Ally Financial (ALLY) 10-K 20 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Feb. 15, 2019	Jun. 29, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	Ally Financial Inc.
Entity Central Index Key	40,729
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Common Stock, Shares Outstanding		402,666,101
Entity Current Reporting Status	Yes
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 11,184,509,795

Consolidated Statement of Incom

Consolidated Statement of Income Consolidated Statement of Income - 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
Financing Revenue and Other Income [Line Items]
Interest and fees on finance receivables and loans									$ 6,688	$ 5,819	$ 5,162
Interest on loans held-for-sale									15	0	0
Interest and dividends on investment securities and other earning assets									788	599	418
Interest on cash and cash equivalents									72	37	14
Operating leases									1,489	1,867	2,711
Total financing revenue and other interest income									9,052	8,322	8,305
Interest Expense [Abstract]
Interest on deposits									1,735	1,077	830
Interest on short-term borrowings									149	127	57
Interest on long-term debt									1,753	1,653	1,742
Total interest expense									3,637	2,857	2,629
Net depreciation expense on operating lease assets									1,025	1,244	1,769
Net financing revenue and other interest income	$ 1,140	$ 1,107	$ 1,094	$ 1,049	$ 1,094	$ 1,081	$ 1,067	$ 979	4,390	4,221	3,907
Other revenue [Abstract]
Insurance premiums and service revenue earned									1,022	973	945
Gain on mortgage and automotive loans, net									25	68	11
Other (loss) gain on investments, net									(50)	102	185
Other income, net of losses									417	401	389
Total other revenue	298	398	364	354	379	381	388	396	1,414	1,544	1,530
Total net revenue									5,804	5,765	5,437
Provision for loan losses									918	1,148	917
Noninterest Expense [Abstract]
Compensation and benefits expense									1,155	1,095	992
Insurance losses and loss adjustment expenses									295	332	342
Other operating expenses									1,814	1,683	1,605
Total noninterest expense	804	807	839	814	769	753	810	778	3,264	3,110	2,939
Income from continuing operations before income tax expense	368	465	461	328	410	395	376	326	1,622	1,507	1,581
Income tax expense from continuing operations	79	91	113	76	231	115	122	113	359	581	470
Net income from continuing operations	289	374	348	252	179	280	254	213	1,263	926	1,111
Net income	290	374	349	250	181	282	252	214	1,263	929	1,067
Income (loss) from discontinued operations, net of tax	$ 1	$ 0	$ 1	$ (2)	$ 2	$ 2	$ (2)	$ 1	$ 0	$ 3	$ (44)
Earnings Per Share, Basic [Abstract]
Net income from continuing operations, basic earnings per common share	$ 0.70	$ 0.89	$ 0.81	$ 0.58	$ 0.40	$ 0.62	$ 0.55	$ 0.46	$ 2.97	$ 2.04	$ 2.25
Income (loss) from discontinued operations, net of tax, basic earnings per common share									0	0.01	(0.09)
Net income, basic earnings per common share	0.70	0.89	0.81	0.57	0.41	0.63	0.55	0.46	2.97	2.05	2.15
Earnings Per Share, Diluted [Abstract]
Net income from continuing operations, diluted earnings per common share	0.70	0.88	0.80	0.57	0.40	0.62	0.55	0.46	2.95	2.03	2.24
Income (loss) from discontinued operations, net of tax, diluted earnings per common share									0	0.01	(0.09)
Net income, diluted earnings per common share	0.70	0.88	0.81	0.57	0.41	0.63	0.55	0.46	2.95	2.04	2.15
Cash dividends declared per common share	$ 0.15	$ 0.15	$ 0.13	$ 0.13	$ 0.12	$ 0.12	$ 0.08	$ 0.08	$ 0.56	$ 0.40	$ 0.16
Retained earnings
Net income									$ 1,263	$ 929	$ 1,067

Consolidated Balance Sheet & Mi

Consolidated Balance Sheet & Mini Balance Sheet - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Assets [Abstract]
Cash and cash equivalents, noninterest-bearing	$ 810	$ 844
Cash and cash equivalents, interest-bearing	3,727	3,408
Total cash and cash equivalents	4,537	4,252
Equity securities	773	518
Available-for-sale securities	25,303	22,303
Held-to-maturity securities	2,362	1,899
Loans held-for-sale, net	314	108
Finance receivables and loans, net [Abstract]
Finance receivables and loans, net of unearned income	129,926	122,893
Allowance for loan losses	1,242	1,276
Total finance receivables and loans, net	128,684	121,617
Investment in operating leases, net	8,417	8,741
Premiums receivable and other insurance assets	2,326	2,047
Other assets	6,153	5,663
Total assets	178,869	167,148
Liabilities and Equity [Abstract]
Deposit liabilities, noninterest-bearing	142	108
Deposit liabilities, interest-bearing	106,036	93,148
Total deposit liabilities	106,178	93,256
Short-term borrowings	9,987	11,413
Long-term debt	44,193	44,226
Interest payable	523	375
Unearned insurance premiums and service revenue	3,044	2,604
Accrued expenses and other liabilities	1,676	1,780
Total liabilities	165,601	153,654
Equity [Abstract]
Common stock and paid-in capital	21,345	21,245
Accumulated deficit	(5,489)	(6,406)
Accumulated other comprehensive loss	(539)	(235)
Treasury stock, at cost	(2,049)	(1,110)
Total equity	13,268	13,494
Total liabilities and equity	178,869	167,148
Variable interest entity
Finance receivables and loans, net [Abstract]
Finance receivables and loans, net of unearned income	18,086	20,623
Allowance for loan losses	114	136
Total finance receivables and loans, net	17,972	20,487
Investment in operating leases, net	164	444
Other assets	767	689
Total assets	18,903	21,620
Liabilities and Equity [Abstract]
Long-term debt	10,482	10,197
Accrued expenses and other liabilities	12	9
Total liabilities	$ 10,494	$ 10,206

Consolidated Balance Sheet & _2

Consolidated Balance Sheet & Mini Balance Sheet (Paranthetical) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Common stock, par value per share	$ 0.01	$ 0.01
Common stock, shares authorized	1,100,000,000	1,100,000,000
Common stock, shares issued	492,797,409	489,883,553
Common stock, shares outstanding	404,899,599	437,053,936
Treasury stock, shares	87,897,810	52,829,617
Held-to-maturity securities, fair value	$ 2,307	$ 1,865

Condensed Consolidated Statemen

Condensed Consolidated Statement of Changes in Equity - USD ($) $ in Millions	Total	Common stock and paid-in capital	Preferred stock	Retained earnings	Accumulated other comprehensive income (loss)	Treasury stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity	$ 13,439	$ 21,100	$ 696	$ (8,110)		$ (16)
Accumulated other comprehensive loss	$ (231)				$ (231)
Common stock dividends, amount per share	$ 0.16
Net income	$ 1,067			1,067
Preferred stock dividends	30			30
Preferred stock redemption	696		696
Share-based compensation	66	66
Other comprehensive income (loss)	(110)				(110)
Common stock repurchases	(341)					(341)
Common stock dividends	(78)			(78)
Equity	13,317	21,166	0	(7,151)		(357)
Accumulated other comprehensive loss	$ (341)				(341)
Common stock dividends, amount per share	$ 0.40
Net income	$ 929			929
Preferred stock dividends	0
Share-based compensation	79	79
Other comprehensive income (loss)	106				106
Common stock repurchases	(753)					(753)
Common stock dividends	(184)			(184)
Equity	13,494	21,245	0	(6,406)		(1,110)
Accumulated other comprehensive loss	$ (235)				(235)
Common stock dividends, amount per share	$ 0.56
Net income	$ 1,263			1,263
Preferred stock dividends	0
Share-based compensation	100	100
Other comprehensive income (loss)	(289)				(289)
Common stock repurchases	(939)					(939)
Common stock dividends	(242)			(242)
Equity	13,268	$ 21,345	$ 0	$ (5,489)		$ (2,049)
Accumulated other comprehensive loss	(539)				$ (539)
Cumulative effect of changes in accounting principles, net of tax | Accounting Standards Update 2014-09	(126)
Cumulative effect of changes in accounting principles, net of tax | Accounting Standards Update 2016-01	(20)
Cumulative effect of changes in accounting principles, net of tax | Accounting Standards Update 2018-02	$ (42)

Consolidated Statement of Cash

Consolidated Statement of Cash Flows $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income	$ 1,263	$ 929	$ 1,067
Depreciation and amortization	1,649	1,859	2,382
Provision for loan losses	918	1,148	917
Gain on mortgage and automotive loans, net	(25)	(68)	(11)
Other loss (gain) on investments, net	50	(102)	(185)
Originations and purchases of loans held-for-sale	(1,016)	(414)	(141)
Proceeds from sales and repayments of loans held-for-sale	948	310	240
Increase (decrease) in deferred income taxes	330	534	458
Increase (decrease) in interest payable	148	24	1
Increase (decrease) in other operating assets	(87)	(153)	(120)
Increase (decrease) in other operating liabilities	2	(69)	(206)
Increase (decrease) in other operating assets and liabilities, net	(30)	81	165
Net cash provided by (used in) operating activities	4,150	4,079	4,567
Net Cash (Used in) Provided by Investing Activities [Abstract]
Purchases of equity securities	(1,076)	(899)	(470)
Proceeds from sales of equity securities	787	1,049	680
Purchases of available-for-sale securities	(7,868)	(10,335)	(15,561)
Proceeds from sale of available-for-sale securities	852	3,584	10,356
Proceeds from repayments of available-for-sale securities	3,215	2,899	3,379
Purchases of held-to-maturity securities	(578)	(1,026)	(841)
Proceeds from repayments of held-to-maturity securities	147	68	0
Purchases of finance receivables and loans held-for-investment	(5,693)	(5,452)	(3,859)
Proceeds from sales of finance receivables and loans initially held-for-investment	91	1,339	4,285
Originations and repayments of finance receivables and loans held-for-investment and other, net	(3,245)	(1,063)	(8,826)
Purchases of operating lease assets	(3,709)	(4,052)	(3,274)
Disposals of operating lease assets	3,089	5,567	6,304
Acquisitions, net of cash acquired	0	0	309
Net change in nonmarketable equity investments	(181)	(187)	(628)
Payments for (proceeds from) other, net	(340)	(219)	(306)
Net cash provided by investing activities	(14,509)	(8,727)	(9,070)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Net change in short-term borrowings	(1,426)	(1,263)	4,564
Net increase in deposits	12,867	14,172	12,508
Proceeds from issuance of long-term debt	18,401	17,969	14,155
Repayments of long-term debt	(17,940)	(27,908)	(26,412)
Repurchase and redemption of preferred stock	0	0	696
Repurchase of common stock	(939)	(753)	(341)
Dividends paid	(242)	(184)	(108)
Net cash provided by (used in) financing activities	10,721	2,033	3,670
Effect of exchange-rate changes on cash and cash equivalents and restricted cash	(5)	3	1
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Net increase (decrease) in cash and cash equivalents and restricted cash	357	(2,612)	(832)
Cash and cash equivalents and restricted cash	5,626	5,269	7,881
Cash and cash equivalents as disclosed on the Consolidated Balance Sheet	4,537	4,252
Restricted cash included in other assets on the Consolidated Balance Sheet	1,089	1,017
Supplemental Cash Flow Information [Abstract]
Cash paid for interest	3,380	2,829	2,647
Cash paid for income taxes	36	51	19
Held-to-maturity securities received in consideration for loans sold, noncash	26	56	0
Finance receivables and loans transferred to loans held-for-sale, noncash	815	1,339	4,282
Proceeds from repayments of mortgage loans held-for-investment originally designated as held-for-sale	$ 23	$ 36	$ 40

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net income	$ 1,263	$ 929	$ 1,067
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent [Abstract]
Other comprehensive income (loss), investment securities, net unrealized gains (losses) arising during the period	(287)	192	33
Other comprehensive income (loss), investment securities, net realized gains (losses) reclassified to net income	8	92	147
Other comprehensive income (loss), investment securities, net change, after tax	(295)	100	(114)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Other comprehensive income (loss), translation adjustments, net unrealized gains (losses) arising during the period	(11)	8	3
Other comprehensive income (loss), translation adjustments, net realized gains (losses) reclassified to net income	0	0	(1)
Other comprehensive income (loss), translation adjustments, net unrealized gains (losses) arising during the period, after tax	(11)	8	4
Other comprehensive income (loss), net investment hedges, net unrealized gains (losses) arising during the period	9	(6)	1
Other comprehensive income (loss), translation adjustments and net investment hedges, net change	(2)	2	5
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract]
Other comprehensive income (loss), cash flow hedges, net unrealized gains (losses) arising during the period	10	3	0
Other comprehensive income (loss), cash flow hedges, net realized gains (losses) reclassified to net income	2	0	0
Other comprehensive income (loss), cash flow hedge, gain (loss), after reclassification and tax	8	3	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax [Abstract]
Other comprehensive (income) loss, defined benefit pension plans, net unrealized gains (losses) arising during the period	0	1	(3)
Other comprehensive income (loss), defined benefit pension plans, net realized gains (losses) reclassified to net income	0	0	(2)
Other comprehensive (income) loss, defined benefit pension plan, net change	0	1	(1)
Other comprehensive income (loss), net of tax	(289)	106	(110)
Comprehensive income	974	1,035	957
Retained earnings
Net income	$ 1,263	$ 929	$ 1,067

Description of Business, Basis

Description of Business, Basis of Presentation, and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies	Description of Business, Basis of Presentation, and Significant Accounting Policies Ally Financial Inc. (together with its consolidated subsidiaries unless the context otherwise requires, Ally, the Company, or we, us, or our) is a leading digital financial-services company . As a customer-centric company with passionate customer service and innovative financial solutions, we are relentlessly focused on “Doing It Right” and being a trusted financial-services provider to our consumer, commercial, and corporate customers. We are one of the largest full-service automotive-finance operations in the country and offer a wide range of financial services and insurance products to dealerships and consumers. Our award-winning online bank (Ally Bank, Member FDIC and Equal Housing Lender) offers mortgage-lending services and a variety of deposit and other banking products, including savings, money-market, and checking accounts, certificates of deposit (CDs), and individual retirement accounts (IRAs). We also support the Ally CashBack Credit Card. Additionally, we offer securities-brokerage and investment-advisory services through Ally Invest. Our robust corporate-finance business offers capital for equity sponsors and middle-market companies . We are a Delaware corporation and are registered as a bank holding company (BHC) under the Bank Holding Company Act of 1956, as amended , and a financial holding company (FHC) under the Gramm-Leach-Bliley Act of 1999, as amended . Consolidation and Basis of Presentation The Consolidated Financial Statements include the accounts of the parent and its consolidated subsidiaries, of which it is deemed to possess control, after eliminating intercompany balances and transactions, and include all variable interest entities (VIEs) in which we are the primary beneficiary. Other entities in which we have invested and have the ability to exercise significant influence over operating and financial policies of the investee, but upon which we do not possess control, are accounted for by the equity method of accounting within the financial statements and they are therefore not consolidated. Refer to Note 11 for further details on our VIEs. Our accounting and reporting policies conform to accounting principles generally accepted in the United States of America (GAAP). Additionally, where applicable, the policies conform to the accounting and reporting guidelines prescribed by bank regulatory authorities. Certain reclassifications may have been made to the prior periods’ financial statements and notes to conform to the current period’s presentation, which did not have a material impact on our Consolidated Financial Statements. In the past, we have operated our international subsidiaries in a similar manner as we operate in the United States of America (U.S. or United States), subject to local laws or other circumstances that may cause us to modify our procedures accordingly. The financial statements of subsidiaries that operate outside of the United States generally are measured using the local currency as the functional currency. All assets and liabilities of foreign subsidiaries are translated into U.S. dollars at year-end exchange rates. The resulting translation adjustments are recorded in accumulated other comprehensive income until the foreign subsidiaries are sold or substantially liquidated at which point the accumulated translation adjustments are recognized directly in earnings as part of the gain or loss on sale or liquidation. Income and expense items are translated at average exchange rates prevailing during the reporting period. The majority of our international operations have ceased and are included in discontinued operations as further described in Note 2 . Use of Estimates and Assumptions 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 that affect income and expenses during the reporting period and related disclosures. In developing the estimates and assumptions, management uses all available evidence; however, actual results could differ because of uncertainties associated with estimating the amounts, timing, and likelihood of possible outcomes. Our most significant estimates pertain to the allowance for loan losses, valuations of automotive operating lease assets and residuals, fair value of financial instruments, and the determination of the provision for income taxes.
Significant Accounting Policies	Significant Accounting Policies Cash and Cash Equivalents Cash and cash equivalents include cash on hand, cash on deposit at other financial institutions, cash items in process of collection, and certain highly liquid investments with original maturities of three months or less from the date of purchase. The book value of cash equivalents approximates fair value because of the short maturities of these instruments and the insignificant risk they present to changes in value with respect to changes in interest rates. Certain securities with original maturities of three months or less from the date of purchase that are held as a portion of longer-term investment portfolios, primarily held by our Insurance operations, are classified as investment securities. Cash and cash equivalents with legal restrictions limiting our ability to withdraw and use the funds are considered restricted cash and restricted cash equivalents and are presented as other assets on our Consolidated Balance Sheet. Investments Our investment portfolio includes various debt and equity securities. Our debt securities include government securities, corporate bonds, asset-backed securities (ABS), and mortgage-backed securities (MBS). Debt securities are classified based on management’s intent to sell or hold the security. We classify debt securities as held-to-maturity only when we have both the intent and ability to hold the securities to maturity. We classify debt securities as trading when the securities are acquired for the purpose of selling or holding them for a short period of time. Debt securities not classified as either held-to-maturity or trading are classified as available-for-sale. Our portfolio includes debt securities classified as available-for-sale and held-to-maturity. Our available-for-sale debt securities are carried at fair value with unrealized gains and losses included in accumulated other comprehensive income and are subject to impairment. Our held-to-maturity debt securities are carried at amortized cost and are subject to impairment. We assess our available-for-sale and held-to-maturity debt securities for potential other-than-temporary impairment. We employ a methodology that considers available evidence in evaluating potential other-than-temporary impairment of our debt securities. If the cost of an investment exceeds its fair value, we evaluate, among other factors, the magnitude and duration of the decline in fair value. We also evaluate the financial health of and business outlook for the issuer, the performance of the underlying assets for interests in securitized assets, and, for debt securities classified as available-for-sale, our intent and ability to hold the investment through recovery of its amortized cost basis. Once a decline in fair value of a debt security is determined to be other-than-temporary, an impairment charge for the credit component is recorded to other gain on investments, net, in our Consolidated Statement of Income, and a new cost basis in the investment is established. The noncredit loss component of a debt security continues to be recorded in other comprehensive income when we do not intend to sell the security and it is not more likely than not that we will have to sell the security prior to the security’s anticipated recovery. Both the credit and noncredit loss components are recorded in earnings when we intend to sell the security or it is more likely than not that we will have to sell the security prior to the security’s anticipated recovery. Subsequent increases and decreases to the fair value of available-for-sale debt securities are included in other comprehensive income, so long as they are not attributable to another other-than-temporary impairment. We amortize premiums and discounts on debt securities as an adjustment to investment yield over the stated maturity of the security. Our investment in equity securities includes securities that are recognized at fair value with changes in the fair value recorded in earnings, and equity securities that are recognized using other measurement principles. Effective January 1, 2018, equity securities that have a readily determinable fair value, as well as certain investments that do not have a readily determinable fair value and are not eligible to be recognized using other measurement principles, are recorded at fair value with changes in fair value recorded in earnings and reported in other gain on investments, net in our Consolidated Statement of Income. These investments, which are primarily attributable to the investment portfolio of our Insurance operations, are included in equity securities on our Consolidated Balance Sheet. Refer to Note 8 for further information on our equity securities that have a readily determinable market value. Our equity securities recognized using other measurement principles include investments in Federal Home Loan Bank (FHLB) and Federal Reserve Bank (FRB) stock held to meet regulatory requirements, equity investments related to low income housing tax credits and the Community Reinvestment Act (CRA), which do not have a readily determinable fair value, and other equity investments that do not have a readily determinable fair value. Our low income housing tax credit investments are accounted for using the proportional amortization method of accounting for qualified affordable housing investments. Our obligations related to unfunded commitments for our low income housing tax credit investments are included in other liabilities. The majority of our other CRA investments are accounted for using the equity method of accounting. Our investments in low income housing tax credits and other CRA investments are included in other assets on our Consolidated Balance Sheet. Our investments in FHLB and FRB stock are carried at cost, less impairment. Our remaining investment in equity securities are recorded at cost, less impairment and adjusted for observable price changes under the measurement alternative provided under GAAP. These investments, along with our investments in FHLB and FRB stock, are included in nonmarketable equity investments in other assets on our Consolidated Balance Sheet. As conditions warrant, we review these investments for impairment and adjust the carrying value of the investment if it is deemed to be impaired. Investments recorded under the measurement alternative are also reviewed at each reporting period to determine if any adjustments are required for observable price changes in identical or similar securities of the same issuer. Realized gains and losses on the sale of securities are determined using the specific identification method and are reported in other gain on investments, net in our Consolidated Statement of Income. Finance Receivables and Loans We initially classify finance receivables and loans as either loans held-for-sale or loans held-for-investment based on management’s assessment of our intent and ability to hold the loans for the foreseeable future or until maturity. Management’s view of the foreseeable future is based on the longest reasonably reliable net income, liquidity, and capital forecast period. Management’s intent and ability with respect to certain loans may change from time to time depending on a number of factors, for example economic, liquidity, and capital conditions. In order to reclassify loans to held-for-sale, management must have the intent to sell the loans and reasonably identify the specific loans to be sold. Loans classified as held-for-sale are presented as loans held-for-sale, net on our Consolidated Balance Sheet and are carried at the lower of their net carrying value or fair value, unless the fair value option was elected, in which case those loans are carried at fair value. Loan origination fees and costs are included in the initial carrying value of loans originated as held-for-sale for which we have not elected the fair value option. Loan origination fees and costs are recognized in earnings when earned or incurred, respectively, for loans classified as held-for-sale for which we have elected the fair value option. We have elected the fair value option for conforming mortgage direct-to-consumer originations for which we have a commitment to sell. The interest rate lock commitment that we enter into for a mortgage loan originated as held-for-sale and certain forward commitments to sell mortgage loans are considered derivative instruments, which are carried at fair value on our Consolidate Balance Sheet. We have elected the fair value option to measure our non-derivative forward commitments. Changes in the fair value of our interest rate lock commitments, derivative forward commitments, and non-derivative forward commitments related to mortgage loans originated as held-for-sale, as well as changes in the carrying value of loans classified as held-for-sale, are reported through gain on mortgage and automotive loans, net in our Consolidated Statement of Comprehensive Income. Interest income on our loans classified as held-for-sale is recognized based upon the contractual rate of interest on the loan and the unpaid principal balance. We report accrued interest receivable on our loans classified as held-for-sale in other assets on the Consolidated Balance Sheet. Loans classified as held-for-investment are presented as finance receivables and loans, net on our Consolidated Balance Sheet. Finance receivables and loans are reported at their gross carrying value, which includes the principal amount outstanding, net of unamortized deferred fees and costs on originated loans, unamortized premiums and discounts on purchased loans, unamortized basis adjustments arising from the designation of finance receivables and loans as the hedged item in qualifying fair value hedge relationships, and cumulative principal charge-offs. We refer to the gross carrying value less the allowance for loan loss as the net carrying value in finance receivables and loans. Unearned rate support received from an automotive manufacturer on certain automotive loans, deferred origination fees and costs, and premiums and discounts on purchased loans, are amortized over the contractual life of the related finance receivable or loan using the effective interest method. We make various incentive payments for consumer automotive loan originations to automotive dealers and account for these payments as direct loan origination costs. Additionally, we make incentive payments to certain commercial automobile wholesale borrowers and account for these payments as a reduction to interest income in the period they are earned. Interest income on our finance receivables and loans is recognized based on the contractual rate of interest plus the amortization of deferred amounts using the effective interest method. We report accrued interest receivable on our finance receivables and loans in other assets on our Consolidated Balance Sheet. Loan commitment fees are generally deferred and amortized over the commitment period. For information on finance receivables and loans, refer to Note 9 . Our portfolio segments are based on the level at which we develop and document our methodology for determining the allowance for loan losses. Additionally, the classes of finance receivables are based on several factors including the method for monitoring and assessing credit risk, the method of measuring carrying value, and the risk characteristics of the finance receivable. Based on an evaluation of our process for developing the allowance for loan losses including the nature and extent of exposure to credit risk arising from finance receivables, we have determined our portfolio segments to be consumer automotive, consumer mortgage, and commercial. • Consumer automotive — Consists of retail automotive financing for new and used vehicles. • Consumer mortgage — Consists of the following classes of finance receivables. • Mortgage Finance — Consists of consumer first-lien mortgages from our ongoing mortgage operations including bulk acquisitions, direct-to-consumer originations, and refinancing of high-quality jumbo mortgages and low-to-moderate income (LMI) mortgages. • Mortgage — Legacy — Consists of consumer mortgage assets originated prior to January 1, 2009, including first-lien mortgages, subordinate-lien mortgages, and home equity mortgages. • Commercial — Consists of the following classes of finance receivables. • Commercial and Industrial • Automotive — Consists of financing operations to fund dealer purchases of new and used vehicles through wholesale floorplan financing. Additional commercial offerings include automotive dealer term loans, and dealer fleet financing. • Other — Consists primarily of senior secured leveraged cash flow and asset-based loans related to our Corporate Finance business. • Commercial Real Estate — Consists of term loans to finance dealership land and buildings, and other commercial lending secured by real estate. Nonaccrual Loans Generally, we recognize loans of all classes as past due when they are 30 days delinquent on making a contractually required payment, and loans are placed on nonaccrual status when principal or interest has been delinquent for 90 days or when full collection is not expected . Interest income recognition is suspended when finance receivables and loans are placed on nonaccrual status. Additionally, amortization of premiums and discounts and deferred fees and costs ceases when finance receivables and loans are placed on nonaccrual. Exceptions include commercial real estate loans that are placed on nonaccrual status when delinquent for 60 days or when full collection is not probable, if sooner. Additionally, our policy is to generally place all loans that have been modified in troubled debt restructurings (TDRs) on nonaccrual status until the loan has been brought fully current, the collection of contractual principal and interest is reasonably assured, and six consecutive months of repayment performance is achieved. In certain cases, if a borrower has been current up to the time of the modification and repayment of the debt subsequent to the modification is reasonably assured, we may choose to continue to accrue interest on the loan. Loans on nonaccrual status are reported as nonperforming loans in Note 9 . The receivable for interest income that is accrued, but not collected, at the date finance receivables and loans are placed on nonaccrual status is reversed against interest income and subsequently recognized only to the extent it is received in cash or until it qualifies for return to accrual status. However, where there is doubt regarding the ultimate collectability of loan principal, all cash received is applied to reduce the carrying value of such loans. Generally, finance receivables and loans are restored to accrual status only when contractually current and the collection of future payments is reasonably assured. Impaired Loans Loans of all classes are considered impaired when we determine it is probable that we will be unable to collect all amounts due (both principal and interest) according to the terms of the loan agreement. For all classes of consumer loans, impaired loans include all loans that have been modified in TDRs. Commercial loans of all classes are considered impaired on an individual basis and reported as impaired when we determine it is probable that we will be unable to collect all amounts due according to the terms of the loan agreement. With the exception of certain consumer TDRs that have been returned to accruing status, for all classes of impaired loans, income recognition is consistent with that of nonaccrual loans discussed above. Impaired loans may return to accrual status as discussed in the preceding nonaccrual loan section at which time, the normal accrual of interest income resumes. For collateral dependent loans, if the recorded investment in the impaired loans exceeds the fair value of the collateral, a charge-off is recorded consistent with the TDR discussion below. Troubled Debt Restructurings When the terms of finance receivables or loans are modified, consideration must be given as to whether or not the modification results in a TDR. A modification is considered to be a TDR when both the borrower is experiencing financial difficulty and we grant a concession to the borrower. These considerations require significant judgment and vary by portfolio segment. In all cases, the cumulative impacts of all modifications are considered at the time of the most recent modification. For consumer loans of all classes, various qualitative factors are utilized for assessing the financial difficulty of the borrower. These include, but are not limited to, the borrower’s default status on any of its debts, bankruptcy and recent changes in financial circumstances (loss of job, etc.). A concession has been granted when as a result of the modification we do not expect to collect all amounts due under the original loan terms, including interest accrued at the original contract rate. Types of modifications that may be considered concessions include, but are not limited to, extensions of terms at a rate that does not constitute a market rate, a reduction, deferral or forgiveness of principal or interest owed and loans that have been discharged in a Chapter 7 Bankruptcy and have not been reaffirmed by the borrower. In addition to the modifications noted above, in our consumer automotive portfolio segment of loans we also provide extensions or deferrals of payments to borrowers whom we deem to be experiencing only temporary financial difficulty. In these cases, there are limits within our operational policies to minimize the number of times a loan can be extended, as well as limits to the length of each extension, including a cumulative cap over the life of the loan. If these limits are breached, the modification is considered a TDR as noted in the following paragraph. Before offering an extension or deferral, we evaluate the capacity of the customer to make the scheduled payments after the deferral period. During the deferral period, we continue to accrue and collect interest on the loan as part of the deferral agreement. We grant these extensions or deferrals when we expect to collect all amounts due including interest accrued at the original contract rate. A restructuring that results in only a delay in payment that is deemed to be insignificant is not a concession and the modification is not considered to be a TDR. In order to assess whether a restructuring that results in a delay in payment is insignificant, we consider the amount of the restructured payments subject to delay in conjunction with the unpaid principal balance or the collateral value of the loan, whether or not the delay is significant with respect to the frequency of payments under the original contract, or the loan’s original expected duration. In the cases where payment extensions on our automotive loan portfolio cumulatively extend beyond 90 days and are more than 10% of the original contractual term or where the cumulative payment extension is beyond 180 days, we deem the delay in payment to be more than insignificant, and as such, classify these types of modifications as TDRs. Otherwise, we believe that the modifications do not represent a concessionary modification and accordingly, they are not classified as TDRs. For commercial loans of all classes, similar qualitative factors are considered when assessing the financial difficulty of the borrower. In addition to the factors noted above, consideration is also given to the borrower’s forecasted ability to service the debt in accordance with the contractual terms, possible regulatory actions and other potential business disruptions (e.g., the loss of a significant customer or other revenue stream). Consideration of a concession is also similar for commercial loans. In addition to the factors noted above, consideration is also given to whether additional guarantees or collateral have been provided. For all loans, TDR classification typically results from our loss mitigation activities. For loans held-for-investment that are not carried at fair value and are TDRs, impairment is typically measured based on the difference between the gross carrying value of the loan and the present value of the expected future cash flows of the loan. The loan may also be measured for impairment based on the fair value of the underlying collateral less costs to sell for loans that are collateral dependent. We recognize impairment by either establishing a valuation allowance or recording a charge-off. The financial impacts of modifications that meet the definition of a TDR are reported in the period in which they are identified as TDRs. Additionally, if a loan that is classified as a TDR redefaults within twelve months of the modification, we are required to disclose the instances of redefault. For the purpose of this disclosure, we have determined that a loan is considered to have redefaulted when the loan meets the requirements for evaluation under our charge-off policy except for commercial loans where redefault is defined as 90 days past due. Impaired loans may return to accrual status as discussed in the preceding nonaccrual loan section at which time, the normal accrual of interest income resumes. Net Charge-offs We disclose the measurement of net charge-offs as the amount of gross charge-offs recognized less recoveries received. Gross charge-offs reflect the amount of the gross carrying value directly written-off. Generally, we recognize recoveries when they are received and record them as an increase to the allowance for loan losses. As a general rule, consumer automotive loans are written down to estimated collateral value, less costs to sell, once a loan becomes 120 days past due. In our consumer mortgage portfolio segment, first-lien mortgages and a subset of our home equity portfolio that are secured by real estate in a first-lien position are written down to the estimated fair value of the collateral, less costs to sell, once a mortgage loan becomes 180 days past due. Consumer mortgage loans that represent second-lien positions are charged off at 180 days past due. Within 60 days of receipt of notification of filing from the bankruptcy court, or within the time frames noted above, consumer automotive and first-lien consumer mortgage loans in bankruptcy are written down to their expected future cash flows, which is generally fair value of the collateral, less costs to sell, and second-lien consumer mortgage loans are fully charged-off, unless it can be clearly demonstrated that repayment is likely to occur. Regardless of other timelines noted within this policy, loans are considered collateral dependent once foreclosure or repossession proceedings begin and are charged-off to the estimated fair value of the underlying collateral, less costs to sell at that time. Commercial loans are individually evaluated and where collectability of the recorded balance is in doubt are written down to the estimated fair value of the collateral less costs to sell. Generally, all commercial loans are charged-off when it becomes unlikely that the borrower is willing or able to repay the remaining balance of the loan and any underlying collateral is not sufficient to recover the outstanding principal. Collateral dependent loans are charged-off to the fair market value of collateral less costs to sell when appropriate. Noncollateral dependent loans are fully written-off. Allowance for Loan Losses The allowance for loan losses (the allowance) is management’s estimate of incurred losses in the lending portfolios. We determine the amount of the allowance required for each of our portfolio segments based on its relative risk characteristics. The evaluation of these factors for both consumer and commercial finance receivables and loans involves quantitative analysis combined with sound management judgment. Additions to the allowance are charged to current period earnings through the provision for loan losses; amounts determined to be uncollectible are charged directly against the allowance, net of amounts recovered on previously charged-off accounts. The allowance is composed of two components: specific reserves established for individual loans evaluated as impaired and portfolio-level reserves established for large groups of typically smaller balance homogeneous loans that are collectively evaluated for impairment. We evaluate the adequacy of the allowance based on the combined total of these two components. Determining the appropriateness of the allowance is complex and requires judgment by management about the effect of matters that are inherently uncertain. It is possible that others, given the same information, may at any point in time reach different reasonable conclusions. Measurement of impairment for specific reserves is generally determined on a loan-by-loan basis. Loans determined to be specifically impaired are measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate, an observable market price, or the estimated fair value of the collateral less estimated costs to sell when appropriate, whichever is determined to be the most appropriate. When these measurement values are lower than the net carrying value of that loan, impairment is recognized. Loans that are not identified as individually impaired are pooled with other loans with similar risk characteristics for evaluation of impairment for the portfolio-level allowance. For the purpose of calculating portfolio-level reserves, we have grouped our loans into three portfolio segments: consumer automotive, consumer mortgage, and commercial. The allowance consists of the combination of a quantitative assessment component based on statistical models, a retrospective evaluation of actual loss information to loss forecasts, and includes a qualitative component based on management judgment. Management takes into consideration relevant qualitative factors, including external and internal trends such as the impacts of changes in underwriting standards, collections and account management effectiveness, geographic concentrations, and economic events, among other factors, that have occurred but are not yet reflected in the quantitative assessment component. Qualitative adjustments are documented, reviewed, and approved through our established risk governance processes and follow regulatory guidance. Management also considers the need for a reserve on unfunded non-derivative loan commitments across our portfolio segments, including lines of credit and standby letters of credit, using similar procedures and methodologies used to determine the allowance for loan losses while also considering historical loss ratios and potential usage levels. The reserve for unfunded loan commitments is recorded within other liabilities on our Consolidated Balance Sheet and the related expense is reported as other noninterest expense in our Consolidated Statement of Comprehensive Income. Refer to Note 28 for information on our unfunded loan commitments. During 2018, we did not substantively change any material aspect of our overall approach used to determine the allowance for loan losses for our portfolio segments. There were no material changes in criteria or estimation techniques as compared to prior periods that impacted the determination of the current period allowance for loan losses for our portfolio segments. Refer to Note 9 for information on the allowance for loan losses. Consumer Loans Our consumer automotive and consumer mortgage portfolio segments are reviewed for impairment based on an analysis of loans that are grouped into common risk categories. We perform periodic and systematic detailed reviews of our lending portfolios to identify inherent risks and to assess the overall collectability of those portfolios. Loss models are utilized for these portfolios, which consider a variety of credit quality indicators including, but not limited to, historical loss experience, current economic conditions, credit scores, and expected loss factors by loan type. Consumer Automotive Portfolio Segment The allowance for loan losses within the consumer automotive portfolio segment is calculated using proprietary statistical models and other risk indicators applied to pools of loans with similar risk characteristics, including credit bureau score and loan-to-value (LTV) ratios to arrive at an estimate of incurred losses in the portfolio. These statistical loss forecasting models are utilized to estimate incurred losses and consider a variety of factors including, but not limited to, historical loss experience, estimated defaults based on portfolio trends, and general economic and business trends. These statistical models predict forecasted losses inherent in the portfolio. The forecasted losses consider historical factors such as frequency (the number of contracts that we expect to default) and loss severity (the loss amount of contracts we expect to default). The loss severity within the consumer automotive portfolio segment is impacted by the market values of vehicles that are repossessed. Vehicle market values are affected by numerous factors including vehicle supply, the condition of the vehicle upon repossession, the overall price and volatility of gasoline or diesel fuel, consumer preference related to specific vehicle segments, and other factors. The quantitative assessment component of the allowance may be supplemented with qualitative reserves based on management’s determination that such adjustments provide a better estimate of credit losses. This qualitative assessment takes into consideration relevant internal and external factors that have occurred, but are not yet reflected in the forecasted losses, and may affect the performance of the portfolio. Consumer Mortgage Portfolio Segment The allowance for loan losses within the consumer mortgage portfolio segment is calculated by using statistical models based on pools of loans with similar risk characteristics, including credit score, LTV, loan age, documentation type, product type, and loan purpose, to arrive at an estimate of incurred losses in the portfolio. These statistical loss forecasting models are utilized to estimate incurred losses and consider a variety of factors including, but not limited to, historical loss experience, estimated foreclosures or defaults based on portfolio trends, delinquencies, and general economic and business trends. The forecasted losses are statistically derived based on a suite of behavioral based transition models. This transition framework predicts various stages of delinquency, default, and voluntary prepayment over the course of the life of the loan. The transition probability is a function of the loan and borrower characteristics and economic variables and considers historical factors such as frequency and loss severity. When a default event is predicted, a severity model is applied to estimate future loan losses. Loss severity within the consumer mortgage portfolio segment is impacted by the market values of foreclosed properties, which is affected by numerous factors, including geographic considerations and the condition of the foreclosed property. The quantitative assessment component of the allowance may be supplemented with qualitative reserves based on management’s determination that such adjustments provide a better estimate of credit losses. This qualitative assessment takes into consideration relevant internal and external factors that have occurred, but are not yet reflected in the forecasted losses, and may affect the performance of the portfolio. Commercial Loans The allowance for loan losses within the commercial portfolio is composed of reserves established for specific loans evaluated as impaired and portfolio-level reserves based on nonimpaired loans grouped into pools based on similar risk characteristics and collectively evaluated. A commercial loan is considered impaired when it is probable that we will be unable to collect all amounts due according to the contractual terms of the loan agreement based on current information and events. These loans are primarily evaluated individually and are risk-rated based on borrower, collateral, and industry-specific information that management believes is relevant in determining the occurrence of a loss event and measuring impairment. Management establishes specific allowances for commercial loans determined to be individually impaired based on the present value of expected future cash flows, discounted at the loan’s effective interes

Discontinued Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2018
Discontinued Operations [Abstract]
Discontinued Operations, Disclosure	Discontinued Operations Prior to the adoption of ASU 2014-08, which was prospectively applied only to newly identified disposals that qualify as discontinued operations beginning after January 1, 2015, we have classified operations as discontinued when operations and cash flows will be eliminated from our ongoing operations and we do not expect to retain any significant continuing involvement in their operations after the respective sale or disposal transactions. For all periods presented, the operating results for these discontinued operations have been removed from continuing operations and presented separately as discontinued operations, net of tax, in the Consolidated Statement of Income . The Notes to the Consolidated Financial Statements have been adjusted to exclude discontinued operations unless otherwise noted. Our discontinued operations relate to previous discontinued operations in our Automotive Finance operations, Insurance operations, and Corporate Finance operating segments, and other operations for which we continue to have wind-down, legal, and minimal operational costs. Pretax loss of our discontinued operations for the year ended December 31, 2018 , was $1 million . There was no net income due to an offsetting tax benefit. Pretax loss and net income were $2 million and $3 million , respectively, for the year ended December 31, 2017 . Pretax loss and net loss were $43 million and $44 million , respectively, for the year ended December 31, 2016 .

