receivable, Fair Value	(179)	568
Difference [Member] | Private Education Loans [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans receivable, Fair Value	713	1,002
Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and investments	5,488	5,034
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and investments	$ 5,488	$ 5,034

Fair Value Measurements - Fai_2

Fair Value Measurements - Fair Values of Financial Assets and Liabilities, Including Derivative Financial Instruments (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Available-for-sale investments, cost basis	$ 0	$ 2
Available-for-sale investments, fair value	$ 0	$ 2

Commitments, Contingencies an_2

Commitments, Contingencies and Guarantees - Additional Information (Detail) - USD ($)	Dec. 31, 2018	Jun. 30, 2018
Unasserted Claim [Member]
Loss Contingencies [Line Items]
Contingency reserve		$ 40,000,000
SLM BankCo [Member] | Indemnification Matters [Member]
Loss Contingencies [Line Items]
Reserve for estimated amounts and costs incurred	$ 0

Income Taxes - Reconciliations

Income Taxes - Reconciliations of Statutory U.S. Federal Income Tax Rates to Our Effective Tax Rate for Continuing Operations (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Statutory rate	21.00%	35.00%	35.00%
DTA Remeasurement Loss		27.20%
State tax, net of federal benefit	3.90%	0.70%	3.80%
Other, net	0.30%	(1.10%)	(0.30%)
Effective tax rate	25.20%	61.80%	38.50%

Income Taxes - Reconciliation_2

Income Taxes - Reconciliations of Statutory U.S. Federal Income Tax Rates to Our Effective Tax Rate for Continuing Operations (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Statutory rate	21.00%	35.00%	35.00%
DTA remeasurement loss		$ 208

Income Taxes - Components of Pr

Income Taxes - Components of Provision for Income Tax Expense (Benefit) (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current provision/(benefit):
Federal									$ 71	$ 77	$ 246
State									13	(3)	47
Foreign									3	3	1
Total current provision/(benefit)									87	77	294
Deferred provision/(benefit):
Federal									33	385	115
State									13	11	18
Foreign										(1)
Total deferred provision/(benefit)									46	395	133
Provision for income tax expense/(benefit)	$ 34	$ 33	$ 30	$ 36	$ 266	$ 93	$ 60	$ 53	$ 133	$ 472	$ 427

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Loan reserves	$ 292	$ 317
Education loan premiums and discounts, net	48	52
Operating loss and credit carryovers	18	22
Stock-based compensation plans	16	18
Accrued expenses not currently deductible	14	24
Other	18	14
Total deferred tax assets	406	447
Deferred tax liabilities:
Market value adjustments on education loans, investments and derivatives	46	14
Acquired intangible assets	12	3
Original issue discount on borrowings	7	11
Debt repurchases	6	8
Other	13	19
Total deferred tax liabilities	84	55
Net deferred tax assets	$ 322	$ 392

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Valuation allowance, Operating loss and credit carryovers	$ 43	$ 42
Unrecognized tax benefits at end of year	65.7	$ 57.4	$ 73	$ 56.3
Unrecognized tax benefits recognition impact on effective tax rate	$ 51.9
Minimum [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Statute of limitation period for open tax reviews	3 years
Maximum [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Statute of limitation period for open tax reviews	4 years
State [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Valuation allowance, Operating loss and credit carryovers	$ 40
Operating loss carryforwards	$ 640
Operating loss carryforwards, expiration dates	2,021
Tax-effected NOL	$ 42
Federal and State [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Capital loss carryforwards	$ 10
Capital loss carryforwards expiration date	2,021
Tax effected Capital loss	$ 3
Capital loss carryforwards valuation allowance	3
Federal [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Valuation allowance, Operating loss and credit carryovers	0
Operating loss carryforwards	$ 78
Operating loss carryforwards, expiration dates	2,031
Tax-effected NOL	$ 16