Revenue from Contracts with Cus

Revenue from Contracts with Customers	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer	Revenue from Contracts with Customers On January 1, 2018, we adopted the amendments to the revenue recognition principles using the modified retrospective approach applied to contracts with customers outstanding as of the date of adoption. Results for reporting periods beginning after January 1, 2018, are presented in accordance with the amendments to the revenue recognition principles, while prior period amounts have not been adjusted and continue to be presented in accordance with the accounting standards in effect for those periods. Refer to Note 1 for additional information. Our primary revenue sources, which include financing revenue and other interest income, are addressed by other GAAP and are not in the scope of the amendments to the revenue recognition principles. As part of our Insurance operations, we recognize revenue from insurance contracts, which are addressed by other GAAP and are not included in the scope of the amendments to the revenue recognition principles. Certain noninsurance contracts within our Insurance operations, including vehicle service contracts (VSCs), guaranteed asset protection (GAP) contracts, and vehicle maintenance contracts (VMCs), are included in the scope of the amendments to the revenue recognition principles. Under the previous guidance, a portion of revenue earned on noninsurance contracts was recognized at contract inception, while the remainder was recognized over the contract term on a basis proportionate to the anticipated cost emergence. In addition, dealer and sales commissions incurred to obtain a noninsurance contract were recognized as expense when incurred, and certain direct-response advertising costs were deferred and recognized as expense over the term of the contract. Upon adoption of the amendments to the revenue recognition principles, all revenue associated with noninsurance contracts is recognized over the contract term on a basis proportionate to the anticipated cost emergence. Further, commissions and sales expense incurred to obtain these contracts are capitalized and recognized as expense over the contract term, and all advertising costs are recognized as expense when incurred. The following table presents the impact to our Consolidated Balance Sheet as of January 1, 2018, as a result of adopting the amendments to the revenue recognition principles. ($ in millions) As reported, December 31, 2017 Adjustment related to adoption As adjusted, January 1, 2018 Assets Premiums receivable and other insurance assets $ 2,047 $ 122 $ 2,169 Other assets 5,663 41 5,704 Total assets $ 167,148 $ 163 $ 167,311 Liabilities Unearned insurance premiums and service revenue $ 2,604 $ 289 $ 2,893 Total liabilities 153,654 289 153,943 Equity Accumulated deficit (6,406 ) (126 ) (6,532 ) Total equity 13,494 (126 ) 13,368 Total liabilities and equity $ 167,148 $ 163 $ 167,311 The following tables present the impact of adopting the amendments to the revenue recognition principles to our Consolidated Statement of Income , Consolidated Statement of Comprehensive Income , and Consolidated Balance Sheet . Year ended December 31, 2018 ($ in millions) As reported Effect of adoption Other revenue Insurance premiums and service revenue earned $ 1,022 $ (26 ) Total other revenue 1,414 (26 ) Total net revenue 5,804 (26 ) Noninterest expense Compensation and benefits expense 1,155 (1 ) Other operating expenses 1,814 (12 ) Total noninterest expense 3,264 (13 ) Income from continuing operations before income tax expense 1,622 (13 ) Income tax expense from continuing operations 359 (3 ) Net income from continuing operations 1,263 (10 ) Net income 1,263 (10 ) Comprehensive income $ 974 $ (10 ) December 31, 2018 ($ in millions) As reported Effect of adoption Assets Premiums receivable and other insurance assets $ 2,326 $ 135 Other assets 6,153 44 Total assets $ 178,869 $ 179 Liabilities Unearned insurance premiums and service revenue $ 3,044 $ 315 Total liabilities 165,601 315 Equity Accumulated deficit (5,489 ) (136 ) Total equity 13,268 (136 ) Total liabilities and equity $ 178,869 $ 179 The following is a description of our primary revenue sources that are derived from contracts with customers. As a result of the adoption of the amendments to the revenue recognition principles, our only revenue source for which the recognition pattern was affected was that of noninsurance contracts, as described in this note. Revenue from contracts with customers is recognized when control of the promised goods or services is transferred to our customers, and in an amount that reflects the consideration that we expect to receive in exchange for those goods or services. For information regarding our revenue recognition policies outside the scope of the amendments to the revenue recognition principles of ASC 606, Revenue from Contracts with Customers , refer to Note 1 . • Noninsurance contracts — We sell VSCs that offer owners mechanical repair protection and roadside assistance for new and used vehicles beyond the manufacturer’s new vehicle limited warranty. We sell GAP contracts that protect the customer against having to pay certain amounts to a lender above the fair market value of their vehicle if the vehicle is damaged and declared a total loss or stolen. We also sell VMCs that provide coverage for certain agreed-upon services, such as oil changes and tire rotations, over the coverage period. We receive payment in full at the inception of each of these contracts. Our performance obligation for these contracts is satisfied over the term of the contract and we recognize revenue over the contract term on a basis proportionate to the anticipated incurrence of costs, as we believe this is the most appropriate method to measure progress towards satisfaction of the performance obligation. Upon adoption of the amendments to the revenue recognition principles, unearned revenue of $289 million was recognized as a component of unearned insurance premiums and service revenue on our Consolidated Balance Sheet associated with outstanding contracts at January 1, 2018, and $91 million of this balance was recognized as insurance premiums and service revenue earned in our Consolidated Statement of Income during the year ended December 31, 2018 . At December 31, 2018 , we had unearned revenue of $2.6 billion associated with outstanding contracts, and with respect to this balance we expect to recognize revenue of $721 million in 2019 , $639 million in 2020 , $519 million in 2021 , $379 million in 2022, and $386 million thereafter. The incremental costs to obtain these contracts are initially deferred and recorded as a component of premiums receivable and other insurance assets on our Consolidated Balance Sheet . These deferred costs are amortized as an expense over the term of the related contract commensurate with how the related revenue is recognized, and are included in compensation and benefits and other operating expenses in our Consolidated Statement of Income . We had deferred insurance assets of $1.5 billion at December 31, 2018 , and recognized $427 million of expense during the year ended December 31, 2018 . • Sale of off-lease vehicles — When a customer’s vehicle lease matures, the customer has the option of purchasing or returning the vehicle. If the vehicle is returned to us, we obtain possession with the intent to sell through SmartAuction—our online auction platform, our dealer channel, or through various other physical auctions. Our performance obligation is satisfied and the remarketing gain or loss is recognized when control of the vehicle has passed to the buyer, which coincides with the sale date. Our actual sales proceeds from remarketing the vehicle may be higher or lower than the estimated residual value resulting in a gain or loss on remarketing recorded through depreciation expense on operating lease assets in our Consolidated Statement of Income . • Remarketing fee income — In addition to using SmartAuction as a remarketing channel for our returned lease vehicles, we maintain the internet auction site and administer the auction process for third-party use. We earn a service fee from dealers for every third-party vehicle sold through SmartAuction. Our performance obligation is to provide the online marketplace for used vehicle transactions to be consummated. This obligation is satisfied and revenue is recognized when control of the vehicle has passed to the buyer, which coincides with the sale date. This revenue is recorded as remarketing fees within other income in our Consolidated Statement of Income . • Brokerage commissions and other revenues through Ally Invest — We charge fees to customers related to their use of certain services on our Ally Invest digital wealth management and online brokerage platform. These fees include commissions on customer-directed trades, account service fees, account management fees on professional portfolio management services, and other ancillary fees. Commissions on customer-directed trades and account service fees are based on published fee schedules and are generated from a customer option to purchase the services offered under the contract. These options do not represent a material right and are only considered a contract when the customer executes their option to purchase these services. Based on this, the term of the contract does not extend beyond services provided, and as such revenue is recognized upon the completion of our performance obligation, which we view as the successful execution of the trade or service. Revenue on professional portfolio management services is calculated monthly based upon a fixed percentage of the client’s assets under management. Due to the fact that this revenue stream is composed of variable consideration that is based on factors outside of our control, we have deemed this revenue as constrained and we are unable to estimate the initial transaction price at the inception of the contract. We have elected to use the practical expedient under GAAP to recognize revenue monthly based on the amount we are able to invoice the customer. We also earn revenue from a fee-sharing agreement with our clearing broker related to the interest income the clearing broker earns on customer cash balances and margin loans made to our customers. We concluded the initial transaction price is exclusively variable consideration and, based on the nature of our performance obligation to allow the clearing broker to collect interest income from cash deposits and customer loans from our customers, we are unable to determine the amount of revenue to be recognized until the total customer cash balance or the total interest income recognized on margin loans has been determined, which occurs monthly. These revenue streams are recorded as other income in our Consolidated Statement of Income . • Brokered/agent commissions through Insurance operations — We have agreements with third parties to offer various vehicle protection products to consumers. We also have agreements with third-party insurers to offer various insurance coverages to dealers. Our performance obligation for these arrangements is satisfied when a customer or dealer has purchased a vehicle protection product or an insurance policy through the third-party provider. In determining the initial transaction price for these agreements, we noted that revenue on brokered/agent commissions is based on the volume of vehicle protection product contracts sold or a percentage of insurance premium written, which is not known to us at the inception of the agreements with these third-party providers. As such, we believe the initial transaction price is exclusively variable consideration and, based on the nature of the performance obligation, we are unable to determine the amount of revenue we will record until the customer purchases a vehicle protection product or a dealer purchases an insurance policy from the third-party provider. Once we are notified of vehicle protection product sales or insurance policies issued by the third-party providers, we record the commission earned as insurance premiums and service revenues earned in our Consolidated Statement of Income . • Deposit account and other banking fees — We charge depositors various account service fees including those for outgoing wires, excessive transactions, overdrafts, stop payments, and returned deposits. These fees are generated from a customer option to purchase services offered under the contract. These options do not represent a material right and are only considered a contract in accordance with the amendments to the revenue recognition principles when the customer exercises their option to purchase these account services. Based on this, the term for our contracts with customers is considered day-to-day, and the contract does not extend beyond the services already provided. Revenue derived from deposit account fees is recorded at the point in time we perform the requested service, and is recorded as other income in our Consolidated Statement of Income . As a debit card issuer, we also generate interchange fee income from merchants during debit card transactions and incur certain corresponding charges from merchant card networks. Our performance obligation is satisfied when we have initiated the payment of funds from a customer’s account to a merchant through our contractual agreements with the merchant card networks. Interchange fees are reported on a net basis as other income in our Consolidated Statement of Income . Gross interchange fee income was $12 million , and interchange expense was $10 million , for the year ended December 31, 2018 . • Other revenue — Other revenue primarily includes service revenue related to various account management functions, fee income derived from third-party loans arranged through Clearlane—our online automotive lender exchange, and revenue associated with licensing and marketing from the Ally CashBack Credit Card—our co-branded credit card. These revenue streams are recorded as other income in our Consolidated Statement of Income . The following table presents a disaggregated view of our revenue from contracts with customers included in other revenue that falls within the scope of the amendments to the revenue recognition principles. Year ended December 31, 2018 ($ in millions) Automotive Finance operations Insurance operations Mortgage Finance operations Corporate Finance operations Corporate and Other Consolidated Revenue from contracts with customers Noninsurance contracts $ — $ 506 $ — $ — $ — $ 506 Remarketing fee income 79 — — — — 79 Brokerage commissions and other revenue — — — — 62 62 Brokered/agent commissions — 15 — — — 15 Deposit account and other banking fees — — — — 13 13 Other 13 1 — — — 14 Total revenue from contracts with customers 92 522 — — 75 689 All other revenue 177 459 7 38 44 725 Total other revenue (a) $ 269 $ 981 $ 7 $ 38 $ 119 $ 1,414 (a) Represents a component of total net revenue. Refer to Note 26 for further information on our reportable operating segments. In addition to the components of other revenue presented above, as part of our Automotive Finance operations, we recognized net remarketing gains of $90 million for the year ended December 31, 2018 , on the sale of off-lease vehicles. These gains are included in depreciation expense on operating lease assets in our Consolidated Statement of Income .

Insurance Premiums and Service

Insurance Premiums and Service Revenue Earned	12 Months Ended
	Dec. 31, 2018
Insurance Premiums and Service Revenue Earned [Abstract]
Insurance Premiums and Service Revenue Earned	Insurance Premiums and Service Revenue Earned The following table is a summary of insurance premiums and service revenue written and earned. 2018 2017 2016 Year ended December 31, ($ in millions) Written Earned Written Earned Written Earned Insurance premiums Direct $ 420 $ 414 $ 384 $ 364 $ 317 $ 318 Assumed — 4 2 5 3 5 Gross insurance premiums 420 418 386 369 320 323 Ceded (219 ) (197 ) (254 ) (188 ) (198 ) (141 ) Net insurance premiums 201 221 132 181 122 182 Service revenue 973 801 864 792 826 763 Insurance premiums and service revenue written and earned $ 1,174 $ 1,022 $ 996 $ 973 $ 948 $ 945

Other Income, Net of Losses

Other Income, Net of Losses	12 Months Ended
	Dec. 31, 2018
Other Nonoperating Income (Expense) [Abstract]
Other Income and Other Expense Disclosure	Other Income, Net of Losses Details of other income, net of losses, were as follows. Year ended December 31, ($ in millions) 2018 2017 2016 Late charges and other administrative fees $ 110 $ 102 $ 98 Remarketing fees 79 104 103 Income from equity-method investments 46 14 18 Servicing fees 27 51 64 Other, net 155 130 106 Total other income, net of losses $ 417 $ 401 $ 389

Reserves for Insurance Losses a

Reserves for Insurance Losses and Loss Adjustment Expenses	12 Months Ended
	Dec. 31, 2018
Reserves for Insurance Losses and Loss Adjustment Expense [Abstract]
Reserves for Insurance Losses and Loss Adjustment Expenses	Reserves for Insurance Losses and Loss Adjustment Expenses The following table shows incurred claims and allocated loss adjustment expenses, net of reinsurance. For the years ended December 31, ($ in millions) December 31, 2018 ($ in millions) Accident year (a) 2012 (b) 2013 (b) 2014 (b) 2015 (b) 2016 2017 2018 Total of incurred-but-not-reported liabilities plus expected development on reported claims (c) Cumulative number of reported claims (c) 2012 $ 435 $ 430 $ 423 $ 423 $ 423 $ 422 $ 422 $ — 772,549 2013 376 365 370 370 369 368 — 672,273 2014 390 389 388 388 388 — 525,297 2015 274 271 272 272 — 342,261 2016 326 327 328 — 475,973 2017 310 314 — 481,319 2018 271 19 482,605 Total $ 2,363 (a) Due to the discontinuation of various product lines and sale of certain international operations, information prior to 2012 has been excluded from the table in order to appropriately reflect the number of years for which claims are typically outstanding. In addition, given the short tail of our insurance contracts, the table above reflects the combined presentation of all business lines. (b) Information presented for the years 2012 through 2015 is unaudited supplementary information. (c) Claims are reported on a claimant basis. Claimant is defined as one vehicle for guaranteed asset protection (GAP) products, one repair visit for vehicle service contracts (VSCs) and vehicle maintenance contracts (VMCs), one dealership for dealer inventory products, and per individual/coverage for run-off personal automotive products. The following table shows cumulative paid claims and allocated loss adjustment expenses, net of reinsurance. For the years ended December 31, ($ in millions) Accident year (a) 2012 (b) 2013 (b) 2014 (b) 2015 (b) 2016 2017 2018 2012 $ 391 $ 412 $ 416 $ 418 $ 419 $ 421 $ 421 2013 347 364 366 368 368 368 2014 369 388 388 388 388 2015 252 272 272 272 2016 302 327 328 2017 289 315 2018 245 Total $ 2,337 All outstanding liabilities for loss and allocated loss adjustment expenses before 2012, net of reinsurance 9 Reserves for insurance losses and allocated loss adjustment expenses, net of reinsurance $ 35 (a) Due to the discontinuation of various product lines and sale of certain international operations, information prior to 2012 has been excluded from the table in order to appropriately reflect the number of years for which claims are typically outstanding. In addition, given the short tail of our insurance contracts, the table above reflects the combined presentation of all business lines. (b) Information presented for the years 2012 through 2015 is unaudited supplementary information. The following table shows the average annual percentage payout of incurred claims by age, net of reinsurance. The information presented is unaudited supplementary information. Year 1 2 3 4 5 6 7 Percentage payout of incurred claims 92.8 % 6.1 % 0.4 % 0.3 % 0.1 % 0.2 % 0.1 % The following table shows a reconciliation of the disclosures of incurred and paid claims development to the reserves for insurance losses and loss adjustment expenses. December 31, ($ in millions) 2018 2017 2016 Reserves for insurance losses and loss adjustment expenses, net of reinsurance $ 35 $ 30 $ 38 Total reinsurance recoverable on unpaid claims 96 108 108 Unallocated loss adjustment expenses 3 2 3 Total gross reserves for insurance losses and loss adjustment expenses $ 134 $ 140 $ 149 The following table shows a rollforward of our reserves for insurance losses and loss adjustment expenses. ($ in millions) 2018 2017 2016 Total gross reserves for insurance losses and loss adjustment expenses at January 1, $ 140 $ 149 $ 169 Less: Reinsurance recoverable 108 108 120 Net reserves for insurance losses and loss adjustment expenses at January 1, 32 41 49 Net insurance losses and loss adjustment expenses incurred related to: Current year 291 332 345 Prior years (a) 4 — (3 ) Total net insurance losses and loss adjustment expenses incurred 295 332 342 Net insurance losses and loss adjustment expenses paid or payable related to: Current year (263 ) (309 ) (320 ) Prior years (26 ) (32 ) (30 ) Total net insurance losses and loss adjustment expenses paid or payable (289 ) (341 ) (350 ) Net reserves for insurance losses and loss adjustment expenses at December 31, 38 32 41 Plus: Reinsurance recoverable 96 108 108 Total gross reserves for insurance losses and loss adjustment expenses at December 31, $ 134 $ 140 $ 149 (a) There have been no material adverse changes to the reserve for prior years.

Other Operating Expenses

Other Operating Expenses	12 Months Ended
	Dec. 31, 2018
Operating Expenses [Abstract]
Other Operating Income and Expense	Other Operating Expenses Details of other operating expenses were as follows. Year ended December 31, ($ in millions) 2018 2017 2016 Insurance commissions $ 440 $ 415 $ 389 Technology and communications 299 284 274 Advertising and marketing 172 133 112 Lease and loan administration 164 159 136 Professional services 133 113 103 Regulatory and licensing fees 121 113 94 Vehicle remarketing and repossession 111 110 95 Premises and equipment depreciation 87 89 84 Occupancy 45 46 51 Non-income taxes 29 21 25 Amortization of intangible assets 11 11 6 Other 202 189 236 Total other operating expenses $ 1,814 $ 1,683 $ 1,605

Investment Securities

Investment Securities	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure	Investment Securities Our investment portfolio includes various debt and equity securities. Our debt securities, which are classified as available-for-sale and held-to-maturity, include government securities, corporate bonds, asset-backed securities, and mortgage-backed securities. The cost, fair value, and gross unrealized gains and losses on available-for-sale and held-to-maturity debt securities were as follows. 2018 2017 Amortized cost Gross unrealized Fair value Amortized cost Gross unrealized Fair value December 31, ($ in millions) gains losses gains losses Available-for-sale securities Debt securities U.S. Treasury and federal agencies $ 1,911 $ — $ (60 ) $ 1,851 $ 1,831 $ — $ (54 ) $ 1,777 U.S. States and political subdivisions 816 3 (17 ) 802 850 11 (7 ) 854 Foreign government 145 1 (1 ) 145 153 2 (1 ) 154 Agency mortgage-backed residential 17,486 47 (395 ) 17,138 14,412 35 (156 ) 14,291 Mortgage-backed residential 2,796 1 (111 ) 2,686 2,517 11 (34 ) 2,494 Mortgage-backed commercial 718 1 (2 ) 717 541 1 (1 ) 541 Asset-backed 723 2 (2 ) 723 933 4 (1 ) 936 Corporate debt 1,286 1 (46 ) 1,241 1,262 5 (11 ) 1,256 Total available-for-sale securities (a) (b) (c) $ 25,881 $ 56 $ (634 ) $ 25,303 $ 22,499 $ 69 $ (265 ) $ 22,303 Held-to-maturity securities Debt securities Agency mortgage-backed residential (d) $ 2,319 $ 6 $ (61 ) $ 2,264 $ 1,863 $ 3 $ (37 ) $ 1,829 Asset-backed retained notes 43 — — 43 36 — — 36 Total held-to-maturity securities $ 2,362 $ 6 $ (61 ) $ 2,307 $ 1,899 $ 3 $ (37 ) $ 1,865 (a) Certain entities related to our Insurance operations are required to deposit securities with state regulatory authorities. These deposited securities totaled $12 million at both December 31, 2018 , and December 31, 2017. (b) Certain available-for-sale securities are included in fair value hedging relationships. Refer to Note 21 for additional information. (c) Available-for-sale securities with a fair value of $9.2 billion and $7.8 billion at December 31, 2018 , and December 31, 2017 , respectively, were pledged to secure advances from the FHLB, short-term borrowings or repurchase agreements, or for other purposes as required by contractual obligation or law. Under these agreements, we have granted the counterparty the right to sell or pledge $821 million and $1.0 billion of the underlying investment securities at December 31, 2018 , and December 31, 2017 , respectively. (d) Held-to-maturity securities with a fair value of $1.2 billion and $664 million at December 31, 2018 , and December 31, 2017, respectively, were pledged to secure advances from the FHLB. The maturity distribution of debt securities outstanding is summarized in the following tables. Call or prepayment options may cause actual maturities to differ from contractual maturities. Total Due in one year or less Due after one year through five years Due after five years through ten years Due after ten years ($ in millions) Amount Yield Amount Yield Amount Yield Amount Yield Amount Yield December 31, 2018 Fair value of available-for-sale securities (a) U.S. Treasury and federal agencies $ 1,851 1.9 % $ 12 1.0 % $ 1,277 1.8 % $ 562 2.0 % $ — — % U.S. States and political subdivisions 802 3.0 49 1.9 43 2.3 252 2.6 458 3.4 Foreign government 145 2.4 18 3.1 60 2.3 67 2.4 — — Agency mortgage-backed residential 17,138 3.3 — — — — 54 1.9 17,084 3.3 Mortgage-backed residential 2,686 3.3 — — — — — — 2,686 3.3 Mortgage-backed commercial 717 3.8 — — 3 3.1 46 3.9 668 3.8 Asset-backed 723 3.5 — — 478 3.4 121 4.0 124 3.3 Corporate debt 1,241 3.1 144 2.8 496 2.9 581 3.3 20 5.5 Total available-for-sale securities $ 25,303 3.2 $ 223 2.6 $ 2,357 2.4 $ 1,683 2.8 $ 21,040 3.3 Amortized cost of available-for-sale securities $ 25,881 $ 224 $ 2,405 $ 1,743 $ 21,509 Amortized cost of held-to-maturity securities Agency mortgage-backed residential $ 2,319 3.2 % $ — — % $ — — % $ — — % $ 2,319 3.2 % Asset-backed retained notes 43 2.0 — — 42 2.0 1 3.3 — — Total held-to-maturity securities $ 2,362 3.2 $ — — $ 42 2.0 $ 1 3.3 $ 2,319 3.2 December 31, 2017 Fair value of available-for-sale securities (a) U.S. Treasury $ 1,777 1.7 % $ — — % $ 487 1.7 % $ 1,290 1.8 % $ — — % U.S. States and political subdivisions 854 2.9 76 1.8 36 2.3 203 2.5 539 3.3 Foreign government 154 2.5 — — 80 2.5 74 2.4 — — Agency mortgage-backed residential 14,291 3.1 — — — — 3 2.9 14,288 3.1 Mortgage-backed residential 2,494 3.1 — — — — — — 2,494 3.1 Mortgage-backed commercial 541 3.2 — — 30 3.1 31 3.1 480 3.2 Asset-backed 936 3.1 — — 698 3.1 106 3.1 132 2.8 Corporate debt 1,256 2.9 140 2.6 513 2.6 564 3.2 39 4.7 Total available-for-sale securities $ 22,303 3.0 $ 216 2.3 $ 1,844 2.5 $ 2,271 2.3 $ 17,972 3.1 Amortized cost of available-for-sale securities $ 22,499 $ 217 $ 1,852 $ 2,314 $ 18,116 Amortized cost of held-to-maturity securities Agency mortgage-backed residential $ 1,863 3.1 % $ — — % $ — — % $ — — % $ 1,863 3.1 % Asset-backed retained notes 36 1.7 — — 35 1.7 1 3.0 — — Total held-to-maturity securities $ 1,899 3.1 $ — — $ 35 1.7 $ 1 3.0 $ 1,863 3.1 (a) Yield is calculated using the effective yield of each security at the end of the period, weighted based on the market value. The effective yield considers the contractual coupon and amortized cost, and excludes expected capital gains and losses. The balances of cash equivalents were $35 million and $10 million at December 31, 2018 , and December 31, 2017 , respectively, and were composed primarily of money market accounts and short-term securities, including U.S. Treasury bills. The following table presents interest and dividends on investment securities. Year ended December 31, ($ in millions) 2018 2017 2016 Taxable interest $ 690 $ 534 $ 375 Taxable dividends 14 12 17 Interest and dividends exempt from U.S. federal income tax 25 22 19 Interest and dividends on investment securities $ 729 $ 568 $ 411 The following table presents gross gains and losses realized upon the sales of available-for-sale securities, and net gains or losses on equity securities held during the period. There were no other-than-temporary impairments of available-for-sale securities for the periods presented. Year ended December 31, ($ in millions) 2018 2017 2016 Available-for-sale securities Gross realized gains $ 12 $ 106 $ 187 Gross realized losses (a) (1 ) (4 ) (2 ) Net realized gains on available-for-sale securities 11 102 185 Net realized gain on equity securities 60 Net unrealized loss on equity securities (b) (121 ) Other (loss) gain on investments, net $ (50 ) $ 102 $ 185 (a) Certain available-for-sale securities were sold at a loss in 2018, 2017, and 2016 as a result of market conditions within these respective periods (e.g., a downgrade in the rating of a debt security) or based on corporate actions outside of our control (such as a call by the issuer). Any such sales were made in accordance with our risk-management policies and practices. (b) As a result of our adoption of ASU 2016-01, beginning January 1, 2018, changes in the fair value of our portfolio of equity securities are recognized in net income. Prior to adoption, equity securities were included in our available-for-sale portfolio and unrealized changes in fair value were recognized through other comprehensive (loss) income until realized, at which point we recorded a gain or loss on sale. We adopted ASU 2016-01 on January 1, 2018, on a modified retrospective basis with a cumulative effect adjustment as of the beginning of the fiscal year of initial adoption. Refer to the section titled Recently Adopted Accounting Standards in Note 1 for additional information. The table below summarizes available-for-sale and held-to-maturity securities in an unrealized loss position, which we evaluated for other than temporary impairment applying the methodology described in Note 1 . As of December 31, 2018 , we did not have the intent to sell the available-for-sale or held-to-maturity securities with an unrealized loss position and we do not believe it is more likely than not that we will be required to sell these securities before recovery of their amortized cost basis. As a result of this evaluation, we believe that the securities with an unrealized loss position are not considered to be other-than-temporarily impaired at December 31, 2018 . 2018 2017 Less than 12 months 12 months or longer Less than 12 months 12 months or longer December 31, ($ in millions) Fair value Unrealized loss Fair value Unrealized loss Fair value Unrealized loss Fair value Unrealized loss Available-for-sale securities Debt securities U.S. Treasury and federal agencies $ 31 $ — $ 1,758 $ (60 ) $ 471 $ (8 ) $ 1,305 $ (46 ) U.S. States and political subdivisions 259 (3 ) 317 (14 ) 242 (2 ) 183 (5 ) Foreign government 6 — 74 (1 ) 80 (1 ) 4 — Agency mortgage-backed residential 5,537 (94 ) 7,808 (301 ) 4,066 (19 ) 5,671 (137 ) Mortgage-backed residential 1,024 (20 ) 1,360 (91 ) 857 (2 ) 773 (32 ) Mortgage-backed commercial 347 (1 ) 36 (1 ) 76 (1 ) 21 — Asset-backed 294 (1 ) 124 (1 ) 220 (1 ) 91 — Corporate debt 576 (19 ) 569 (27 ) 529 (4 ) 194 (7 ) Total temporarily impaired available-for-sale securities $ 8,074 $ (138 ) $ 12,046 $ (496 ) $ 6,541 $ (38 ) $ 8,242 $ (227 ) Held-to-maturity securities Debt securities Agency mortgage-backed residential $ 457 $ (6 ) $ 1,376 $ (55 ) $ 773 $ (5 ) $ 687 $ (32 ) Asset-backed retained notes 16 — 19 — 35 — — — Total held-to-maturity debt securities $ 473 $ (6 ) $ 1,395 $ (55 ) $ 808 $ (5 ) $ 687 $ (32 )

Finance Receivables and Loans,

Finance Receivables and Loans, Net	12 Months Ended
	Dec. 31, 2018
Loans and Leases Receivable, Net Amount [Abstract]
Loans, Notes, Trade and Other Receivables Disclosure	Finance Receivables and Loans, Net The composition of finance receivables and loans reported at gross carrying value was as follows. December 31, ($ in millions) 2018 2017 Consumer automotive (a) $ 70,539 $ 68,071 Consumer mortgage Mortgage Finance (b) 15,155 11,657 Mortgage — Legacy (c) 1,546 2,093 Total consumer mortgage 16,701 13,750 Total consumer 87,240 81,821 Commercial Commercial and industrial Automotive 33,672 33,025 Other 4,205 3,887 Commercial real estate 4,809 4,160 Total commercial 42,686 41,072 Total finance receivables and loans (d) $ 129,926 $ 122,893 (a) Certain finance receivables and loans are included in fair value hedging relationships. Refer to Note 21 for additional information. (b) Includes loans originated as interest-only mortgage loans of $18 million and $20 million at December 31, 2018 , and December 31, 2017 , respectively, 34% of which are expected to start principal amortization in 2019 , and 41% in 2020 . The remainder of these loans have exited the interest-only period. (c) Includes loans originated as interest-only mortgage loans of $341 million and $496 million at December 31, 2018 , and December 31, 2017 , respectively, of which 99% have exited the interest-only period. (d) Totals include net unearned income, unamortized premiums and discounts, and deferred fees and costs of $587 million and $551 million at December 31, 2018 , and December 31, 2017 , respectively. The following tables present an analysis of the activity in the allowance for loan losses on finance receivables and loans. ($ in millions) Consumer automotive Consumer mortgage Commercial Total Allowance at January 1, 2018 $ 1,066 $ 79 $ 131 $ 1,276 Charge-offs (a) (1,383 ) (35 ) (15 ) (1,433 ) Recoveries 456 25 7 488 Net charge-offs (927 ) (10 ) (8 ) (945 ) Provision for loan losses 911 (15 ) 22 918 Other (b) (2 ) (1 ) (4 ) (7 ) Allowance at December 31, 2018 $ 1,048 $ 53 $ 141 $ 1,242 Allowance for loan losses at December 31, 2018 Individually evaluated for impairment $ 44 $ 23 $ 56 $ 123 Collectively evaluated for impairment 1,004 30 85 1,119 Finance receivables and loans at gross carrying value Ending balance $ 70,539 $ 16,701 $ 42,686 $ 129,926 Individually evaluated for impairment 495 231 349 1,075 Collectively evaluated for impairment 70,044 16,470 42,337 128,851 (a) Represents the amount of the gross carrying value directly written off. For consumer and commercial loans, the loss from a charge-off is measured as the difference between the gross carrying value of a loan and the fair value of the collateral, less costs to sell. Refer to Note 1 for more information regarding our charge-off policies. (b) Primarily related to the transfer of finance receivables and loans from held-for-investment to held-for-sale. ($ in millions) Consumer automotive Consumer mortgage Commercial Total Allowance at January 1, 2017 $ 932 $ 91 $ 121 $ 1,144 Charge-offs (a) (1,344 ) (30 ) (18 ) (1,392 ) Recoveries 358 24 — 382 Net charge-offs (986 ) (6 ) (18 ) (1,010 ) Provision for loan losses 1,127 (7 ) 28 1,148 Other (b) (7 ) 1 — (6 ) Allowance at December 31, 2017 $ 1,066 $ 79 $ 131 $ 1,276 Allowance for loan losses at December 31, 2017 Individually evaluated for impairment $ 36 $ 27 $ 14 $ 77 Collectively evaluated for impairment 1,030 52 117 1,199 Finance receivables and loans at gross carrying value Ending balance $ 68,071 $ 13,750 $ 41,072 $ 122,893 Individually evaluated for impairment 430 231 72 733 Collectively evaluated for impairment 67,641 13,519 41,000 122,160 (a) Represents the amount of the gross carrying value directly written off. For consumer and commercial loans, the loss from a charge-off is measured as the difference between the gross carrying value of a loan and the fair value of the collateral, less costs to sell. Refer to Note 1 for more information regarding our charge-off policies. (b) Primarily related to the transfer of finance receivables and loans from held-for-investment to held-for-sale. The following table presents information about significant sales of finance receivables and loans and transfers of finance receivables and loans from held-for-investment to held-for-sale based on net carrying value. December 31, ($ in millions) 2018 2017 Consumer automotive $ 578 $ 1,339 Consumer mortgage 10 9 Commercial 238 — Total sales and transfers $ 826 $ 1,348 The following table presents information about significant purchases of finance receivables and loans based on unpaid principal balance at the time of purchase. ($ in millions) 2018 2017 Consumer automotive $ 896 $ 865 Consumer mortgage 4,446 4,481 Commercial 15 — Total purchases of finance receivables and loans $ 5,357 $ 5,346 The following table presents an analysis of our past-due finance receivables and loans recorded at gross carrying value. December 31, ($ in millions) 30–59 days past due 60–89 days past due 90 days or more past due Total past due Current Total finance receivables and loans 2018 Consumer automotive $ 2,107 $ 537 $ 296 $ 2,940 $ 67,599 $ 70,539 Consumer mortgage Mortgage Finance 67 5 4 76 15,079 15,155 Mortgage — Legacy 30 10 42 82 1,464 1,546 Total consumer mortgage 97 15 46 158 16,543 16,701 Total consumer 2,204 552 342 3,098 84,142 87,240 Commercial Commercial and industrial Automotive — 1 31 32 33,640 33,672 Other — 4 16 20 4,185 4,205 Commercial real estate — — 1 1 4,808 4,809 Total commercial — 5 48 53 42,633 42,686 Total consumer and commercial $ 2,204 $ 557 $ 390 $ 3,151 $ 126,775 $ 129,926 2017 Consumer automotive $ 1,994 $ 478 $ 268 $ 2,740 $ 65,331 $ 68,071 Consumer mortgage Mortgage Finance 60 11 18 89 11,568 11,657 Mortgage — Legacy 43 25 62 130 1,963 2,093 Total consumer mortgage 103 36 80 219 13,531 13,750 Total consumer 2,097 514 348 2,959 78,862 81,821 Commercial Commercial and industrial Automotive 5 — 3 8 33,017 33,025 Other — — — — 3,887 3,887 Commercial real estate — — — — 4,160 4,160 Total commercial 5 — 3 8 41,064 41,072 Total consumer and commercial $ 2,102 $ 514 $ 351 $ 2,967 $ 119,926 $ 122,893 The following table presents the gross carrying value of our finance receivables and loans on nonaccrual status. December 31, ($ in millions) 2018 2017 Consumer automotive $ 664 $ 603 Consumer mortgage Mortgage Finance 9 25 Mortgage — Legacy 70 92 Total consumer mortgage 79 117 Total consumer 743 720 Commercial Commercial and industrial Automotive 203 27 Other 142 44 Commercial real estate 4 1 Total commercial 349 72 Total consumer and commercial finance receivables and loans $ 1,092 $ 792 Management performs a quarterly analysis of the consumer automotive, consumer mortgage, and commercial portfolios using a range of credit quality indicators to assess the adequacy of the allowance for loan losses based on historical and current trends. The following tables present the population of loans by quality indicators for our consumer automotive, consumer mortgage, and commercial portfolios. The following table presents performing and nonperforming credit quality indicators in accordance with our internal accounting policies for our consumer finance receivables and loans recorded at gross carrying value. Nonperforming loans include finance receivables and loans on nonaccrual status when the principal or interest has been delinquent for at least 90 days or when full collection is not expected. Refer to Note 1 for additional information. 2018 2017 December 31, ($ in millions) Performing Nonperforming Total Performing Nonperforming Total Consumer automotive $ 69,875 $ 664 $ 70,539 $ 67,468 $ 603 $ 68,071 Consumer mortgage Mortgage Finance 15,146 9 15,155 11,632 25 11,657 Mortgage — Legacy 1,476 70 1,546 2,001 92 2,093 Total consumer mortgage 16,622 79 16,701 13,633 117 13,750 Total consumer $ 86,497 $ 743 $ 87,240 $ 81,101 $ 720 $ 81,821 The following table presents pass and criticized credit quality indicators based on regulatory definitions for our commercial finance receivables and loans recorded at gross carrying value. 2018 2017 December 31, ($ in millions) Pass Criticized (a) Total Pass Criticized (a) Total Commercial and industrial Automotive $ 30,799 $ 2,873 $ 33,672 $ 30,982 $ 2,043 $ 33,025 Other 3,373 832 4,205 2,986 901 3,887 Commercial real estate 4,538 271 4,809 4,023 137 4,160 Total commercial $ 38,710 $ 3,976 $ 42,686 $ 37,991 $ 3,081 $ 41,072 (a) Includes loans classified as special mention, substandard, or doubtful. These classifications are based on regulatory definitions and generally represent loans within our portfolio that have a higher default risk or have already defaulted. Impaired Loans and Troubled Debt Restructurings Impaired Loans Loans are considered impaired when we determine it is probable that we will be unable to collect all amounts due according to the terms of the loan agreement. For more information on our impaired finance receivables and loans, refer to Note 1 . The following table presents information about our impaired finance receivables and loans. December 31, ($ in millions) Unpaid principal balance (a) Gross carrying value Impaired with no allowance Impaired with an allowance Allowance for impaired loans 2018 Consumer automotive $ 503 $ 495 $ 105 $ 390 $ 44 Consumer mortgage Mortgage Finance 15 15 6 9 1 Mortgage — Legacy 221 216 65 151 22 Total consumer mortgage 236 231 71 160 23 Total consumer 739 726 176 550 67 Commercial Commercial and industrial Automotive 203 203 112 91 10 Other 159 142 40 102 46 Commercial real estate 4 4 4 — — Total commercial 366 349 156 193 56 Total consumer and commercial finance receivables and loans $ 1,105 $ 1,075 $ 332 $ 743 $ 123 2017 Consumer automotive $ 438 $ 430 $ 91 $ 339 $ 36 Consumer mortgage Mortgage Finance 8 8 4 4 — Mortgage — Legacy 228 223 58 165 27 Total consumer mortgage 236 231 62 169 27 Total consumer 674 661 153 508 63 Commercial Commercial and industrial Automotive 27 27 9 18 3 Other 54 44 10 34 11 Commercial real estate 1 1 — 1 — Total commercial 82 72 19 53 14 Total consumer and commercial finance receivables and loans $ 756 $ 733 $ 172 $ 561 $ 77 (a) Adjusted for charge-offs. The following table presents average balance and interest income for our impaired finance receivables and loans. 2018 2017 2016 Year ended December 31, ($ in millions) Average balance Interest income Average balance Interest income Average balance Interest income Consumer automotive $ 478 $ 28 $ 391 $ 21 $ 344 $ 17 Consumer mortgage Mortgage Finance 11 1 8 — 8 — Mortgage — Legacy 218 10 234 10 248 9 Total consumer mortgage 229 11 242 10 256 9 Total consumer 707 39 633 31 600 26 Commercial Commercial and industrial Automotive 93 4 49 2 35 1 Other 84 — 69 9 60 1 Commercial real estate 5 1 5 — 6 — Total commercial 182 5 123 11 101 2 Total consumer and commercial finance receivables and loans $ 889 $ 44 $ 756 $ 42 $ 701 $ 28 Troubled Debt Restructurings TDRs are loan modifications where concessions were granted to borrowers experiencing financial difficulties. For consumer automotive loans, we may offer several types of assistance to aid our customers, including payment extensions and rewrites of the loan terms. Additionally, for mortgage loans, as part of certain programs, we offer mortgage loan modifications to qualified borrowers. These programs are in place to provide support to our mortgage customers in financial distress, including principal forgiveness, maturity extensions, delinquent interest capitalization, and changes to contractual interest rates. Total TDRs recorded at gross carrying value were $812 million , $712 million , and $663 million at December 31, 2018 , 2017, and 2016, respectively. Total commitments to lend additional funds to borrowers whose terms had been modified in a TDR were $4 million , $6 million , and $2 million at December 31, 2018 , 2017, and 2016, respectively. Refer to Note 1 for additional information. The following tables present information related to finance receivables and loans recorded at gross carrying value modified in connection with a TDR during the period. Year ended December 31, ($ in millions) Number of loans Pre-modification gross carrying value Post-modification gross carrying value 2018 Consumer automotive 26,748 $ 426 $ 378 Consumer mortgage Mortgage Finance 23 9 9 Mortgage — Legacy 204 30 29 Total consumer mortgage 227 39 38 Total consumer finance receivables and loans 26,975 $ 465 $ 416 2017 Consumer automotive 26,156 $ 380 $ 333 Consumer mortgage Mortgage Finance 4 1 1 Mortgage — Legacy 122 21 21 Total consumer mortgage 126 22 22 Total consumer finance receivables and loans 26,282 $ 402 $ 355 2016 Consumer automotive 20,227 $ 347 $ 293 Consumer mortgage Mortgage Finance 7 3 3 Mortgage — Legacy 120 18 18 Total consumer mortgage 127 21 21 Total consumer finance receivables and loans 20,354 $ 368 $ 314 Year ended December 31, ($ in millions) Number of loans Pre-modification gross carrying value Post-modification gross carrying value 2018 Commercial and industrial Automotive 3 $ 4 $ 4 Other 3 85 82 Total commercial finance receivables and loans 6 $ 89 $ 86 2017 Commercial and industrial Automotive 4 $ 16 $ 15 Other — 44 44 Commercial real estate 2 3 3 Total commercial finance receivables and loans 6 $ 63 $ 62 2016 Commercial and industrial Automotive 1 $ 7 $ 7 Total commercial finance receivables and loans 1 $ 7 $ 7 The following table presents information about finance receivables and loans recorded at gross carrying value that have redefaulted during the reporting period and were within twelve months or less of being modified as a TDR. Redefault is when finance receivables and loans meet the requirements for evaluation under our charge-off policy (refer to Note 1 for additional information) except for commercial finance receivables and loans, where redefault is defined as 90 days past due. Year ended December 31, ($ in millions) Number of loans Gross carrying value Charge-off amount 2018 Consumer automotive 9,711 $ 111 $ 73 Consumer mortgage Mortgage — Legacy 2 — — Total consumer finance receivables and loans 9,713 $ 111 $ 73 2017 Consumer automotive 8,829 $ 102 $ 71 Consumer mortgage Mortgage Finance 1 1 — Mortgage — Legacy 2 — — Total consumer finance receivables and loans 8,832 $ 103 $ 71 2016 Consumer automotive 7,800 $ 94 $ 56 Consumer mortgage Mortgage — Legacy 4 — — Total consumer finance receivables and loans 7,804 $ 94 $ 56 Concentration Risk Consumer We monitor our consumer loan portfolio for concentration risk across the states in which we lend. The highest concentrations of loans are in California and Texas, which represent an aggregate of 25.4% and 24.7% of our total outstanding consumer finance receivables and loans at December 31, 2018, and December 31, 2017, respectively. The following table shows the percentage of total consumer finance receivables and loans recorded at gross carrying value by state concentration. 2018 (a) 2017 December 31, Consumer automotive Consumer mortgage Consumer automotive Consumer mortgage California 8.4 % 36.9 % 8.2 % 34.6 % Texas 12.8 6.2 13.2 6.5 Florida 8.8 4.7 8.5 4.8 Pennsylvania 4.5 1.4 4.6 1.5 Illinois 4.1 3.0 4.2 3.2 Georgia 4.1 2.8 4.2 2.5 North Carolina 3.9 1.7 3.7 1.8 New York 3.1 2.4 3.0 2.2 Ohio 3.5 0.4 3.4 0.5 New Jersey 2.7 2.1 2.6 2.1 Other United States 44.1 38.4 44.4 40.3 Total consumer loans 100.0 % 100.0 % 100.0 % 100.0 % (a) Presentation is in descending order as a percentage of total consumer finance receivables and loans at December 31, 2018 . Commercial Real Estate The commercial real estate portfolio consists of finance receivables and loans issued primarily to automotive dealers. The following table shows the percentage of total commercial real estate finance receivables and loans reported at gross carrying value by state concentration. December 31, 2018 2017 Texas 15.5 % 15.7 % Florida 11.6 10.3 California 8.3 8.2 Michigan 6.8 7.7 New York 4.8 2.1 Georgia 4.0 4.6 North Carolina 3.6 3.6 South Carolina 3.4 3.5 New Jersey 3.1 3.6 Utah 2.6 1.6 Other United States 36.3 39.1 Total commercial real estate finance receivables and loans 100.0 % 100.0 % Commercial Criticized Exposure Finance receivables and loans classified as special mention, substandard, or doubtful are reported as criticized. These classifications are based on regulatory definitions and generally represent finance receivables and loans within our portfolio that have a higher default risk or have already defaulted. These finance receivables and loans require additional monitoring and review including specific actions to mitigate our potential loss. The following table presents the percentage of total commercial criticized finance receivables and loans reported at gross carrying value by industry concentrations. December 31, 2018 2017 Automotive 80.6 % 76.3 % Services 5.0 6.7 Health/Medical 3.7 4.9 Other 10.7 12.1 Total commercial criticized finance receivables and loans 100.0 % 100.0 %

Investment in Operating Leases,

Investment in Operating Leases, Net	12 Months Ended
	Dec. 31, 2018
Leases, Operating [Abstract]
Lessor, Operating Leases	Investment in Operating Leases, Net Investment in operating leases were as follows. December 31, ($ in millions) 2018 2017 Vehicles $ 9,995 $ 10,556 Accumulated depreciation (1,578 ) (1,815 ) Investment in operating leases, net $ 8,417 $ 8,741 Depreciation expense on operating lease assets includes remarketing gains and losses recognized on the sale of operating lease assets. The following summarizes the components of depreciation expense on operating lease assets. Year ended December 31, ($ in millions) 2018 2017 2016 Depreciation expense on operating lease assets (excluding remarketing gains) $ 1,115 $ 1,368 $ 1,982 Remarketing gains, net (90 ) (124 ) (213 ) Net depreciation expense on operating lease assets $ 1,025 $ 1,244 $ 1,769 The following table presents the future lease nonresidual rental payments due from customers for vehicles on operating leases. Year ended December 31, ($ in millions) 2019 $ 1,308 2020 830 2021 297 2022 27 2023 and thereafter 3 Total $ 2,465

Securitizations and Variable In

Securitizations and Variable Interest Entities	12 Months Ended
	Dec. 31, 2018
Securitizations And Variable Interest Entities [Abstract]
Variable Interest Entity Disclosure	Securitizations and Variable Interest Entities Overview We securitize, transfer, and service consumer and commercial automotive loans, and operating leases. We often securitize these loans and notes secured by operating leases (collectively referred to as financial assets) using special purpose entities (SPEs). SPEs are often VIEs and may or may not be included on our Consolidated Balance Sheet . Securitizations In executing a securitization, we typically sell pools of financial assets to a wholly owned, bankruptcy-remote SPE, which then transfers the financial assets to a separate, transaction-specific SPE for cash, and typically, other retained interests. The SPE is funded through the issuance of beneficial interests, which could take the form of notes or residual interests and can be sold to investors or retained by us. We typically hold retained beneficial interests in our securitizations including, but not limited to, retained notes, certificated residual interests, as well as certain noncertificated interests retained from the sale of automotive finance receivables. If sold, the beneficial interests only entitle the investors to specified cash flows generated from the underlying securitized assets. If retained, the interests provide credit enhancement to the SPE as they may absorb credit losses or other cash shortfalls and may represent a form of significant continuing economic interests. In addition to providing a source of liquidity and cost-efficient funding, securitizing these financial assets also reduces our credit exposure to the borrowers beyond any economic interest we may retain. The SPEs are limited to specific activities by their respective legal documents, but are generally allowed to acquire the financial assets, to issue beneficial interests to investors to fund the acquisition of the financial assets, and to enter into interest rate hedges to mitigate certain risks related to the financial assets or beneficial interests of the entity. A servicer, who is generally us, is appointed pursuant to the underlying legal documents to service the assets the SPE holds and the beneficial interests it issues. Servicing functions include, but are not limited to, general collections activity on current and noncurrent accounts, loss mitigation efforts including repossession and sale of collateral, as well as preparing and furnishing statements summarizing the asset and beneficial interest performance. These servicing responsibilities constitute continued involvement in the transferred financial assets. Cash flows from the securitized financial assets represent the sole source for payment of distributions on the beneficial interests issued by the SPE and for payments to the parties that perform services for the SPE, such as the servicer or the trustee. We generally hold certain conditional repurchase options specific to securitizations that allow us to repurchase assets from the securitization entity. The majority of the securitizations provide us, as servicer, with a call option that allows us to repurchase the remaining transferred financial assets or redeem outstanding beneficial interests at our discretion once the asset pool reaches a predefined level, which represents the point where servicing becomes administratively burdensome (a clean-up call option). The repurchase price is typically the discounted securitization balance of the assets plus accrued interest when applicable. We generally have discretion regarding when or if we will exercise these options, but we would do so only when it is in our best interest. Other than our customary representation and warranty provisions, these securitizations are nonrecourse to us, thereby transferring the risk of future credit losses to the extent the beneficial interests in the SPEs are held by third parties. Representation and warranty provisions generally require us to repurchase assets or indemnify the investor or other party for incurred losses to the extent it is determined that the assets were ineligible or were otherwise defective at the time of sale. We did not provide any non-contractual financial support to any of these entities during 2018, 2017, or 2016. Variable Interest Entities The VIEs included on the Consolidated Balance Sheet represent separate entities where we are deemed to be the primary beneficiary, primarily due to our servicing activities and our beneficial interests in the VIE that could be potentially significant. We determine whether we have a potentially significant beneficial interest in the VIE based on the consideration of both qualitative and quantitative factors regarding the nature, size, and form of our involvement in the VIE. The third-party investors in the obligations of consolidated VIEs have legal recourse only to the assets of the VIEs and do not have such recourse to us, except for the customary representation and warranty provisions. In addition, the cash flows from the assets are restricted only to pay such liabilities. Thus, our economic exposure to loss from outstanding third-party financing related to consolidated VIEs is limited to the carrying value of the consolidated VIE assets. Generally, all assets of consolidated VIEs are restricted for the beneficial interest holders. For additional information regarding our significant accounting policies for consolidated VIEs, refer to the Securitizations and Variable Interest Entities section of Note 1 . The nature, purpose, and activities of nonconsolidated SPEs are similar to those of our consolidated SPEs with the primary difference being the nature and extent of our continuing involvement. For nonconsolidated SPEs, the transferred financial assets are removed from our balance sheet provided the conditions for sale accounting are met. The financial assets obtained from the securitization are primarily reported as cash or retained interests (if applicable). Liabilities incurred as part of these securitizations, are recorded at fair value at the time of sale and are reported as accrued expenses and other liabilities on our Consolidated Balance Sheet . Upon the sale of the loans, we recognize a gain or loss on sale for the difference between the assets recognized, the assets derecognized, and the liabilities recognized as part of the transaction. With respect to our ongoing right to service the assets we sell, the servicing fee we receive represents adequate compensation, and consequently, we do not recognize a servicing asset or liability. The pretax gain on sales of financial assets into nonconsolidated VIEs was $1 million for the year ended December 31, 2018 . There was a pretax gain of $2 million for the year ended December 31, 2017 , while there were no pretax gains or losses for the year ended December 31, 2016 . For additional information regarding the company’s significant accounting policies for nonconsolidated VIEs, refer to the Variable Interest Entities and Securitizations section of Note 1 . We provide long-term guarantee contracts to investors in certain nonconsolidated affordable housing entities and have extended a line of credit to provide liquidity. Since we do not have control over the entities or the power to make decisions, we do not consolidate the entities and our involvement is limited to the guarantee and the line of credit. We are involved with various other nonconsolidated equity investments, including affordable housing entities and venture capital funds and loan funds. We do not consolidate these entities and our involvement is limited to our outstanding investment, additional capital committed to these funds plus any previously recognized low income housing tax credits that are subject to recapture. The following table presents our involvement in consolidated and nonconsolidated VIEs in which we hold variable interests. For additional detail related to the assets and liabilities of consolidated variable interest entities refer to the Consolidated Balance Sheet . December 31, ($ in millions) Carrying value of total assets Carrying value of total liabilities Assets sold to nonconsolidated VIEs (a) Maximum exposure to loss in nonconsolidated VIEs 2018 On-balance sheet variable interest entities Consumer automotive $ 16,255 (b) $ 6,573 (c) Commercial automotive 11,089 3,946 Off-balance sheet variable interest entities Consumer automotive (d) 45 (e) — $ 1,235 $ 1,280 (f) Commercial other 806 (g) 326 (h) — 1,054 (i) Total $ 28,195 $ 10,845 $ 1,235 $ 2,334 2017 On-balance sheet variable interest entities Consumer automotive $ 17,597 (b) $ 7,677 (c) Commercial automotive 12,550 2,558 Off-balance sheet variable interest entities Consumer automotive 37 (e) — $ 1,964 $ 2,001 (f) Commercial other 592 (g) 248 (h) — 790 (i) Total $ 30,776 $ 10,483 $ 1,964 $ 2,791 (a) Asset values represent the current unpaid principal balance of outstanding consumer finance receivables and loans within the VIEs. (b) Includes $8.4 billion and $ 8.5 billion of assets that were not encumbered by VIE beneficial interests held by third parties at December 31, 2018 , and December 31, 2017 , respectively. Ally or consolidated affiliates hold the interests in these assets. (c) Includes $25 million and $29 million of liabilities that were not obligations to third-party beneficial interest holders at December 31, 2018 , and December 31, 2017 , respectively. (d) In September 2018, we sold residual interests related to an on-balance sheet VIE to an unrelated third party. As a result of this sale, we are no longer the primary beneficiary of the VIE, and as such have deconsolidated its assets and liabilities from our Consolidated Balance Sheet including $545 million and $497 million of consumer automotive loans and long-term debt, respectively. We received cash proceeds of $24 million related to this sale, and recognized a pretax gain on sale of $1 million . We will continue to service the assets previously transferred to the VIE. (e) Represents retained notes and certificated residual interests, of which $43 million and $36 million were classified as held-to-maturity securities at December 31, 2018 , and December 31, 2017 , respectively, and $2 million and $1 million were classified as other assets at December 31, 2018 , and December 31, 2017 , respectively. These assets represent our compliance with the risk retention rules under the Dodd-Frank Act, requiring us to retain at least five percent of the credit risk of the assets underlying asset-backed securitizations. (f) Maximum exposure to loss represents the current unpaid principal balance of outstanding loans, retained notes, certificated residual interests, as well as certain noncertificated interests retained from the sale of automotive finance receivables. This measure is based on the very unlikely event that all of our sold loans have defects that would trigger a representation and warranty provision and the underlying collateral supporting the loans becomes worthless. This required disclosure is not an indication of our expected loss. (g) Amounts are classified as other assets. (h) Amounts are classified as accrued expenses and other liabilities. (i) For certain nonconsolidated affordable housing entities, maximum exposure to loss represents the yield we guaranteed investors through long-term guarantee contracts. The amount disclosed is based on the unlikely event that the underlying properties cease generating yield to investors and the yield delivered to investors in the form of low income tax housing credits is recaptured. For nonconsolidated equity investments, maximum exposure to loss represents our outstanding investment, additional committed capital, and low income housing tax credits subject to recapture. The amount disclosed is based on the unlikely event that our committed capital is funded, our investments become worthless, and the tax credits previously delivered to us are recaptured. This required disclosure is not an indication of our expected loss. On-balance Sheet Variable Interest Entities The assets of consolidated VIEs that can be used only to settle obligations of the consolidated VIEs and the liabilities of those entities for which creditors or beneficial interest holders do not have recourse to our general credit were as follows. December 31, ($ in millions) 2018 2017 Assets Finance receivables and loans, net Consumer $ 7,282 $ 8,186 Commercial 10,804 12,437 Allowance for loan losses (114 ) (136 ) Total finance receivables and loans, net 17,972 20,487 Investment in operating leases, net 164 444 Other assets 767 689 Total assets $ 18,903 $ 21,620 Liabilities Long-term debt $ 10,482 $ 10,197 Accrued expenses and other liabilities 12 9 Total liabilities $ 10,494 $ 10,206 Cash Flows with Off-balance Sheet Securitization Entities The following table summarizes cash flows received and paid related to SPEs and asset-backed financings where the transfer is accounted for as a sale and we have a continuing involvement with the transferred consumer automotive assets (e.g., servicing) that were outstanding during the years ended December 31, 2018 , 2017 , and 2016 . Additionally, this table contains information regarding cash flows received from and paid to nonconsolidated SPEs that existed during each period. Year ended December 31, ($ in millions) Consumer automotive Consumer mortgage 2018 Cash proceeds from transfers completed during the period $ 24 $ — Cash flows received on retained interests in securitization entities 20 — Servicing fees 18 — Cash disbursements for repurchases during the period (4 ) — Representation and warranty recoveries — 2 2017 Cash proceeds from transfers completed during the period $ 1,187 $ — Cash disbursements for repurchases during the period (a) (491 ) — Servicing fees 31 — Cash flows received on retained interests in securitization entities 21 — Other cash flows 4 — 2016 Cash proceeds from transfers completed during the period $ 1,715 $ — Servicing fees 35 — Other cash flows 8 — (a) During the second quarter of 2017, we elected to not renew a consumer automotive credit conduit facility and also purchased the related consumer automotive loans and settled associated retained interests. Delinquencies and Net Credit Losses The following tables present quantitative information about delinquencies and net credit losses for off-balance sheet securitizations and whole-loan sales where we have continuing involvement. Total amount Amount 60 days or more past due December 31, ($ in millions) 2018 2017 2018 2017 Off-balance sheet securitization entities Consumer automotive $ 1,235 $ 1,964 $ 13 $ 16 Whole-loan sales (a) Consumer automotive 634 1,399 3 4 Total $ 1,869 $ 3,363 $ 16 $ 20 (a) Whole-loan sales are not part of a securitization transaction, but represent consumer automotive pools of loans sold to third-party investors. Net credit losses Year ended December 31, ($ in millions) 2018 2017 Off-balance sheet securitization entities Consumer automotive $ 10 $ 13 Whole-loan sales (a) Consumer automotive 2 3 Total $ 12 $ 16 (a) Whole-loan sales are not part of a securitization transaction, but represent consumer automotive pools of loans sold to third-party investors.

Premiums Receivable and Other I

Premiums Receivable and Other Insurance Assets	12 Months Ended
	Dec. 31, 2018
Premiums Receivable and Other Insurance Assets [Abstract]
Premiums Receivable Note	Premiums Receivable and Other Insurance Assets Premiums receivable and other insurance assets consisted of the following. December 31, ($ in millions) 2018 2017 Prepaid reinsurance premiums $ 527 $ 507 Reinsurance recoverable on unpaid losses 96 108 Reinsurance recoverable on paid losses 22 19 Premiums receivable 88 84 Deferred policy acquisition costs 1,593 1,329 Total premiums receivable and other insurance assets $ 2,326 $ 2,047

Other Assets

Other Assets	12 Months Ended
	Dec. 31, 2018
Other Assets [Abstract]
Other Assets Disclosure	Other Assets The components of other assets were as follows. December 31, ($ in millions) 2018 2017 Property and equipment at cost $ 1,250 $ 1,064 Accumulated depreciation (686 ) (608 ) Net property and equipment 564 456 Nonmarketable equity investments (a) 1,410 1,233 Restricted cash held for securitization trusts (b) 965 923 Investment in qualified affordable housing projects (c) 649 472 Accrued interest, fees, and rent receivables 599 550 Net deferred tax assets 317 461 Equity method-investments (d) 262 220 Goodwill (e) 240 240 Other accounts receivable 203 116 Restricted cash and cash equivalents (f) 124 94 Fair value of derivative contracts in receivable position (g) 41 39 Cash collateral placed with counterparties 26 29 Other assets 753 830 Total other assets $ 6,153 $ 5,663 (a) Includes investments in FHLB stock of $903 million and $745 million at December 31, 2018 , and 2017, respectively; FRB stock of $448 million and $445 million at December 31, 2018 , and 2017, respectively; and equity securities without a readily determinable fair value of $59 million at December 31, 2018 , measured at cost with adjustments for impairment and observable changes in price. During the year ended December 31, 2018 , we recorded $2 million in impairment related to equity securities without a readily determinable fair value. (b) Includes restricted cash collected from customer payments on securitized receivables, which are distributed by us to investors as payments on the related secured debt, and cash reserve deposits utilized as a form of credit enhancement for various securitization transactions. (c) Investment in qualified affordable housing projects are accounted for using the proportional amortization method of accounting and include $319 million and $240 million of unfunded commitments to provide additional capital contributions to investees at December 31, 2018 , and 2017, respectively. Substantially all of the unfunded commitments at December 31, 2018 , are expected to be paid out over the next five years. (d) Primarily relates to investments made in connection with our CRA program. (e) Includes goodwill of $27 million within our Insurance operations at both December 31, 2018 , and 2017; $193 million within Corporate and Other at both December 31, 2018 , and 2017; and $20 million within Automotive Finance operations at both December 31, 2018 , and 2017. As a result of our acquisition of TradeKing Group, Inc. (TradeKing), we recognized $193 million of goodwill within Corporate and Other on June 1, 2016. On August 1, 2016, we purchased assets from Blue Yield and recognized $20 million of goodwill within Automotive Finance operations. No other changes to the carrying amount of goodwill were recorded during the years ended December 31, 2018 , 2017 , and 2016 . (f) Primarily represents a number of arrangements with third parties where certain restrictions are placed on balances we hold due to collateral agreements associated with operational processes with a third-party bank, or letter of credit arrangements and corresponding collateral requirements. (g) For additional information on derivative instruments and hedging activities, refer to Note 21 .

Deposit Liabilities

Deposit Liabilities	12 Months Ended
	Dec. 31, 2018
Deposits [Abstract]
Deposit Liabilities Disclosures	Deposit Liabilities Deposit liabilities consisted of the following. December 31, ($ in millions) 2018 2017 Noninterest-bearing deposits $ 142 $ 108 Interest-bearing deposits Savings and money market checking accounts 56,050 49,267 Certificates of deposit 49,985 43,869 Dealer deposits 1 12 Total deposit liabilities $ 106,178 $ 93,256 At December 31, 2018 , and December 31, 2017 , certificates of deposit included $21.0 billion and $18.9 billion , respectively, of those in denominations of $100 thousand or more. At December 31, 2018 , and December 31, 2017 , certificates of deposit included $6.1 billion and $5.3 billion , respectively, of those in denominations in excess of $250 thousand federal insurance limits. The following table presents the scheduled maturity of total certificates of deposit at December 31, 2018 . ($ in millions) Due in 2019 $ 31,518 Due in 2020 11,687 Due in 2021 4,569 Due in 2022 1,493 Due in 2023 718 Total certificates of deposit $ 49,985

Debt

Debt	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Debt Disclosure	Debt Short-term Borrowings The following table presents the composition of our short-term borrowings portfolio. 2018 2017 December 31, ($ in millions) Unsecured Secured (a) Total Unsecured Secured (a) Total Demand notes $ 2,477 $ — $ 2,477 $ 3,171 $ — $ 3,171 Federal Home Loan Bank — 6,825 6,825 — 7,350 7,350 Securities sold under agreements to repurchase — 685 685 — 892 892 Total short-term borrowings $ 2,477 $ 7,510 $ 9,987 $ 3,171 $ 8,242 $ 11,413 Weighted average interest rate (b) 2.5 % 1.5 % (a) Refer to the section below titled Long-term Debt for further details on assets restricted as collateral for payment of the related debt. (b) Based on the debt outstanding and the interest rate at December 31 of each year. We periodically enter into term repurchase agreements, short-term borrowing agreements in which we sell securities to one or more investors while simultaneously committing to repurchase them at a specified future date, at the stated price plus accrued interest. As of December 31, 2018 , the securities sold under agreements to repurchase consisted of $436 million of U.S. Treasury securities and $249 million of agency mortgage-backed residential debt securities set to mature as follows: $575 million within 30 days, and $110 million within 31 to 60 days . Refer to Note 8 and Note 25 for further details. The primary risk associated with these repurchase agreements is that the counterparty will be unable to perform under the terms of the contract. As the borrower, we are exposed to the excess market value of the securities pledged over the amount borrowed. Daily mark-to-market collateral management is designed to limit this risk to the initial margin. However, should a counterparty declare bankruptcy or become insolvent, we may incur additional delays and costs. In some instances, we may place or receive cash collateral with counterparties under collateral arrangements associated with our repurchase agreements. At December 31, 2018 , we did not place any collateral, and we received cash collateral totaling $8 million and noncash collateral totaling $4 million . At December 31, 2017 , we placed cash collateral totaling $10 million and received cash collateral totaling $1 million . Long-term Debt The following tables present the composition of our long-term debt portfolio. December 31, ($ in millions) Amount Stated interest rate Weighted-average stated interest rate (a) Due date range 2018 Unsecured debt Fixed rate (b) $ 9,406 Variable rate 1 Trust preferred securities (c) 2,572 Hedge basis adjustment (d) 128 Total unsecured debt 12,107 2.42–8.40% 6.29 % 2019–2049 Secured debt Fixed rate 23,514 Variable rate (e) 8,633 Hedge basis adjustment (d) (61 ) Total secured debt (f) (g) (h) 32,086 1.26–4.50% 2.54 % 2019–2037 Total long-term debt $ 44,193 2017 Unsecured debt Fixed rate (b) $ 12,820 Variable rate 1 Trust preferred securities (c) 2,570 Hedge basis adjustment (d) 240 Total unsecured debt 15,631 1.48–8.00% 5.68 % 2018–2049 Secured debt Fixed rate 18,845 Variable rate (e) 9,782 Hedge basis adjustment (d) (32 ) Total secured debt (f) (g) (h) 28,595 0.63–4.50% 1.96 % 2018–2036 Total long-term debt $ 44,226 (a) Based on the debt outstanding and the interest rate at December 31 of each year excluding any impacts of interest rate hedges. (b) Includes subordinated debt of $1.0 billion and $1.4 billion at December 31, 2018, and 2017, respectively. (c) Refer to the section below titled Trust Preferred Securities for further information. (d) Represents the basis adjustment associated with the application of hedge accounting on certain of our long-term debt positions. Refer to Note 21 for additional information. (e) Includes $5 million and $8 million at December 31, 2018, and 2017, respectively, of long-term debt that does not have a stated interest rate. (f) Includes $10.5 billion and $10.2 billion of VIE secured debt at December 31, 2018, and 2017, respectively. (g) Includes $6.7 billion and $8.1 billion of debt outstanding from our automotive committed secured credit facilities at December 31, 2018, and 2017, respectively. (h) Includes advances from the FHLB of Pittsburgh of $14.9 billion and $10.3 billion at December 31, 2018, and 2017, respectively. 2018 2017 December 31, ($ in millions) Unsecured Secured Total Unsecured Secured Total Long-term debt (a) Due within one year $ 1,663 $ 7,313 $ 8,976 $ 3,540 $ 7,497 $ 11,037 Due after one year 10,444 24,773 35,217 12,091 21,098 33,189 Total long-term debt $ 12,107 $ 32,086 $ 44,193 $ 15,631 $ 28,595 $ 44,226 (a) Includes basis adjustments related to the application of hedge accounting. Amounts for December 31, 2017, have been updated to conform to this change in presentation. To achieve the desired balance between fixed- and variable-rate debt, we utilize interest rate swap agreements. The use of these derivative financial instruments had the effect of synthetically converting $3.8 billion of our fixed-rate debt into variable-rate obligations, and $3.4 billion of our variable-rate debt into fixed-rate obligations at December 31, 2017. We did not have any derivative financial instruments that synthetically converted fixed-rate debt into variable-rate obligations or variable-rate debt into fixed rate obligations at December 31, 2018. The following table presents the scheduled remaining maturity of long-term debt at December 31, 2018 , assuming no early redemptions will occur. The amounts below include adjustments to the carrying value resulting from the application of hedge accounting. The actual payment of secured debt may vary based on the payment activity of the related pledged assets. ($ in millions) 2019 2020 2021 2022 2023 2024 and thereafter Total Unsecured Long-term debt $ 1,704 $ 2,257 $ 698 $ 1,069 $ 12 $ 7,502 $ 13,242 Original issue discount (41 ) (41 ) (45 ) (49 ) (56 ) (903 ) (1,135 ) Total unsecured 1,663 2,216 653 1,020 (44 ) 6,599 12,107 Secured Long-term debt 7,313 7,363 10,195 5,321 1,230 664 32,086 Total long-term debt $ 8,976 $ 9,579 $ 10,848 $ 6,341 $ 1,186 $ 7,263 $ 44,193 The following summarizes assets restricted as collateral for the payment of the related debt obligation primarily arising from securitization transactions accounted for as secured borrowings and repurchase agreements. 2018 2017 December 31, ($ in millions) Total (a) Ally Bank Total (a) Ally Bank Investment securities (b) $ 10,280 $ 9,564 $ 8,371 $ 7,443 Mortgage assets held-for-investment and lending receivables 16,498 16,498 13,579 13,579 Consumer automotive finance receivables 17,015 9,715 19,787 6,200 Commercial automotive finance receivables 15,563 15,563 16,567 16,472 Operating leases 170 — 457 — Total assets restricted as collateral (c) (d) $ 59,526 $ 51,340 $ 58,761 $ 43,694 Secured debt $ 39,596 (e) $ 32,072 $ 36,837 (e) $ 23,278 (a) Ally Bank is a component of the total column. (b) A portion of the restricted investment securities at December 31, 2018 , and December 31, 2017 , were restricted under repurchase agreements. Refer to the section above titled Short-term Borrowings for information on the repurchase agreements. (c) Ally Bank has an advance agreement with the FHLB, and had assets pledged to secure borrowings that were restricted as collateral to the FHLB totaling $30.8 billion and $25.2 billion at December 31, 2018 , and December 31, 2017 , respectively. These assets were composed primarily of consumer mortgage finance receivables and loans and investment securities. Ally Bank has access to the FRB Discount Window. Ally Bank had assets pledged and restricted as collateral to the FRB totaling $2.4 billion and $2.3 billion at December 31, 2018 , and December 31, 2017 , respectively. These assets were composed of consumer automotive finance receivables and loans. Availability under these programs is only for the operations of Ally Bank and cannot be used to fund the operations or liabilities of Ally or its subsidiaries. (d) Excludes restricted cash and cash reserves for securitization trusts recorded within other assets on the Consolidated Balance Sheet . Refer to Note 13 for additional information. (e) Includes $7.5 billion and $8.2 billion of short-term borrowings at December 31, 2018 , and December 31, 2017 , respectively. Trust Preferred Securities At December 31, 2018 , we have issued and outstanding approximately $2.6 billion in aggregate liquidation preference of 8.125% Fixed Rate/Floating Rate Trust Preferred Securities, Series 2 (Series 2 TRUPS). Each Series 2 TRUPS security has a liquidation amount of $25. Distributions are cumulative and are payable until redemption at the applicable coupon rate. Distributions are payable at an annual rate equal to three-month London interbank offer rate plus 5.785% payable quarterly in arrears. Ally has the right to defer payments of interest for a period not exceeding 20 consecutive quarters. The Series 2 TRUPS have no stated maturity date, but must be redeemed upon the redemption or maturity of the related debentures (Debentures), which mature on February 15, 2040. Ally at any time may redeem the Series 2 TRUPS at a redemption price equal to 100% of the principal amount being redeemed, plus accrued and unpaid interest through the date of redemption. The Series 2 TRUPS are generally nonvoting, other than with respect to certain limited matters. During any period in which any Series 2 TRUPS remain outstanding but in which distributions on the Series 2 TRUPS have not been fully paid, none of Ally or its subsidiaries will be permitted to (i) declare or pay dividends on, make any distributions with respect to, or redeem, purchase, acquire or otherwise make a liquidation payment with respect to, any of Ally’s capital stock or make any guarantee payment with respect thereto; or (ii) make any payments of principal, interest, or premium on, or repay, repurchase or redeem, any debt securities or guarantees that rank on a parity with or junior in interest to the Debentures with certain specified exceptions in each case. Covenants and Other Requirements In secured funding transactions, there are trigger events that could cause the debt to be prepaid at an accelerated rate or could cause our usage of the committed secured credit facility to be discontinued. The triggers are generally based on the financial health and performance of the servicer as well as performance criteria for the pool of receivables, such as delinquency ratios, loss ratios, and commercial payment rates. During 2018, there were no trigger events that resulted in the repayment of debt at an accelerated rate or impacted the usage of our facilities. Funding Facilities We utilize both committed secured credit facilities and other collateralized funding vehicles. The debt outstanding under our various funding facilities is included on our Consolidated Balance Sheet . As of December 31, 2018 , Ally Bank had exclusive access to $4.8 billion of funding capacity from committed credit facilities. Ally Bank’s credit facilities are complemented by the FRB and FHLB funding programs. The total capacity in our credit facilities is provided by banks through private transactions. The facilities can be revolving in nature, generally having an original tenor ranging from 364 days to two years, and allow for additional funding during the commitment period, or they can be amortizing and not allow for any further funding after the commitment period. At December 31, 2018 , all of our $8.6 billion of capacity was revolving. As of December 31, 2018 , we had $7.0 billion of capacity from facilities with a remaining tenor greater than 364 days. Committed Secured Credit Facilities Outstanding Unused capacity (a) Total capacity December 31, ($ in millions) 2018 2017 2018 2017 2018 2017 Bank funding Secured $ 3,500 $ 1,785 $ 1,300 $ 890 $ 4,800 $ 2,675 Parent funding Secured 3,165 6,330 635 2,920 3,800 9,250 Total committed secured credit facilities $ 6,665 $ 8,115 $ 1,935 $ 3,810 $ 8,600 $ 11,925 (a) Funding from committed secured credit facilities is available on request in the event excess collateral resides in certain facilities or the extent incremental collateral is available and contributed to the facilities.

Accrued Expenses and Other Liab

Accrued Expenses and Other Liabilities	12 Months Ended
	Dec. 31, 2018
Accounts Payable and Accrued Liabilities [Abstract]
Accounts Payable and Accrued Liabilities Disclosure	Accrued Expenses and Other Liabilities The components of accrued expenses and other liabilities were as follows. December 31, ($ in millions) 2018 2017 Accounts payable $ 516 $ 746 Unfunded commitments for investment in qualified affordable housing projects 319 240 Employee compensation and benefits 255 248 Reserves for insurance losses and loss adjustment expenses 134 140 Cash collateral received from counterparties 41 17 Fair value of derivative contracts in payable position (a) 37 41 Deferred revenue 27 32 Other liabilities 347 316 Total accrued expenses and other liabilities $ 1,676 $ 1,780 (a) For additional information on derivative instruments and hedging activities, refer to Note 21 .

Equity

Equity	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Stockholders' Equity Note Disclosure	Equity Common Stock The following table presents changes in the number of shares issued and outstanding. Year ended December 31, (shares in thousands) (a) 2018 2017 2016 Common stock Total issued at January 1, 489,884 485,708 482,791 New issuances Employee benefits and compensation plans 2,914 4,176 2,917 Total issued at December 31, 492,797 489,884 485,708 Treasury balance at January 1, (52,830 ) (18,707 ) (811 ) Repurchase of common stock (b) (35,068 ) (34,122 ) (17,897 ) Total treasury stock at December 31, (87,898 ) (52,830 ) (18,707 ) Total outstanding at December 31, 404,900 437,054 467,000 (a) Figures in the table may not recalculate exactly due to rounding. Number of shares issued, in treasury, and outstanding are calculated based on unrounded numbers. (b) Includes shares of common stock withheld to cover income taxes owed by participants in our share-based incentive plans. Refer to the section titled Capital Planning and Stress Tests in Note 20 for additional information regarding our common-stock-repurchase program.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	12 Months Ended
	Dec. 31, 2018
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Comprehensive Income (Loss) Note	Accumulated Other Comprehensive Loss The following table presents changes, net of tax, in each component of accumulated other comprehensive loss. ($ in millions) Unrealized (losses) gains on investment securities (a) Translation adjustments and net investment hedges (b) Cash flow hedges (b) Defined benefit pension plans Accumulated other comprehensive loss Balance at January 1, 2016 $ (159 ) $ 9 $ 8 $ (89 ) $ (231 ) 2016 net change (114 ) 5 — (1 ) (110 ) Balance at December 31, 2016 (273 ) 14 8 (90 ) (341 ) 2017 net change 100 2 3 1 106 Balance at December 31, 2017, before cumulative effect of adjustments $ (173 ) $ 16 $ 11 $ (89 ) $ (235 ) Cumulative effect of changes in accounting principles, net of tax (c) Adoption of Accounting Standards Update 2016-01 27 — — — 27 Adoption of Accounting Standards Update 2018-02 (40 ) 4 — (6 ) (42 ) Balance at January 1, 2018, after cumulative effect of adjustments (186 ) 20 11 (95 ) (250 ) 2018 net change (295 ) (2 ) 8 — (289 ) Balance at December 31, 2018 $ (481 ) $ 18 $ 19 $ (95 ) $ (539 ) (a) Represents the after-tax difference between the fair value and amortized cost of our available-for-sale securities portfolio. (b) For additional information on derivative instruments and hedging activities, refer to Note 21 . (c) Refer to the section titled Recently Adopted Accounting Standards in Note 1 for additional information. The following tables present the before- and after-tax changes in each component of accumulated other comprehensive (loss) income. Year ended December 31, 2018 ($ in millions) Before tax Tax effect After tax Investment securities Net unrealized losses arising during the period $ (375 ) $ 88 $ (287 ) Less: Net realized gains reclassified to income from continuing operations 11 (a) (3 ) (b) 8 Net change (386 ) 91 (295 ) Translation adjustments Net unrealized losses arising during the period (14 ) 3 (11 ) Net investment hedges (c) Net unrealized gains arising during the period 12 (3 ) 9 Cash flow hedges (c) Net unrealized gains arising during the period 12 (2 ) 10 Less: Net realized gains reclassified to income from continuing operations 2 (d) — 2 Net change 10 (2 ) 8 Defined benefit pension plans Net unrealized gains arising during the period 1 (1 ) — Other comprehensive loss $ (377 ) $ 88 $ (289 ) (a) Includes gains reclassified to other loss on investments, net in our Consolidated Statement of Income . (b) Includes amounts reclassified to income tax expense from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 21 . (d) Includes gains reclassified to interest on deposits and interest on long-term debt in our Consolidated Statement of Income . Year ended December 31, 2017 ($ in millions) Before tax Tax effect After tax Investment securities Net unrealized gains arising during the period $ 237 $ (45 ) $ 192 Less: Net realized gains reclassified to income from continuing operations 105 (a) (13 ) (b) 92 Net change 132 (32 ) 100 Translation adjustments Net unrealized gains arising during the period 12 (4 ) 8 Net investment hedges (c) Net unrealized losses arising during the period (10 ) 4 (6 ) Cash flow hedges (c) Net unrealized gains arising during the period 5 (2 ) 3 Defined benefit pension plans Net unrealized gains arising during the period 1 — 1 Other comprehensive income $ 140 $ (34 ) $ 106 (a) Includes gains reclassified to other gain on investments, net in our Consolidated Statement of Income . (b) Includes amounts reclassified to income tax expense from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 21 . Year ended December 31, 2016 ($ in millions) Before tax Tax effect After tax Investment securities Net unrealized gains arising during the period $ 13 $ 20 $ 33 Less: Net realized gains reclassified to income from continuing operations 185 (a) (38 ) (b) 147 Net change (172 ) 58 (114 ) Translation adjustments Net unrealized gains arising during the period 5 (2 ) 3 Less: Net realized losses reclassified to income from discontinued operations, net of tax (1 ) — (1 ) Net change 6 (2 ) 4 Net investment hedges (c) Net unrealized gains arising during the period 1 — 1 Defined benefit pension plans Net unrealized losses arising during the period (5 ) 2 (3 ) Less: Net realized losses reclassified to income from continuing operations (4 ) (d) 2 (b) (2 ) Net change (1 ) — (1 ) Other comprehensive loss $ (166 ) $ 56 $ (110 ) (a) Includes gains reclassified to other gain on investments, net in our Consolidated Statement of Income . (b) Includes amounts reclassified to income tax expense from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 21 . (d) Includes gains reclassified to compensation and benefits expense in our Consolidated Statement of Income .

Earnings per Common Share

Earnings per Common Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Earnings per Common Share The following table presents the calculation of basic and diluted earnings per common share. Year ended December 31, ($ in millions, except per share data; shares in thousands) (a) 2018 2017 2016 Net income from continuing operations $ 1,263 $ 926 $ 1,111 Preferred stock dividends — — (30 ) Net income from continuing operations attributable to common stockholders 1,263 926 1,081 Income (loss) from discontinued operations, net of tax — 3 (44 ) Net income attributable to common stockholders $ 1,263 $ 929 $ 1,037 Basic weighted-average common shares outstanding (b) 425,165 453,704 481,105 Diluted weighted-average common shares outstanding (b) 427,680 455,350 482,182 Basic earnings per common share Net income from continuing operations $ 2.97 $ 2.04 $ 2.25 Income (loss) from discontinued operations, net of tax — 0.01 (0.09 ) Net income $ 2.97 $ 2.05 $ 2.15 Diluted earnings per common share Net income from continuing operations $ 2.95 $ 2.03 $ 2.24 Income (loss) from discontinued operations, net of tax — 0.01 (0.09 ) Net income $ 2.95 $ 2.04 $ 2.15 (a) Figures in the table may not recalculate exactly due to rounding. Earnings per share is calculated based on unrounded numbers. (b) Includes shares related to share-based compensation that vested but were not yet issued .