Income Taxes - Summary of Chang

Income Taxes - Summary of Changes in Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Unrecognized tax benefits at beginning of year	$ 57.4	$ 73	$ 56.3
Increases resulting from tax positions taken during a prior period	8	0.7	19.9
Decreases resulting from tax positions taken during a prior period	(0.3)	(1.8)	(5.6)
Increases resulting from tax positions taken during the current period	3.8	4.4	4.4
Decreases related to settlements with taxing authorities	(1.4)	(5.1)	(0.1)
Reductions related to the lapse of statute of limitations	(1.8)	(13.8)	(1.9)
Unrecognized tax benefits at end of year	$ 65.7	$ 57.4	$ 73

Revenue from Contract with Cu_3

Revenue from Contract with Customers Accounted in Accordance with ASC 606 - Summary of Disaggregation of Revenue from Contracts Accounted Under ASC 606 with Customers (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Disaggregation Of Revenue [Line Items]
Total Revenue	$ 359
Federal Government [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	28
Guarantor Agencies [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	58
Other Institutions [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	12
State and Local Government [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	92
Tolling Authorities [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	76
Hospitals and Other Healthcare Providers [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	93
Federal Education Loan Asset Recovery Services [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	91
Government Services [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	175
Healthcare Services [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	93
Federal Education Loans [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	91
Federal Education Loans [Member] | Federal Government [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	21
Federal Education Loans [Member] | Guarantor Agencies [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	58
Federal Education Loans [Member] | Other Institutions [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	12
Federal Education Loans [Member] | Federal Education Loan Asset Recovery Services [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	91
Business Processing [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	268
Business Processing [Member] | Federal Government [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	7
Business Processing [Member] | State and Local Government [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	92
Business Processing [Member] | Tolling Authorities [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	76
Business Processing [Member] | Hospitals and Other Healthcare Providers [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	93
Business Processing [Member] | Government Services [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	175
Business Processing [Member] | Healthcare Services [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	$ 93

Revenue from Contract with Cu_4

Revenue from Contract with Customers Accounted in Accordance with ASC 606 - Additional Information (Detail) - USD ($)	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Disaggregation Of Revenue [Line Items]
Accounts receivable	$ 95,000,000		$ 108,000,000
ASU 2014-09 [Member]
Disaggregation Of Revenue [Line Items]
Accounts receivable	74,000,000	$ 63,000,000
Contract assets	0
Contract liability	$ 0

Segment Reporting - Additional

Segment Reporting - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)SegmentClient	Dec. 31, 2017USD ($)
Segment Reporting Information [Line Items]
Number of reportable operating segments | Segment	4
Total assets	$ 104,176	$ 114,991
Business Processing [Member]
Segment Reporting Information [Line Items]
Number of clients for business processing services | Client	600
Total assets	$ 448	466
Other Segment [Member]
Segment Reporting Information [Line Items]
Total assets	$ 2,000	$ 2,100

Segment Reporting - Asset Infor

Segment Reporting - Asset Information for Loans Segment (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Loans, net	$ 94,498	$ 105,122
Other	3,404	4,025
Total assets	104,176	114,991
Federal Education Loans [Member]
Segment Reporting Information [Line Items]
Loans, net	72,253	81,703
Cash and investments	3,368	2,821
Other	2,100	2,601
Total assets	77,721	87,125
Consumer Lending [Member]
Segment Reporting Information [Line Items]
Loans, net	22,245	23,419
Cash and investments	732	706
Other	1,076	1,143
Total assets	$ 24,053	$ 25,268