Regulatory Capital and Other Re

Regulatory Capital and Other Regulatory Matters	12 Months Ended
	Dec. 31, 2018
Regulatory Capital Requirements [Abstract]
Regulatory Capital Requirements under Banking Regulations	Regulatory Capital and Other Regulatory Matters The FRB and other U.S. banking agencies have adopted risk-based and leverage capital standards that establish minimum capital-to-asset ratios for BHCs, like Ally, and depository institutions, like Ally Bank. The risk-based capital ratios are based on a banking organization’s risk-weighted assets (RWAs), which are generally determined under the standardized approach applicable to Ally and Ally Bank by (1) assigning on-balance sheet exposures to broad risk weight categories according to the counterparty or, if relevant, the guarantor or collateral (with higher risk weights assigned to categories of exposures perceived as representing greater risk), and (2) multiplying off-balance sheet exposures by specified credit conversion factors to calculate credit equivalent amounts and assigning those credit equivalent amounts to the relevant risk weight categories. The leverage ratio, in contrast, is based on an institution’s average unweighted on-balance sheet exposures. Ally and Ally Bank are subject to capital requirements issued by U.S. banking regulators that require us to maintain risk-based and leverage capital ratios above minimum levels. As of January 1, 2015, Ally and Ally Bank became subject to the rules implementing the 2010 Basel III capital framework in the United States (U.S. Basel III), which generally reflects higher capital requirements, capital buffers, and changes to regulatory capital definitions, deductions and adjustments, relative to the predecessor requirements implementing the Basel I capital framework in the United States. Certain aspects of U.S. Basel III, including the capital buffers were subject to a phase-in period through December 31, 2018. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary action by regulators that, if undertaken, could have a direct material effect on the Consolidated Financial Statements or the results of operations and financial condition of Ally and Ally Bank. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, we and Ally Bank must meet specific capital guidelines that involve quantitative measures of capital, assets and certain off-balance sheet items. These measures and related classifications, which are used in the calculation of our risk-based and leverage capital ratios and those of Ally Bank, are also subject to qualitative judgments by the regulators about the components of capital, the risk-weightings of assets and other exposures, and other factors. The FRB also uses these ratios and guidelines as part of the capital planning and stress testing processes. In addition, in order for Ally to maintain its status as an FHC, Ally and its bank subsidiary, Ally Bank, must remain well capitalized and well managed, as defined under applicable laws. The well capitalized standard for insured depository institutions, such as Ally Bank, reflects the capital requirements under U.S. Basel III. Under U.S. Basel III, Ally and Ally Bank must maintain a minimum Common Equity Tier 1 risk-based capital ratio of 4.5% , a minimum Tier 1 risk-based capital ratio of 6% , and a minimum total risk-based capital ratio of 8% . In addition to these minimum risk-based capital ratios, Ally and Ally Bank are also subject to a Common Equity Tier 1 capital conservation buffer of more than 2.5% , subject to a phase-in period from January 1, 2016, through December 31, 2018. Failure to maintain the full amount of the buffer would result in restrictions on the ability of Ally and Ally Bank to make capital distributions, including dividend payments and stock repurchases and redemptions, and to pay discretionary bonuses to executive officers. U.S. Basel III also subjects Ally and Ally Bank to a minimum Tier 1 leverage ratio of 4% . U.S. Basel III also revised the eligibility criteria for regulatory capital instruments and provides for the phase-out of instruments that had previously been recognized as capital but that do not satisfy these criteria. For example, subject to certain exceptions (e.g., certain debt or equity issued to the U.S. government under the Emergency Economic Stabilization Act), trust preferred and other hybrid securities were excluded from a BHC’s Tier 1 capital as of January 1, 2016. Also, subject to a phase-in schedule, certain items are deducted from Common Equity Tier 1 capital under U.S. Basel III that had not previously been deducted from regulatory capital, and certain other deductions from regulatory capital have been modified. Among other things, U.S. Basel III requires significant investments in the common stock of unconsolidated financial institutions, mortgage servicing assets, and certain deferred tax assets that exceed specified individual and aggregate thresholds to be deducted from Common Equity Tier 1 capital. U.S. Basel III also revised the standardized approach for calculating RWAs by, among other things, modifying certain risk weights and the methods for calculating RWAs for certain types of assets and exposures. Ally and Ally Bank are subject to the U.S. Basel III standardized approach for counterparty credit risk, but not to the U.S. Basel III advanced approaches for credit risk or operational risk. Ally is also not subject to the U.S. market risk capital rule, which applies only to banking organizations with significant trading assets and liabilities. In December 2018, the FRB and other U.S. banking agencies approved a final rule to mitigate the impact of CECL on regulatory capital by allowing BHCs and banks, including Ally, to phase in the day-one impact of CECL over a period of three years for regulatory capital purposes. In addition, the FRB announced that although BHCs subject to company-run stress tests as part of CCAR must incorporate CECL beginning in the 2020 cycle, the FRB also further clarified that, in order to reduce uncertainty, it will maintain its current modeling framework for the allowance for loan losses in supervisory stress tests through the 2021 cycle. In May 2018, targeted amendments to the Dodd-Frank Act and other financial-services laws were enacted through the Economic Growth, Regulatory Relief, and Consumer Protection Act (EGRRCP Act), including amendments that affect whether and, if so, how the FRB applies enhanced prudential standards to BHCs like us with $100 billion or more but less than $250 billion in total consolidated assets. During the fourth quarter of 2018, the FRB and other U.S. banking agencies issued proposals that would implement these amendments in the EGRRCP Act and establish risk-based categories for determining the prudential standards and the capital and liquidity requirements that apply to large U.S. banking organizations. Under the proposals, Ally would be treated as a Category IV firm and, as such, would be (1) made subject to the FRB’s Comprehensive Capital Analysis and Review (CCAR) on a two-year cycle rather than the current one-year cycle, (2) made subject to supervisory stress testing on a two-year cycle rather than the current one-year cycle, (3) required to continue submitting an annual capital plan to the FRB for non-objection, (4) allowed to continue excluding accumulated other comprehensive income (AOCI) from regulatory capital, (5) required to continue maintaining a buffer of unencumbered highly liquid assets to meet projected net cash outflows for 30 days, (6) required to conduct liquidity stress tests on a quarterly basis rather than the current monthly basis, (7) allowed to engage in more tailored liquidity risk management, including monthly rather than weekly calculations of collateral positions, the elimination of limits for activities that are not relevant to the firm, and fewer required elements of monitoring of intraday liquidity exposures, (8) exempted from company-run stress testing, the modified liquidity coverage ratio (LCR), and the proposed modified net stable funding ratio (NSFR), and (9) allowed to remain exempted from the supplementary leverage ratio, the countercyclical capital buffer, and single counterparty credit limits. In April 2018, the FRB issued a proposal to more closely align forward-looking stress testing results with the FRB’s non-stress regulatory capital requirements for banking organizations with $50 billion or more in total consolidated assets. The proposal would introduce a stress capital buffer based on firm-specific stress test performance, which would effectively replace the non-stress capital conservation buffer. The proposal would also make several changes to the CCAR process, such as eliminating the CCAR quantitative objection, narrowing the set of planned capital actions assumed to occur in the stress scenario, and eliminating the 30% dividend payout ratio as a criterion for heightened scrutiny of a firm’s capital plan. In December 2017, the Basel Committee approved revisions to the global Basel III capital framework (commonly known as Basel IV), many of which—if adopted in the United States—could heighten regulatory capital standards even more. At this time, how all of these proposals and revisions will be harmonized and finalized in the United States is not clear or predictable and we continue to evaluate the impacts these proposals and revisions may have to us. Compliance with capital requirements is a strategic priority for Ally. We expect to be in compliance with all applicable requirements within the established timeframes. The following table summarizes our capital ratios under the U.S. Basel III capital framework. December 31, 2018 December 31, 2017 Required minimum (a) Well-capitalized minimum ($ in millions) Amount Ratio Amount Ratio Capital ratios Common Equity Tier 1 (to risk-weighted assets) Ally Financial Inc. $ 13,397 9.14 % $ 13,237 9.53 % 4.50 % (b) Ally Bank 16,552 12.61 17,059 15.04 4.50 6.50 % Tier 1 (to risk-weighted assets) Ally Financial Inc. $ 15,831 10.80 % $ 15,628 11.25 % 6.00 % 6.00 % Ally Bank 16,552 12.61 17,059 15.04 6.00 8.00 Total (to risk-weighted assets) Ally Financial Inc. $ 18,046 12.31 % $ 17,974 12.94 % 8.00 % 10.00 % Ally Bank 17,620 13.42 17,886 15.77 8.00 10.00 Tier 1 leverage (to adjusted quarterly average assets) (c) Ally Financial Inc. $ 15,831 9.00 % $ 15,628 9.53 % 4.00 % (b) Ally Bank 16,552 10.69 17,059 12.87 4.00 5.00 % (a) In addition to the minimum risk-based capital requirements for common equity Tier 1 capital, Tier 1 capital, and total capital ratios, Ally and Ally Bank were required to maintain a minimum capital conservation buffer of 1.875% and 1.25% at December 31, 2018 , and December 31, 2017 , respectively, which increased to 2.5% on January 1, 2019. (b) Currently, there is no ratio component for determining whether a BHC is “well-capitalized.” (c) Federal regulatory reporting guidelines require the calculation of adjusted quarterly average assets using a daily average methodology. At December 31, 2018 , Ally and Ally Bank were “well-capitalized” and met all applicable capital requirements to which each was subject. Capital Planning and Stress Tests Pending the adoption of proposals issued by the FRB and other U.S. banking agencies during the fourth quarter of 2018 that would implement the EGRRCP Act , Ally is required to conduct semi-annual company-run stress tests, is subject to an annual supervisory stress test conducted by the FRB, and must submit a proposed capital plan to the FRB. Ally’s proposed capital plan must include an assessment of our expected uses and sources of capital and a description of all planned capital actions over a nine-quarter planning horizon, including any issuance of a debt or equity capital instrument, any dividend or other capital distribution, and any similar action that the FRB determines could have an impact on Ally’s capital. The proposed capital plan must also include a discussion of how Ally, under expected and stressful conditions, will maintain capital commensurate with its risks and above the minimum regulatory capital ratios, and will serve as a source of strength to Ally Bank. The FRB will either object to Ally’s proposed capital plan, in whole or in part, or provide a notice of non-objection. If the FRB objects to the proposed capital plan, or if certain material events occur after approval of the plan, Ally must submit a revised capital plan within 30 days. Even if the FRB does not object to our capital plan, Ally may be precluded from or limited in paying dividends or other capital distributions without the FRB’s approval under certain circumstances—for example, when we would not meet minimum regulatory capital ratios and capital buffers after giving effect to the distributions. The following table presents information related to our common stock for each quarter since the commencement of our common-stock-repurchase programs and initiation of a quarterly cash dividend on common stock. Common stock repurchased during period (a) Number of common shares outstanding Cash dividends declared per common share (b) ($ in millions, except per share data; shares in thousands) Approximate dollar value Number of shares Beginning of period End of period 2016 Third quarter $ 159 8,298 483,753 475,470 $ 0.08 Fourth quarter 167 8,745 475,470 467,000 0.08 2017 First quarter $ 169 8,097 467,000 462,193 $ 0.08 Second quarter 204 10,485 462,193 452,292 0.08 Third quarter 190 8,507 452,292 443,796 0.12 Fourth quarter 190 7,033 443,796 437,054 0.12 2018 First quarter $ 185 6,473 437,054 432,691 $ 0.13 Second quarter 195 7,280 432,691 425,752 0.13 Third quarter 250 9,194 425,752 416,591 0.15 Fourth quarter 309 12,121 416,591 404,900 0.15 (a) Includes shares of common stock withheld to cover income taxes owed by participants in our share-based incentive plans. (b) On January 14, 2019 , the Ally Board of Directors (the Board) declared a quarterly cash dividend of $0.17 per share on all common stock, payable on February 15, 2019 . Refer to Note 31 for further information regarding this common stock dividend. Ally submitted its 2018 capital plan and company-run stress test results to the FRB on April 5, 2018. On June 21, 2018, we publicly disclosed summary results of the stress test under the severely adverse scenario in accordance with applicable regulatory requirements. On June 28, 2018, we received from the FRB a non-objection to our capital plan, which included increases in both our stock-repurchase program and our planned dividends. Consistent with the capital plan, the Board authorized a 32% increase in our stock-repurchase program, permitting us to repurchase up to $1.0 billion of our common stock from time to time from the third quarter of 2018 through the second quarter of 2019. Also consistent with the capital plan, on January 14, 2019, the Board declared a quarterly cash dividend of $0.17 per share of our common stock. Refer to Note 31 for further information on the most recent dividend. On October 5, 2018 , we submitted to the FRB the results of our company-run mid-cycle stress test and publicly disclosed summary results under the severely adverse scenario in accordance with applicable regulatory requirements. D uring the first quarter of 2019, the FRB announced that a number of large and noncomplex BHCs with $100 billion or more but less than $250 billion in total consolidated assets, including Ally, will not be required to submit a capital plan to the FRB, participate in the supervisory stress test or CCAR, or conduct company-run stress tests during the 2019 cycle. Instead, Ally’s capital actions during this cycle will be largely based on the results from its 2018 supervisory stress test. Our ability to make capital distributions, including our ability to pay dividends or repurchase shares of our common stock, will continue to be subject to the FRB’s review. The amount and size of any future dividends and share repurchases also will depend upon our results of operations, capital levels, future opportunities, consideration and approval by the Board, and other considerations. In January 2017, the FRB amended its capital planning and stress testing rules, effective for the 2017 cycle and beyond. As a result of this amendment, the FRB may no longer object to the capital plan of a large and noncomplex BHC, like Ally, on the basis of qualitative deficiencies in its capital planning process. Instead, the qualitative assessment of Ally’s capital planning process is now conducted outside of CCAR through the supervisory review process. The amendment also decreased the de minimis threshold for the amount of capital that Ally could distribute to stockholders outside of an approved capital plan without the FRB’s prior approval, and modified Ally’s reporting requirements to reduce unnecessary burdens. Depository Institutions Ally Bank is a member of the Federal Reserve System and is subject to regulation, supervision, and examination by the FRB and the UDFI. Ally Bank’s deposits are insured by the Federal Deposit Insurance Corporation (FDIC), and Ally Bank is required to file periodic reports with the FDIC concerning its financial condition. Total assets of Ally Bank were $159.0 billion and $137.4 billion at December 31, 2018 , and 2017 , respectively. Federal and Utah law place a number of conditions, restrictions, and limitations on dividends and other capital distributions that may be paid by Ally Bank to Ally. Dividends or other distributions made by Ally Bank to Ally were $2.6 billion and $3.3 billion in 2018 and 2017 , respectively. The FRB requires banks to maintain minimum average reserve balances. The amount of the required reserve balance for Ally Bank was $279 million and $370 million at December 31, 2018 , and 2017 , respectively. Ally Bank is required to satisfy regulatory net worth requirements. Failure to meet minimum capital requirements can initiate certain mandatory actions by federal, state, and foreign agencies that could have a material effect on our results of operations and financial condition. Ally Bank was in compliance with these requirements at December 31, 2018 . Insurance Companies Certain of our Insurance operations are subject to certain minimum aggregate capital requirements, net asset and dividend restrictions under applicable state and foreign insurance laws, and the rules and regulations promulgated by various U.S. and foreign regulatory agencies. Under various state and foreign insurance regulations, dividend distributions may be made only from statutory unassigned surplus, with approvals required from the regulatory authorities for dividends in excess of certain statutory limitations. At December 31, 2018 , the maximum dividend that could be paid by the U.S. insurance subsidiaries over the next twelve months without prior statutory approval was $134 million .

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities Disclosure	Derivative Instruments and Hedging Activities We enter into derivative instruments, which may include interest rate, foreign-currency, and equity swaps, futures, forwards, and options in connection with our risk-management activities. Our primary objective for utilizing derivative financial instruments is to manage interest rate risk associated with our fixed- and variable-rate assets and liabilities, foreign exchange risks related to our foreign-currency denominated assets and liabilities, and other market risks related to our investment portfolio. Interest Rate Risk We monitor our mix of fixed- and variable-rate assets and liabilities and may enter into interest rate swaps, forwards, futures, options, and swaptions to achieve our desired mix of fixed- and variable-rate assets and liabilities. We execute these trades to modify our exposure to interest rate risk by converting certain fixed-rate instruments to a variable-rate and certain variable-rate instruments to a fixed-rate. We use a mix of both derivatives that qualify for hedge accounting treatment and economic hedges. Derivatives qualifying for hedge accounting can include receive-fixed swaps designated as fair value hedges of specific fixed-rate unsecured debt obligations, receive-fixed swaps designated as fair value hedges of specific fixed-rate FHLB advances, pay-fixed swaps designated as fair value hedges of securities within our available-for-sale portfolio, and pay-fixed swaps designated as fair value hedges of closed portfolios of fixed-rate held-for-investment consumer automotive loan assets in which the hedged item is the last layer expected to be remaining at the end of the hedging relationship. Other derivatives qualifying for hedge accounting consist of pay-fixed swaps designated as cash flow hedges of the expected future cash flows in the form of interest payments on certain variable-rate borrowings and deposit liabilities. We may also execute economic hedges, which consist of interest rate swaps, interest rate caps, forwards, futures, options, and swaptions to mitigate interest rate risk. We also enter into interest rate lock commitments and forward-sale commitments that are executed as part of our mortgage business that meet the accounting definition of a derivative. Foreign Exchange Risk We enter into derivative financial instrument contracts to mitigate the risk associated with variability in cash flows related to our various foreign-currency exposures. We enter into foreign-currency forwards with external counterparties as net investment hedges of foreign exchange exposure on our investment in foreign subsidiaries. Our equity is impacted by the cumulative translation adjustments resulting from the translation of foreign subsidiary results; this impact is reflected in our accumulated other comprehensive loss. We also periodically enter into foreign-currency forwards to economically hedge any foreign-denominated debt, centralized lending, and foreign-denominated third-party loans. These foreign-currency forwards that are used as economic hedges are recorded at fair value with changes recorded as income offsetting the gains and losses on the associated foreign-currency transactions. Equity Risk We enter into equity options to economically hedge our exposure to the equity markets. Counterparty Credit Risk Derivative financial instruments contain an element of credit risk if counterparties are unable to meet the terms of the agreements. Credit risk associated with derivative financial instruments is measured as the net replacement cost should the counterparties that owe us under the contract completely fail to perform under the terms of those contracts, assuming no recoveries of underlying collateral as measured by the market value of the derivative financial instrument. We manage our risk to financial counterparties through internal credit analysis, limits, and monitoring. Additionally, derivatives and repurchase agreements are entered into with approved counterparties using industry standard agreements. The agreements generally require both parties to post collateral in the event the fair values of the derivative financial instruments meet posting thresholds established under the agreements. In the event that either party defaults on the obligation, the secured party may seize the collateral. Generally, our collateral arrangements are bilateral such that we and the counterparty post collateral for the value of our total obligation to each other. Contractual terms provide for standard and customary exchange of collateral based on changes in the market value of the outstanding derivatives. The securing party posts additional collateral when their obligation rises or removes collateral when it falls. These payments are characterized as collateral for over-the-counter (OTC) derivatives. We execute certain derivatives such as interest rate swaps with clearinghouses, which requires us to post and receive collateral. For these clearinghouse derivatives, these payments are recognized as settlements rather than collateral. Certain derivative instruments contain provisions that require us to either post additional collateral or immediately settle any outstanding liability balances upon the occurrence of a specified credit-risk-related event. No such specified credit-risk-related events occurred during the years ended December 31, 2018 , or 2017 . We placed cash collateral totaling $26 million and noncash collateral totaling $105 million supporting our derivative positions at December 31, 2018 , and $20 million and $97 million at December 31, 2017 , respectively, in accounts maintained by counterparties. This amount excludes cash and noncash collateral pledged under repurchase agreements. Refer to Note 15 for details on the repurchase agreements. The receivables for cash collateral placed are included on our Consolidated Balance Sheet in other assets. We received cash collateral from counterparties totaling $30 million and noncash collateral totaling $3 million at December 31, 2018 , and $17 million and $2 million at December 31, 2017 , respectively, in accounts maintained by counterparties. These amounts exclude cash and noncash collateral pledged under repurchase agreements. Refer to Note 15 for details on repurchase agreements. The payables for cash collateral received are included on our Consolidated Balance Sheet in accrued expenses and other liabilities. Included in these amounts is noncash collateral where we have been granted the right to sell or pledge the underlying assets. We have not sold or pledged any of the noncash collateral received under these agreements. Balance Sheet Presentation The following table summarizes the amounts of derivative instruments reported on our Consolidated Balance Sheet . The amounts are presented on a gross basis, are segregated by derivatives that are designated and qualifying as hedging instruments or those that are not, and are further segregated by type of contract within those two categories. Derivative contracts in a receivable and payable position exclude open trade equity on derivatives cleared through central clearing counterparties. Any associated collateral exchanged with our central clearing counterparties are treated as settlements of the derivative exposure, rather than collateral. Such payments are recognized as settlements of the derivatives contracts in a receivable and payable position on our Consolidated Balance Sheet . Notional amounts are reference amounts from which contractual obligations are derived and are not recorded on the balance sheet. In our view, derivative notional is not an accurate measure of our derivative exposure when viewed in isolation from other factors, such as market rate fluctuations and counterparty credit risk. 2018 2017 Derivative contracts in a Notional amount Derivative contracts in a Notional amount December 31, ($ in millions) receivable position payable position receivable position payable position Derivatives designated as accounting hedges Interest rate contracts Swaps $ — $ — $ 24,203 $ — $ — $ 6,915 Foreign exchange contracts Forwards 1 — 136 — 1 136 Total derivatives designated as accounting hedges 1 — 24,339 — 1 7,051 Derivatives not designated as accounting hedges Interest rate contracts Futures and forwards — — 11 — — 23 Written options — 37 6,793 1 39 8,327 Purchased options 37 — 6,742 38 — 8,237 Total interest rate risk 37 37 13,546 39 39 16,587 Foreign exchange contracts Futures and forwards 3 — 181 — 1 124 Total foreign exchange risk 3 — 181 — 1 124 Total derivatives not designated as accounting hedges 40 37 13,727 39 40 16,711 Total derivatives $ 41 $ 37 $ 38,066 $ 39 $ 41 $ 23,762 The following table presents amounts recorded on our Consolidated Balance Sheet related to cumulative basis adjustments for fair value hedges. December 31, ($ in millions) Carrying amount of the hedged items Cumulative amount of fair value hedging adjustment included in the carrying amount of the hedged items Total Discontinued (a) 2018 2017 2018 2017 2018 2017 Assets Available-for-sale securities (b) (c) $ 1,485 $ 173 $ — $ 2 $ (5 ) $ 2 Finance receivables and loans, net (d) 40,850 2,305 24 18 5 19 Liabilities Long-term debt $ 13,001 $ 14,640 $ 67 $ 208 $ 67 $ 235 (a) Represents the fair value hedging adjustment on qualifying hedges for which the hedging relationship was discontinued. This represents a subset of the amounts reported in the total hedging adjustment. (b) The carrying amount of hedged available-for-sale securities is presented above using amortized cost. Refer to Note 8 for a reconciliation of the amortized cost and fair value of available-for-sale securities. (c) Includes the amortized cost basis of closed portfolios used to designate hedging relationships in which the hedged item is the last layer expected to be remaining at the end of the hedging relationship. At December 31, 2018, the amortized cost basis of the closed portfolios used in these hedging relationships was $47 million , there was no basis adjustment associated with the last-of-layer relationships, and the amount identified as the last of layer in the hedge relationship was $28 million . A last-of-layer hedge strategy did not exist at December 31, 2017 . (d) The hedged item represents the carrying value of the hedged portfolio of assets. The amount identified as the last of layer in the hedge relationship was $21.4 billion as of December 31, 2018 . The basis adjustment associated with the last-of-layer relationship was a $19 million asset as of December 31, 2018 , which would be allocated across the entire remaining closed pool upon termination or maturity of the hedge relationship. A last-of-layer hedge strategy did not exist at December 31, 2017 . Statement of Income Presentation The following table summarizes the location and amounts of gains and losses on derivative instruments not designated as accounting hedges reported in our Consolidated Statement of Income . Year ended December 31, ($ in millions) 2018 2017 2016 Gain (loss) recognized in earnings Interest rate contracts Gain on mortgage and automotive loans, net $ — $ 1 $ — Other income, net of losses — (3 ) — Total interest rate contracts — (2 ) — Foreign exchange contracts Interest on long-term debt — — (2 ) Other income, net of losses 13 (7 ) 1 Total foreign exchange contracts 13 (7 ) (1 ) Gain (loss) recognized in earnings $ 13 $ (9 ) $ (1 ) The following table summarizes the location and amounts of gains and losses on derivative instruments designated as fair value and cash flow hedges reported in our Consolidated Statement of Income . Interest and fees on finance receivables and loans Interest and dividends on investment securities and other earning assets Interest on deposits Interest on long-term debt Year ended December 31, ($ in millions) 2018 2017 2016 2018 2017 2016 2018 2017 2016 2018 2017 2016 Gain (loss) on fair value hedging relationships Interest rate contracts Hedged fixed-rate unsecured debt $ — $ — $ — $ — $ — $ — $ — $ — $ — $ 62 $ 8 $ (78 ) Derivatives designated as hedging instruments on fixed-rate unsecured debt — — — — — — — — — (61 ) (3 ) 73 Hedged fixed-rate FHLB advances — — — — — — — — — 47 22 8 Derivatives designated as hedging instruments on fixed-rate FHLB advances — — — — — — — — — (47 ) (22 ) (8 ) Hedged available-for-sale securities — — — (3 ) (1 ) — — — — — — — Derivatives designated as hedging instruments on available-for-sale securities — — — 3 1 — — — — — — — Hedged fixed-rate consumer automotive loans 19 (3 ) — — — — — — — — — — Derivatives designated as hedging instruments on fixed-rate consumer automotive loans (19 ) 1 (2 ) — — — — — — — — — Total (loss) gain on fair value hedging relationships — (2 ) (2 ) — — — — — — 1 5 (5 ) Gain on cash flow hedging relationships Interest rate contracts Hedged deposit liabilities Reclassified from accumulated other comprehensive income into income — — — — — — 1 — — — — — Hedged variable-rate borrowings Reclassified from accumulated other comprehensive income into income — — — — — — — — — 1 — — Total gain on cash flow hedging relationships $ — $ — $ — $ — $ — $ — $ 1 $ — $ — $ 1 $ — $ — Total amounts presented in the Consolidated Statement of Income $ 6,688 $ 5,819 $ 5,162 $ 788 $ 599 $ 418 1,735 $ 1,077 $ 830 $ 1,753 $ 1,653 $ 1,742 During the next twelve months, we estimate $15 million will be reclassified into pretax earnings from derivatives designated as cash flow hedges. The following table summarizes the location and amounts of gains and losses related to interest and amortization on derivative instruments designated as fair value and cash flow hedges reported in our Consolidated Statement of Income . Interest and fees on finance receivables and loans Interest and dividends on investment securities and other earning assets Interest on deposits Interest on long-term debt Year ended December 31, ($ in millions) 2018 2017 2016 2018 2017 2016 2018 2017 2016 2018 2017 2016 Gain (loss) on fair value hedging relationships Interest rate contracts Amortization of deferred unsecured debt basis adjustments $ — $ — $ — $ — $ — $ — $ — $ — $ — $ 51 $ 77 $ 84 Interest for qualifying accounting hedges of unsecured debt — — — — — — — — — 8 24 40 Amortization of deferred secured debt basis adjustments FHLB advances) — — — — — — — — — (17 ) (2 ) — Interest for qualifying accounting hedges of secured debt (FHLB advances) — — — — — — — — — 6 3 5 Interest for qualifying accounting hedges of available-for-sale securities — — — (1 ) — — — — — — — — Amortization of deferred loan basis adjustments (14 ) (21 ) (20 ) — — — — — — — — — Interest for qualifying accounting hedges of consumer automotive loans held-for-investment 16 (1 ) (18 ) — — — — — — — — — Total gain (loss) on fair value hedging relationships 2 (22 ) (38 ) (1 ) — — — — — 48 102 129 Gain (loss) on cash flow hedging relationships Interest rate contracts Interest for qualifying accounting hedges of variable-rate borrowings — — — — — — — — — 8 (1 ) — Interest for qualifying accounting hedges of deposit liabilities — — — — — — 3 — — — — — Total gain (loss) on cash flow hedging relationships $ — $ — $ — $ — $ — $ — $ 3 $ — $ — $ 8 $ (1 ) $ — The following table summarizes the effect of cash flow hedges on accumulated other comprehensive loss. Year ended December 31, ($ in millions) 2018 2017 2016 Interest rate contracts Gain recognized in other comprehensive loss $ 10 $ 5 $ — The following table summarizes the effect of net investment hedges on accumulated other comprehensive loss and the Consolidated Statement of Comprehensive Income . Year ended December 31, ($ in millions) 2018 2017 2016 Foreign exchange contracts (a) (b) Gain (loss) recognized in other comprehensive loss $ 12 $ (10 ) $ 1 (a) There were no amounts excluded from effectiveness testing for the years ended December 31, 2018 , 2017 , or 2016. (b) Gains and losses reclassified from accumulated other comprehensive loss are reported as other income, net of losses, in the Consolidated Statement of Income. There were no amounts reclassified for the years ended December 31, 2018 , 2017 , or 2016.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Tax Disclosure	Income Taxes The significant components of income tax expense from continuing operations were as follows. Year ended December 31, ($ in millions) 2018 2017 2016 Current income tax (benefit) expense U.S. federal $ (12 ) $ (17 ) $ — Foreign 5 6 8 State and local 35 53 9 Total current expense 28 42 17 Deferred income tax expense (benefit) U.S. federal 328 566 423 State and local 3 (27 ) 30 Total deferred expense 331 539 453 Total income tax expense from continuing operations $ 359 $ 581 $ 470 A reconciliation of income tax expense from continuing operations with the amounts at the statutory U.S. federal income tax rate is shown in the following table. Year ended December 31, ($ in millions) 2018 2017 2016 Statutory U.S. federal tax expense (a) $ 340 $ 527 $ 553 Change in tax resulting from Nondeductible expenses 28 4 7 State and local income taxes, net of federal income tax benefit (b) 26 7 35 Tax law enactment (23 ) 119 — Changes in unrecognized tax benefits (c) 22 1 (161 ) Tax credits, excluding expirations (20 ) (12 ) (15 ) Valuation allowance change, excluding expirations (8 ) (49 ) 51 Other, net (6 ) (16 ) — Total income tax expense from continuing operations $ 359 $ 581 $ 470 (a) The statutory U.S. federal tax rate was 21% for 2018 and 35% for both 2017 and 2016. (b) Amount for 2017 includes state deferred tax adjustments primarily offset in the valuation allowance change caption. (c) Amount for 2016 is primarily the result of a U.S. tax reserve release in the second quarter of 2016 related to a prior-year federal return. For the year ended December 31, 2018 , consolidated income tax expense from continuing operations was largely driven by tax attributable to pretax earnings for the year. For the year ended December 31, 2017 , consolidated income tax expense from continuing operations was largely driven by tax attributable to pretax earnings for the year and income tax expense attributable to changes to our net deferred tax assets as a result of the Tax Act, partially offset by changes to our valuation allowance balances related to capital-in-nature deferred tax assets and foreign tax credit carryforwards. For the year ended December 31, 2016 , consolidated income tax expense from continuing operations was largely driven by tax attributable to pretax earnings for the year and the establishment of a valuation allowance on capital loss carryforwards, offset by a reduction in the liability for unrecognized tax benefits that resulted from the completion of a U.S. federal audit related to a prior tax year. As of each reporting date, we consider existing evidence, both positive and negative, that could impact our view with regard to future realization of deferred tax assets. We continue to believe it is more likely than not that the benefit for certain foreign tax credit carryforwards and state net operating loss carryforwards will not be realized. In recognition of this risk, we continue to provide a partial valuation allowance on the deferred tax assets relating to these carryforwards and it is reasonably possible that the valuation allowance may change in the next twelve months. The significant components of deferred tax assets and liabilities are reflected in the following table. December 31, ($ in millions) 2018 2017 Deferred tax assets Tax credit carryforwards $ 1,796 $ 2,002 Adjustments to loan value 366 450 State and local taxes 168 200 Unearned insurance premiums 90 85 Hedging transactions 27 49 Tax loss carryforwards 8 302 Other 222 108 Gross deferred tax assets 2,677 3,196 Valuation allowance (1,057 ) (1,123 ) Deferred tax assets, net of valuation allowance 1,620 2,073 Deferred tax liabilities Lease transactions 850 1,212 Deferred acquisition costs 321 269 Debt transactions 93 95 Other 56 44 Gross deferred tax liabilities 1,320 1,620 Net deferred tax assets (a) $ 300 $ 453 (a) Amounts include $317 million and $461 million of net deferred tax assets included in other assets on our Consolidated Balance Sheet for tax jurisdictions in a total net deferred tax asset position at December 31, 2018 , and 2017 , respectively, and $17 million and $8 million included in accrued expenses and other liabilities on our Consolidated Balance Sheet for tax jurisdictions in a total net deferred tax liability position. The following table summarizes net deferred tax assets including related valuation allowances at December 31, 2018 . ($ in millions) Deferred tax asset (liability) Valuation allowance Net deferred tax asset (liability) Years of expiration Tax credit carryforwards Foreign tax credits $ 1,522 $ (963 ) $ 559 2022–2028 General business credits 274 — 274 2025–2038 Total tax credit carryforwards 1,796 (963 ) 833 Tax loss carryforwards Net operating losses — federal 8 — 8 2027–2036 Net operating losses — state 198 (a) (94 ) 104 2019–2038 Total federal and state tax loss carryforwards 206 (94 ) 112 Other net deferred tax liabilities (645 ) — (645 ) n/a Net deferred tax assets $ 1,357 $ (1,057 ) $ 300 (a) State net operating loss carryforwards are included in the state and local taxes and other liabilities totals disclosed in our deferred inventory table above. As of December 31, 2018 , we continue to not assert that foreign earnings are indefinitely reinvested outside of the United States. Deferred tax liabilities for incremental U.S. tax that stem from temporary differences related to investment in foreign subsidiaries or corporate joint ventures are negligible and have been recognized as of December 31, 2018 . The following table provides a reconciliation of the beginning and ending amount of unrecognized tax benefits. ($ in millions) 2018 2017 2016 Balance at January 1, $ 15 $ 14 $ 185 Additions based on tax positions related to the current year — — — Additions for tax positions of prior years 29 3 12 Reductions for tax positions of prior years — (1 ) — Settlements — — (182 ) Expiration of statute of limitations — (1 ) (1 ) Balance at December 31, $ 44 $ 15 $ 14 Included in the unrecognized tax benefits balances are some items, the recognition of which would not affect the effective tax rate, such as the tax effect of certain temporary differences and the portion of gross state unrecognized tax benefits that would be offset by the tax benefit of the associated federal deduction. At December 31, 2018 , 2017 , and 2016 , the balance of unrecognized tax benefits that, if recognized, would affect our effective tax rate were $34 million , $12 million , and $9 million , respectively. We recognize accrued interest and penalties related to uncertain income tax positions in interest expense and other operating expenses, respectively. For the years ended December 31, 2018 , 2017 , and 2016 , the cumulative accrued balance for interest and penalties was less than $1 million and interest and penalties of $1 million or less were accrued each year. It is reasonably possible that the unrecognized tax benefits will decrease by up to $41 million over the next twelve months if certain tax matters ultimately settle with the applicable taxing jurisdictions. We file tax returns in the U.S. federal jurisdiction and various states and foreign jurisdictions. Our most significant operations are in the United States and Canada. The oldest tax years that remain subject to examination for those jurisdictions are 2015 and 2011, respectively.

Share-based Compensation Plans

Share-based Compensation Plans	12 Months Ended
	Dec. 31, 2018
Share-based Compensation Plans [Abstract]
Compensation and Employee Benefit Plans	Share-based Compensation Plans We grant Restricted Stock Units or Awards (RSUs) and Performance Stock Units or Awards (PSUs) to certain employees under the Ally Financial Inc. Incentive Compensation Plan (AICP). The AICP allows us to grant an array of equity-based and other incentive awards to our named executive officers and other employees. These awards are structured to align with long-term value creation for our stockholders, to provide appropriate incentives for participating employees, and to achieve the other objectives of our compensation philosophy. At December 31, 2018 , we had 34,864,368 shares available for future grants of equity-based awards remaining under the AICP. Our equity-based awards generally settle in Ally common stock and are classified as equity awards under GAAP. The cost of the awards is ratably charged to compensation and benefits expense in our Consolidated Statement of Income over their applicable service period and are based on the grant date fair value of Ally common stock. The awards typically include retirement eligibility and qualifying termination provisions, which fully vest as of the date upon meeting the eligibility requirements and are paid on the original settlement date. PSUs and RSUs PSUs are payable contingent upon Ally achieving certain predefined performance objectives over a two-year measurement period and a three-year service condition. The number of awards payable upon vesting can range from zero to 150% of the grant amount. The PSUs settle in the form of Ally common stock. We accrue dividend equivalents for our PSUs that are paid upon vesting and based on the number of awards payable. RSUs are awarded to employees at no cost to the recipient upon their grant. The compensation costs related to these awards are ratably charged to expense over the applicable service period. The majority of the existing RSUs settle in the form of Ally common stock. RSUs generally vest one third ratably each year over a three-year period starting on the date the award was issued and are converted into shares of common stock as of the vesting date. We accrue dividend equivalents for our RSUs that are paid upon vesting. Ally has awards that vested but were not yet distributed for the years ended December 31, 2018 , 2017 , and 2016 . The following table presents the changes in outstanding non-vested PSUs and RSUs activity during 2018 . (in thousands, except per share data) Number of units Weighted-average grant date fair value per share RSUs and PSUs Outstanding non-vested at January 1, 2018 5,592 $ 19.89 Granted 2,577 29.41 Vested (3,167 ) 21.61 Forfeited (138 ) 23.54 Outstanding non-vested at December 31, 2018 4,864 23.71 We recognized expense related to PSUs and RSUs of $72 million , $60 million , and $54 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively.

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Disclosures	Fair Value Fair Value Measurements For purposes of this disclosure, fair value is defined as the exchange price that would be received to sell an asset or paid to transfer a liability (exit price) in the principal or most advantageous market in an orderly transaction between market participants at the measurement date under current market conditions. Fair value is based on the assumptions we believe market participants would use when pricing an asset or liability. Additionally, entities are required to consider all aspects of nonperformance risk, including the entity’s own credit standing, when measuring the fair value of a liability. Judgment is used in estimating inputs to our internal valuation models used to estimate our Level 3 fair value measurements. Level 3 inputs such as interest rate movements, prepayment speeds, credit losses, and discount rates are inherently difficult to estimate. Changes to these inputs can have a significant effect on fair value measurements and amounts that could be realized. GAAP specifies a three-level hierarchy that is used when measuring and disclosing fair value. The fair value hierarchy gives the highest priority to quoted prices available in active markets (i.e., observable inputs) and the lowest priority to data lacking transparency (i.e., unobservable inputs). An instrument’s categorization within the fair value hierarchy is based on the lowest level of significant input to its valuation. The following is a description of the three hierarchy levels. Level 1 Inputs are quoted prices in active markets for identical assets or liabilities at the measurement date. Additionally, the entity must have the ability to access the active market, and the quoted prices cannot be adjusted by the entity. Level 2 Inputs are other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices in active markets for similar assets or liabilities; quoted prices in inactive markets for identical or similar assets or liabilities; or inputs that are observable or can be corroborated by observable market data by correlation or other means for substantially the full term of the assets or liabilities. Level 3 Unobservable inputs are supported by little or no market activity. The unobservable inputs represent management’s best assumptions of how market participants would price the assets or liabilities. Generally, Level 3 assets and liabilities are valued using pricing models, discounted cash flow methodologies, or similar techniques that require significant judgment or estimation. The following are descriptions of the valuation methodologies used to measure material assets and liabilities at fair value and details of the valuation models, key inputs to those models, and significant assumptions utilized. • Equity Securities — Includes various marketable equity securities measured at fair value with changes in fair value recognized in net income. Measurements based on observable market prices are classified as Level 1. • Available-for-sale securities — All classes of available-for-sale securities are carried at fair value based on observable market prices, when available. If observable market prices are not available, our valuations are based on internally developed discounted cash flow models (an income approach) that use a market-based discount rate and consider recent market transactions, experience with similar securities, current business conditions, and analysis of the underlying collateral, as available. To estimate cash flows, we are required to utilize various significant assumptions including market observable inputs (e.g., forward interest rates) and internally developed inputs (including prepayment speeds, delinquency levels, and credit losses). • Interests retained in financial asset sales — Includes certain noncertificated interests retained from the sale of automotive finance receivables. Due to inactivity in the market, valuations are based on internally developed discounted cash flow models (an income approach) that use a market-based discount rate; therefore, we classified these assets as Level 3. The valuation considers recent market transactions, experience with similar assets, current business conditions, and analysis of the underlying collateral, as available. To estimate cash flows, we utilize various significant assumptions, including market observable inputs (e.g., forward interest rates) and internally developed inputs (e.g., prepayment speeds, delinquency levels, and credit losses). • Derivative instruments — We enter into a variety of derivative financial instruments as part of our risk-management strategies. Certain of these derivatives are exchange traded, such as Eurodollar futures, options of Eurodollar futures, and equity options. To determine the fair value of these instruments, we utilize the quoted market prices for the particular derivative contracts; therefore, we classified these contracts as Level 1. We also execute OTC and centrally-cleared derivative contracts, such as interest rate swaps, swaptions, foreign-currency denominated forward contracts, caps, floors, and agency to-be-announced securities. We utilize third-party-developed valuation models that are widely accepted in the market to value these derivative contracts. The specific terms of the contract and market observable inputs (such as interest rate forward curves, interpolated volatility assumptions, or equity pricing) are used in the model. We classified these derivative contracts as Level 2 because all significant inputs into these models were market observable. We also enter into interest rate lock commitments and forward-sale commitments that are executed as part of our mortgage business, certain of which meet the accounting definition of a derivative and therefore are recorded as derivatives on our Consolidated Balance Sheet . Because these derivatives are valued using internal pricing models with unobservable inputs, they are classified as Level 3. We are required to consider all aspects of nonperformance risk, including our own credit standing, when measuring fair value of a liability. We reduce credit risk on the majority of our derivatives by entering into legally enforceable agreements that enable the posting and receiving of collateral associated with the fair value of our derivative positions on an ongoing basis. In the event that we do not enter into legally enforceable agreements that enable the posting and receiving of collateral, we will consider our credit risk and the credit risk of our counterparties in the valuation of derivative instruments through a credit valuation adjustment (CVA), if warranted. The CVA calculation utilizes the credit default swap spreads of the counterparty. Recurring Fair Value The following tables display the assets and liabilities measured at fair value on a recurring basis including financial instruments elected for the fair value option. We often economically hedge the fair value change of our assets or liabilities with derivatives and other financial instruments. The tables below display the hedges separately from the hedged items; therefore, they do not directly display the impact of our risk-management activities. Recurring fair value measurements December 31, 2018 ($ in millions) Level 1 Level 2 Level 3 Total Assets Investment securities Equity securities (a) $ 766 $ — $ 7 $ 773 Available-for-sale securities Debt securities U.S. Treasury and federal agencies 1,850 1 — 1,851 U.S. States and political subdivisions — 802 — 802 Foreign government 7 138 — 145 Agency mortgage-backed residential — 17,138 — 17,138 Mortgage-backed residential — 2,686 — 2,686 Mortgage-backed commercial — 717 — 717 Asset-backed — 723 — 723 Corporate debt — 1,241 — 1,241 Total available-for-sale securities 1,857 23,446 — 25,303 Mortgage loans held-for-sale (b) — — 8 8 Interests retained in financial asset sales — — 4 4 Derivative contracts in a receivable position Interest rate — 37 — 37 Foreign currency — 4 — 4 Total derivative contracts in a receivable position — 41 — 41 Total assets $ 2,623 $ 23,487 $ 19 $ 26,129 Liabilities Accrued expenses and other liabilities Derivative contracts in a payable position Interest rate $ — $ 37 $ — $ 37 Total derivative contracts in a payable position — 37 — 37 Total liabilities $ — $ 37 $ — $ 37 (a) Our investment in any one industry did not exceed 9% . (b) Carried at fair value due to fair value option elections. Recurring fair value measurements December 31, 2017 ($ in millions) Level 1 Level 2 Level 3 Total Assets Investment securities Equity securities (a) $ 518 $ — $ — $ 518 Available-for-sale securities Debt securities U.S. Treasury 1,777 — — 1,777 U.S. States and political subdivisions — 854 — 854 Foreign government 8 146 — 154 Agency mortgage-backed residential — 14,291 — 14,291 Mortgage-backed residential — 2,494 — 2,494 Mortgage-backed commercial — 541 — 541 Asset-backed — 936 — 936 Corporate debt — 1,256 — 1,256 Total available-for-sale securities 1,785 20,518 — 22,303 Mortgage loans held-for-sale (b) — — 13 13 Interests retained in financial asset sales — — 5 5 Derivative contracts in a receivable position Interest rate — 38 1 39 Total derivative contracts in a receivable position — 38 1 39 Total assets $ 2,303 $ 20,556 $ 19 $ 22,878 Liabilities Accrued expenses and other liabilities Derivative contracts in a payable position Interest rate $ — $ 39 $ — $ 39 Foreign currency — 2 — 2 Total derivative contracts in a payable position — 41 — 41 Total liabilities $ — $ 41 $ — $ 41 (a) Our investment in any one industry did not exceed 14% . (b) Carried at fair value due to fair value option elections. The following tables present the reconciliation for all Level 3 assets and liabilities measured at fair value on a recurring basis. There were no transfers into or out of Level 3 in the periods presented. We often economically hedge the fair value change of our assets or liabilities with derivatives and other financial instruments. The Level 3 items presented below may be hedged by derivatives and other financial instruments that are classified as Level 1 or Level 2. Thus, the following tables do not fully reflect the impact of our risk-management activities. Level 3 recurring fair value measurements Net realized/unrealized (losses) gains Fair value at Dec. 31, 2018 Net unrealized losses still held at December 31, 2018 ($ in millions) Fair value at Jan. 1, 2018 included in earnings included in OCI Purchases Sales Issuances Settlements included in earnings included in OCI Assets Equity securities (a) $ 19 $ (7 ) (b) $ — $ — $ — $ — $ (5 ) $ 7 $ (10 ) $ — Mortgage loans held-for-sale (c) 13 5 (d) — 303 (313 ) — — 8 — — Other assets Interests retained in financial asset sales 5 — — — — — (1 ) 4 — — Derivative assets 1 (1 ) (d) — — — — — — — — Total assets $ 38 $ (3 ) $ — $ 303 $ (313 ) $ — $ (6 ) $ 19 $ (10 ) $ — (a) In connection with our adoption of ASU 2016-01 on January 1, 2018, certain of our equity securities previously measured using the cost method of accounting are now measured at fair value on a recurring basis, and have been categorized as Level 3 within the fair value hierarchy. Accordingly, the fair value of such investments has been included in the opening balance of the reconciliation above. (b) Reported as other gain on investments, net, in the Consolidated Statement of Income. (c) Carried at fair value due to fair value option elections. (d) Reported as gain on mortgage and automotive loans, net, in the Consolidated Statement of Income. Level 3 recurring fair value measurements Fair value at Jan. 1, 2017 Net realized/unrealized gains Purchases Sales Issuances Settlements Fair value at Dec. 31, 2017 Net unrealized gains included in earnings still held at Dec. 31, 2017 ($ in millions) included in earnings included in OCI Assets Mortgage loans held-for-sale (a) $ — $ 2 (b) $ — $ 137 $ (126 ) $ — $ — $ 13 $ — Other assets Interests retained in financial asset sales 29 1 (c) — — 8 — (33 ) 5 — Derivative assets — 1 (b) — — — — — 1 1 Total assets $ 29 $ 4 $ — $ 137 $ (118 ) $ — $ (33 ) $ 19 $ 1 (a) Carried at fair value due to fair value option elections. (b) Reported as gain on mortgage and automotive loans, net, in the Consolidated Statement of Income. (c) Reported as other income, net of losses, in the Consolidated Statement of Income. Nonrecurring Fair Value We may be required to measure certain assets and liabilities at fair value from time to time. These periodic fair value measures typically result from the application of lower-of-cost or fair value accounting or certain impairment measures. These items would constitute nonrecurring fair value measures. The following tables display assets and liabilities measured at fair value on a nonrecurring basis and still held at December 31, 2018 , and 2017, respectively. The amounts are as of the end of each period presented, which approximate the fair value measurements that occurred during each period. Nonrecurring fair value measurements Lower-of-cost or fair value or valuation reserve allowance Total gain (loss) included in earnings December 31, 2018 ($ in millions) Level 1 Level 2 Level 3 Total Assets Loans held-for-sale, net Automotive (a) $ — $ — $ 210 $ 210 $ (2 ) n/m (b) Other — — 96 96 — n/m (b) Total loans held-for-sale, net — — 306 306 (2 ) n/m (b) Commercial finance receivables and loans, net (c) Automotive — — 84 84 (10 ) n/m (b) Other — — 55 55 (46 ) n/m (b) Total commercial finance receivables and loans, net — — 139 139 (56 ) n/m (b) Other assets Nonmarketable equity investments — — 1 1 (1 ) n/m (b) Equity-method investments — — 3 3 — n/m (b) Repossessed and foreclosed assets (d) — — 13 13 (1 ) n/m (b) Total assets $ — $ — $ 462 $ 462 $ (60 ) n/m n/m = not meaningful (a) Represents loans within our commercial automotive portfolio. Of this amount, $104 million was valued based upon a sales price for a transaction that closed in January 2019, and $106 million was valued using a discounted cash flow analysis, with a spread over forward interest rates as a significant unobservable input utilizing a range of 0.08 – 1.09 % and weighted average of 0.72 %. (b) We consider the applicable valuation or loan loss allowance to be the most relevant indicator of the impact on earnings caused by the fair value measurement. Accordingly, the table above excludes total gains and losses included in earnings for these items. The carrying values are inclusive of the respective valuation or loan loss allowance. (c) Represents the portion of the portfolio specifically impaired during 2018 . The related valuation allowance represents the cumulative adjustment to fair value of those specific receivables. (d) The allowance provided for repossessed and foreclosed assets represents any cumulative valuation adjustment recognized to adjust the assets to fair value. Nonrecurring fair value measurements Lower-of-cost or fair value or valuation reserve allowance Total gain (loss) included in earnings December 31, 2017 ($ in millions) Level 1 Level 2 Level 3 Total Assets Loans held-for-sale, net $ — $ — $ 77 $ 77 $ — n/m (a) Commercial finance receivables and loans, net (b) Automotive — — 20 20 (3 ) n/m (a) Other — — 22 22 (12 ) n/m (a) Total commercial finance receivables and loans, net — — 42 42 (15 ) n/m (a) Other assets Repossessed and foreclosed assets (c) — — 14 14 (1 ) n/m (a) Other — — 3 3 — n/m (a) Total assets $ — $ — $ 136 $ 136 $ (16 ) n/m n/m = not meaningful (a) We consider the applicable valuation or loan loss allowance to be the most relevant indicator of the impact on earnings caused by the fair value measurement. Accordingly, the table above excludes total gains and losses included in earnings for these items. The carrying values are inclusive of the respective valuation or loan loss allowance. (b) Represents the portion of the portfolio specifically impaired during 2017 . The related valuation allowance represents the cumulative adjustment to fair value of those specific receivables. (c) The allowance provided for repossessed and foreclosed assets represents any cumulative valuation adjustment recognized to adjust the assets to fair value. Fair Value Option for Financial Assets We elected the fair value option for an insignificant amount of conforming mortgage loans held-for-sale. We elected the fair value option to mitigate earnings volatility by better matching the accounting for the assets with the related derivatives. Our intent in electing fair value measurement was to mitigate a divergence between accounting gains or losses and economic exposure for certain assets and liabilities. Fair Value of Financial Instruments The following table presents the carrying and estimated fair value of financial instruments, except for those recorded at fair value on a recurring basis presented in the previous section of this note titled Recurring Fair Value. When possible, we use quoted market prices to determine fair value. Where quoted market prices are not available, the fair value is internally derived based on appropriate valuation methodologies with respect to the amount and timing of future cash flows and estimated discount rates. However, considerable judgment is required in interpreting current market data to develop the market assumptions and inputs necessary to estimate fair value. As such, the actual amount received to sell an asset or the amount paid to settle a liability could differ from our estimates. Fair value information presented herein was based on information available at December 31, 2018 , and December 31, 2017 . Estimated fair value ($ in millions) Carrying value Level 1 Level 2 Level 3 Total December 31, 2018 Financial assets Held-to-maturity securities $ 2,362 $ — $ 2,307 $ — $ 2,307 Loans held-for-sale, net 306 — — 306 306 Finance receivables and loans, net 128,684 — — 130,878 130,878 FHLB/FRB stock (a) 1,351 — 1,351 — 1,351 Financial liabilities Deposit liabilities (b) $ 51,985 $ — $ — $ 51,997 $ 51,997 Short-term borrowings 9,987 — — 9,992 9,992 Long-term debt 44,193 — 23,846 21,800 45,646 December 31, 2017 Financial assets Held-to-maturity securities $ 1,899 $ — $ 1,865 $ — $ 1,865 Loans held-for-sale, net 95 — — 95 95 Finance receivables and loans, net 121,617 — — 123,302 123,302 Nonmarketable equity investments 1,233 — 1,190 49 1,239 Financial liabilities Deposit liabilities (b) $ 45,869 $ — $ — $ 45,827 $ 45,827 Short-term borrowings 11,413 — — 11,417 11,417 Long-term debt 44,226 — 27,807 18,817 46,624 (a) Included in other assets (nonmarketable equity investments) on our Consolidated Balance Sheet. (b) In connection with our adoption of ASU 2016-01 on January 1, 2018, deposit liabilities with no defined or contractual maturities are no longer included in the table above. Amounts for December 31, 2017, have been adjusted to conform to the current presentation and exclude $47.4 billion and $45.2 billion of deposit liabilities with no defined or contractual maturities from the carrying value and Level 3 fair value, respectively. Refer to Note 14 for information regarding the composition of our deposits portfolio, and Note 1 for further information regarding recently adopted accounting standards.