Segment Reporting - Segment Res

Segment Reporting - Segment Results and Reconciliations to GAAP (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest income:
Cash and investments									$ 97	$ 43	$ 22
Total interest income									4,908	4,383	4,146
Total interest expense									3,668	2,971	2,441
Net interest income	$ 307	$ 306	$ 298	$ 329	$ 366	$ 355	$ 351	$ 340	1,240	1,412	1,705
Less: provisions for loan losses	85	85	112	87	109	105	105	107	370	426	429
Net interest income after provisions for loan losses	222	221	186	242	257	250	246	233	870	986	1,276
Other income (loss):
Servicing revenue									274	290	304
Asset recovery and business processing revenue									430	475	390
Other income (loss)									(21)	31	124
Gains on sales of loans and investments										3
Gains (losses) on debt repurchases									19	(3)	1
Total other income									702	796	819
Expenses:
Direct operating expenses									696	659	664
Unallocated shared services expenses									288	307	287
Total operating expenses	252	255	201	275	260	238	230	238	984	966	951
Goodwill and acquired intangible asset impairment and amortization	8	23	6	9	5	6	6	6	47	23	36
Restructuring/other reorganization expenses	4	1	2	7	29				13	29
Total expenses									1,044	1,018	987
Income before income tax expense									528	764	1,108
Income tax expense (benefit)	34	33	30	36	266	93	60	53	133	472	427
Net income (loss)	$ 72	$ 114	$ 83	$ 126	$ (84)	$ 176	$ 112	$ 88	395	292	681
Operating Segments [Member]
Interest income:
Cash and investments									97	43	22
Total interest income									4,961	4,369	4,013
Total interest expense									3,672	2,990	2,410
Net interest income									1,289	1,379	1,603
Less: provisions for loan losses									370	426	429
Net interest income after provisions for loan losses									919	953	1,174
Other income (loss):
Servicing revenue									274	290	304
Asset recovery and business processing revenue									430	475	390
Other income (loss)									30	19	14
Gains on sales of loans and investments										3
Gains (losses) on debt repurchases									9	(3)	1
Total other income									743	784	709
Expenses:
Direct operating expenses									696	659	664
Unallocated shared services expenses									288	307	287
Total operating expenses									984	966	951
Restructuring/other reorganization expenses									13	29
Total expenses									997	995	951
Income before income tax expense									665	742	932
Income tax expense (benefit)									146	491	345
Net income (loss)									519	251	587
Operating Segments [Member] | Federal Education Loans [Member]
Interest income:
Cash and investments									46	29	16
Total interest income									3,130	2,721	2,420
Total interest expense									2,467	2,022	1,597
Net interest income									663	699	823
Less: provisions for loan losses									70	44	46
Net interest income after provisions for loan losses									593	655	777
Other income (loss):
Servicing revenue									262	280	289
Asset recovery and business processing revenue									163	263	216
Other income (loss)									24	3
Gains on sales of loans and investments										3
Total other income									449	549	505
Expenses:
Direct operating expenses									298	316	366
Total operating expenses									298	316	366
Total expenses									298	316	366
Income before income tax expense									744	888	916
Income tax expense (benefit)									164	321	338
Net income (loss)									580	567	578
Operating Segments [Member] | Consumer Lending [Member]
Interest income:
Cash and investments									13	5	2
Total interest income									1,793	1,639	1,589
Total interest expense									1,013	825	704
Net interest income									780	814	885
Less: provisions for loan losses									300	382	383
Net interest income after provisions for loan losses									480	432	502
Other income (loss):
Servicing revenue									12	10	15
Total other income									12	10	15
Expenses:
Direct operating expenses									169	156	149
Total operating expenses									169	156	149
Total expenses									169	156	149
Income before income tax expense									323	286	368
Income tax expense (benefit)									71	103	137
Net income (loss)									252	183	231
Operating Segments [Member] | Business Processing [Member]
Other income (loss):
Asset recovery and business processing revenue									267	212	174
Total other income									267	212	174
Expenses:
Direct operating expenses									229	187	149
Total operating expenses									229	187	149
Total expenses									229	187	149
Income before income tax expense									38	25	25
Income tax expense (benefit)									8	9	9
Net income (loss)									30	16	16
Operating Segments [Member] | Other Segment [Member]
Interest income:
Cash and investments									38	9	4
Total interest income									38	9	4
Total interest expense									192	143	109
Net interest income									(154)	(134)	(105)
Net interest income after provisions for loan losses									(154)	(134)	(105)
Other income (loss):
Other income (loss)									6	16	14
Gains (losses) on debt repurchases									9	(3)	1
Total other income									15	13	15
Expenses:
Unallocated shared services expenses									288	307	287
Total operating expenses									288	307	287
Restructuring/other reorganization expenses									13	29
Total expenses									301	336	287
Income before income tax expense									(440)	(457)	(377)
Income tax expense (benefit)									(97)	58	(139)
Net income (loss)									(343)	(515)	(238)
Adjustments [Member] | Reclassifications [Member]
Interest income:
Total interest income									17	69	247
Total interest expense									8	(8)	31
Net interest income									9	77	216
Net interest income after provisions for loan losses									9	77	216
Other income (loss):
Other income (loss)									(22)	(77)	(216)
Gains (losses) on debt repurchases									13
Total other income									(9)	(77)	(216)
Adjustments [Member] | Additions (Subtractions) [Member]
Interest income:
Total interest income									(70)	(55)	(114)
Total interest expense									(12)	(11)
Net interest income									(58)	(44)	(114)
Net interest income after provisions for loan losses									(58)	(44)	(114)
Other income (loss):
Other income (loss)									(29)	89	326
Gains (losses) on debt repurchases									(3)
Total other income									(32)	89	326
Expenses:
Goodwill and acquired intangible asset impairment and amortization									47	23	36
Total expenses									47	23	36
Income before income tax expense									(137)	22	176
Income tax expense (benefit)									(13)	(19)	82
Net income (loss)									(124)	41	94
Adjustments [Member] | Total Adjustments [Member]
Interest income:
Total interest income									(53)	14	133
Total interest expense									(4)	(19)	31
Net interest income									(49)	33	102
Net interest income after provisions for loan losses									(49)	33	102
Other income (loss):
Other income (loss)									(51)	12	110
Gains (losses) on debt repurchases									10
Total other income									(41)	12	110
Expenses:
Goodwill and acquired intangible asset impairment and amortization									47	23	36
Total expenses									47	23	36
Income before income tax expense									(137)	22	176
Income tax expense (benefit)									(13)	(19)	82
Net income (loss)									(124)	41	94
Education Loan Portfolio [Member]
Interest income:
Total interest income									4,805	4,327	4,115
Education Loan Portfolio [Member] | Operating Segments [Member]
Interest income:
Total interest income									4,858	4,313	3,982
Education Loan Portfolio [Member] | Operating Segments [Member] | Federal Education Loans [Member]
Interest income:
Total interest income									3,080	2,679	2,395
Education Loan Portfolio [Member] | Operating Segments [Member] | Consumer Lending [Member]
Interest income:
Total interest income									1,778	1,634	1,587
Education Loan Portfolio [Member] | Adjustments [Member] | Reclassifications [Member]
Interest income:
Total interest income									17	69	247
Education Loan Portfolio [Member] | Adjustments [Member] | Additions (Subtractions) [Member]
Interest income:
Total interest income									(70)	(55)	(114)
Education Loan Portfolio [Member] | Adjustments [Member] | Total Adjustments [Member]
Interest income:
Total interest income									(53)	14	133
Other Loans [Member]
Interest income:
Total interest income									6	13	9
Other Loans [Member] | Operating Segments [Member]
Interest income:
Total interest income									6	13	9
Other Loans [Member] | Operating Segments [Member] | Federal Education Loans [Member]
Interest income:
Total interest income									4	$ 13	$ 9
Other Loans [Member] | Operating Segments [Member] | Consumer Lending [Member]
Interest income:
Total interest income									$ 2