Offsetting Assets and Liabiliti

Offsetting Assets and Liabilities	12 Months Ended
	Dec. 31, 2018
Offsetting Assets and Liabilities [Abstract]
Offsetting Assets and Liabilities	Offsetting Assets and Liabilities Our derivative contracts and repurchase/reverse repurchase transactions are supported by qualifying master netting and master repurchase agreements. These agreements are legally enforceable bilateral agreements that (i) create a single legal obligation for all individual transactions covered by the agreement to the nondefaulting entity upon an event of default of the counterparty, including bankruptcy, insolvency, or similar proceeding, and (ii) provide the nondefaulting entity the right to accelerate, terminate, and close-out on a net basis all transactions under the agreement and to liquidate or set off collateral promptly upon an event of default of the counterparty. To further mitigate the risk of counterparty default related to derivative instruments, we maintain collateral agreements with certain counterparties. The agreements require both parties to maintain collateral in the event the fair values of the derivative financial instruments meet established thresholds. In the event that either party defaults on the obligation, the secured party may seize the collateral. Generally, our collateral arrangements are bilateral such that we and the counterparty post collateral for the obligation. Contractual terms provide for standard and customary exchange of collateral based on changes in the market value of the outstanding derivatives. A party posts additional collateral when their obligation rises or removes collateral when it falls, such that the net replacement cost of the nondefaulting party is covered in the event of counterparty default. In certain instances as it relates to our derivative instruments, we have the option to report derivative assets and liabilities as well as assets and liabilities associated with cash collateral received or delivered that is governed by a master netting agreement on a net basis as long as certain qualifying criteria are met. Similarly, for our repurchase/reverse repurchase transactions, we have the option to report recognized assets and liabilities subject to a master netting agreement on a net basis if certain qualifying criteria are met. At December 31, 2018 , these instruments are reported as gross assets and gross liabilities on the Consolidated Balance Sheet . The composition of offsetting derivative instruments, financial assets, and financial liabilities was as follows. Gross amounts of recognized assets/liabilities Gross amounts offset on the Consolidated Balance Sheet Net amounts of assets/liabilities presented on the Consolidated Balance Sheet Gross amounts not offset on the Consolidated Balance Sheet December 31, 2018 ($ in millions) Financial instruments Collateral (a) (b) (c) Net amount Assets Derivative assets in net asset positions (d) $ 41 $ — $ 41 $ — $ (4 ) $ 37 Total assets $ 41 $ — $ 41 $ — $ (4 ) $ 37 Liabilities Derivative liabilities in net liability positions (d) $ 37 $ — $ 37 $ — $ — $ 37 Securities sold under agreements to repurchase (e) 685 — 685 — (685 ) — Total liabilities $ 722 $ — $ 722 $ — $ (685 ) $ 37 (a) Financial collateral received/pledged shown as a balance based on the sum of all net asset and liability positions between Ally and each individual derivative counterparty. (b) Amounts disclosed are limited to the financial asset or liability balance and, accordingly, exclude excess collateral received or pledged and noncash collateral received. There was $3 million of noncash derivative collateral, and $4 million of noncash collateral associated with our repurchase agreements, pledged to us that was excluded at December 31, 2018 . We do not record such collateral received on our Consolidated Balance Sheet unless certain conditions are met. (c) Certain agreements grant us the right to sell or pledge the noncash assets we receive as collateral. Noncash collateral pledged to us where the agreement grants us the right to sell or pledge the underlying assets had a fair value of $7 million at December 31, 2018 . We have not sold or pledged any of the noncash collateral received under these agreements as of December 31, 2018 . (d) For additional information on derivative instruments and hedging activities, refer to Note 21 . (e) For additional information on securities sold under agreements to repurchase, refer to Note 15 . Gross amounts of recognized assets/liabilities Gross amounts offset on the Consolidated Balance Sheet Net amounts of assets/liabilities presented on the Consolidated Balance Sheet Gross amounts not offset on the Consolidated Balance Sheet December 31, 2017 ($ in millions) Financial instruments Collateral (a) (b) (c) Net amount Assets Derivative assets in net asset positions $ 38 $ — $ 38 $ — $ — $ 38 Derivative assets with no offsetting arrangements 1 — 1 — — 1 Total assets (d) $ 39 $ — $ 39 $ — $ — $ 39 Liabilities Derivative liabilities in net liability positions (d) $ 41 $ — $ 41 $ — $ (1 ) $ 40 Securities sold under agreements to repurchase (e) 892 — 892 — (892 ) — Total liabilities $ 933 $ — $ 933 $ — $ (893 ) $ 40 (a) Financial collateral received/pledged shown as a balance based on the sum of all net asset and liability positions between Ally and each individual derivative counterparty. (b) Amounts disclosed are limited to the financial asset or liability balance and, accordingly, exclude excess collateral received or pledged and noncash collateral received. There was $2 million of noncash derivative collateral pledged to us that was excluded at December 31, 2017 . We do not record such collateral received on our Consolidated Balance Sheet unless certain conditions are met. (c) Certain agreements grant us the right to sell or pledge the noncash assets we receive as collateral. Noncash collateral pledged to us where the agreement grants us the right to sell or pledge the underlying assets had a fair value of $2 million at December 31, 2017 . We have not sold or pledged any of the noncash collateral received under these agreements as of December 31, 2017 . (d) For additional information on derivative instruments and hedging activities, refer to Note 21 . (e) For additional information on securities sold under agreements to repurchase, refer to Note 15 .

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Segment Reporting Disclosure	Segment Information Operating segments are defined as components of an enterprise that engage in business activity from which revenues are earned and expenses incurred for which discrete financial information is available that is evaluated regularly by our chief operating decision maker in deciding how to allocate resources and in assessing performance. We report our results of operations on a business-line basis through four operating segments: Automotive Finance operations, Insurance operations, Mortgage Finance operations, and Corporate Finance operations, with the remaining activity reported in Corporate and Other. The operating segments are determined based on the products and services offered, and reflect the manner in which financial information is currently evaluated by management. The following is a description of each of our reportable operating segments. Automotive Finance operations — One of the largest full service automotive finance operations in the United States providing automotive financing services to consumers, automotive dealers, companies, and municipalities. Our automotive finance services include providing retail installment sales contracts, loans and operating leases, offering term loans to dealers, financing dealer floorplans and other lines of credit to dealers, warehouse lines to automotive retailers, fleet financing, providing financing to companies and municipalities for the purchase or lease of vehicles, and vehicle-remarketing services. Insurance operations — A complementary automotive-focused business offering both consumer finance protection and insurance products sold primarily through the automotive dealer channel, and commercial insurance products sold directly to dealers. As part of our focus on offering dealers a broad range of consumer financial and insurance products, we provide VSCs, VMCs, and GAP products. We also underwrite select commercial insurance coverages, which primarily insure dealers’ vehicle inventory. Mortgage Finance operations — Primarily consists of the management of a held-for-investment consumer mortgage finance loan portfolio, which includes bulk purchases of high-quality jumbo and LMI mortgage loans originated by third parties. In late 2016, we introduced our direct-to-consumer mortgage offering, named Ally Home, consisting of a variety of jumbo and conforming fixed- and adjustable-rate mortgage products with the assistance of a third-party fulfillment provider. Jumbo mortgage loans are generally held on our balance sheet and are accounted for as held-for-investment. Conforming mortgage loans are generally originated as held-for-sale and then sold to the fulfillment provider , and we retain no mortgage servicing rights associated with those loans that are sold. Corporate Finance operations — Primarily provides senior secured leveraged cash flow and asset-based loans to mostly U.S.-based middle-market companies. Our primary focus is on businesses owned by private equity sponsors with loans typically used for leveraged buyouts, mergers and acquisitions, debt refinancing, restructurings, and working capital. In 2017, we introduced a commercial real estate product to serve companies in the healthcare industry. Corporate and Other primarily consists of centralized corporate treasury activities such as management of the cash and corporate investment securities and loan portfolios, short- and long-term debt, retail and brokered deposit liabilities, derivative instruments, original issue discount, and the residual impacts of our corporate funds-transfer pricing (FTP) and treasury asset liability management (ALM) activities. Corporate and Other also includes certain equity investments, which primarily consist of FHLB and FRB stock, the management of our legacy mortgage portfolio, which primarily consists of loans originated prior to January 1, 2009, and reclassifications and eliminations between the reportable operating segments. Additionally, financial results related to Ally Invest are currently included within Corporate and Other. We utilize an FTP methodology for the majority of our business operations. The FTP methodology assigns charge rates and credit rates to classes of assets and liabilities based on expected duration and the benchmark rate curve plus an assumed credit spread. Matching duration allocates interest income and interest expense to these reportable segments so their respective results are insulated from interest rate risk. This methodology is consistent with our ALM practices, which includes managing interest rate risk centrally at a corporate level. The net residual impact of the FTP methodology is included within the results of Corporate and Other. The information presented in our reportable operating segments is based in part on internal allocations, which involve management judgment. Financial information for our reportable operating segments is summarized as follows. Year ended December 31, ($ in millions) Automotive Finance operations Insurance operations Mortgage Finance operations Corporate Finance operations Corporate and Other Consolidated (a) 2018 Net financing revenue and other interest income $ 3,769 $ 54 $ 179 $ 204 $ 184 $ 4,390 Other revenue 269 981 7 38 119 1,414 Total net revenue 4,038 1,035 186 242 303 5,804 Provision for loan losses 920 — 1 12 (15 ) 918 Total noninterest expense 1,750 955 140 86 333 3,264 Income (loss) from continuing operations before income tax expense $ 1,368 $ 80 $ 45 $ 144 $ (15 ) $ 1,622 Total assets $ 117,304 $ 7,734 $ 15,211 $ 4,670 $ 33,950 $ 178,869 2017 Net financing revenue and other interest income $ 3,713 $ 59 $ 132 $ 167 $ 150 $ 4,221 Other revenue 355 1,059 4 45 81 1,544 Total net revenue 4,068 1,118 136 212 231 5,765 Provision for loan losses 1,134 — 8 22 (16 ) 1,148 Total noninterest expense 1,714 950 108 76 262 3,110 Income (loss) from continuing operations before income tax expense $ 1,220 $ 168 $ 20 $ 114 $ (15 ) $ 1,507 Total assets $ 114,089 $ 7,464 $ 11,708 $ 3,979 $ 29,908 $ 167,148 2016 Net financing revenue and other interest income (loss) $ 3,665 $ 61 $ 97 $ 121 $ (37 ) $ 3,907 Other revenue 306 1,036 — 26 162 1,530 Total net revenue 3,971 1,097 97 147 125 5,437 Provision for loan losses 924 — (4 ) 10 (13 ) 917 Total noninterest expense 1,667 940 67 66 199 2,939 Income (loss) from continuing operations before income tax expense $ 1,380 $ 157 $ 34 $ 71 $ (61 ) $ 1,581 Total assets $ 116,347 $ 7,172 $ 8,307 $ 3,183 $ 28,719 $ 163,728 (a) Net financing revenue and other interest income after the provision for loan losses totaled $3.5 billion , $3.1 billion , and $3.0 billion for the years ended December 31, 2018 , 2017 , and 2016 , respectively.

Parent and Guarantor Condensed

Parent and Guarantor Condensed Consolidating Financial Statements	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Financial Statements	Parent and Guarantor Consolidating Financial Statements Certain of our senior notes issued by the parent are guaranteed by 100% directly owned subsidiaries of Ally (the Guarantors). As of December 31, 2018 , the Guarantors include Ally US LLC and IB Finance Holding Company, LLC (IB Finance), each of which fully and unconditionally guarantee the senior notes on a joint and several basis. The following financial statements present condensed consolidating financial data for (i) Ally Financial Inc. (on a parent company-only basis); (ii) the Guarantors; (iii) the nonguarantor subsidiaries (all other subsidiaries); and (iv) a column for adjustments to arrive at (v) the information for the parent company, the Guarantors, and nonguarantors on a consolidated basis. Investment in subsidiaries is accounted for by the parent company and the Guarantors using the equity method for this presentation. Results of operations of subsidiaries are therefore classified in the parent company’s and Guarantors’ investment in subsidiaries accounts. The elimination entries set forth in the following condensed consolidating financial statements eliminate distributed and undistributed income of subsidiaries, investment in subsidiaries, and intercompany balances and transactions between the parent, the Guarantors, and nonguarantors. Condensed Consolidating Statements of Comprehensive Income Year ended December 31, 2018 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing revenue and other interest income Interest and fees on finance receivables and loans $ (40 ) $ — $ 6,728 $ — $ 6,688 Interest and fees on finance receivables and loans — intercompany 12 — 5 (17 ) — Interest on loans held-for-sale — — 15 — 15 Interest and dividends on investment securities and other earning assets — — 789 (1 ) 788 Interest on cash and cash equivalents 8 — 64 — 72 Interest-bearing cash — intercompany 8 — 9 (17 ) — Operating leases 5 — 1,484 — 1,489 Total financing (loss) revenue and other interest income (7 ) — 9,094 (35 ) 9,052 Interest expense Interest on deposits — — 1,735 — 1,735 Interest on short-term borrowings 44 — 105 — 149 Interest on long-term debt 1,009 — 744 — 1,753 Interest on intercompany debt 15 — 20 (35 ) — Total interest expense 1,068 — 2,604 (35 ) 3,637 Net depreciation expense on operating lease assets 8 — 1,017 — 1,025 Net financing (loss) revenue (1,083 ) — 5,473 — 4,390 Cash dividends from subsidiaries Bank subsidiary 2,600 2,600 — (5,200 ) — Nonbank subsidiaries 443 — — (443 ) — Other revenue Insurance premiums and service revenue earned — — 1,022 — 1,022 Gain on mortgage and automotive loans, net 70 — 9 (54 ) 25 Other gain on investments, net — — (50 ) — (50 ) Other income, net of losses 411 — 770 (764 ) 417 Total other revenue 481 — 1,751 (818 ) 1,414 Total net revenue 2,441 2,600 7,224 (6,461 ) 5,804 Provision for loan losses 176 — 796 (54 ) 918 Noninterest expense Compensation and benefits expense 83 — 1,072 — 1,155 Insurance losses and loss adjustment expenses — — 295 — 295 Other operating expenses 681 — 1,897 (764 ) 1,814 Total noninterest expense 764 — 3,264 (764 ) 3,264 Income from continuing operations before income tax (benefit) expense and undistributed (loss) income of subsidiaries 1,501 2,600 3,164 (5,643 ) 1,622 Income tax (benefit) expense from continuing operations (300 ) — 659 — 359 Net income from continuing operations 1,801 2,600 2,505 (5,643 ) 1,263 (Loss) income from discontinued operations, net of tax (2 ) — 2 — — Undistributed (loss) income of subsidiaries Bank subsidiary (614 ) (614 ) — 1,228 — Nonbank subsidiaries 78 — — (78 ) — Net income 1,263 1,986 2,507 (4,493 ) 1,263 Other comprehensive loss, net of tax (289 ) (243 ) (308 ) 551 (289 ) Comprehensive income $ 974 $ 1,743 $ 2,199 $ (3,942 ) $ 974 Year ended December 31, 2017 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing revenue and other interest income Interest and fees on finance receivables and loans $ (27 ) $ — $ 5,846 $ — $ 5,819 Interest and fees on finance receivables and loans — intercompany 12 — 6 (18 ) — Interest and dividends on investment securities and other earning assets — — 601 (2 ) 599 Interest on cash and cash equivalents 7 — 30 — 37 Interest-bearing cash — intercompany 4 — 7 (11 ) — Operating leases 11 — 1,856 — 1,867 Total financing revenue and other interest income 7 — 8,346 (31 ) 8,322 Interest expense Interest on deposits 3 — 1,078 (4 ) 1,077 Interest on short-term borrowings 60 — 67 — 127 Interest on long-term debt 1,101 — 552 — 1,653 Interest on intercompany debt 15 — 12 (27 ) — Total interest expense 1,179 — 1,709 (31 ) 2,857 Net depreciation expense on operating lease assets 11 — 1,233 — 1,244 Net financing (loss) revenue (1,183 ) — 5,404 — 4,221 Cash dividends from subsidiaries Bank subsidiary 3,300 3,300 — (6,600 ) — Nonbank subsidiaries 752 — — (752 ) — Other revenue Insurance premiums and service revenue earned — — 973 — 973 Gain on mortgage and automotive loans, net 40 — 28 — 68 Other gain on investments, net — — 102 — 102 Other income, net of losses 675 — 834 (1,108 ) 401 Total other revenue 715 — 1,937 (1,108 ) 1,544 Total net revenue 3,584 3,300 7,341 (8,460 ) 5,765 Provision for loan losses 465 — 683 — 1,148 Noninterest expense Compensation and benefits expense 180 — 915 — 1,095 Insurance losses and loss adjustment expenses — — 332 — 332 Other operating expenses 899 — 1,892 (1,108 ) 1,683 Total noninterest expense 1,079 — 3,139 (1,108 ) 3,110 Income from continuing operations before income tax expense and undistributed (loss) income of subsidiaries 2,040 3,300 3,519 (7,352 ) 1,507 Income tax expense from continuing operations 337 — 244 — 581 Net income from continuing operations 1,703 3,300 3,275 (7,352 ) 926 Income (loss) from discontinued operations, net of tax 7 — (4 ) — 3 Undistributed (loss) income of subsidiaries Bank subsidiary (1,168 ) (1,168 ) — 2,336 — Nonbank subsidiaries 387 — — (387 ) — Net income 929 2,132 3,271 (5,403 ) 929 Other comprehensive income, net of tax 106 65 104 (169 ) 106 Comprehensive income $ 1,035 $ 2,197 $ 3,375 $ (5,572 ) $ 1,035 Year ended December 31, 2016 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing revenue and other interest income Interest and fees on finance receivables and loans $ (104 ) $ — $ 5,266 $ — $ 5,162 Interest and fees on finance receivables and loans — intercompany 11 — 8 (19 ) — Interest and dividends on investment securities and other earning assets — — 421 (3 ) 418 Interest on cash and cash equivalents 5 — 9 — 14 Interest-bearing cash — intercompany — — 9 (9 ) — Operating leases 17 — 2,694 — 2,711 Total financing (loss) revenue and other interest income (71 ) — 8,407 (31 ) 8,305 Interest expense Interest on deposits 8 — 822 — 830 Interest on short-term borrowings 40 — 17 — 57 Interest on long-term debt 1,161 — 581 — 1,742 Interest on intercompany debt 20 — 11 (31 ) — Total interest expense 1,229 — 1,431 (31 ) 2,629 Net depreciation expense on operating lease assets 14 — 1,755 — 1,769 Net financing (loss) revenue (1,314 ) — 5,221 — 3,907 Cash dividends from subsidiaries Nonbank subsidiaries 965 — — (965 ) — Other revenue Insurance premiums and service revenue earned — — 945 — 945 (Loss) gain on mortgage and automotive loans, net (11 ) — 22 — 11 Other gain on investments, net — — 176 9 185 Other income, net of losses 1,250 — 935 (1,796 ) 389 Total other revenue 1,239 — 2,078 (1,787 ) 1,530 Total net revenue 890 — 7,299 (2,752 ) 5,437 Provision for loan losses 408 — 509 — 917 Noninterest expense Compensation and benefits expense 573 — 419 — 992 Insurance losses and loss adjustment expenses — — 342 — 342 Other operating expenses 1,261 — 2,130 (1,786 ) 1,605 Total noninterest expense 1,834 — 2,891 (1,786 ) 2,939 (Loss) income from continuing operations before income tax (benefit) expense and undistributed income (loss) of subsidiaries (1,352 ) — 3,899 (966 ) 1,581 Income tax (benefit) expense from continuing operations (279 ) (82 ) 831 — 470 Net (loss) income from continuing operations (1,073 ) 82 3,068 (966 ) 1,111 Loss from discontinued operations, net of tax (39 ) — (5 ) — (44 ) Undistributed income (loss) of subsidiaries Bank subsidiary 1,273 1,273 — (2,546 ) — Nonbank subsidiaries 906 (2 ) — (904 ) — Net income 1,067 1,353 3,063 (4,416 ) 1,067 Other comprehensive loss, net of tax (110 ) (63 ) (106 ) 169 (110 ) Comprehensive income $ 957 $ 1,290 $ 2,957 $ (4,247 ) $ 957 Condensed Consolidating Balance Sheet December 31, 2018 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Assets Cash and cash equivalents Noninterest-bearing $ 55 $ — $ 755 $ — $ 810 Interest-bearing 5 — 3,722 — 3,727 Interest-bearing — intercompany 1,249 — 521 (1,770 ) — Total cash and cash equivalents 1,309 — 4,998 (1,770 ) 4,537 Equity securities — — 773 — 773 Available-for-sale securities — — 25,303 — 25,303 Held-to-maturity securities — — 2,382 (20 ) 2,362 Loans held-for-sale, net — — 314 — 314 Finance receivables and loans, net Finance receivables and loans, net 2,349 — 127,577 — 129,926 Intercompany loans to Nonbank subsidiaries 882 — 397 (1,279 ) — Allowance for loan losses (55 ) — (1,187 ) — (1,242 ) Total finance receivables and loans, net 3,176 — 126,787 (1,279 ) 128,684 Investment in operating leases, net 5 — 8,412 — 8,417 Intercompany receivables from Bank subsidiary 158 — — (158 ) — Nonbank subsidiaries 45 — 129 (174 ) — Investment in subsidiaries Bank subsidiary 16,213 16,213 — (32,426 ) — Nonbank subsidiaries 6,928 — — (6,928 ) — Premiums receivable and other insurance assets — — 2,326 — 2,326 Other assets 2,226 — 5,453 (1,526 ) 6,153 Total assets $ 30,060 $ 16,213 $ 176,877 $ (44,281 ) $ 178,869 Liabilities and equity Deposit liabilities Noninterest-bearing $ — $ — $ 142 $ — $ 142 Interest-bearing 1 — 106,035 — 106,036 Interest-bearing — intercompany — — 1,249 (1,249 ) — Total deposit liabilities 1 — 107,426 (1,249 ) 106,178 Short-term borrowings 2,477 — 7,510 — 9,987 Long-term debt 12,774 — 31,419 — 44,193 Intercompany debt to Bank subsidiary 20 — — (20 ) — Nonbank subsidiaries 918 — 882 (1,800 ) — Intercompany payables to Bank subsidiary 45 — — (45 ) — Nonbank subsidiaries 124 — 129 (253 ) — Interest payable 159 — 364 — 523 Unearned insurance premiums and service revenue — — 3,044 — 3,044 Accrued expenses and other liabilities 274 — 2,962 (1,560 ) 1,676 Total liabilities 16,792 — 153,736 (4,927 ) 165,601 Total equity 13,268 16,213 23,141 (39,354 ) 13,268 Total liabilities and equity $ 30,060 $ 16,213 $ 176,877 $ (44,281 ) $ 178,869 December 31, 2017 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Assets Cash and cash equivalents Noninterest-bearing $ 74 $ — $ 770 $ — $ 844 Interest-bearing 5 — 3,403 — 3,408 Interest-bearing — intercompany 1,138 — 695 (1,833 ) — Total cash and cash equivalents 1,217 — 4,868 (1,833 ) 4,252 Equity securities — — 518 — 518 Available-for-sale securities — — 22,303 — 22,303 Held-to-maturity securities — — 1,973 (74 ) 1,899 Loans held-for-sale, net — — 108 — 108 Finance receivables and loans, net Finance receivables and loans, net 7,434 — 115,459 — 122,893 Intercompany loans to Nonbank subsidiaries 879 — 408 (1,287 ) — Allowance for loan losses (185 ) — (1,091 ) — (1,276 ) Total finance receivables and loans, net 8,128 — 114,776 (1,287 ) 121,617 Investment in operating leases, net 19 — 8,722 — 8,741 Intercompany receivables from Bank subsidiary 80 — — (80 ) — Nonbank subsidiaries 71 — 77 (148 ) — Investment in subsidiaries Bank subsidiary 16,962 16,962 — (33,924 ) — Nonbank subsidiaries 8,111 — — (8,111 ) — Premiums receivable and other insurance assets — — 2,082 (35 ) 2,047 Other assets 2,207 — 5,105 (1,649 ) 5,663 Total assets $ 36,795 $ 16,962 $ 160,532 $ (47,141 ) $ 167,148 Liabilities and equity Deposit liabilities Noninterest-bearing $ — $ — $ 108 $ — $ 108 Interest-bearing 12 — 93,136 — 93,148 Interest-bearing — intercompany — — 1,139 (1,139 ) — Total deposit liabilities 12 — 94,383 (1,139 ) 93,256 Short-term borrowings 3,171 — 8,242 — 11,413 Long-term debt 17,966 — 26,260 — 44,226 Intercompany debt to Bank subsidiary 74 — — (74 ) — Nonbank subsidiaries 1,103 — 879 (1,982 ) — Intercompany payables to Bank subsidiary 4 — — (4 ) — Nonbank subsidiaries 132 — 127 (259 ) — Interest payable 200 — 175 — 375 Unearned insurance premiums and service revenue — — 2,604 — 2,604 Accrued expenses and other liabilities 639 — 2,790 (1,649 ) 1,780 Total liabilities 23,301 — 135,460 (5,107 ) 153,654 Total equity 13,494 16,962 25,072 (42,034 ) 13,494 Total liabilities and equity $ 36,795 $ 16,962 $ 160,532 $ (47,141 ) $ 167,148 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2018 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 1,659 $ 2,600 $ 5,536 $ (5,645 ) $ 4,150 Investing activities Purchases of equity securities — — (1,076 ) — (1,076 ) Proceeds from sales of equity securities — — 787 — 787 Purchases of available-for-sale securities — — (7,868 ) — (7,868 ) Proceeds from sales of available-for-sale securities — — 852 — 852 Proceeds from repayments of available-for-sale securities — — 3,215 — 3,215 Purchases of held-to-maturity securities — — (578 ) — (578 ) Proceeds from repayments of held-to-maturity securities — — 147 — 147 Net change in investment securities — intercompany — — 54 (54 ) — Purchases of finance receivables and loans held-for-investment (131 ) — (7,101 ) 1,539 (5,693 ) Proceeds from sales of finance receivables and loans initially held-for-investment 1,596 — 34 (1,539 ) 91 Originations and repayments of finance receivables and loans held-for-investment and other, net 3,489 — (6,734 ) — (3,245 ) Net change in loans — intercompany (20 ) — (2 ) 22 — Purchases of operating lease assets — — (3,709 ) — (3,709 ) Disposals of operating lease assets 10 — 3,079 — 3,089 Capital contributions to subsidiaries (61 ) (6 ) — 67 — Returns of contributed capital 266 — — (266 ) — Net change in nonmarketable equity investments (16 ) — (165 ) — (181 ) Other, net — — (340 ) — (340 ) Net cash provided by (used in) investing activities 5,133 (6 ) (19,405 ) (231 ) (14,509 ) Financing activities Net change in short-term borrowings — third party (694 ) — (732 ) — (1,426 ) Net (decrease) increase in deposits (11 ) — 12,989 (111 ) 12,867 Proceeds from issuance of long-term debt — third party 69 — 18,332 — 18,401 Repayments of long-term debt — third party (4,774 ) — (13,166 ) — (17,940 ) Net change in debt — intercompany (198 ) — (10 ) 208 — Repurchase of common stock (939 ) — — — (939 ) Dividends paid — third party (242 ) — — — (242 ) Dividends paid and returns of contributed capital — intercompany — (2,600 ) (3,309 ) 5,909 — Capital contributions from parent — 6 61 (67 ) — Net cash (used in) provided by financing activities (6,789 ) (2,594 ) 14,165 5,939 10,721 Effect of exchange-rate changes on cash and cash equivalents and restricted cash — — (5 ) — (5 ) Net increase in cash and cash equivalents and restricted cash 3 — 291 63 357 Cash and cash equivalents and restricted cash at beginning of year 1,395 — 5,707 (1,833 ) 5,269 Cash and cash equivalents and restricted cash at end of year $ 1,398 $ — $ 5,998 $ (1,770 ) $ 5,626 The following table provides a reconciliation of cash and cash equivalents and restricted cash from the Condensed Consolidated Balance Sheet to the Condensed Consolidated Statement of Cash Flows. December 31, 2018 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Cash and cash equivalents on the Consolidated Balance Sheet $ 1,309 $ — $ 4,998 $ (1,770 ) $ 4,537 Restricted cash included in other assets on the Consolidated Balance Sheet (a) 89 — 1,000 — 1,089 Total cash and cash equivalents and restricted cash in the Consolidated Statement of Cash Flows $ 1,398 $ — $ 5,998 $ (1,770 ) $ 5,626 (a) Restricted cash balances relate primarily to Ally securitization arrangements. Refer to Note 13 for additional details describing the nature of restricted cash balances. Year ended December 31, 2017 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 4,591 $ 3,300 $ 3,466 $ (7,278 ) $ 4,079 Investing activities Purchases of equity securities — — (899 ) — (899 ) Proceeds from sales of equity securities — — 1,049 — 1,049 Purchases of available-for-sale securities — — (10,335 ) — (10,335 ) Proceeds from sales of available-for-sale securities — — 3,584 — 3,584 Proceeds from repayments of available-for-sale securities — — 2,899 — 2,899 Purchases of held-to-maturity securities — — (1,026 ) — (1,026 ) Proceeds from repayments of held-to-maturity securities — — 68 — 68 Net change in investment securities — intercompany 7 — 291 (298 ) — Purchases of finance receivables and loans held-for-investment (35 ) — (5,417 ) — (5,452 ) Proceeds from sales of finance receivables and loans initially held-for-investment 106 — 1,233 — 1,339 Originations and repayments of finance receivables and loans held-for-investment and other, net 860 — 33 (1,956 ) (1,063 ) Net change in loans — intercompany 2,068 — 217 (2,285 ) — Purchases of operating lease assets — — (4,052 ) — (4,052 ) Disposals of operating lease assets 13 — 5,554 — 5,567 Capital contributions to subsidiaries (1,212 ) (5 ) — 1,217 — Returns of contributed capital 1,567 — — (1,567 ) — Net change in nonmarketable equity investments — — (187 ) — (187 ) Other, net (31 ) — (99 ) (89 ) (219 ) Net cash provided by (used in) investing activities 3,343 (5 ) (7,087 ) (4,978 ) (8,727 ) Financing activities Net change in short-term borrowings — third party (453 ) — (810 ) — (1,263 ) Net (decrease) increase in deposits (156 ) — 15,466 (1,138 ) 14,172 Proceeds from issuance of long-term debt — third party 354 — 15,654 1,961 17,969 Repayments of long-term debt — third party (6,111 ) — (21,797 ) — (27,908 ) Net change in debt — intercompany (225 ) — (2,074 ) 2,299 — Repurchase of common stock (753 ) — — — (753 ) Dividends paid — third party (184 ) — — — (184 ) Dividends paid and returns of contributed capital — intercompany — (3,300 ) (5,619 ) 8,919 — Capital contributions from parent — 5 1,212 (1,217 ) — Net cash (used in) provided by financing activities (7,528 ) (3,295 ) 2,032 10,824 2,033 Effect of exchange-rate changes on cash and cash equivalents — — 3 — 3 Net increase (decrease) in cash and cash equivalents and restricted cash 406 — (1,586 ) (1,432 ) (2,612 ) Cash and cash equivalents and restricted cash at beginning of year 989 — 7,293 (401 ) 7,881 Cash and cash equivalents and restricted cash at end of year $ 1,395 $ — $ 5,707 $ (1,833 ) $ 5,269 The following table provides a reconciliation of cash and cash equivalents and restricted cash from the Condensed Consolidated Balance Sheet to the Condensed Consolidated Statement of Cash Flows. December 31, 2017 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Cash and cash equivalents on the Consolidated Balance Sheet $ 1,217 $ — $ 4,868 $ (1,833 ) $ 4,252 Restricted cash included in other assets on the Consolidated Balance Sheet (a) 178 — 839 — 1,017 Total cash and cash equivalents and restricted cash in the Consolidated Statement of Cash Flows $ 1,395 $ — $ 5,707 $ (1,833 ) $ 5,269 (a) Restricted cash balances relate primarily to Ally securitization arrangements. Refer to Note 13 for additional details describing the nature of restricted cash balances. Year ended December 31, 2016 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 241 $ 6 $ 5,383 $ (1,063 ) $ 4,567 Investing activities Purchases of equity securities — — (470 ) — (470 ) Proceeds from sales of equity securities — — 680 — 680 Purchases of available-for-sale securities — — (15,561 ) — (15,561 ) Proceeds from sales of available-for-sale securities — — 10,356 — 10,356 Proceeds from repayments of available-for-sale securities — — 3,379 — 3,379 Purchases of held-to-maturity securities — — (841 ) — (841 ) Purchases of finance receivables and loans held-for-investment (4 ) — (3,855 ) — (3,859 ) Proceeds from sales of finance receivables and loans initially held-for-investment — — 4,285 — 4,285 Originations and repayments of finance receivables and loans held-for-investment and other, net 2,013 — (10,839 ) — (8,826 ) Net change in loans — intercompany 877 — (67 ) (810 ) — Purchases of operating lease assets — — (3,274 ) — (3,274 ) Disposals of operating lease assets 25 — 6,279 — 6,304 Acquisitions, net of cash acquired (309 ) — — — (309 ) Capital contributions to subsidiaries (3,908 ) — — 3,908 — Returns of contributed capital 3,678 8 — (3,686 ) — Net change in nonmarketable equity investments — — (628 ) — (628 ) Other, net (206 ) — (191 ) 91 (306 ) Net cash provided by (used in) investing activities 2,166 8 (10,747 ) (497 ) (9,070 ) Financing activities Net change in short-term borrowings — third party 169 — 4,395 — 4,564 Net (decrease) increase in deposits (61 ) — 12,569 — 12,508 Proceeds from issuance of long-term debt — third party 979 — 13,176 — 14,155 Repayments of long-term debt — third party (2,662 ) — (23,750 ) — (26,412 ) Net change in debt — intercompany (382 ) — (877 ) 1,259 — Redemption of preferred stock (696 ) — — — (696 ) Repurchase of common stock (341 ) — — — (341 ) Dividends paid — third party (108 ) — — — (108 ) Dividends paid and returns of contributed capital — intercompany — (14 ) (4,644 ) 4,658 — Capital contributions from parent — — 3,908 (3,908 ) — Net cash (used in) provided by financing activities (3,102 ) (14 ) 4,777 2,009 3,670 Effect of exchange-rate changes on cash and cash equivalents — — 1 — 1 Net decrease in cash and cash equivalents and restricted cash (695 ) — (586 ) 449 (832 ) Cash and cash equivalents and restricted cash at beginning of year 1,684 — 7,879 (850 ) 8,713 Cash and cash equivalents and restricted cash at end of year $ 989 $ — $ 7,293 $ (401 ) $ 7,881

Guarantees and Commitments

Guarantees and Commitments	12 Months Ended
	Dec. 31, 2018
Guarantees and Commitments [Abstract]
Guarantees	Guarantees and Commitments Guarantees Guarantees are defined as contracts or indemnification agreements that contingently require us to make payments to third parties based on changes in the underlying agreements with the guaranteed parties. The following summarizes our outstanding guarantees, including those of our discontinued operations, made to third parties on our Consolidated Balance Sheet , for the periods shown. 2018 2017 December 31, ($ in millions) Maximum liability Carrying value of liability Maximum liability Carrying value of liability Standby letters of credit and other guarantees $ 218 $ 7 $ 227 $ 8 Corporate Finance has exposure to standby letters of credit that represent irrevocable guarantees of payment of specified financial obligations. Third-party beneficiaries primarily accept standby letters of credit as insurance in the event of nonperformance by our borrowers. Our borrowers may request letters of credit under their revolving loan facility up to a certain sub-limit amount. We may also require collateral to be posted by our borrowers. As of December 31, 2018 , we received $2 million of cash collateral related to these letters of credit. Expiration dates on letters of credit range from certain ongoing commitments that will expire during the upcoming year to terms of several years for certain letters of credit. If the beneficiary draws under a letter of credit, we will be liable to the beneficiary for payment of the amount drawn under such letter of credit, with our recourse being a charge to the borrower’s loan facility or transfer of ownership to us of the related collateral. As many of these commitments are subject to borrowing base agreements and other restrictive covenants or may expire without being fully drawn, the stated amounts of the letters of credit are not necessarily indicative of future cash requirements. In connection with our Ally Invest wealth management business, we introduce customer securities accounts to a clearing broker, which clears and maintains custody of all customer assets and account activity. We are responsible for obtaining from each customer such funds or securities as are required to be deposited or maintained in their accounts. As a result, we are liable for any loss, liability, damage, cost, or expense incurred or sustained by the clearing broker as a result of the failure of any customer to timely make payments or deposits of securities to satisfy their contractual obligations. In addition, customer securities activities are transacted on either a cash or margin basis. In margin transactions, we may extend credit to the customer, through our clearing broker, subject to various regulatory rules and margin lending practices, collateralized by cash and securities in the customer’s account. In connection with these activities, we also execute customer transactions involving the sale of securities not yet purchased. Such transactions may expose us to credit risk in the event the customer’s assets are not sufficient to fully cover losses, which the customer may incur. In the event the customer fails to satisfy its obligations, we will purchase or sell financial instruments in the customer’s account in order to fulfill the customer’s obligations. The maximum potential exposure under these arrangements is difficult to estimate; however, the potential for us to incur material losses pursuant to these arrangements is remote. Commitments Financing Commitments The contractual commitments were as follows. December 31, ($ in millions) 2018 2017 Unused revolving credit line commitments and other (a) $ 3,435 $ 2,341 Commitments to provide capital to investees (b) 394 283 Home equity lines of credit (c) 253 318 Mortgage loan origination commitments (d) 171 95 Construction-lending commitments (e) 85 144 (a) The unused portion of revolving lines of credit reset at prevailing market rates and, as such, approximate market value. (b) We are committed to contribute capital to certain investees. (c) We are committed to fund the remaining unused balances on home equity lines of credit. (d) Commitments with mortgage loan applicants in which the loan terms, including interest rate and price, are guaranteed for a designated period of time subject to the completion of underwriting procedures. (e) We are committed to fund the remaining unused balance while loans are in the construction period. Revolving credit line commitments contain an element of credit risk. We manage the credit risk for unused revolving credit line commitments by applying the same credit policies in making commitments as we do for extending loans. Lease Commitments Future minimum rental payments required under operating leases, primarily for real property, with noncancelable lease terms expiring after December 31, 2018 , are as follows. Year ended December 31, ($ in millions) 2019 $ 48 2020 47 2021 46 2022 37 2023 31 2024 and thereafter 294 Total minimum payment required $ 503 Certain of the leases contain escalation clauses and renewal or purchase options. Rental expenses under operating leases were $45 million , $46 million , and $51 million for the years ended December 31, 2018 , 2017, and 2016, respectively. Contractual Commitments We have entered into multiple agreements for information technology, voice and communication technology, and related maintenance. Many of the agreements are subject to variable price provisions, fixed or minimum price provisions, and termination or renewal provisions. Year ended December 31, ($ in millions) 2019 $ 70 2020 and 2021 47 2022 and thereafter — Total future payment obligations $ 117

Contingencies and Other Risks

Contingencies and Other Risks	12 Months Ended
	Dec. 31, 2018
Loss Contingency [Abstract]
Contingencies Disclosure	Contingencies and Other Risks Concentration with GM and Chrysler While we are continuing to diversify our automotive finance and insurance businesses and to expand into other financial services, General Motors Company (GM) and Fiat Chrysler Automobiles US LLC (Chrysler) dealers and their retail customers continue to constitute a significant portion of our customer base. GM, Chrysler, and their captive finance companies compete vigorously with us and could take further actions that negatively impact the amount of business that we do with GM and Chrysler dealers and their customers. Further, a significant adverse change in GM’s or Chrysler’s business—including, for example, in the production or sale of GM or Chrysler vehicles, the quality or resale value of GM or Chrysler vehicles, GM’s or Chrysler’s relationships with its key suppliers, or the rate or volume of recalls of GM or Chrysler vehicles—could negatively impact our GM and Chrysler dealer and retail customer bases and the value of collateral securing our extensions of credit to them. Any future reductions in GM and Chrysler business that we are not able to offset could adversely affect our business and financial results. Legal Matters Ally and its subsidiaries, including Ally Bank, are or may be subject to potential liability in connection with pending or threatened legal proceedings and other matters. These legal matters may be formal or informal and include litigation and arbitration with one or more identified claimants, certified or purported class actions with yet-to-be-identified claimants, and regulatory or other governmental information-gathering requests, examinations, investigations, and enforcement proceedings. Our legal matters exist in varying stages of adjudication, arbitration, negotiation, or investigation and span our business lines and operations. Claims may be based in law or equity—such as those arising under contracts or in tort and those involving banking, consumer-protection, securities, tax, employment, and other laws—and some can present novel legal theories and allege substantial or indeterminate damages. We accrue for a legal matter when a loss becomes probable and the amount of loss can be reasonably estimated. Accruals are evaluated each quarter and may be adjusted, upward or downward, based on our best judgment after consultation with counsel. No assurance exists that our accruals will not need to be adjusted in the future. When a probable or reasonably possible loss on a legal matter could be material to our consolidated financial condition, results of operations, or cash flows, we provide disclosure in this note as prescribed by ASC 450, Contingencies . The course and outcome of legal matters are inherently unpredictable. This is especially so when a matter is still in its early stages, the damages sought are indeterminate or unsupported, significant facts are unclear or disputed, novel questions of law or other meaningful legal uncertainties exist, a request to certify a proceeding as a class action is outstanding or granted, multiple parties are named, or regulatory or other governmental entities are involved. As a result, we often are unable to determine how or when threatened or pending legal matters will be resolved and what losses may be incurred. Actual losses may be higher or lower than any amounts accrued or estimated for those matters, possibly to a significant degree. Descriptions of our material legal matters follow. We do not believe, however, that an estimate of reasonably possible losses or a range of reasonably possible losses—whether in excess of any related accrual or where no accrual exists—can be made for any of these matters for some or all of the reasons identified in the preceding paragraph. Securities Litigation In October 2016, a purported class action—Bucks County Employees Retirement Fund v. Ally Financial Inc. et al.—was filed in the Circuit Court for Wayne County in the State of Michigan (Case No. 16-013616-CZ). The complaint alleged material misstatements and omissions in connection with Ally’s initial public offering in April 2014, including a failure to adequately disclose the severity of rising subprime automotive loan delinquency rates, deficient underwriting measures employed in the origination of subprime automotive loans, and aggressive tactics used with low-income borrowers. The request for relief included an indeterminate amount of damages, fees, and costs and other remedies. In January 2017, another purported class action—National Shopmen Pension Fund v. Ally Financial Inc. et al.—was filed in the Circuit Court for Oakland County in the State of Michigan (Case No. 2017-156719-CB). In March 2017, a third purported class action—James McIntire v. Ally Financial Inc. et al.—was filed in the Circuit Court for Wayne County in the State of Michigan (Case No. 17-003811-CZ). The allegations and requested relief in the National Shopmen Pension Fund and James McIntire complaints were substantially similar to those included in the complaint filed by Bucks County Employees Retirement Fund. All three matters were initially removed to the U.S. District Court for the Eastern District of Michigan, were then remanded back to the state circuit courts, and were consolidated for discovery in Wayne County Circuit Court as In re Ally Financial, Inc. Securities Litigation (Case No. 16-013616-CB). In November 2017, the plaintiffs filed a consolidated amended complaint. In January 2019, the Wayne County Circuit Court entered an order granting a motion by the defendants to dismiss the complaint. The order was not appealed, and the case has been closed. Other Contingencies Ally and its subsidiaries, including Ally Bank, are or may be subject to potential liability under various other contingent exposures, including indemnification, tax, self-insurance, and other miscellaneous contingencies. We accrue for a contingent exposure when a loss becomes probable and the amount of loss can be reasonably estimated. Accruals are evaluated each quarter and may be adjusted, upward or downward, based on our best judgment. No assurance exists that our accruals will not need to be adjusted in the future, and actual losses may be higher or lower than any amounts accrued or estimated for those exposures, possibly to a significant degree. On the basis of information currently available, we do not believe that these other contingent exposures will be material to our consolidated financial condition, results of operations, or cash flows. Refer to Note 1 for additional information related to our policy for establishing reserves for legal and regulatory matters.