Segment Reporting - Segment R_2

Segment Reporting - Segment Result and Reconciliations to GAAP - Core Earnings Adjustments (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest income (loss) after provisions for loan losses	$ 222	$ 221	$ 186	$ 242	$ 257	$ 250	$ 246	$ 233	$ 870	$ 986	$ 1,276
Total other income (loss)									702	796	819
Goodwill and acquired intangible asset impairment and amortization	8	23	6	9	5	6	6	6	47	23	36
Income tax expense (benefit)	34	33	30	36	266	93	60	53	133	472	427
Net income (loss)	$ 72	$ 114	$ 83	$ 126	$ (84)	$ 176	$ 112	$ 88	395	292	681
Total Adjustments [Member] | Adjustments [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest income (loss) after provisions for loan losses									(49)	33	102
Total other income (loss)									(41)	12	110
Goodwill and acquired intangible asset impairment and amortization									47	23	36
Total Core Earnings adjustments to GAAP									(137)	22	176
Income tax expense (benefit)									(13)	(19)	82
Net income (loss)									(124)	41	94
Net Impact of Goodwill and Acquired Intangible Assets [Member] | Total Adjustments [Member] | Adjustments [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Goodwill and acquired intangible asset impairment and amortization									47	23	36
Total Core Earnings adjustments to GAAP									(47)	(23)	(36)
Net Impact of Derivative Accounting [Member] | Total Adjustments [Member] | Adjustments [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest income (loss) after provisions for loan losses									(49)	33	102
Total other income (loss)									(41)	12	110
Total Core Earnings adjustments to GAAP									$ (90)	$ 45	$ 212