Quarterly Financial Statements

Quarterly Financial Statements (unaudited)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information (unaudited) [Abstract]
Quarterly Financial Information	Quarterly Financial Statements (unaudited) ($ in millions) First quarter Second quarter Third quarter Fourth quarter 2018 Net financing revenue and other interest income $ 1,049 $ 1,094 $ 1,107 $ 1,140 Other revenue 354 364 398 298 Total net revenue 1,403 1,458 1,505 1,438 Provision for loan losses 261 158 233 266 Total noninterest expense 814 839 807 804 Income from continuing operations before income tax expense 328 461 465 368 Income tax expense from continuing operations 76 113 91 79 Net income from continuing operations 252 348 374 289 (Loss) income from discontinued operations, net of tax (2 ) 1 — 1 Net income $ 250 $ 349 $ 374 $ 290 Basic earnings per common share (a) Net income from continuing operations $ 0.58 $ 0.81 $ 0.89 $ 0.70 Net income 0.57 0.81 0.89 0.70 Diluted earnings per common share (a) Net income from continuing operations $ 0.57 $ 0.80 $ 0.88 $ 0.70 Net income 0.57 0.81 0.88 0.70 Cash dividends declared per common share $ 0.13 $ 0.13 $ 0.15 $ 0.15 2017 Net financing revenue and other interest income $ 979 $ 1,067 $ 1,081 $ 1,094 Other revenue 396 388 381 379 Total net revenue 1,375 1,455 1,462 1,473 Provision for loan losses 271 269 314 294 Total noninterest expense 778 810 753 769 Income from continuing operations before income tax expense 326 376 395 410 Income tax expense from continuing operations (b) 113 122 115 231 Net income from continuing operations 213 254 280 179 Income (loss) from discontinued operations, net of tax 1 (2 ) 2 2 Net income $ 214 $ 252 $ 282 $ 181 Basic earnings per common share (a) Net income from continuing operations $ 0.46 $ 0.55 $ 0.62 $ 0.40 Net income 0.46 0.55 0.63 0.41 Diluted earnings per common share (a) Net income from continuing operations $ 0.46 $ 0.55 $ 0.62 $ 0.40 Net income 0.46 0.55 0.63 0.41 Cash dividends declared per common share $ 0.08 $ 0.08 $ 0.12 $ 0.12 (a) Earnings per share is calculated quarterly on an independent basis, therefore the total of the amounts presented for each year above may not reconcile to the annual amounts presented in Note 19 . (b) Amount for the fourth quarter of 2017 includes $119 million of tax expense attributable to tax reform enacted on December 22, 2017.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Declaration of Quarterly Dividend On January 14, 2019 , the Board declared a quarterly cash dividend of $0.17 per share on all common stock, a $0.02 per share increase relative to our prior quarterly cash dividend. The dividend was paid on February 15, 2019 , to stockholders of record at the close of business on February 1, 2019.

Description of Business, Basi_2

Description of Business, Basis of Presentation, and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Consolidation, Policy	The Consolidated Financial Statements include the accounts of the parent and its consolidated subsidiaries, of which it is deemed to possess control, after eliminating intercompany balances and transactions, and include all variable interest entities (VIEs) in which we are the primary beneficiary. Other entities in which we have invested and have the ability to exercise significant influence over operating and financial policies of the investee, but upon which we do not possess control, are accounted for by the equity method of accounting within the financial statements and they are therefore not consolidated. Refer to Note 11 for further details on our VIEs.
Basis of Accounting, Policy	Our accounting and reporting policies conform to accounting principles generally accepted in the United States of America (GAAP). Additionally, where applicable, the policies conform to the accounting and reporting guidelines prescribed by bank regulatory authorities. Certain reclassifications may have been made to the prior periods’ financial statements and notes to conform to the current period’s presentation, which did not have a material impact on our Consolidated Financial Statements.
Use of Estimates and Assumptions, Policy	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 that affect income and expenses during the reporting period and related disclosures. In developing the estimates and assumptions, management uses all available evidence; however, actual results could differ because of uncertainties associated with estimating the amounts, timing, and likelihood of possible outcomes. Our most significant estimates pertain to the allowance for loan losses, valuations of automotive operating lease assets and residuals, fair value of financial instruments, and the determination of the provision for income taxes.
Cash and Cash Equivalents, Policy	Cash and cash equivalents include cash on hand, cash on deposit at other financial institutions, cash items in process of collection, and certain highly liquid investments with original maturities of three months or less from the date of purchase. The book value of cash equivalents approximates fair value because of the short maturities of these instruments and the insignificant risk they present to changes in value with respect to changes in interest rates. Certain securities with original maturities of three months or less from the date of purchase that are held as a portion of longer-term investment portfolios, primarily held by our Insurance operations, are classified as investment securities. Cash and cash equivalents with legal restrictions limiting our ability to withdraw and use the funds are considered restricted cash and restricted cash equivalents and are presented as other assets on our Consolidated Balance Sheet.
Investments, Policy	Our investment portfolio includes various debt and equity securities. Our debt securities include government securities, corporate bonds, asset-backed securities (ABS), and mortgage-backed securities (MBS). Debt securities are classified based on management’s intent to sell or hold the security. We classify debt securities as held-to-maturity only when we have both the intent and ability to hold the securities to maturity. We classify debt securities as trading when the securities are acquired for the purpose of selling or holding them for a short period of time. Debt securities not classified as either held-to-maturity or trading are classified as available-for-sale. Our portfolio includes debt securities classified as available-for-sale and held-to-maturity. Our available-for-sale debt securities are carried at fair value with unrealized gains and losses included in accumulated other comprehensive income and are subject to impairment. Our held-to-maturity debt securities are carried at amortized cost and are subject to impairment. We assess our available-for-sale and held-to-maturity debt securities for potential other-than-temporary impairment. We employ a methodology that considers available evidence in evaluating potential other-than-temporary impairment of our debt securities. If the cost of an investment exceeds its fair value, we evaluate, among other factors, the magnitude and duration of the decline in fair value. We also evaluate the financial health of and business outlook for the issuer, the performance of the underlying assets for interests in securitized assets, and, for debt securities classified as available-for-sale, our intent and ability to hold the investment through recovery of its amortized cost basis. Once a decline in fair value of a debt security is determined to be other-than-temporary, an impairment charge for the credit component is recorded to other gain on investments, net, in our Consolidated Statement of Income, and a new cost basis in the investment is established. The noncredit loss component of a debt security continues to be recorded in other comprehensive income when we do not intend to sell the security and it is not more likely than not that we will have to sell the security prior to the security’s anticipated recovery. Both the credit and noncredit loss components are recorded in earnings when we intend to sell the security or it is more likely than not that we will have to sell the security prior to the security’s anticipated recovery. Subsequent increases and decreases to the fair value of available-for-sale debt securities are included in other comprehensive income, so long as they are not attributable to another other-than-temporary impairment. We amortize premiums and discounts on debt securities as an adjustment to investment yield over the stated maturity of the security. Our investment in equity securities includes securities that are recognized at fair value with changes in the fair value recorded in earnings, and equity securities that are recognized using other measurement principles. Effective January 1, 2018, equity securities that have a readily determinable fair value, as well as certain investments that do not have a readily determinable fair value and are not eligible to be recognized using other measurement principles, are recorded at fair value with changes in fair value recorded in earnings and reported in other gain on investments, net in our Consolidated Statement of Income. These investments, which are primarily attributable to the investment portfolio of our Insurance operations, are included in equity securities on our Consolidated Balance Sheet. Refer to Note 8 for further information on our equity securities that have a readily determinable market value. Our equity securities recognized using other measurement principles include investments in Federal Home Loan Bank (FHLB) and Federal Reserve Bank (FRB) stock held to meet regulatory requirements, equity investments related to low income housing tax credits and the Community Reinvestment Act (CRA), which do not have a readily determinable fair value, and other equity investments that do not have a readily determinable fair value. Our low income housing tax credit investments are accounted for using the proportional amortization method of accounting for qualified affordable housing investments. Our obligations related to unfunded commitments for our low income housing tax credit investments are included in other liabilities. The majority of our other CRA investments are accounted for using the equity method of accounting. Our investments in low income housing tax credits and other CRA investments are included in other assets on our Consolidated Balance Sheet. Our investments in FHLB and FRB stock are carried at cost, less impairment. Our remaining investment in equity securities are recorded at cost, less impairment and adjusted for observable price changes under the measurement alternative provided under GAAP. These investments, along with our investments in FHLB and FRB stock, are included in nonmarketable equity investments in other assets on our Consolidated Balance Sheet. As conditions warrant, we review these investments for impairment and adjust the carrying value of the investment if it is deemed to be impaired. Investments recorded under the measurement alternative are also reviewed at each reporting period to determine if any adjustments are required for observable price changes in identical or similar securities of the same issuer. Realized gains and losses on the sale of securities are determined using the specific identification method and are reported in other gain on investments, net in our Consolidated Statement of Income.
Finance Receivables and Loans, Policy	We initially classify finance receivables and loans as either loans held-for-sale or loans held-for-investment based on management’s assessment of our intent and ability to hold the loans for the foreseeable future or until maturity. Management’s view of the foreseeable future is based on the longest reasonably reliable net income, liquidity, and capital forecast period. Management’s intent and ability with respect to certain loans may change from time to time depending on a number of factors, for example economic, liquidity, and capital conditions. In order to reclassify loans to held-for-sale, management must have the intent to sell the loans and reasonably identify the specific loans to be sold. Loans classified as held-for-sale are presented as loans held-for-sale, net on our Consolidated Balance Sheet and are carried at the lower of their net carrying value or fair value, unless the fair value option was elected, in which case those loans are carried at fair value. Loan origination fees and costs are included in the initial carrying value of loans originated as held-for-sale for which we have not elected the fair value option. Loan origination fees and costs are recognized in earnings when earned or incurred, respectively, for loans classified as held-for-sale for which we have elected the fair value option. We have elected the fair value option for conforming mortgage direct-to-consumer originations for which we have a commitment to sell. The interest rate lock commitment that we enter into for a mortgage loan originated as held-for-sale and certain forward commitments to sell mortgage loans are considered derivative instruments, which are carried at fair value on our Consolidate Balance Sheet. We have elected the fair value option to measure our non-derivative forward commitments. Changes in the fair value of our interest rate lock commitments, derivative forward commitments, and non-derivative forward commitments related to mortgage loans originated as held-for-sale, as well as changes in the carrying value of loans classified as held-for-sale, are reported through gain on mortgage and automotive loans, net in our Consolidated Statement of Comprehensive Income. Interest income on our loans classified as held-for-sale is recognized based upon the contractual rate of interest on the loan and the unpaid principal balance. We report accrued interest receivable on our loans classified as held-for-sale in other assets on the Consolidated Balance Sheet. Loans classified as held-for-investment are presented as finance receivables and loans, net on our Consolidated Balance Sheet. Finance receivables and loans are reported at their gross carrying value, which includes the principal amount outstanding, net of unamortized deferred fees and costs on originated loans, unamortized premiums and discounts on purchased loans, unamortized basis adjustments arising from the designation of finance receivables and loans as the hedged item in qualifying fair value hedge relationships, and cumulative principal charge-offs. We refer to the gross carrying value less the allowance for loan loss as the net carrying value in finance receivables and loans. Unearned rate support received from an automotive manufacturer on certain automotive loans, deferred origination fees and costs, and premiums and discounts on purchased loans, are amortized over the contractual life of the related finance receivable or loan using the effective interest method. We make various incentive payments for consumer automotive loan originations to automotive dealers and account for these payments as direct loan origination costs. Additionally, we make incentive payments to certain commercial automobile wholesale borrowers and account for these payments as a reduction to interest income in the period they are earned. Interest income on our finance receivables and loans is recognized based on the contractual rate of interest plus the amortization of deferred amounts using the effective interest method. We report accrued interest receivable on our finance receivables and loans in other assets on our Consolidated Balance Sheet. Loan commitment fees are generally deferred and amortized over the commitment period. For information on finance receivables and loans, refer to Note 9 . Our portfolio segments are based on the level at which we develop and document our methodology for determining the allowance for loan losses. Additionally, the classes of finance receivables are based on several factors including the method for monitoring and assessing credit risk, the method of measuring carrying value, and the risk characteristics of the finance receivable. Based on an evaluation of our process for developing the allowance for loan losses including the nature and extent of exposure to credit risk arising from finance receivables, we have determined our portfolio segments to be consumer automotive, consumer mortgage, and commercial. • Consumer automotive — Consists of retail automotive financing for new and used vehicles. • Consumer mortgage — Consists of the following classes of finance receivables. • Mortgage Finance — Consists of consumer first-lien mortgages from our ongoing mortgage operations including bulk acquisitions, direct-to-consumer originations, and refinancing of high-quality jumbo mortgages and low-to-moderate income (LMI) mortgages. • Mortgage — Legacy — Consists of consumer mortgage assets originated prior to January 1, 2009, including first-lien mortgages, subordinate-lien mortgages, and home equity mortgages. • Commercial — Consists of the following classes of finance receivables. • Commercial and Industrial • Automotive — Consists of financing operations to fund dealer purchases of new and used vehicles through wholesale floorplan financing. Additional commercial offerings include automotive dealer term loans, and dealer fleet financing. • Other — Consists primarily of senior secured leveraged cash flow and asset-based loans related to our Corporate Finance business. • Commercial Real Estate — Consists of term loans to finance dealership land and buildings, and other commercial lending secured by real estate. Nonaccrual Loans Generally, we recognize loans of all classes as past due when they are 30 days delinquent on making a contractually required payment, and loans are placed on nonaccrual status when principal or interest has been delinquent for 90 days or when full collection is not expected . Interest income recognition is suspended when finance receivables and loans are placed on nonaccrual status. Additionally, amortization of premiums and discounts and deferred fees and costs ceases when finance receivables and loans are placed on nonaccrual. Exceptions include commercial real estate loans that are placed on nonaccrual status when delinquent for 60 days or when full collection is not probable, if sooner. Additionally, our policy is to generally place all loans that have been modified in troubled debt restructurings (TDRs) on nonaccrual status until the loan has been brought fully current, the collection of contractual principal and interest is reasonably assured, and six consecutive months of repayment performance is achieved. In certain cases, if a borrower has been current up to the time of the modification and repayment of the debt subsequent to the modification is reasonably assured, we may choose to continue to accrue interest on the loan. Loans on nonaccrual status are reported as nonperforming loans in Note 9 . The receivable for interest income that is accrued, but not collected, at the date finance receivables and loans are placed on nonaccrual status is reversed against interest income and subsequently recognized only to the extent it is received in cash or until it qualifies for return to accrual status. However, where there is doubt regarding the ultimate collectability of loan principal, all cash received is applied to reduce the carrying value of such loans. Generally, finance receivables and loans are restored to accrual status only when contractually current and the collection of future payments is reasonably assured. Impaired Loans Loans of all classes are considered impaired when we determine it is probable that we will be unable to collect all amounts due (both principal and interest) according to the terms of the loan agreement. For all classes of consumer loans, impaired loans include all loans that have been modified in TDRs. Commercial loans of all classes are considered impaired on an individual basis and reported as impaired when we determine it is probable that we will be unable to collect all amounts due according to the terms of the loan agreement. With the exception of certain consumer TDRs that have been returned to accruing status, for all classes of impaired loans, income recognition is consistent with that of nonaccrual loans discussed above. Impaired loans may return to accrual status as discussed in the preceding nonaccrual loan section at which time, the normal accrual of interest income resumes. For collateral dependent loans, if the recorded investment in the impaired loans exceeds the fair value of the collateral, a charge-off is recorded consistent with the TDR discussion below. Troubled Debt Restructurings When the terms of finance receivables or loans are modified, consideration must be given as to whether or not the modification results in a TDR. A modification is considered to be a TDR when both the borrower is experiencing financial difficulty and we grant a concession to the borrower. These considerations require significant judgment and vary by portfolio segment. In all cases, the cumulative impacts of all modifications are considered at the time of the most recent modification. For consumer loans of all classes, various qualitative factors are utilized for assessing the financial difficulty of the borrower. These include, but are not limited to, the borrower’s default status on any of its debts, bankruptcy and recent changes in financial circumstances (loss of job, etc.). A concession has been granted when as a result of the modification we do not expect to collect all amounts due under the original loan terms, including interest accrued at the original contract rate. Types of modifications that may be considered concessions include, but are not limited to, extensions of terms at a rate that does not constitute a market rate, a reduction, deferral or forgiveness of principal or interest owed and loans that have been discharged in a Chapter 7 Bankruptcy and have not been reaffirmed by the borrower. In addition to the modifications noted above, in our consumer automotive portfolio segment of loans we also provide extensions or deferrals of payments to borrowers whom we deem to be experiencing only temporary financial difficulty. In these cases, there are limits within our operational policies to minimize the number of times a loan can be extended, as well as limits to the length of each extension, including a cumulative cap over the life of the loan. If these limits are breached, the modification is considered a TDR as noted in the following paragraph. Before offering an extension or deferral, we evaluate the capacity of the customer to make the scheduled payments after the deferral period. During the deferral period, we continue to accrue and collect interest on the loan as part of the deferral agreement. We grant these extensions or deferrals when we expect to collect all amounts due including interest accrued at the original contract rate. A restructuring that results in only a delay in payment that is deemed to be insignificant is not a concession and the modification is not considered to be a TDR. In order to assess whether a restructuring that results in a delay in payment is insignificant, we consider the amount of the restructured payments subject to delay in conjunction with the unpaid principal balance or the collateral value of the loan, whether or not the delay is significant with respect to the frequency of payments under the original contract, or the loan’s original expected duration. In the cases where payment extensions on our automotive loan portfolio cumulatively extend beyond 90 days and are more than 10% of the original contractual term or where the cumulative payment extension is beyond 180 days, we deem the delay in payment to be more than insignificant, and as such, classify these types of modifications as TDRs. Otherwise, we believe that the modifications do not represent a concessionary modification and accordingly, they are not classified as TDRs. For commercial loans of all classes, similar qualitative factors are considered when assessing the financial difficulty of the borrower. In addition to the factors noted above, consideration is also given to the borrower’s forecasted ability to service the debt in accordance with the contractual terms, possible regulatory actions and other potential business disruptions (e.g., the loss of a significant customer or other revenue stream). Consideration of a concession is also similar for commercial loans. In addition to the factors noted above, consideration is also given to whether additional guarantees or collateral have been provided. For all loans, TDR classification typically results from our loss mitigation activities. For loans held-for-investment that are not carried at fair value and are TDRs, impairment is typically measured based on the difference between the gross carrying value of the loan and the present value of the expected future cash flows of the loan. The loan may also be measured for impairment based on the fair value of the underlying collateral less costs to sell for loans that are collateral dependent. We recognize impairment by either establishing a valuation allowance or recording a charge-off. The financial impacts of modifications that meet the definition of a TDR are reported in the period in which they are identified as TDRs. Additionally, if a loan that is classified as a TDR redefaults within twelve months of the modification, we are required to disclose the instances of redefault. For the purpose of this disclosure, we have determined that a loan is considered to have redefaulted when the loan meets the requirements for evaluation under our charge-off policy except for commercial loans where redefault is defined as 90 days past due. Impaired loans may return to accrual status as discussed in the preceding nonaccrual loan section at which time, the normal accrual of interest income resumes. Net Charge-offs We disclose the measurement of net charge-offs as the amount of gross charge-offs recognized less recoveries received. Gross charge-offs reflect the amount of the gross carrying value directly written-off. Generally, we recognize recoveries when they are received and record them as an increase to the allowance for loan losses. As a general rule, consumer automotive loans are written down to estimated collateral value, less costs to sell, once a loan becomes 120 days past due. In our consumer mortgage portfolio segment, first-lien mortgages and a subset of our home equity portfolio that are secured by real estate in a first-lien position are written down to the estimated fair value of the collateral, less costs to sell, once a mortgage loan becomes 180 days past due. Consumer mortgage loans that represent second-lien positions are charged off at 180 days past due. Within 60 days of receipt of notification of filing from the bankruptcy court, or within the time frames noted above, consumer automotive and first-lien consumer mortgage loans in bankruptcy are written down to their expected future cash flows, which is generally fair value of the collateral, less costs to sell, and second-lien consumer mortgage loans are fully charged-off, unless it can be clearly demonstrated that repayment is likely to occur. Regardless of other timelines noted within this policy, loans are considered collateral dependent once foreclosure or repossession proceedings begin and are charged-off to the estimated fair value of the underlying collateral, less costs to sell at that time. Commercial loans are individually evaluated and where collectability of the recorded balance is in doubt are written down to the estimated fair value of the collateral less costs to sell. Generally, all commercial loans are charged-off when it becomes unlikely that the borrower is willing or able to repay the remaining balance of the loan and any underlying collateral is not sufficient to recover the outstanding principal. Collateral dependent loans are charged-off to the fair market value of collateral less costs to sell when appropriate. Noncollateral dependent loans are fully written-off.
Allowance for Loan Losses, Policy	The allowance for loan losses (the allowance) is management’s estimate of incurred losses in the lending portfolios. We determine the amount of the allowance required for each of our portfolio segments based on its relative risk characteristics. The evaluation of these factors for both consumer and commercial finance receivables and loans involves quantitative analysis combined with sound management judgment. Additions to the allowance are charged to current period earnings through the provision for loan losses; amounts determined to be uncollectible are charged directly against the allowance, net of amounts recovered on previously charged-off accounts. The allowance is composed of two components: specific reserves established for individual loans evaluated as impaired and portfolio-level reserves established for large groups of typically smaller balance homogeneous loans that are collectively evaluated for impairment. We evaluate the adequacy of the allowance based on the combined total of these two components. Determining the appropriateness of the allowance is complex and requires judgment by management about the effect of matters that are inherently uncertain. It is possible that others, given the same information, may at any point in time reach different reasonable conclusions. Measurement of impairment for specific reserves is generally determined on a loan-by-loan basis. Loans determined to be specifically impaired are measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate, an observable market price, or the estimated fair value of the collateral less estimated costs to sell when appropriate, whichever is determined to be the most appropriate. When these measurement values are lower than the net carrying value of that loan, impairment is recognized. Loans that are not identified as individually impaired are pooled with other loans with similar risk characteristics for evaluation of impairment for the portfolio-level allowance. For the purpose of calculating portfolio-level reserves, we have grouped our loans into three portfolio segments: consumer automotive, consumer mortgage, and commercial. The allowance consists of the combination of a quantitative assessment component based on statistical models, a retrospective evaluation of actual loss information to loss forecasts, and includes a qualitative component based on management judgment. Management takes into consideration relevant qualitative factors, including external and internal trends such as the impacts of changes in underwriting standards, collections and account management effectiveness, geographic concentrations, and economic events, among other factors, that have occurred but are not yet reflected in the quantitative assessment component. Qualitative adjustments are documented, reviewed, and approved through our established risk governance processes and follow regulatory guidance. Management also considers the need for a reserve on unfunded non-derivative loan commitments across our portfolio segments, including lines of credit and standby letters of credit, using similar procedures and methodologies used to determine the allowance for loan losses while also considering historical loss ratios and potential usage levels. The reserve for unfunded loan commitments is recorded within other liabilities on our Consolidated Balance Sheet and the related expense is reported as other noninterest expense in our Consolidated Statement of Comprehensive Income. Refer to Note 28 for information on our unfunded loan commitments. During 2018, we did not substantively change any material aspect of our overall approach used to determine the allowance for loan losses for our portfolio segments. There were no material changes in criteria or estimation techniques as compared to prior periods that impacted the determination of the current period allowance for loan losses for our portfolio segments. Refer to Note 9 for information on the allowance for loan losses. Consumer Loans Our consumer automotive and consumer mortgage portfolio segments are reviewed for impairment based on an analysis of loans that are grouped into common risk categories. We perform periodic and systematic detailed reviews of our lending portfolios to identify inherent risks and to assess the overall collectability of those portfolios. Loss models are utilized for these portfolios, which consider a variety of credit quality indicators including, but not limited to, historical loss experience, current economic conditions, credit scores, and expected loss factors by loan type. Consumer Automotive Portfolio Segment The allowance for loan losses within the consumer automotive portfolio segment is calculated using proprietary statistical models and other risk indicators applied to pools of loans with similar risk characteristics, including credit bureau score and loan-to-value (LTV) ratios to arrive at an estimate of incurred losses in the portfolio. These statistical loss forecasting models are utilized to estimate incurred losses and consider a variety of factors including, but not limited to, historical loss experience, estimated defaults based on portfolio trends, and general economic and business trends. These statistical models predict forecasted losses inherent in the portfolio. The forecasted losses consider historical factors such as frequency (the number of contracts that we expect to default) and loss severity (the loss amount of contracts we expect to default). The loss severity within the consumer automotive portfolio segment is impacted by the market values of vehicles that are repossessed. Vehicle market values are affected by numerous factors including vehicle supply, the condition of the vehicle upon repossession, the overall price and volatility of gasoline or diesel fuel, consumer preference related to specific vehicle segments, and other factors. The quantitative assessment component of the allowance may be supplemented with qualitative reserves based on management’s determination that such adjustments provide a better estimate of credit losses. This qualitative assessment takes into consideration relevant internal and external factors that have occurred, but are not yet reflected in the forecasted losses, and may affect the performance of the portfolio. Consumer Mortgage Portfolio Segment The allowance for loan losses within the consumer mortgage portfolio segment is calculated by using statistical models based on pools of loans with similar risk characteristics, including credit score, LTV, loan age, documentation type, product type, and loan purpose, to arrive at an estimate of incurred losses in the portfolio. These statistical loss forecasting models are utilized to estimate incurred losses and consider a variety of factors including, but not limited to, historical loss experience, estimated foreclosures or defaults based on portfolio trends, delinquencies, and general economic and business trends. The forecasted losses are statistically derived based on a suite of behavioral based transition models. This transition framework predicts various stages of delinquency, default, and voluntary prepayment over the course of the life of the loan. The transition probability is a function of the loan and borrower characteristics and economic variables and considers historical factors such as frequency and loss severity. When a default event is predicted, a severity model is applied to estimate future loan losses. Loss severity within the consumer mortgage portfolio segment is impacted by the market values of foreclosed properties, which is affected by numerous factors, including geographic considerations and the condition of the foreclosed property. The quantitative assessment component of the allowance may be supplemented with qualitative reserves based on management’s determination that such adjustments provide a better estimate of credit losses. This qualitative assessment takes into consideration relevant internal and external factors that have occurred, but are not yet reflected in the forecasted losses, and may affect the performance of the portfolio. Commercial Loans The allowance for loan losses within the commercial portfolio is composed of reserves established for specific loans evaluated as impaired and portfolio-level reserves based on nonimpaired loans grouped into pools based on similar risk characteristics and collectively evaluated. A commercial loan is considered impaired when it is probable that we will be unable to collect all amounts due according to the contractual terms of the loan agreement based on current information and events. These loans are primarily evaluated individually and are risk-rated based on borrower, collateral, and industry-specific information that management believes is relevant in determining the occurrence of a loss event and measuring impairment. Management establishes specific allowances for commercial loans determined to be individually impaired based on the present value of expected future cash flows, discounted at the loan’s effective interest rate, observable market prices, or the fair value of collateral—whichever is determined to be the most appropriate. Estimated costs to sell or realize the value of the collateral on a discounted basis are included in the impairment measurement, when appropriate. Loans not identified as impaired are grouped into pools based on similar risk characteristics and collectively evaluated. Our risk rating models use historical loss experience, concentrations, current economic conditions, and performance trends. The commercial historical loss experience is updated quarterly to incorporate the most recent data reflective of the current economic environment. The determination of the allowance is influenced by numerous assumptions and many factors that may materially affect estimates of loss, including volatility of loss given default, probability of default, and rating migration. In assessing the risk rating of a particular loan, several factors are considered including an evaluation of historical and current information involving subjective assessments and interpretations. In addition, the allowance related to the commercial portfolio segment is influenced by estimated recoveries from automotive manufacturers in those cases where we have guarantees or agreements with them to repurchase vehicles used as collateral to secure the loans. The quantitative assessment component of the allowance may be supplemented with qualitative reserves based on management’s determination that such adjustments provide a better estimate of credit losses. This qualitative assessment takes into consideration relevant internal and external factors that have occurred, but are not yet reflected in the forecasted losses, and may affect the performance of the portfolio.
Variable Interest Entities and Securitizations, Policy	VIEs are legal entities that either have an insufficient amount of equity at risk for the entity to finance its activities without additional subordinated financial support or, as a group, the holders of equity investment at risk lack the ability to direct the entity’s activities that most significantly impact economic performance through voting or similar rights, or do not have the obligation to absorb the expected losses or the right to receive expected residual returns of the entity. For all VIEs in which we are involved, we assess whether we are the primary beneficiary of the VIE on an ongoing basis. In circumstances where we have both the power to direct the activities that most significantly impact the VIEs performance and the obligation to absorb losses or the right to receive the benefits of the VIE that could be significant, we would conclude that we are the primary beneficiary of the VIE, and would consolidate the VIE (also referred to as on-balance sheet). In situations where we are not deemed to be the primary beneficiary of the VIE, we do not consolidate the VIE and only recognize our interests in the VIE (also referred to as off-balance sheet). We are involved in securitizations that typically involve the use of VIEs. For information regarding the company’s securitization activities, refer to Note 11 . In the case of a consolidated on-balance sheet VIE used for a securitization, the underlying assets remain on our Consolidated Balance Sheet with the corresponding obligations to third party beneficial interest holders reflected as debt. We recognize income on the assets, interest expense on the debt issued by the VIE, and losses on the assets as incurred. Consolidation of the VIE precludes us from recording an accounting sale on the transaction. In securitizations where we are not determined to be the primary beneficiary of the VIE, we must determine whether we achieve a sale for accounting purposes. To achieve a sale for accounting purposes, the financial assets being transferred must be legally isolated, not be constrained by restrictions from further transfer, and be deemed to be beyond our control. We would deem the transaction to be an off-balance sheet securitization if the preceding three criteria for sale accounting are met. If we were to fail any of these three criteria for sale accounting, the transfer would be accounted for as a secured borrowing consistent with the preceding paragraph regarding on-balance sheet VIEs. The gain or loss recognized on off-balance sheet securitizations take into consideration any assets received or liabilities assumed, including any retained interests, and servicing assets or liabilities (if applicable), which are initially recorded at fair value at the date of sale. Upon the sale of the financial assets, we recognize a gain or loss on sale for the difference between the assets and liabilities recognized, and the assets derecognized. The financial assets obtained from off-balance sheet securitizations are primarily reported as cash or if applicable, retained interests. Retained interests are classified as securities or as other assets depending on their form and structure. The estimate of the fair value of the retained interests and servicing requires us to exercise significant judgment about the timing and amount of future cash flows from the interests. For a discussion on fair value estimates, refer to Note 24 . Gains or losses on off-balance sheet securitizations are reported in gain on mortgage and automotive loans, net, in our Consolidated Statement of Income. We retain the right to service our consumer and commercial automotive loan and operating lease securitizations. We may receive servicing fees for off-balance sheet securitizations based on the securitized asset balances and certain ancillary fees, all of which are reported in servicing fees in the Consolidated Statement of Income. Typically, the fee we are paid for servicing represents adequate compensation, and consequently, does not result in the recognition of a servicing asset or liability.
Repossessed and Foreclosed Assets, Policy	Assets securing our finance receivables and loans are classified as repossessed and foreclosed and included in other assets when physical possession of the collateral is taken, which includes the transfer of title through foreclosure or other similar proceedings. Repossessed and foreclosed assets are initially recognized at the lower of the outstanding balance at the time of repossession or foreclosure or the fair value of the asset less estimated costs to sell. Losses on the revaluation of repossessed and foreclosed assets (and generally, declines in value shortly after repossession or foreclosure) are recognized as a charge-off of the allowance for loan losses. Subsequent declines in value are charged to other operating expenses.
Investment in Operating Leases, Policy	Investment in operating leases, net, represents the automobiles that are underlying our automotive operating lease contracts and is reported at cost, less accumulated depreciation and net of impairment charges and origination fees or costs. Depreciation of vehicles is recorded on a straight-line basis to an estimated residual value over the lease term. Manufacturer support payments that we receive upfront are treated as a reduction to the cost-basis in the underlying operating lease asset, which has the effect of reducing depreciation expense over the life of the contract. We periodically evaluate our depreciation rate for leased vehicles based on expected residual values and adjust depreciation expense over the remaining life of the lease if deemed necessary. Income from operating lease assets that includes lease origination fees, net of lease origination costs, is recognized as operating lease revenue on a straight-line basis over the scheduled lease term. We have significant investments in the residual values of the assets in our operating lease portfolio. The residual values represent an estimate of the values of the assets at the end of the lease contracts. At contract inception, we determine pricing based on the projected residual value of the leased vehicle. This evaluation is primarily based on a proprietary model, which includes variables such as age, expected mileage, seasonality, segment factors, vehicle type, economic indicators, production cycle, automotive manufacturer incentives, and shifts in used vehicle supply. This internally-generated data is compared against third-party, independent data for reasonableness. Realization of the residual values is dependent on our future ability to market the vehicles under the prevailing market conditions. Over the life of the lease, we evaluate the adequacy of our estimate of the residual value and make adjustments to the depreciation rates to the extent the expected value of the vehicle at lease termination changes. In addition to estimating the residual value at lease termination, we also evaluate the current value of the operating lease asset and test for impairment to the extent necessary when there is an indication of impairment based on market considerations and portfolio characteristics. Impairment is determined to exist if fair value of the leased asset is less than carrying value and it is determined that the net carrying value is not recoverable. The net carrying value of a leased asset is not recoverable if it exceeds the sum of the undiscounted expected future cash flows expected to result from the operating lease payments and the estimated residual value upon eventual disposition. If our operating lease assets are considered to be impaired, the impairment is measured as the amount by which the carrying amount of the assets exceeds the fair value as estimated by discounted cash flows. No impairment was recognized in 2018 , 2017 , or 2016 . We accrue rental income on our operating leases when collection is reasonably assured. We generally discontinue the accrual of revenue on operating leases at the time an account is determined to be uncollectible, which we determine to be the earliest of (i) the time of repossession, (ii) within 60 days of bankruptcy notification, unless it can be clearly demonstrated that repayment is likely to occur, or (iii) greater than 120 days past due. When a leased vehicle is returned to us, either at the end of the lease term or through repossession, the asset is reclassified from investment in operating leases, net, to other assets and recorded at the lower-of-cost or estimated fair value, less costs to sell, on our Consolidated Balance Sheet. Any losses recognized at this time are recorded as depreciation expense. Subsequent decline in value and any gain or loss recognized at the time of sale is recognized as a remarketing gain or loss and presented as a component of depreciation expense.
Impairment of Long-lived Assets, Policy	The net carrying values of long-lived assets (including property and equipment) are evaluated for impairment whenever events or changes in circumstances indicate that their net carrying values may not be recoverable from the estimated undiscounted future cash flows expected to result from their use and eventual disposition. Recoverability of assets to be held and used is measured by a comparison of their net carrying amount to future net undiscounted cash flows expected to be generated by the assets. If these assets are considered to be impaired, the impairment is measured as the amount by which the net carrying amount of the assets exceeds the fair value estimated using a discounted cash flow method. No material impairment was recognized in 2018 , 2017 , or 2016 . An impairment test on an asset group to be sold or otherwise disposed of is performed upon occurrence of a triggering event or when certain criteria are met (e.g., the asset is planned to be disposed of within twelve months, appropriate levels of authority have approved the sale, there is an active program to locate a buyer, etc.), which cause the disposal group to be classified as held-for-sale. Long-lived assets held-for-sale are recorded at the lower of their carrying amount or estimated fair value less cost to sell. If the net carrying value of the assets held-for-sale exceeds the fair value less cost to sell, we recognize an impairment loss based on the excess of the net carrying amount over the fair value of the assets less cost to sell. Refer to Note 2 for a discussion of discontinued operations.
Property and Equipment, Policy	Property and equipment stated at cost, net of accumulated depreciation and amortization, are reported in other assets on our Consolidated Balance Sheet. Included in property and equipment are certain buildings, furniture and fixtures, leasehold improvements, IT hardware and software, capitalized software costs, and assets under construction. We begin depreciating these assets when they are ready for their intended use. Depreciation is recorded on a straight-line basis over the estimated useful lives of the assets, which generally ranges from three to thirty years depending on the asset class. Capitalized software is generally amortized on a straight-line basis over its useful life, which generally ranges from three to five years. Capitalized software that is not expected to provide substantive service potential or for which development costs significantly exceed the amount originally expected is considered impaired and written down to fair value. Software expenditures that are considered general, administrative, or of a maintenance nature are expensed as incurred.
Goodwill and Other Intangibles, Policy	Goodwill and intangible assets, net of accumulated amortization, are reported in other assets. Our intangible assets primarily consist of acquired customer relationships and developed technology, and are amortized using a straight line methodology over their estimated useful lives. We review intangible assets for impairment at least annually, or whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable. If it is determined the carrying amount of the asset is not recoverable, an impairment charge is recorded. Goodwill represents the excess of the cost of an acquisition over the fair value of net assets acquired, including identifiable intangibles. We allocate goodwill to applicable reporting units based on the relative fair value of the other net assets allocated to those reporting units at the time of the acquisition. In the event we restructure our business, we may reallocate goodwill. We test goodwill for impairment annually, or more frequently if events and changes in circumstances indicate that it is more likely than not that impairment exists. Our annual goodwill impairment test is performed as of August 31 of each year. In certain situations, we may perform a qualitative assessment to test goodwill for impairment. We may also decide to bypass the qualitative assessment and perform a quantitative assessment. If we perform the qualitative assessment to test goodwill for impairment and conclude that it is more likely than not that the reporting unit’s fair value is greater than its carrying value, then the quantitative assessment is not required. However, if we perform the qualitative assessment and determine that it is more likely than not that a reporting unit’s fair value is less than its carrying value, then we must perform the quantitative assessment. The quantitative assessment uses a two-step process. The first step of the assessment requires us to compare the fair value of each of the reporting units to their respective carrying value. The fair value of the reporting units in our quantitative assessment is determined based on various analyses including discounted cash flow projections using assumptions a market participant would use. If the carrying value is less than the fair value, no impairment exists, and the second step does not need to be completed. If the carrying value is greater than the fair value or there is an indication that impairment may exist, a second step must be performed where we determine the implied value of goodwill based on the individual fair values of the reporting unit’s assets and liabilities, including unrecognized intangibles, to compute the amount of the impairment.
Unearned Insurance Premiums and Service Revenue, Policy	Insurance premiums, net of premiums ceded to reinsurers, and service revenue are earned over the terms of the policies. The portion of premiums and service revenue written applicable to the unexpired terms of the policies is recorded as unearned insurance premiums or unearned service revenue. For vehicle service and maintenance contracts, premiums and service revenues are earned on a basis proportionate to the anticipated cost emergence. For additional information related to these contracts, refer to Note 3 . For other short duration contracts, premiums and service revenue are earned on a pro rata basis. For further information, refer to Note 4 .
Deferred Insurance Policy Acquisition Costs, Policy	Certain incremental direct costs incurred to originate a policy are deferred and recorded in other assets. These costs primarily include commissions paid to dealers to originate these policies and vary with the production of business. Deferred policy acquisition costs are amortized over the terms of the related policies and service contracts on the same basis as premiums and service revenue are earned. We group costs incurred for acquiring like contracts and consider anticipated investment income in determining the recoverability of these costs.
Reserves for Insurance Losses and Loss Adjustment Expenses, Policy	Reserves for insurance losses and loss adjustment expenses are reported in accrued expenses and other liabilities on our Consolidated Balance Sheet. They are established for the unpaid cost of insured events that have occurred as of a point in time. More specifically, the reserves for insurance losses and loss adjustment expenses represent the accumulation of estimates for both reported losses and those incurred, but not reported, including loss adjustment expenses relating to direct insurance and assumed reinsurance agreements. We use a combination of methods commonly used in the insurance industry, including the chain ladder development factor, expected loss, Bornhuetter Ferguson (BF), and frequency and severity methods to determine the ultimate losses for an individual business line as well as accident year basis depending on the maturity of the accident period and business-line specifics. These methodologies are based on different assumptions and use various inputs to develop alternative estimates of losses. The chain ladder development factor is used for more mature years where expected loss, BF, and frequency and severity methods are used for less mature years. Both paid and incurred loss and loss adjustment expenses are reviewed where available and a weighted average of estimates or a single method may be considered in selecting the final estimate for an individual accident period. We did not change our methodology for developing reserves for insurance losses for the year ended December 31, 2018 . Estimates for salvage and subrogation recoverable are recognized at the time losses are incurred and netted against the provision for insurance losses and loss adjustment expenses. Reserves are established for each business at the lowest meaningful level of homogeneous data. Since the reserves are based on estimates, the ultimate liability may vary from such estimates. The estimates are regularly reviewed and adjustments, which can potentially be significant, are included in earnings in the period in which they are deemed necessary.
Legal and Regulatory Reserves, Policy	Reserves for legal and regulatory matters are established when those matters present loss contingencies that are both probable and estimable, with a corresponding amount recorded to other operating expense. In cases where we have an accrual for losses, it is our policy to include an estimate for probable and estimable legal expenses related to the case. If, at the time of evaluation, the loss contingency related to a legal or regulatory matter is not both probable and estimable, we do not establish a liability for the contingency. We continue to monitor legal and regulatory matters for further developments that could affect the requirement to establish a liability or that may impact the amount of a previously established liability. There may be exposure to loss in excess of any amounts recognized. For certain other matters where the risk of loss is determined to be reasonably possible, estimable, and material to the financial statements, disclosure regarding details of the matter and an estimated range of loss is required. The estimated range of possible loss does not represent our maximum loss exposure. We also disclose matters that are deemed probable or reasonably possible, material to the financial statements, but for which an estimated range of loss is not possible to determine. While we believe our reserves are adequate, the outcome of legal and regulatory proceedings is extremely difficult to predict and we may settle claims or be subject to judgments for amounts that differ from our estimates. For information regarding the nature of all material contingencies, refer to Note 29 .
Earnings per Common Share, Policy	We compute basic earnings per common share by dividing net income from continuing operations attributable to common stockholders after deducting dividends on preferred stock by the weighted-average number of common shares outstanding during the period. We compute diluted earnings per common share by dividing net income from continuing operations after deducting dividends on preferred stock by the weighted-average number of common shares outstanding during the period plus the dilution resulting from incremental shares that would have been outstanding if dilutive potential common shares had been issued (assuming it does not have the effect of antidilution), if applicable.
Derivative Instruments and Hedging Activities, Policy	We use derivative instruments primarily for risk management purposes. We do not use derivative instruments for speculative purposes. Certain of our derivative instruments are designated as accounting hedges in qualifying relationships, whereas other derivative instruments have not been designated as accounting hedges. In accordance with applicable accounting standards, all derivative instruments, whether designated for hedge accounting or not, are required to be recorded on the balance sheet as assets or liabilities and measured at fair value. We have elected to report the fair value of derivative assets and liabilities on a gross basis—including the fair value for the right to reclaim cash collateral or the obligation to return cash collateral—arising from instruments executed with the same counterparty under a master netting arrangement where we do not have the intent to offset. For additional information on derivative instruments and hedging activities, refer to Note 21 . At the inception of a hedge accounting relationship, we designate each qualifying hedge relationship as a hedge of the fair value of a specifically identified asset or liability (fair value hedge); as a hedge of the variability of cash flows to be received or paid, or forecasted to be received or paid, related to a recognized asset or liability (cash flow hedge); or as a hedge of the foreign-currency exposure of a net investment in a foreign operation (net investment hedge). We formally document all relationships between hedging instruments and hedged items, as well as the risk management objectives for undertaking various hedge transactions. Both at hedge inception and on an ongoing basis, we formally assess whether the derivatives that are used in hedging relationships are highly effective in offsetting changes in fair values or cash flows of hedged items. Changes in the fair value of derivative instruments qualifying as fair value hedges, along with the gain or loss on the hedged asset or liability attributable to the hedged risk, are recorded in current period earnings. For qualifying cash flow hedges, changes in the fair value of the derivative financial instruments are recorded in accumulated other comprehensive income, and recognized in the income statement when the hedged cash flows affect earnings. For a qualifying net investment hedge, the gain or loss is reported in accumulated other comprehensive income as part of the cumulative translation adjustment. Hedge accounting treatment is no longer applied if a derivative financial instrument is terminated, or if the hedge designation is removed or assessed to be no longer highly effective. For terminated fair value hedges, any changes to the hedged asset or liability remain as part of the basis of the hedged asset or liability and are recognized into income over the remaining life of the asset or liability. For terminated cash flow hedges, unless it is probable that the forecasted cash flows will not occur within a specified period, any changes in fair value of the derivative financial instrument previously recognized remain in accumulated other comprehensive income, and are reclassified into earnings in the same period that the hedged cash flows affect earnings. Any previously recognized gain or loss for a net investment hedge continues to remain in accumulated other comprehensive income until earnings are impacted by sale or liquidation of the associated foreign operation. In all instances, after hedge accounting is no longer applied, any subsequent changes in fair value of the derivative instrument will be recorded into earnings. Changes in the fair value of derivative financial instruments held for risk management purposes that are not designated as accounting hedges under GAAP are reported in current period earnings.
Income Taxes, Policy	Our income tax expense, deferred tax assets and liabilities, and reserves for unrecognized tax benefits reflect management’s best assessment of estimated future taxes to be paid. We are subject to income taxes predominantly in the United States. Significant judgments and estimates are required in determining the consolidated income tax expense. Deferred income taxes arise from temporary differences between the tax and financial statement recognition of revenue and expense. In evaluating our ability to recover our deferred tax assets within the jurisdiction from which they arise we consider all available positive and negative evidence including scheduled reversals of deferred tax liabilities, projected future taxable income, tax planning strategies and recent financial operations. In projecting future taxable income, we begin with historical results adjusted for the results of discontinued operations and changes in accounting policies and incorporate assumptions including the amount of future state, federal and foreign pretax operating income, the reversal of temporary differences, and the implementation of feasible and prudent tax planning strategies. We use the portfolio method with respect to reclassification of stranded income tax effects in accumulated other comprehensive income. We recognize the financial statement effects of uncertain income tax positions when it is more likely than not, based on the technical merits, that the position will be sustained upon examination. Also, we recognize accrued interest and penalties related to liabilities for uncertain income tax positions in interest expense and other operating expenses, respectively. For additional information regarding our provision for income taxes, refer to Note 22 .
Share-based Compensation, Policy	Our compensation and benefits expenses include the cost of share-based awards issued to employees. For equity classified share-based awards, compensation cost is ratably charged to expense based on the grant date fair value of the awards over the applicable service periods. For liability classified share-based awards, the associated liability is measured quarterly at fair value based on our share price and services rendered at the time of measurement until the awards are paid, with changes in fair value charged to compensation expense in the period in which the change occurs. We have made an accounting policy election to account for forfeitures of share-based awards as they occur. Refer to Note 23 for a discussion of our share-based compensation plans.
Foreign Exchange, Policy	Foreign-denominated assets and liabilities resulting from foreign-currency transactions are valued using period-end foreign-exchange rates and the results of operations and cash flows are determined using approximate weighted average exchange rates for the period. Translation adjustments are related to foreign subsidiaries using local currency as their functional currency and are reported as a separate component of accumulated other comprehensive income. Translation gains or losses are reclassified to earnings upon the substantial sale or liquidation of our investments in foreign operations. We may elect to enter into foreign-currency derivatives to mitigate our exposure to changes in foreign-exchange rates. Refer to the Derivative Instruments and Hedging Activities section above for a discussion of our hedging activities of the foreign-currency exposure of a net investment in a foreign operation.
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy	In May 2014, the Financial Accounting Standards Board (FASB) issued ASU 2014-09. The purpose of this guidance is to streamline and consolidate existing revenue recognition principles in GAAP and to converge revenue recognition principles with International Financial Reporting Standards. The core principle of the amendments is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to receive in exchange for those goods or services. The amendments include a five step process for consideration of the core principle, guidance on the accounting treatment for costs associated with a contract, and disclosure requirements related to the revenue process. The FASB issued several additional ASUs to clarify guidance and provide implementation support for ASU 2014-09. The clarifying guidance elaborates on the key concepts within ASU 2014-09 and clarifies how those concepts interact with other GAAP requirements. On January 1, 2018, we adopted ASU 2014-09 and all subsequent ASUs that modified ASU 2014-09 (collectively, the amendments to the revenue recognition principles), which have been codified in ASC 606, Revenue from Contracts with Customers, and ASC 610-20, Gains and Losses from the Derecognition of Nonfinancial Assets, respectively. We elected to adopt this guidance using the modified retrospective approach applied to all contracts with customers that were not completed as of January 1, 2018. The adoption of the amendments resulted in a reduction to our opening retained earnings of approximately $126 million , net of income taxes. Refer to Note 3 for further details.
Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy	As of January 1, 2018, we adopted ASU 2016-01. The amendments in this update modify the requirements related to the measurement of certain financial instruments in the statement of financial condition and results of operations. The FASB subsequently issued ASU 2018-03 to clarify guidance and provide implementation support for ASU 2016-01, which we elected to early-adopt as of January 1, 2018, to align with the adoption of ASU 2016-01. For equity investments (other than investments accounted for using the equity method), entities must measure such instruments at fair value with changes in fair value recognized in net income. Changes in fair value for equity securities are no longer recognized through other comprehensive (loss) income, which creates additional volatility in our Consolidated Statement of Comprehensive Income. Reporting entities may continue to elect to measure certain equity investments that do not have a readily determinable fair value at cost with adjustments for impairment and observable changes in price. In addition, for a liability (other than a derivative liability) that an entity measures at fair value, any change in fair value related to the instrument-specific credit risk, that is the entity’s own-credit, should be presented separately in other comprehensive (loss) income and not as a component of net income. We adopted these amendments, as required, on a modified retrospective basis with a cumulative effect adjustment as of the beginning of the fiscal year of initial adoption. The adoption of the amendments resulted in an increase to our opening accumulated deficit of approximately $20 million , net of income taxes.
Accounting Standards Update 2017-12
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy	As of January 1, 2018, we elected to early-adopt ASU 2017-12. The amendments in this update enhance the financial reporting of hedging relationships to better align hedge accounting with an entity’s risk-management activities. This update also makes certain targeted improvements to simplify the application of the hedge accounting guidance in current GAAP and better portrays economic results through changes to both the designation and measurement guidance for qualifying hedging relationships and presentation of hedge results. We adopted the amendments to all cash flow and net investment hedge relationships that existed on the date of adoption using a modified retrospective approach. No cumulative effect adjustment to our opening retained earnings was required as a result of the adoption. The presentation and disclosure requirements included in this update were adopted prospectively. Refer to Note 21 for further details.
Accounting Standards Update 2018-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy	In February 2018, the FASB issued ASU 2018-02. The amendments in this update provide guidance concerning the treatment of the impact of income tax effects resulting from the Tax Cuts and Jobs Act of 2017 (the Tax Act) on items included in accumulated other comprehensive income. Our policy is to use the portfolio method with respect to reclassification of stranded income tax effects in accumulated other comprehensive loss. The amendments in ASU 2018-02 provide entities an election to reclassify the income tax effect of the Tax Act from accumulated other comprehensive income to retained earnings. We elected to early-adopt this standard as of January 1, 2018, and reclassified the effect of the change in the federal corporate income tax rate on items included in accumulated other comprehensive loss. This election resulted in a reclassification of $42 million from accumulated other comprehensive loss to accumulated deficit.
Accounting Standards Update 2018-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy	In August 2018, the FASB issued ASU 2018-13. The amendments in this update modify, remove, and add certain disclosure requirements for fair value measurements based on the FASB Concepts Statement, Conceptual Framework for Financial Reporting—Chapter 8: Notes to Financial Statements. The ASU is effective on January 1, 2020, and early adoption is permitted. The amendments include (i) the removal of certain disclosure requirements related to transfers between fair value input levels and the valuation process for Level 3 fair value measurements, (ii) modification of the disclosures on measurement uncertainty and certain disclosures related to investment in entities that calculate net asset value, and (iii) additional disclosure requirements related to changes in unrealized gains and losses included in other comprehensive income for recurring Level 3 measurements and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. The modification of the narrative disclosure on measurement uncertainty, the disclosure of changes in unrealized gains and losses, and disclosure of the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements should be applied prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. We elected to early-adopt the amendments that allow for removal and modification of certain disclosure requirements, as well as the amendments that require additional fair value measurement disclosures, as of September 30, 2018, and December 31, 2018, respectively. The adoption of these amendments did not result in significant changes to our disclosures and did not have an impact on our financial position or results of operations. Refer to Note 24 for further details.
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy	In February 2016, the FASB issued ASU 2016-02. The amendments in this update primarily replace the existing accounting requirements for operating leases for lessees. Lessee accounting requirements for finance leases and lessor accounting requirements for operating leases and sales type and direct financing leases (sales-type and direct financing leases were both previously referred to as capital leases) are largely unchanged. The amendments require the lessee of an operating lease to record a balance sheet gross-up upon lease commencement by recognizing a right-of-use asset and lease liability equal to the present value of the lease payments. The right-of-use asset and lease liability should be derecognized in a manner that effectively yields a straight line lease expense over the lease term. In addition to the changes to the lessee operating lease accounting requirements, the amendments also change the types of costs that can be capitalized related to a lease agreement for both lessees and lessors. The amendments also require additional disclosures for all lease types for both lessees and lessors. The FASB has subsequently issued additional ASUs intended to clarify guidance, provide implementation support, and provide an additional transition election. The amendments are effective on January 1, 2019, with early adoption permitted. The amendments must be applied on a modified retrospective basis, and we have selected the transition option that will allow us to record a cumulative adjustment as of the adoption date. We have elected certain practical expedients permitted within the ASU that allow us to not reassess (i) current lease classifications, (ii) whether existing contracts meet the definition of a lease under the amendments to the lease guidance, and (iii) whether current initial direct costs meet the new criteria for capitalization, for all existing leases as of the adoption date. Upon adoption of the amendments on January 1, 2019, we expect to recognize a right-of-use asset of approximately $161 million from operating leases, primarily for our various corporate facilities, a $29 million reduction to accrued expenses and other liabilities for accrued rent and unamortized tenant improvement allowances, and a lease liability of approximately $190 million . Additionally, upon adoption we expect to expand our financial statement disclosures as required by the amendments, as well as implement any necessary changes to our control environment and reporting processes to reflect the requirements of the amendments.
Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy	In June 2016, the FASB issued ASU 2016-13. The amendments in this update introduce a new accounting model to measure credit losses for financial assets measured at amortized cost . Credit losses for financial assets measured at amortized cost should be determined based on the total current expected credit losses over the life of the financial asset or group of financial assets. In effect, the financial asset or group of financial assets should be presented at the net amount expected to be collected. Credit losses will no longer be recorded under the current incurred loss model for financial assets measured at amortized cost. The amendments also modify the accounting for available-for-sale debt securities whereby credit losses will be recorded through an allowance for credit losses rather than a write-down to the security’s cost basis, which allows for reversals of credit losses when estimated credit losses decline. Credit losses for available-for-sale debt securities should be measured in a manner similar to current GAAP. The amendments are effective on January 1, 2020, with early adoption permitted as of January 1, 2019. The amendments must be applied using a modified retrospective approach with a cumulative-effect adjustment through retained earnings as of the beginning of the fiscal year upon adoption. The new accounting model for credit losses represents a significant departure from existing GAAP, and will likely materially increase the allowance for credit losses with a resulting negative adjustment to retained earnings. The amount of the change in the allowance for credit losses will also be impacted by the composition of our portfolio at the adoption date, as well as economic conditions and forecasts at that time. Management created a cross-functional working group to govern the implementation of these amendments, including consideration of model development, data integrity, technology, reporting and disclosure requirements, key accounting interpretations, control environment, and corporate governance. We are in the process of refining and testing the models and procedures that will be used to calculate the credit loss reserves in accordance with these amendments and we plan to run parallel testing during 2019. We plan to adopt these amendments on January 1, 2020, and expect to use the modified retrospective approach as required.
Accounting Standards Update 2017-08
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy	In March 2017, the FASB issued ASU 2017-08. The amendments in this update require premiums on purchased callable debt securities to be amortized to the security’s earliest call date. Prior to this ASU, premiums and discounts on purchased callable debt securities were generally required to be amortized to the security’s maturity date. The amendments do not require an accounting change for securities held at a discount. The amendments are effective on January 1, 2019, with early adoption permitted. The amendments must be applied using a modified retrospective approach with a cumulative-effect adjustment through retained earnings as of the beginning of the fiscal year upon adoption. Upon adoption of the amendments on January 1, 2019, we expect to recognize the cumulative effect of adoption by recording an increase to our opening accumulated deficit of approximately $10 million , net of taxes. This reduction to total equity will be partially offset by an $8 million decrease to accumulated other comprehensive loss, net of taxes. Additionally, upon adoption we expect to implement any necessary changes to our control environment and reporting processes to reflect the requirements of the amendments.

Discontinued Operations (Polici

Discontinued Operations (Policies)	12 Months Ended
	Dec. 31, 2018
Discontinued Operations [Abstract]
Discontinued Operations, Policy	Prior to the adoption of ASU 2014-08, which was prospectively applied only to newly identified disposals that qualify as discontinued operations beginning after January 1, 2015, we have classified operations as discontinued when operations and cash flows will be eliminated from our ongoing operations and we do not expect to retain any significant continuing involvement in their operations after the respective sale or disposal transactions. For all periods presented, the operating results for these discontinued operations have been removed from continuing operations and presented separately as discontinued operations, net of tax, in the Consolidated Statement of Income . The Notes to the Consolidated Financial Statements have been adjusted to exclude discontinued operations unless otherwise noted.

Fair Value Fair Value (Policies

Fair Value Fair Value (Policies)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurement, Policy	GAAP specifies a three-level hierarchy that is used when measuring and disclosing fair value. The fair value hierarchy gives the highest priority to quoted prices available in active markets (i.e., observable inputs) and the lowest priority to data lacking transparency (i.e., unobservable inputs). An instrument’s categorization within the fair value hierarchy is based on the lowest level of significant input to its valuation. The following is a description of the three hierarchy levels. Level 1 Inputs are quoted prices in active markets for identical assets or liabilities at the measurement date. Additionally, the entity must have the ability to access the active market, and the quoted prices cannot be adjusted by the entity. Level 2 Inputs are other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices in active markets for similar assets or liabilities; quoted prices in inactive markets for identical or similar assets or liabilities; or inputs that are observable or can be corroborated by observable market data by correlation or other means for substantially the full term of the assets or liabilities. Level 3 Unobservable inputs are supported by little or no market activity. The unobservable inputs represent management’s best assumptions of how market participants would price the assets or liabilities. Generally, Level 3 assets and liabilities are valued using pricing models, discounted cash flow methodologies, or similar techniques that require significant judgment or estimation.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	The following table presents the impact to our Consolidated Balance Sheet as of January 1, 2018, as a result of adopting the amendments to the revenue recognition principles. ($ in millions) As reported, December 31, 2017 Adjustment related to adoption As adjusted, January 1, 2018 Assets Premiums receivable and other insurance assets $ 2,047 $ 122 $ 2,169 Other assets 5,663 41 5,704 Total assets $ 167,148 $ 163 $ 167,311 Liabilities Unearned insurance premiums and service revenue $ 2,604 $ 289 $ 2,893 Total liabilities 153,654 289 153,943 Equity Accumulated deficit (6,406 ) (126 ) (6,532 ) Total equity 13,494 (126 ) 13,368 Total liabilities and equity $ 167,148 $ 163 $ 167,311
Impact of ASU 2014-09 on Balance Sheet and Income Statement	The following tables present the impact of adopting the amendments to the revenue recognition principles to our Consolidated Statement of Income , Consolidated Statement of Comprehensive Income , and Consolidated Balance Sheet . Year ended December 31, 2018 ($ in millions) As reported Effect of adoption Other revenue Insurance premiums and service revenue earned $ 1,022 $ (26 ) Total other revenue 1,414 (26 ) Total net revenue 5,804 (26 ) Noninterest expense Compensation and benefits expense 1,155 (1 ) Other operating expenses 1,814 (12 ) Total noninterest expense 3,264 (13 ) Income from continuing operations before income tax expense 1,622 (13 ) Income tax expense from continuing operations 359 (3 ) Net income from continuing operations 1,263 (10 ) Net income 1,263 (10 ) Comprehensive income $ 974 $ (10 ) December 31, 2018 ($ in millions) As reported Effect of adoption Assets Premiums receivable and other insurance assets $ 2,326 $ 135 Other assets 6,153 44 Total assets $ 178,869 $ 179 Liabilities Unearned insurance premiums and service revenue $ 3,044 $ 315 Total liabilities 165,601 315 Equity Accumulated deficit (5,489 ) (136 ) Total equity 13,268 (136 ) Total liabilities and equity $ 178,869 $ 179
Disaggregation of Revenue	The following table presents a disaggregated view of our revenue from contracts with customers included in other revenue that falls within the scope of the amendments to the revenue recognition principles. Year ended December 31, 2018 ($ in millions) Automotive Finance operations Insurance operations Mortgage Finance operations Corporate Finance operations Corporate and Other Consolidated Revenue from contracts with customers Noninsurance contracts $ — $ 506 $ — $ — $ — $ 506 Remarketing fee income 79 — — — — 79 Brokerage commissions and other revenue — — — — 62 62 Brokered/agent commissions — 15 — — — 15 Deposit account and other banking fees — — — — 13 13 Other 13 1 — — — 14 Total revenue from contracts with customers 92 522 — — 75 689 All other revenue 177 459 7 38 44 725 Total other revenue (a) $ 269 $ 981 $ 7 $ 38 $ 119 $ 1,414 (a) Represents a component of total net revenue. Refer to Note 26 for further information on our reportable operating segments. In addition to the components of other revenue presented above, as part of our Automotive Finance operations, we recognized net remarketing gains of $90 million for the year ended December 31, 2018 , on the sale of off-lease vehicles. These gains are included in depreciation expense on operating lease assets in our Consolidated Statement of Income .

Insurance Premiums and Servic_2

Insurance Premiums and Service Revenue Earned (Tables)	12 Months Ended
	Dec. 31, 2018
Insurance Premiums and Service Revenue Earned [Abstract]
Insurance Premiums and Service Revenue Earned	The following table is a summary of insurance premiums and service revenue written and earned. 2018 2017 2016 Year ended December 31, ($ in millions) Written Earned Written Earned Written Earned Insurance premiums Direct $ 420 $ 414 $ 384 $ 364 $ 317 $ 318 Assumed — 4 2 5 3 5 Gross insurance premiums 420 418 386 369 320 323 Ceded (219 ) (197 ) (254 ) (188 ) (198 ) (141 ) Net insurance premiums 201 221 132 181 122 182 Service revenue 973 801 864 792 826 763 Insurance premiums and service revenue written and earned $ 1,174 $ 1,022 $ 996 $ 973 $ 948 $ 945

Other Income, Net of Losses (Ta

Other Income, Net of Losses (Tables)	12 Months Ended
	Dec. 31, 2018
Other Nonoperating Income (Expense) [Abstract]
Schedule of Other Nonoperating Income, by Component	Details of other income, net of losses, were as follows. Year ended December 31, ($ in millions) 2018 2017 2016 Late charges and other administrative fees $ 110 $ 102 $ 98 Remarketing fees 79 104 103 Income from equity-method investments 46 14 18 Servicing fees 27 51 64 Other, net 155 130 106 Total other income, net of losses $ 417 $ 401 $ 389

Reserves for Insurance Losses_2

Reserves for Insurance Losses and Loss Adjustment Expenses (Tables)	12 Months Ended
	Dec. 31, 2018
Reserves for Insurance Losses and Loss Adjustment Expense [Abstract]
Short-duration Insurance Contracts, Claims Development	Reserves for Insurance Losses and Loss Adjustment Expenses The following table shows incurred claims and allocated loss adjustment expenses, net of reinsurance. For the years ended December 31, ($ in millions) December 31, 2018 ($ in millions) Accident year (a) 2012 (b) 2013 (b) 2014 (b) 2015 (b) 2016 2017 2018 Total of incurred-but-not-reported liabilities plus expected development on reported claims (c) Cumulative number of reported claims (c) 2012 $ 435 $ 430 $ 423 $ 423 $ 423 $ 422 $ 422 $ — 772,549 2013 376 365 370 370 369 368 — 672,273 2014 390 389 388 388 388 — 525,297 2015 274 271 272 272 — 342,261 2016 326 327 328 — 475,973 2017 310 314 — 481,319 2018 271 19 482,605 Total $ 2,363 (a) Due to the discontinuation of various product lines and sale of certain international operations, information prior to 2012 has been excluded from the table in order to appropriately reflect the number of years for which claims are typically outstanding. In addition, given the short tail of our insurance contracts, the table above reflects the combined presentation of all business lines. (b) Information presented for the years 2012 through 2015 is unaudited supplementary information. (c) Claims are reported on a claimant basis. Claimant is defined as one vehicle for guaranteed asset protection (GAP) products, one repair visit for vehicle service contracts (VSCs) and vehicle maintenance contracts (VMCs), one dealership for dealer inventory products, and per individual/coverage for run-off personal automotive products. The following table shows cumulative paid claims and allocated loss adjustment expenses, net of reinsurance. For the years ended December 31, ($ in millions) Accident year (a) 2012 (b) 2013 (b) 2014 (b) 2015 (b) 2016 2017 2018 2012 $ 391 $ 412 $ 416 $ 418 $ 419 $ 421 $ 421 2013 347 364 366 368 368 368 2014 369 388 388 388 388 2015 252 272 272 272 2016 302 327 328 2017 289 315 2018 245 Total $ 2,337 All outstanding liabilities for loss and allocated loss adjustment expenses before 2012, net of reinsurance 9 Reserves for insurance losses and allocated loss adjustment expenses, net of reinsurance $ 35 (a) Due to the discontinuation of various product lines and sale of certain international operations, information prior to 2012 has been excluded from the table in order to appropriately reflect the number of years for which claims are typically outstanding. In addition, given the short tail of our insurance contracts, the table above reflects the combined presentation of all business lines. (b) Information presented for the years 2012 through 2015 is unaudited supplementary information.
Short-duration Insurance Contracts, Schedule of Historical Claims Duration	The following table shows the average annual percentage payout of incurred claims by age, net of reinsurance. The information presented is unaudited supplementary information. Year 1 2 3 4 5 6 7 Percentage payout of incurred claims 92.8 % 6.1 % 0.4 % 0.3 % 0.1 % 0.2 % 0.1 %
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability	The following table shows a reconciliation of the disclosures of incurred and paid claims development to the reserves for insurance losses and loss adjustment expenses. December 31, ($ in millions) 2018 2017 2016 Reserves for insurance losses and loss adjustment expenses, net of reinsurance $ 35 $ 30 $ 38 Total reinsurance recoverable on unpaid claims 96 108 108 Unallocated loss adjustment expenses 3 2 3 Total gross reserves for insurance losses and loss adjustment expenses $ 134 $ 140 $ 149
Short-Duration Insurance and Deposit Contracts	The following table shows a rollforward of our reserves for insurance losses and loss adjustment expenses. ($ in millions) 2018 2017 2016 Total gross reserves for insurance losses and loss adjustment expenses at January 1, $ 140 $ 149 $ 169 Less: Reinsurance recoverable 108 108 120 Net reserves for insurance losses and loss adjustment expenses at January 1, 32 41 49 Net insurance losses and loss adjustment expenses incurred related to: Current year 291 332 345 Prior years (a) 4 — (3 ) Total net insurance losses and loss adjustment expenses incurred 295 332 342 Net insurance losses and loss adjustment expenses paid or payable related to: Current year (263 ) (309 ) (320 ) Prior years (26 ) (32 ) (30 ) Total net insurance losses and loss adjustment expenses paid or payable (289 ) (341 ) (350 ) Net reserves for insurance losses and loss adjustment expenses at December 31, 38 32 41 Plus: Reinsurance recoverable 96 108 108 Total gross reserves for insurance losses and loss adjustment expenses at December 31, $ 134 $ 140 $ 149 (a) There have been no material adverse changes to the reserve for prior years.

Other Operating Expenses (Table

Other Operating Expenses (Tables)	12 Months Ended
	Dec. 31, 2018
Operating Expenses [Abstract]
Schedule of Other Operating Cost and Expense, by Component	Details of other operating expenses were as follows. Year ended December 31, ($ in millions) 2018 2017 2016 Insurance commissions $ 440 $ 415 $ 389 Technology and communications 299 284 274 Advertising and marketing 172 133 112 Lease and loan administration 164 159 136 Professional services 133 113 103 Regulatory and licensing fees 121 113 94 Vehicle remarketing and repossession 111 110 95 Premises and equipment depreciation 87 89 84 Occupancy 45 46 51 Non-income taxes 29 21 25 Amortization of intangible assets 11 11 6 Other 202 189 236 Total other operating expenses $ 1,814 $ 1,683 $ 1,605

Investment Securities (Tables)

Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	Our investment portfolio includes various debt and equity securities. Our debt securities, which are classified as available-for-sale and held-to-maturity, include government securities, corporate bonds, asset-backed securities, and mortgage-backed securities. The cost, fair value, and gross unrealized gains and losses on available-for-sale and held-to-maturity debt securities were as follows. 2018 2017 Amortized cost Gross unrealized Fair value Amortized cost Gross unrealized Fair value December 31, ($ in millions) gains losses gains losses Available-for-sale securities Debt securities U.S. Treasury and federal agencies $ 1,911 $ — $ (60 ) $ 1,851 $ 1,831 $ — $ (54 ) $ 1,777 U.S. States and political subdivisions 816 3 (17 ) 802 850 11 (7 ) 854 Foreign government 145 1 (1 ) 145 153 2 (1 ) 154 Agency mortgage-backed residential 17,486 47 (395 ) 17,138 14,412 35 (156 ) 14,291 Mortgage-backed residential 2,796 1 (111 ) 2,686 2,517 11 (34 ) 2,494 Mortgage-backed commercial 718 1 (2 ) 717 541 1 (1 ) 541 Asset-backed 723 2 (2 ) 723 933 4 (1 ) 936 Corporate debt 1,286 1 (46 ) 1,241 1,262 5 (11 ) 1,256 Total available-for-sale securities (a) (b) (c) $ 25,881 $ 56 $ (634 ) $ 25,303 $ 22,499 $ 69 $ (265 ) $ 22,303 Held-to-maturity securities Debt securities Agency mortgage-backed residential (d) $ 2,319 $ 6 $ (61 ) $ 2,264 $ 1,863 $ 3 $ (37 ) $ 1,829 Asset-backed retained notes 43 — — 43 36 — — 36 Total held-to-maturity securities $ 2,362 $ 6 $ (61 ) $ 2,307 $ 1,899 $ 3 $ (37 ) $ 1,865 (a) Certain entities related to our Insurance operations are required to deposit securities with state regulatory authorities. These deposited securities totaled $12 million at both December 31, 2018 , and December 31, 2017. (b) Certain available-for-sale securities are included in fair value hedging relationships. Refer to Note 21 for additional information. (c) Available-for-sale securities with a fair value of $9.2 billion and $7.8 billion at December 31, 2018 , and December 31, 2017 , respectively, were pledged to secure advances from the FHLB, short-term borrowings or repurchase agreements, or for other purposes as required by contractual obligation or law. Under these agreements, we have granted the counterparty the right to sell or pledge $821 million and $1.0 billion of the underlying investment securities at December 31, 2018 , and December 31, 2017 , respectively. (d) Held-to-maturity securities with a fair value of $1.2 billion and $664 million at December 31, 2018 , and December 31, 2017, respectively, were pledged to secure advances from the FHLB.
Investments Classified by Contractual Maturity Date	The maturity distribution of debt securities outstanding is summarized in the following tables. Call or prepayment options may cause actual maturities to differ from contractual maturities. Total Due in one year or less Due after one year through five years Due after five years through ten years Due after ten years ($ in millions) Amount Yield Amount Yield Amount Yield Amount Yield Amount Yield December 31, 2018 Fair value of available-for-sale securities (a) U.S. Treasury and federal agencies $ 1,851 1.9 % $ 12 1.0 % $ 1,277 1.8 % $ 562 2.0 % $ — — % U.S. States and political subdivisions 802 3.0 49 1.9 43 2.3 252 2.6 458 3.4 Foreign government 145 2.4 18 3.1 60 2.3 67 2.4 — — Agency mortgage-backed residential 17,138 3.3 — — — — 54 1.9 17,084 3.3 Mortgage-backed residential 2,686 3.3 — — — — — — 2,686 3.3 Mortgage-backed commercial 717 3.8 — — 3 3.1 46 3.9 668 3.8 Asset-backed 723 3.5 — — 478 3.4 121 4.0 124 3.3 Corporate debt 1,241 3.1 144 2.8 496 2.9 581 3.3 20 5.5 Total available-for-sale securities $ 25,303 3.2 $ 223 2.6 $ 2,357 2.4 $ 1,683 2.8 $ 21,040 3.3 Amortized cost of available-for-sale securities $ 25,881 $ 224 $ 2,405 $ 1,743 $ 21,509 Amortized cost of held-to-maturity securities Agency mortgage-backed residential $ 2,319 3.2 % $ — — % $ — — % $ — — % $ 2,319 3.2 % Asset-backed retained notes 43 2.0 — — 42 2.0 1 3.3 — — Total held-to-maturity securities $ 2,362 3.2 $ — — $ 42 2.0 $ 1 3.3 $ 2,319 3.2 December 31, 2017 Fair value of available-for-sale securities (a) U.S. Treasury $ 1,777 1.7 % $ — — % $ 487 1.7 % $ 1,290 1.8 % $ — — % U.S. States and political subdivisions 854 2.9 76 1.8 36 2.3 203 2.5 539 3.3 Foreign government 154 2.5 — — 80 2.5 74 2.4 — — Agency mortgage-backed residential 14,291 3.1 — — — — 3 2.9 14,288 3.1 Mortgage-backed residential 2,494 3.1 — — — — — — 2,494 3.1 Mortgage-backed commercial 541 3.2 — — 30 3.1 31 3.1 480 3.2 Asset-backed 936 3.1 — — 698 3.1 106 3.1 132 2.8 Corporate debt 1,256 2.9 140 2.6 513 2.6 564 3.2 39 4.7 Total available-for-sale securities $ 22,303 3.0 $ 216 2.3 $ 1,844 2.5 $ 2,271 2.3 $ 17,972 3.1 Amortized cost of available-for-sale securities $ 22,499 $ 217 $ 1,852 $ 2,314 $ 18,116 Amortized cost of held-to-maturity securities Agency mortgage-backed residential $ 1,863 3.1 % $ — — % $ — — % $ — — % $ 1,863 3.1 % Asset-backed retained notes 36 1.7 — — 35 1.7 1 3.0 — — Total held-to-maturity securities $ 1,899 3.1 $ — — $ 35 1.7 $ 1 3.0 $ 1,863 3.1 (a) Yield is calculated using the effective yield of each security at the end of the period, weighted based on the market value. The effective yield considers the contractual coupon and amortized cost, and excludes expected capital gains and losses.
Investment Income	The following table presents interest and dividends on investment securities. Year ended December 31, ($ in millions) 2018 2017 2016 Taxable interest $ 690 $ 534 $ 375 Taxable dividends 14 12 17 Interest and dividends exempt from U.S. federal income tax 25 22 19 Interest and dividends on investment securities $ 729 $ 568 $ 411
Schedule of Realized Gain (Loss)	The following table presents gross gains and losses realized upon the sales of available-for-sale securities, and net gains or losses on equity securities held during the period. There were no other-than-temporary impairments of available-for-sale securities for the periods presented. Year ended December 31, ($ in millions) 2018 2017 2016 Available-for-sale securities Gross realized gains $ 12 $ 106 $ 187 Gross realized losses (a) (1 ) (4 ) (2 ) Net realized gains on available-for-sale securities 11 102 185 Net realized gain on equity securities 60 Net unrealized loss on equity securities (b) (121 ) Other (loss) gain on investments, net $ (50 ) $ 102 $ 185 (a) Certain available-for-sale securities were sold at a loss in 2018, 2017, and 2016 as a result of market conditions within these respective periods (e.g., a downgrade in the rating of a debt security) or based on corporate actions outside of our control (such as a call by the issuer). Any such sales were made in accordance with our risk-management policies and practices. (b) As a result of our adoption of ASU 2016-01, beginning January 1, 2018, changes in the fair value of our portfolio of equity securities are recognized in net income. Prior to adoption, equity securities were included in our available-for-sale portfolio and unrealized changes in fair value were recognized through other comprehensive (loss) income until realized, at which point we recorded a gain or loss on sale. We adopted ASU 2016-01 on January 1, 2018, on a modified retrospective basis with a cumulative effect adjustment as of the beginning of the fiscal year of initial adoption. Refer to the section titled Recently Adopted Accounting Standards in Note 1 for additional information.
Schedule of Unrealized Loss on Investments	The table below summarizes available-for-sale and held-to-maturity securities in an unrealized loss position, which we evaluated for other than temporary impairment applying the methodology described in Note 1 . As of December 31, 2018 , we did not have the intent to sell the available-for-sale or held-to-maturity securities with an unrealized loss position and we do not believe it is more likely than not that we will be required to sell these securities before recovery of their amortized cost basis. As a result of this evaluation, we believe that the securities with an unrealized loss position are not considered to be other-than-temporarily impaired at December 31, 2018 . 2018 2017 Less than 12 months 12 months or longer Less than 12 months 12 months or longer December 31, ($ in millions) Fair value Unrealized loss Fair value Unrealized loss Fair value Unrealized loss Fair value Unrealized loss Available-for-sale securities Debt securities U.S. Treasury and federal agencies $ 31 $ — $ 1,758 $ (60 ) $ 471 $ (8 ) $ 1,305 $ (46 ) U.S. States and political subdivisions 259 (3 ) 317 (14 ) 242 (2 ) 183 (5 ) Foreign government 6 — 74 (1 ) 80 (1 ) 4 — Agency mortgage-backed residential 5,537 (94 ) 7,808 (301 ) 4,066 (19 ) 5,671 (137 ) Mortgage-backed residential 1,024 (20 ) 1,360 (91 ) 857 (2 ) 773 (32 ) Mortgage-backed commercial 347 (1 ) 36 (1 ) 76 (1 ) 21 — Asset-backed 294 (1 ) 124 (1 ) 220 (1 ) 91 — Corporate debt 576 (19 ) 569 (27 ) 529 (4 ) 194 (7 ) Total temporarily impaired available-for-sale securities $ 8,074 $ (138 ) $ 12,046 $ (496 ) $ 6,541 $ (38 ) $ 8,242 $ (227 ) Held-to-maturity securities Debt securities Agency mortgage-backed residential $ 457 $ (6 ) $ 1,376 $ (55 ) $ 773 $ (5 ) $ 687 $ (32 ) Asset-backed retained notes 16 — 19 — 35 — — — Total held-to-maturity debt securities $ 473 $ (6 ) $ 1,395 $ (55 ) $ 808 $ (5 ) $ 687 $ (32 )