Segment Reporting - Core Earnin

Segment Reporting - Core Earnings Adjustments to GAAP (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Adjustments Required To Reconcile Core Earnings [Line Items]
Net income (loss)	$ 72	$ 114	$ 83	$ 126	$ (84)	$ 176	$ 112	$ 88	$ 395	$ 292	$ 681
Net income tax effect	$ (34)	$ (33)	$ (30)	$ (36)	$ (266)	$ (93)	$ (60)	$ (53)	(133)	(472)	(427)
Operating Segments [Member]
Adjustments Required To Reconcile Core Earnings [Line Items]
Net income (loss)									519	251	587
Net income tax effect									(146)	(491)	(345)
Total Adjustments [Member] | Adjustments [Member]
Adjustments Required To Reconcile Core Earnings [Line Items]
Net income (loss)									(124)	41	94
Core Earnings adjustments to GAAP									(137)	22	176
Net income tax effect									13	19	(82)
Net Impact of Derivative Accounting [Member] | Total Adjustments [Member] | Adjustments [Member]
Adjustments Required To Reconcile Core Earnings [Line Items]
Core Earnings adjustments to GAAP									(90)	45	212
Net Impact of Goodwill and Acquired Intangible Assets [Member] | Total Adjustments [Member] | Adjustments [Member]
Adjustments Required To Reconcile Core Earnings [Line Items]
Core Earnings adjustments to GAAP									$ (47)	$ (23)	$ (36)

Segment Reporting - Core Earn_2

Segment Reporting - Core Earnings Adjustments to GAAP (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2018USD ($)
Segment Reporting [Abstract]
Amount that will be equal to mark-to-market gain or loss over the life of the contract	$ 0

Quarterly Financial Informati_3

Quarterly Financial Information (Unaudited) - Schedule of Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Net interest income	$ 307	$ 306	$ 298	$ 329	$ 366	$ 355	$ 351	$ 340	$ 1,240	$ 1,412	$ 1,705
Less: provisions for loan losses	85	85	112	87	109	105	105	107	370	426	429
Net interest income after provisions for loan losses	222	221	186	242	257	250	246	233	870	986	1,276
Other income	196	203	176	163	181	238	187	168
Gains (losses) on derivative and hedging activities, net	(48)	2	(40)	48	38	25	(25)	(16)	(38)	22	117
Operating expenses	252	255	201	275	260	238	230	238	984	966	951
Goodwill and acquired intangible asset impairment and amortization expense	8	23	6	9	5	6	6	6	47	23	36
Restructuring/other reorganization expenses	4	1	2	7	29				13	29
Income tax expense	34	33	30	36	266	93	60	53	133	472	427
Net income (loss)	$ 72	$ 114	$ 83	$ 126	$ (84)	$ 176	$ 112	$ 88	$ 395	$ 292	$ 681
Basic earnings (loss) per common share	$ 0.28	$ 0.44	$ 0.31	$ 0.48	$ (0.32)	$ 0.65	$ 0.40	$ 0.31	$ 1.52	$ 1.06	$ 2.15
Diluted earnings (loss) per common share	$ 0.28	$ 0.43	$ 0.31	$ 0.47	$ (0.32)	$ 0.64	$ 0.39	$ 0.30	$ 1.49	$ 1.04	$ 2.12