Finance Receivables and Loans_2

Finance Receivables and Loans, Net (Tables)	12 Months Ended
	Dec. 31, 2018
Loans and Leases Receivable, Net Amount [Abstract]
Schedule of Accounts, Notes, Loans and Financing Receivable	The composition of finance receivables and loans reported at gross carrying value was as follows. December 31, ($ in millions) 2018 2017 Consumer automotive (a) $ 70,539 $ 68,071 Consumer mortgage Mortgage Finance (b) 15,155 11,657 Mortgage — Legacy (c) 1,546 2,093 Total consumer mortgage 16,701 13,750 Total consumer 87,240 81,821 Commercial Commercial and industrial Automotive 33,672 33,025 Other 4,205 3,887 Commercial real estate 4,809 4,160 Total commercial 42,686 41,072 Total finance receivables and loans (d) $ 129,926 $ 122,893 (a) Certain finance receivables and loans are included in fair value hedging relationships. Refer to Note 21 for additional information. (b) Includes loans originated as interest-only mortgage loans of $18 million and $20 million at December 31, 2018 , and December 31, 2017 , respectively, 34% of which are expected to start principal amortization in 2019 , and 41% in 2020 . The remainder of these loans have exited the interest-only period. (c) Includes loans originated as interest-only mortgage loans of $341 million and $496 million at December 31, 2018 , and December 31, 2017 , respectively, of which 99% have exited the interest-only period. (d) Totals include net unearned income, unamortized premiums and discounts, and deferred fees and costs of $587 million and $551 million at December 31, 2018 , and December 31, 2017 , respectively
Allowance for Credit Losses on Financing Receivables	The following tables present an analysis of the activity in the allowance for loan losses on finance receivables and loans. ($ in millions) Consumer automotive Consumer mortgage Commercial Total Allowance at January 1, 2018 $ 1,066 $ 79 $ 131 $ 1,276 Charge-offs (a) (1,383 ) (35 ) (15 ) (1,433 ) Recoveries 456 25 7 488 Net charge-offs (927 ) (10 ) (8 ) (945 ) Provision for loan losses 911 (15 ) 22 918 Other (b) (2 ) (1 ) (4 ) (7 ) Allowance at December 31, 2018 $ 1,048 $ 53 $ 141 $ 1,242 Allowance for loan losses at December 31, 2018 Individually evaluated for impairment $ 44 $ 23 $ 56 $ 123 Collectively evaluated for impairment 1,004 30 85 1,119 Finance receivables and loans at gross carrying value Ending balance $ 70,539 $ 16,701 $ 42,686 $ 129,926 Individually evaluated for impairment 495 231 349 1,075 Collectively evaluated for impairment 70,044 16,470 42,337 128,851 (a) Represents the amount of the gross carrying value directly written off. For consumer and commercial loans, the loss from a charge-off is measured as the difference between the gross carrying value of a loan and the fair value of the collateral, less costs to sell. Refer to Note 1 for more information regarding our charge-off policies. (b) Primarily related to the transfer of finance receivables and loans from held-for-investment to held-for-sale. ($ in millions) Consumer automotive Consumer mortgage Commercial Total Allowance at January 1, 2017 $ 932 $ 91 $ 121 $ 1,144 Charge-offs (a) (1,344 ) (30 ) (18 ) (1,392 ) Recoveries 358 24 — 382 Net charge-offs (986 ) (6 ) (18 ) (1,010 ) Provision for loan losses 1,127 (7 ) 28 1,148 Other (b) (7 ) 1 — (6 ) Allowance at December 31, 2017 $ 1,066 $ 79 $ 131 $ 1,276 Allowance for loan losses at December 31, 2017 Individually evaluated for impairment $ 36 $ 27 $ 14 $ 77 Collectively evaluated for impairment 1,030 52 117 1,199 Finance receivables and loans at gross carrying value Ending balance $ 68,071 $ 13,750 $ 41,072 $ 122,893 Individually evaluated for impairment 430 231 72 733 Collectively evaluated for impairment 67,641 13,519 41,000 122,160 (a) Represents the amount of the gross carrying value directly written off. For consumer and commercial loans, the loss from a charge-off is measured as the difference between the gross carrying value of a loan and the fair value of the collateral, less costs to sell. Refer to Note 1 for more information regarding our charge-off policies. (b) Primarily related to the transfer of finance receivables and loans from held-for-investment to held-for-sale.
Schedule Of Sales Of Financing Receivables And Loans	The following table presents information about significant sales of finance receivables and loans and transfers of finance receivables and loans from held-for-investment to held-for-sale based on net carrying value. December 31, ($ in millions) 2018 2017 Consumer automotive $ 578 $ 1,339 Consumer mortgage 10 9 Commercial 238 — Total sales and transfers $ 826 $ 1,348
Schedule of Purchases of Financing Receivables and Loans	The following table presents information about significant purchases of finance receivables and loans based on unpaid principal balance at the time of purchase. ($ in millions) 2018 2017 Consumer automotive $ 896 $ 865 Consumer mortgage 4,446 4,481 Commercial 15 — Total purchases of finance receivables and loans $ 5,357 $ 5,346
Past Due Financing Receivables	The following table presents an analysis of our past-due finance receivables and loans recorded at gross carrying value. December 31, ($ in millions) 30–59 days past due 60–89 days past due 90 days or more past due Total past due Current Total finance receivables and loans 2018 Consumer automotive $ 2,107 $ 537 $ 296 $ 2,940 $ 67,599 $ 70,539 Consumer mortgage Mortgage Finance 67 5 4 76 15,079 15,155 Mortgage — Legacy 30 10 42 82 1,464 1,546 Total consumer mortgage 97 15 46 158 16,543 16,701 Total consumer 2,204 552 342 3,098 84,142 87,240 Commercial Commercial and industrial Automotive — 1 31 32 33,640 33,672 Other — 4 16 20 4,185 4,205 Commercial real estate — — 1 1 4,808 4,809 Total commercial — 5 48 53 42,633 42,686 Total consumer and commercial $ 2,204 $ 557 $ 390 $ 3,151 $ 126,775 $ 129,926 2017 Consumer automotive $ 1,994 $ 478 $ 268 $ 2,740 $ 65,331 $ 68,071 Consumer mortgage Mortgage Finance 60 11 18 89 11,568 11,657 Mortgage — Legacy 43 25 62 130 1,963 2,093 Total consumer mortgage 103 36 80 219 13,531 13,750 Total consumer 2,097 514 348 2,959 78,862 81,821 Commercial Commercial and industrial Automotive 5 — 3 8 33,017 33,025 Other — — — — 3,887 3,887 Commercial real estate — — — — 4,160 4,160 Total commercial 5 — 3 8 41,064 41,072 Total consumer and commercial $ 2,102 $ 514 $ 351 $ 2,967 $ 119,926 $ 122,893
Schedule of Financing Receivables, Non Accrual Status	The following table presents the gross carrying value of our finance receivables and loans on nonaccrual status. December 31, ($ in millions) 2018 2017 Consumer automotive $ 664 $ 603 Consumer mortgage Mortgage Finance 9 25 Mortgage — Legacy 70 92 Total consumer mortgage 79 117 Total consumer 743 720 Commercial Commercial and industrial Automotive 203 27 Other 142 44 Commercial real estate 4 1 Total commercial 349 72 Total consumer and commercial finance receivables and loans $ 1,092 $ 792
Financing Receivable Credit Quality Indicators	The following table presents performing and nonperforming credit quality indicators in accordance with our internal accounting policies for our consumer finance receivables and loans recorded at gross carrying value. Nonperforming loans include finance receivables and loans on nonaccrual status when the principal or interest has been delinquent for at least 90 days or when full collection is not expected. Refer to Note 1 for additional information. 2018 2017 December 31, ($ in millions) Performing Nonperforming Total Performing Nonperforming Total Consumer automotive $ 69,875 $ 664 $ 70,539 $ 67,468 $ 603 $ 68,071 Consumer mortgage Mortgage Finance 15,146 9 15,155 11,632 25 11,657 Mortgage — Legacy 1,476 70 1,546 2,001 92 2,093 Total consumer mortgage 16,622 79 16,701 13,633 117 13,750 Total consumer $ 86,497 $ 743 $ 87,240 $ 81,101 $ 720 $ 81,821
Schedule Of Pass And Criticized Credit Quality Indicators Of Finance Receivables	The following table presents pass and criticized credit quality indicators based on regulatory definitions for our commercial finance receivables and loans recorded at gross carrying value. 2018 2017 December 31, ($ in millions) Pass Criticized (a) Total Pass Criticized (a) Total Commercial and industrial Automotive $ 30,799 $ 2,873 $ 33,672 $ 30,982 $ 2,043 $ 33,025 Other 3,373 832 4,205 2,986 901 3,887 Commercial real estate 4,538 271 4,809 4,023 137 4,160 Total commercial $ 38,710 $ 3,976 $ 42,686 $ 37,991 $ 3,081 $ 41,072 (a) Includes loans classified as special mention, substandard, or doubtful. These classifications are based on regulatory definitions and generally represent loans within our portfolio that have a higher default risk or have already defaulted.
Impaired Financing Receivables	The following table presents information about our impaired finance receivables and loans. December 31, ($ in millions) Unpaid principal balance (a) Gross carrying value Impaired with no allowance Impaired with an allowance Allowance for impaired loans 2018 Consumer automotive $ 503 $ 495 $ 105 $ 390 $ 44 Consumer mortgage Mortgage Finance 15 15 6 9 1 Mortgage — Legacy 221 216 65 151 22 Total consumer mortgage 236 231 71 160 23 Total consumer 739 726 176 550 67 Commercial Commercial and industrial Automotive 203 203 112 91 10 Other 159 142 40 102 46 Commercial real estate 4 4 4 — — Total commercial 366 349 156 193 56 Total consumer and commercial finance receivables and loans $ 1,105 $ 1,075 $ 332 $ 743 $ 123 2017 Consumer automotive $ 438 $ 430 $ 91 $ 339 $ 36 Consumer mortgage Mortgage Finance 8 8 4 4 — Mortgage — Legacy 228 223 58 165 27 Total consumer mortgage 236 231 62 169 27 Total consumer 674 661 153 508 63 Commercial Commercial and industrial Automotive 27 27 9 18 3 Other 54 44 10 34 11 Commercial real estate 1 1 — 1 — Total commercial 82 72 19 53 14 Total consumer and commercial finance receivables and loans $ 756 $ 733 $ 172 $ 561 $ 77 (a) Adjusted for charge-offs.
Schedule of Average Balance And Interest Income Of Impaired Finance Receivables	The following table presents average balance and interest income for our impaired finance receivables and loans. 2018 2017 2016 Year ended December 31, ($ in millions) Average balance Interest income Average balance Interest income Average balance Interest income Consumer automotive $ 478 $ 28 $ 391 $ 21 $ 344 $ 17 Consumer mortgage Mortgage Finance 11 1 8 — 8 — Mortgage — Legacy 218 10 234 10 248 9 Total consumer mortgage 229 11 242 10 256 9 Total consumer 707 39 633 31 600 26 Commercial Commercial and industrial Automotive 93 4 49 2 35 1 Other 84 — 69 9 60 1 Commercial real estate 5 1 5 — 6 — Total commercial 182 5 123 11 101 2 Total consumer and commercial finance receivables and loans $ 889 $ 44 $ 756 $ 42 $ 701 $ 28
Troubled Debt Restructurings on Financing Receivables	The following tables present information related to finance receivables and loans recorded at gross carrying value modified in connection with a TDR during the period. Year ended December 31, ($ in millions) Number of loans Pre-modification gross carrying value Post-modification gross carrying value 2018 Consumer automotive 26,748 $ 426 $ 378 Consumer mortgage Mortgage Finance 23 9 9 Mortgage — Legacy 204 30 29 Total consumer mortgage 227 39 38 Total consumer finance receivables and loans 26,975 $ 465 $ 416 2017 Consumer automotive 26,156 $ 380 $ 333 Consumer mortgage Mortgage Finance 4 1 1 Mortgage — Legacy 122 21 21 Total consumer mortgage 126 22 22 Total consumer finance receivables and loans 26,282 $ 402 $ 355 2016 Consumer automotive 20,227 $ 347 $ 293 Consumer mortgage Mortgage Finance 7 3 3 Mortgage — Legacy 120 18 18 Total consumer mortgage 127 21 21 Total consumer finance receivables and loans 20,354 $ 368 $ 314 Year ended December 31, ($ in millions) Number of loans Pre-modification gross carrying value Post-modification gross carrying value 2018 Commercial and industrial Automotive 3 $ 4 $ 4 Other 3 85 82 Total commercial finance receivables and loans 6 $ 89 $ 86 2017 Commercial and industrial Automotive 4 $ 16 $ 15 Other — 44 44 Commercial real estate 2 3 3 Total commercial finance receivables and loans 6 $ 63 $ 62 2016 Commercial and industrial Automotive 1 $ 7 $ 7 Total commercial finance receivables and loans 1 $ 7 $ 7
Finance receivables and loans redefaulted during the period	The following table presents information about finance receivables and loans recorded at gross carrying value that have redefaulted during the reporting period and were within twelve months or less of being modified as a TDR. Redefault is when finance receivables and loans meet the requirements for evaluation under our charge-off policy (refer to Note 1 for additional information) except for commercial finance receivables and loans, where redefault is defined as 90 days past due. Year ended December 31, ($ in millions) Number of loans Gross carrying value Charge-off amount 2018 Consumer automotive 9,711 $ 111 $ 73 Consumer mortgage Mortgage — Legacy 2 — — Total consumer finance receivables and loans 9,713 $ 111 $ 73 2017 Consumer automotive 8,829 $ 102 $ 71 Consumer mortgage Mortgage Finance 1 1 — Mortgage — Legacy 2 — — Total consumer finance receivables and loans 8,832 $ 103 $ 71 2016 Consumer automotive 7,800 $ 94 $ 56 Consumer mortgage Mortgage — Legacy 4 — — Total consumer finance receivables and loans 7,804 $ 94 $ 56
Consumer Concentration Risk	The following table shows the percentage of total consumer finance receivables and loans recorded at gross carrying value by state concentration. 2018 (a) 2017 December 31, Consumer automotive Consumer mortgage Consumer automotive Consumer mortgage California 8.4 % 36.9 % 8.2 % 34.6 % Texas 12.8 6.2 13.2 6.5 Florida 8.8 4.7 8.5 4.8 Pennsylvania 4.5 1.4 4.6 1.5 Illinois 4.1 3.0 4.2 3.2 Georgia 4.1 2.8 4.2 2.5 North Carolina 3.9 1.7 3.7 1.8 New York 3.1 2.4 3.0 2.2 Ohio 3.5 0.4 3.4 0.5 New Jersey 2.7 2.1 2.6 2.1 Other United States 44.1 38.4 44.4 40.3 Total consumer loans 100.0 % 100.0 % 100.0 % 100.0 % (a) Presentation is in descending order as a percentage of total consumer finance receivables and loans at December 31, 2018 .
Commercial Concentration Risk	The commercial real estate portfolio consists of finance receivables and loans issued primarily to automotive dealers. The following table shows the percentage of total commercial real estate finance receivables and loans reported at gross carrying value by state concentration. December 31, 2018 2017 Texas 15.5 % 15.7 % Florida 11.6 10.3 California 8.3 8.2 Michigan 6.8 7.7 New York 4.8 2.1 Georgia 4.0 4.6 North Carolina 3.6 3.6 South Carolina 3.4 3.5 New Jersey 3.1 3.6 Utah 2.6 1.6 Other United States 36.3 39.1 Total commercial real estate finance receivables and loans 100.0 % 100.0 %
Commercial Criticized Risk Exposure	The following table presents the percentage of total commercial criticized finance receivables and loans reported at gross carrying value by industry concentrations. December 31, 2018 2017 Automotive 80.6 % 76.3 % Services 5.0 6.7 Health/Medical 3.7 4.9 Other 10.7 12.1 Total commercial criticized finance receivables and loans 100.0 % 100.0 %

Investment in Operating Lease_2

Investment in Operating Leases, Net (Tables)	12 Months Ended
	Dec. 31, 2018
Leases, Operating [Abstract]
Schedule of Property Subject to or Available for Operating Lease	Investment in operating leases were as follows. December 31, ($ in millions) 2018 2017 Vehicles $ 9,995 $ 10,556 Accumulated depreciation (1,578 ) (1,815 ) Investment in operating leases, net $ 8,417 $ 8,741
Depreciation Expense On Operating Lease Assets	Depreciation expense on operating lease assets includes remarketing gains and losses recognized on the sale of operating lease assets. The following summarizes the components of depreciation expense on operating lease assets. Year ended December 31, ($ in millions) 2018 2017 2016 Depreciation expense on operating lease assets (excluding remarketing gains) $ 1,115 $ 1,368 $ 1,982 Remarketing gains, net (90 ) (124 ) (213 ) Net depreciation expense on operating lease assets $ 1,025 $ 1,244 $ 1,769
Lessor, Operating Lease, Payments to be Received, Maturity [Table Text Block]	The following table presents the future lease nonresidual rental payments due from customers for vehicles on operating leases. Year ended December 31, ($ in millions) 2019 $ 1,308 2020 830 2021 297 2022 27 2023 and thereafter 3 Total $ 2,465

Securitizations and Variable _2

Securitizations and Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2018
Securitizations And Variable Interest Entities [Abstract]
Schedule of Variable Interest Entities	The following table presents our involvement in consolidated and nonconsolidated VIEs in which we hold variable interests. For additional detail related to the assets and liabilities of consolidated variable interest entities refer to the Consolidated Balance Sheet . December 31, ($ in millions) Carrying value of total assets Carrying value of total liabilities Assets sold to nonconsolidated VIEs (a) Maximum exposure to loss in nonconsolidated VIEs 2018 On-balance sheet variable interest entities Consumer automotive $ 16,255 (b) $ 6,573 (c) Commercial automotive 11,089 3,946 Off-balance sheet variable interest entities Consumer automotive (d) 45 (e) — $ 1,235 $ 1,280 (f) Commercial other 806 (g) 326 (h) — 1,054 (i) Total $ 28,195 $ 10,845 $ 1,235 $ 2,334 2017 On-balance sheet variable interest entities Consumer automotive $ 17,597 (b) $ 7,677 (c) Commercial automotive 12,550 2,558 Off-balance sheet variable interest entities Consumer automotive 37 (e) — $ 1,964 $ 2,001 (f) Commercial other 592 (g) 248 (h) — 790 (i) Total $ 30,776 $ 10,483 $ 1,964 $ 2,791 (a) Asset values represent the current unpaid principal balance of outstanding consumer finance receivables and loans within the VIEs. (b) Includes $8.4 billion and $ 8.5 billion of assets that were not encumbered by VIE beneficial interests held by third parties at December 31, 2018 , and December 31, 2017 , respectively. Ally or consolidated affiliates hold the interests in these assets. (c) Includes $25 million and $29 million of liabilities that were not obligations to third-party beneficial interest holders at December 31, 2018 , and December 31, 2017 , respectively. (d) In September 2018, we sold residual interests related to an on-balance sheet VIE to an unrelated third party. As a result of this sale, we are no longer the primary beneficiary of the VIE, and as such have deconsolidated its assets and liabilities from our Consolidated Balance Sheet including $545 million and $497 million of consumer automotive loans and long-term debt, respectively. We received cash proceeds of $24 million related to this sale, and recognized a pretax gain on sale of $1 million . We will continue to service the assets previously transferred to the VIE. (e) Represents retained notes and certificated residual interests, of which $43 million and $36 million were classified as held-to-maturity securities at December 31, 2018 , and December 31, 2017 , respectively, and $2 million and $1 million were classified as other assets at December 31, 2018 , and December 31, 2017 , respectively. These assets represent our compliance with the risk retention rules under the Dodd-Frank Act, requiring us to retain at least five percent of the credit risk of the assets underlying asset-backed securitizations. (f) Maximum exposure to loss represents the current unpaid principal balance of outstanding loans, retained notes, certificated residual interests, as well as certain noncertificated interests retained from the sale of automotive finance receivables. This measure is based on the very unlikely event that all of our sold loans have defects that would trigger a representation and warranty provision and the underlying collateral supporting the loans becomes worthless. This required disclosure is not an indication of our expected loss. (g) Amounts are classified as other assets. (h) Amounts are classified as accrued expenses and other liabilities. (i) For certain nonconsolidated affordable housing entities, maximum exposure to loss represents the yield we guaranteed investors through long-term guarantee contracts. The amount disclosed is based on the unlikely event that the underlying properties cease generating yield to investors and the yield delivered to investors in the form of low income tax housing credits is recaptured. For nonconsolidated equity investments, maximum exposure to loss represents our outstanding investment, additional committed capital, and low income housing tax credits subject to recapture. The amount disclosed is based on the unlikely event that our committed capital is funded, our investments become worthless, and the tax credits previously delivered to us are recaptured. This required disclosure is not an indication of our expected loss.
Securitization and Variable Interest Entities On-balance Sheet Variable Interest Entities [Table Text Block]	The assets of consolidated VIEs that can be used only to settle obligations of the consolidated VIEs and the liabilities of those entities for which creditors or beneficial interest holders do not have recourse to our general credit were as follows. December 31, ($ in millions) 2018 2017 Assets Finance receivables and loans, net Consumer $ 7,282 $ 8,186 Commercial 10,804 12,437 Allowance for loan losses (114 ) (136 ) Total finance receivables and loans, net 17,972 20,487 Investment in operating leases, net 164 444 Other assets 767 689 Total assets $ 18,903 $ 21,620 Liabilities Long-term debt $ 10,482 $ 10,197 Accrued expenses and other liabilities 12 9 Total liabilities $ 10,494 $ 10,206
Schedule Of Cash Flow Received And Paid To Nonconsolidated Securitization Entities	The following table summarizes cash flows received and paid related to SPEs and asset-backed financings where the transfer is accounted for as a sale and we have a continuing involvement with the transferred consumer automotive assets (e.g., servicing) that were outstanding during the years ended December 31, 2018 , 2017 , and 2016 . Additionally, this table contains information regarding cash flows received from and paid to nonconsolidated SPEs that existed during each period. Year ended December 31, ($ in millions) Consumer automotive Consumer mortgage 2018 Cash proceeds from transfers completed during the period $ 24 $ — Cash flows received on retained interests in securitization entities 20 — Servicing fees 18 — Cash disbursements for repurchases during the period (4 ) — Representation and warranty recoveries — 2 2017 Cash proceeds from transfers completed during the period $ 1,187 $ — Cash disbursements for repurchases during the period (a) (491 ) — Servicing fees 31 — Cash flows received on retained interests in securitization entities 21 — Other cash flows 4 — 2016 Cash proceeds from transfers completed during the period $ 1,715 $ — Servicing fees 35 — Other cash flows 8 — (a) During the second quarter of 2017, we elected to not renew a consumer automotive credit conduit facility and also purchased the related consumer automotive loans and settled associated retained interests.
Schedule of Quantitative Information and Net Credit Losses about Securitized and Other Financial Assets Managed Together	The following tables present quantitative information about delinquencies and net credit losses for off-balance sheet securitizations and whole-loan sales where we have continuing involvement. Total amount Amount 60 days or more past due December 31, ($ in millions) 2018 2017 2018 2017 Off-balance sheet securitization entities Consumer automotive $ 1,235 $ 1,964 $ 13 $ 16 Whole-loan sales (a) Consumer automotive 634 1,399 3 4 Total $ 1,869 $ 3,363 $ 16 $ 20 (a) Whole-loan sales are not part of a securitization transaction, but represent consumer automotive pools of loans sold to third-party investors. Net credit losses Year ended December 31, ($ in millions) 2018 2017 Off-balance sheet securitization entities Consumer automotive $ 10 $ 13 Whole-loan sales (a) Consumer automotive 2 3 Total $ 12 $ 16 (a) Whole-loan sales are not part of a securitization transaction, but represent consumer automotive pools of loans sold to third-party investors.

Premiums Receivable and Other_2

Premiums Receivable and Other Insurance Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Premiums Receivable and Other Insurance Assets [Abstract]
Premiums Receivable and Other Insurance Assets	Premiums receivable and other insurance assets consisted of the following. December 31, ($ in millions) 2018 2017 Prepaid reinsurance premiums $ 527 $ 507 Reinsurance recoverable on unpaid losses 96 108 Reinsurance recoverable on paid losses 22 19 Premiums receivable 88 84 Deferred policy acquisition costs 1,593 1,329 Total premiums receivable and other insurance assets $ 2,326 $ 2,047

Other Assets (Tables)

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Other Assets [Abstract]
Schedule of Other Assets	The components of other assets were as follows. December 31, ($ in millions) 2018 2017 Property and equipment at cost $ 1,250 $ 1,064 Accumulated depreciation (686 ) (608 ) Net property and equipment 564 456 Nonmarketable equity investments (a) 1,410 1,233 Restricted cash held for securitization trusts (b) 965 923 Investment in qualified affordable housing projects (c) 649 472 Accrued interest, fees, and rent receivables 599 550 Net deferred tax assets 317 461 Equity method-investments (d) 262 220 Goodwill (e) 240 240 Other accounts receivable 203 116 Restricted cash and cash equivalents (f) 124 94 Fair value of derivative contracts in receivable position (g) 41 39 Cash collateral placed with counterparties 26 29 Other assets 753 830 Total other assets $ 6,153 $ 5,663 (a) Includes investments in FHLB stock of $903 million and $745 million at December 31, 2018 , and 2017, respectively; FRB stock of $448 million and $445 million at December 31, 2018 , and 2017, respectively; and equity securities without a readily determinable fair value of $59 million at December 31, 2018 , measured at cost with adjustments for impairment and observable changes in price. During the year ended December 31, 2018 , we recorded $2 million in impairment related to equity securities without a readily determinable fair value. (b) Includes restricted cash collected from customer payments on securitized receivables, which are distributed by us to investors as payments on the related secured debt, and cash reserve deposits utilized as a form of credit enhancement for various securitization transactions. (c) Investment in qualified affordable housing projects are accounted for using the proportional amortization method of accounting and include $319 million and $240 million of unfunded commitments to provide additional capital contributions to investees at December 31, 2018 , and 2017, respectively. Substantially all of the unfunded commitments at December 31, 2018 , are expected to be paid out over the next five years. (d) Primarily relates to investments made in connection with our CRA program. (e) Includes goodwill of $27 million within our Insurance operations at both December 31, 2018 , and 2017; $193 million within Corporate and Other at both December 31, 2018 , and 2017; and $20 million within Automotive Finance operations at both December 31, 2018 , and 2017. As a result of our acquisition of TradeKing Group, Inc. (TradeKing), we recognized $193 million of goodwill within Corporate and Other on June 1, 2016. On August 1, 2016, we purchased assets from Blue Yield and recognized $20 million of goodwill within Automotive Finance operations. No other changes to the carrying amount of goodwill were recorded during the years ended December 31, 2018 , 2017 , and 2016 . (f) Primarily represents a number of arrangements with third parties where certain restrictions are placed on balances we hold due to collateral agreements associated with operational processes with a third-party bank, or letter of credit arrangements and corresponding collateral requirements. (g) For additional information on derivative instruments and hedging activities, refer to Note 21 .

Deposit Liabilities (Tables)

Deposit Liabilities (Tables)	12 Months Ended
	Dec. 31, 2018
Deposits [Abstract]
Deposit Liabilities, Type	Deposit liabilities consisted of the following. December 31, ($ in millions) 2018 2017 Noninterest-bearing deposits $ 142 $ 108 Interest-bearing deposits Savings and money market checking accounts 56,050 49,267 Certificates of deposit 49,985 43,869 Dealer deposits 1 12 Total deposit liabilities $ 106,178 $ 93,256
Time Deposit Maturities	The following table presents the scheduled maturity of total certificates of deposit at December 31, 2018 . ($ in millions) Due in 2019 $ 31,518 Due in 2020 11,687 Due in 2021 4,569 Due in 2022 1,493 Due in 2023 718 Total certificates of deposit $ 49,985

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Schedule of Short-term Debt	The following table presents the composition of our short-term borrowings portfolio. 2018 2017 December 31, ($ in millions) Unsecured Secured (a) Total Unsecured Secured (a) Total Demand notes $ 2,477 $ — $ 2,477 $ 3,171 $ — $ 3,171 Federal Home Loan Bank — 6,825 6,825 — 7,350 7,350 Securities sold under agreements to repurchase — 685 685 — 892 892 Total short-term borrowings $ 2,477 $ 7,510 $ 9,987 $ 3,171 $ 8,242 $ 11,413 Weighted average interest rate (b) 2.5 % 1.5 % (a) Refer to the section below titled Long-term Debt for further details on assets restricted as collateral for payment of the related debt. (b) Based on the debt outstanding and the interest rate at December 31 of each year.
Long-term Debt	The following tables present the composition of our long-term debt portfolio. December 31, ($ in millions) Amount Stated interest rate Weighted-average stated interest rate (a) Due date range 2018 Unsecured debt Fixed rate (b) $ 9,406 Variable rate 1 Trust preferred securities (c) 2,572 Hedge basis adjustment (d) 128 Total unsecured debt 12,107 2.42–8.40% 6.29 % 2019–2049 Secured debt Fixed rate 23,514 Variable rate (e) 8,633 Hedge basis adjustment (d) (61 ) Total secured debt (f) (g) (h) 32,086 1.26–4.50% 2.54 % 2019–2037 Total long-term debt $ 44,193 2017 Unsecured debt Fixed rate (b) $ 12,820 Variable rate 1 Trust preferred securities (c) 2,570 Hedge basis adjustment (d) 240 Total unsecured debt 15,631 1.48–8.00% 5.68 % 2018–2049 Secured debt Fixed rate 18,845 Variable rate (e) 9,782 Hedge basis adjustment (d) (32 ) Total secured debt (f) (g) (h) 28,595 0.63–4.50% 1.96 % 2018–2036 Total long-term debt $ 44,226 (a) Based on the debt outstanding and the interest rate at December 31 of each year excluding any impacts of interest rate hedges. (b) Includes subordinated debt of $1.0 billion and $1.4 billion at December 31, 2018, and 2017, respectively. (c) Refer to the section below titled Trust Preferred Securities for further information. (d) Represents the basis adjustment associated with the application of hedge accounting on certain of our long-term debt positions. Refer to Note 21 for additional information. (e) Includes $5 million and $8 million at December 31, 2018, and 2017, respectively, of long-term debt that does not have a stated interest rate. (f) Includes $10.5 billion and $10.2 billion of VIE secured debt at December 31, 2018, and 2017, respectively. (g) Includes $6.7 billion and $8.1 billion of debt outstanding from our automotive committed secured credit facilities at December 31, 2018, and 2017, respectively. (h) Includes advances from the FHLB of Pittsburgh of $14.9 billion and $10.3 billion at December 31, 2018, and 2017, respectively.
Schedule of Long-term Debt Instruments	2018 2017 December 31, ($ in millions) Unsecured Secured Total Unsecured Secured Total Long-term debt (a) Due within one year $ 1,663 $ 7,313 $ 8,976 $ 3,540 $ 7,497 $ 11,037 Due after one year 10,444 24,773 35,217 12,091 21,098 33,189 Total long-term debt $ 12,107 $ 32,086 $ 44,193 $ 15,631 $ 28,595 $ 44,226 (a) Includes basis adjustments related to the application of hedge accounting. Amounts for December 31, 2017, have been updated to conform to this change in presentation.
Scheduled of Maturities of Long-term Debt	The following table presents the scheduled remaining maturity of long-term debt at December 31, 2018 , assuming no early redemptions will occur. The amounts below include adjustments to the carrying value resulting from the application of hedge accounting. The actual payment of secured debt may vary based on the payment activity of the related pledged assets. ($ in millions) 2019 2020 2021 2022 2023 2024 and thereafter Total Unsecured Long-term debt $ 1,704 $ 2,257 $ 698 $ 1,069 $ 12 $ 7,502 $ 13,242 Original issue discount (41 ) (41 ) (45 ) (49 ) (56 ) (903 ) (1,135 ) Total unsecured 1,663 2,216 653 1,020 (44 ) 6,599 12,107 Secured Long-term debt 7,313 7,363 10,195 5,321 1,230 664 32,086 Total long-term debt $ 8,976 $ 9,579 $ 10,848 $ 6,341 $ 1,186 $ 7,263 $ 44,193
Pledged assets for the payment of the related secured borrowings and repurchase agreements	The following summarizes assets restricted as collateral for the payment of the related debt obligation primarily arising from securitization transactions accounted for as secured borrowings and repurchase agreements. 2018 2017 December 31, ($ in millions) Total (a) Ally Bank Total (a) Ally Bank Investment securities (b) $ 10,280 $ 9,564 $ 8,371 $ 7,443 Mortgage assets held-for-investment and lending receivables 16,498 16,498 13,579 13,579 Consumer automotive finance receivables 17,015 9,715 19,787 6,200 Commercial automotive finance receivables 15,563 15,563 16,567 16,472 Operating leases 170 — 457 — Total assets restricted as collateral (c) (d) $ 59,526 $ 51,340 $ 58,761 $ 43,694 Secured debt $ 39,596 (e) $ 32,072 $ 36,837 (e) $ 23,278 (a) Ally Bank is a component of the total column. (b) A portion of the restricted investment securities at December 31, 2018 , and December 31, 2017 , were restricted under repurchase agreements. Refer to the section above titled Short-term Borrowings for information on the repurchase agreements. (c) Ally Bank has an advance agreement with the FHLB, and had assets pledged to secure borrowings that were restricted as collateral to the FHLB totaling $30.8 billion and $25.2 billion at December 31, 2018 , and December 31, 2017 , respectively. These assets were composed primarily of consumer mortgage finance receivables and loans and investment securities. Ally Bank has access to the FRB Discount Window. Ally Bank had assets pledged and restricted as collateral to the FRB totaling $2.4 billion and $2.3 billion at December 31, 2018 , and December 31, 2017 , respectively. These assets were composed of consumer automotive finance receivables and loans. Availability under these programs is only for the operations of Ally Bank and cannot be used to fund the operations or liabilities of Ally or its subsidiaries. (d) Excludes restricted cash and cash reserves for securitization trusts recorded within other assets on the Consolidated Balance Sheet . Refer to Note 13 for additional information. (e) Includes $7.5 billion and $8.2 billion of short-term borrowings at December 31, 2018 , and December 31, 2017 , respectively.
Schedule Of Committed Funding Facilities	Outstanding Unused capacity (a) Total capacity December 31, ($ in millions) 2018 2017 2018 2017 2018 2017 Bank funding Secured $ 3,500 $ 1,785 $ 1,300 $ 890 $ 4,800 $ 2,675 Parent funding Secured 3,165 6,330 635 2,920 3,800 9,250 Total committed secured credit facilities $ 6,665 $ 8,115 $ 1,935 $ 3,810 $ 8,600 $ 11,925 (a) Funding from committed secured credit facilities is available on request in the event excess collateral resides in certain facilities or the extent incremental collateral is available and contributed to the facilities.

Accrued Expenses and Other Li_2

Accrued Expenses and Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2018
Accounts Payable and Accrued Liabilities [Abstract]
Schedule of Accrued Liabilities	The components of accrued expenses and other liabilities were as follows. December 31, ($ in millions) 2018 2017 Accounts payable $ 516 $ 746 Unfunded commitments for investment in qualified affordable housing projects 319 240 Employee compensation and benefits 255 248 Reserves for insurance losses and loss adjustment expenses 134 140 Cash collateral received from counterparties 41 17 Fair value of derivative contracts in payable position (a) 37 41 Deferred revenue 27 32 Other liabilities 347 316 Total accrued expenses and other liabilities $ 1,676 $ 1,780 (a) For additional information on derivative instruments and hedging activities, refer to Note 21 .

Equity Equity (Tables)

Equity Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Schedule of Stockholders Equity	The following table presents changes in the number of shares issued and outstanding. Year ended December 31, (shares in thousands) (a) 2018 2017 2016 Common stock Total issued at January 1, 489,884 485,708 482,791 New issuances Employee benefits and compensation plans 2,914 4,176 2,917 Total issued at December 31, 492,797 489,884 485,708 Treasury balance at January 1, (52,830 ) (18,707 ) (811 ) Repurchase of common stock (b) (35,068 ) (34,122 ) (17,897 ) Total treasury stock at December 31, (87,898 ) (52,830 ) (18,707 ) Total outstanding at December 31, 404,900 437,054 467,000 (a) Figures in the table may not recalculate exactly due to rounding. Number of shares issued, in treasury, and outstanding are calculated based on unrounded numbers. (b) Includes shares of common stock withheld to cover income taxes owed by participants in our share-based incentive plans. Refer to the section titled Capital Planning and Stress Tests in Note 20 for additional information regarding our common-stock-repurchase program.

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	12 Months Ended
	Dec. 31, 2018
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Loss	The following table presents changes, net of tax, in each component of accumulated other comprehensive loss. ($ in millions) Unrealized (losses) gains on investment securities (a) Translation adjustments and net investment hedges (b) Cash flow hedges (b) Defined benefit pension plans Accumulated other comprehensive loss Balance at January 1, 2016 $ (159 ) $ 9 $ 8 $ (89 ) $ (231 ) 2016 net change (114 ) 5 — (1 ) (110 ) Balance at December 31, 2016 (273 ) 14 8 (90 ) (341 ) 2017 net change 100 2 3 1 106 Balance at December 31, 2017, before cumulative effect of adjustments $ (173 ) $ 16 $ 11 $ (89 ) $ (235 ) Cumulative effect of changes in accounting principles, net of tax (c) Adoption of Accounting Standards Update 2016-01 27 — — — 27 Adoption of Accounting Standards Update 2018-02 (40 ) 4 — (6 ) (42 ) Balance at January 1, 2018, after cumulative effect of adjustments (186 ) 20 11 (95 ) (250 ) 2018 net change (295 ) (2 ) 8 — (289 ) Balance at December 31, 2018 $ (481 ) $ 18 $ 19 $ (95 ) $ (539 ) (a) Represents the after-tax difference between the fair value and amortized cost of our available-for-sale securities portfolio. (b) For additional information on derivative instruments and hedging activities, refer to Note 21 . (c) Refer to the section titled Recently Adopted Accounting Standards in Note 1 for additional information.
Reclassification out of Accumulated Other Comprehensive Income	The following tables present the before- and after-tax changes in each component of accumulated other comprehensive (loss) income. Year ended December 31, 2018 ($ in millions) Before tax Tax effect After tax Investment securities Net unrealized losses arising during the period $ (375 ) $ 88 $ (287 ) Less: Net realized gains reclassified to income from continuing operations 11 (a) (3 ) (b) 8 Net change (386 ) 91 (295 ) Translation adjustments Net unrealized losses arising during the period (14 ) 3 (11 ) Net investment hedges (c) Net unrealized gains arising during the period 12 (3 ) 9 Cash flow hedges (c) Net unrealized gains arising during the period 12 (2 ) 10 Less: Net realized gains reclassified to income from continuing operations 2 (d) — 2 Net change 10 (2 ) 8 Defined benefit pension plans Net unrealized gains arising during the period 1 (1 ) — Other comprehensive loss $ (377 ) $ 88 $ (289 ) (a) Includes gains reclassified to other loss on investments, net in our Consolidated Statement of Income . (b) Includes amounts reclassified to income tax expense from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 21 . (d) Includes gains reclassified to interest on deposits and interest on long-term debt in our Consolidated Statement of Income . Year ended December 31, 2017 ($ in millions) Before tax Tax effect After tax Investment securities Net unrealized gains arising during the period $ 237 $ (45 ) $ 192 Less: Net realized gains reclassified to income from continuing operations 105 (a) (13 ) (b) 92 Net change 132 (32 ) 100 Translation adjustments Net unrealized gains arising during the period 12 (4 ) 8 Net investment hedges (c) Net unrealized losses arising during the period (10 ) 4 (6 ) Cash flow hedges (c) Net unrealized gains arising during the period 5 (2 ) 3 Defined benefit pension plans Net unrealized gains arising during the period 1 — 1 Other comprehensive income $ 140 $ (34 ) $ 106 (a) Includes gains reclassified to other gain on investments, net in our Consolidated Statement of Income . (b) Includes amounts reclassified to income tax expense from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 21 . Year ended December 31, 2016 ($ in millions) Before tax Tax effect After tax Investment securities Net unrealized gains arising during the period $ 13 $ 20 $ 33 Less: Net realized gains reclassified to income from continuing operations 185 (a) (38 ) (b) 147 Net change (172 ) 58 (114 ) Translation adjustments Net unrealized gains arising during the period 5 (2 ) 3 Less: Net realized losses reclassified to income from discontinued operations, net of tax (1 ) — (1 ) Net change 6 (2 ) 4 Net investment hedges (c) Net unrealized gains arising during the period 1 — 1 Defined benefit pension plans Net unrealized losses arising during the period (5 ) 2 (3 ) Less: Net realized losses reclassified to income from continuing operations (4 ) (d) 2 (b) (2 ) Net change (1 ) — (1 ) Other comprehensive loss $ (166 ) $ 56 $ (110 ) (a) Includes gains reclassified to other gain on investments, net in our Consolidated Statement of Income . (b) Includes amounts reclassified to income tax expense from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 21 . (d) Includes gains reclassified to compensation and benefits expense in our Consolidated Statement of Income .

Earnings per Common Share (Tabl

Earnings per Common Share (Tables)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table presents the calculation of basic and diluted earnings per common share. Year ended December 31, ($ in millions, except per share data; shares in thousands) (a) 2018 2017 2016 Net income from continuing operations $ 1,263 $ 926 $ 1,111 Preferred stock dividends — — (30 ) Net income from continuing operations attributable to common stockholders 1,263 926 1,081 Income (loss) from discontinued operations, net of tax — 3 (44 ) Net income attributable to common stockholders $ 1,263 $ 929 $ 1,037 Basic weighted-average common shares outstanding (b) 425,165 453,704 481,105 Diluted weighted-average common shares outstanding (b) 427,680 455,350 482,182 Basic earnings per common share Net income from continuing operations $ 2.97 $ 2.04 $ 2.25 Income (loss) from discontinued operations, net of tax — 0.01 (0.09 ) Net income $ 2.97 $ 2.05 $ 2.15 Diluted earnings per common share Net income from continuing operations $ 2.95 $ 2.03 $ 2.24 Income (loss) from discontinued operations, net of tax — 0.01 (0.09 ) Net income $ 2.95 $ 2.04 $ 2.15 (a) Figures in the table may not recalculate exactly due to rounding. Earnings per share is calculated based on unrounded numbers. (b) Includes shares related to share-based compensation that vested but were not yet issued .

Regulatory Capital and Other _2

Regulatory Capital and Other Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2018
Regulatory Capital Requirements [Abstract]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations	The following table summarizes our capital ratios under the U.S. Basel III capital framework. December 31, 2018 December 31, 2017 Required minimum (a) Well-capitalized minimum ($ in millions) Amount Ratio Amount Ratio Capital ratios Common Equity Tier 1 (to risk-weighted assets) Ally Financial Inc. $ 13,397 9.14 % $ 13,237 9.53 % 4.50 % (b) Ally Bank 16,552 12.61 17,059 15.04 4.50 6.50 % Tier 1 (to risk-weighted assets) Ally Financial Inc. $ 15,831 10.80 % $ 15,628 11.25 % 6.00 % 6.00 % Ally Bank 16,552 12.61 17,059 15.04 6.00 8.00 Total (to risk-weighted assets) Ally Financial Inc. $ 18,046 12.31 % $ 17,974 12.94 % 8.00 % 10.00 % Ally Bank 17,620 13.42 17,886 15.77 8.00 10.00 Tier 1 leverage (to adjusted quarterly average assets) (c) Ally Financial Inc. $ 15,831 9.00 % $ 15,628 9.53 % 4.00 % (b) Ally Bank 16,552 10.69 17,059 12.87 4.00 5.00 % (a) In addition to the minimum risk-based capital requirements for common equity Tier 1 capital, Tier 1 capital, and total capital ratios, Ally and Ally Bank were required to maintain a minimum capital conservation buffer of 1.875% and 1.25% at December 31, 2018 , and December 31, 2017 , respectively, which increased to 2.5% on January 1, 2019. (b) Currently, there is no ratio component for determining whether a BHC is “well-capitalized.” (c) Federal regulatory reporting guidelines require the calculation of adjusted quarterly average assets using a daily average methodology.
Schedule of Common Share Repurchase Activity	The following table presents information related to our common stock for each quarter since the commencement of our common-stock-repurchase programs and initiation of a quarterly cash dividend on common stock. Common stock repurchased during period (a) Number of common shares outstanding Cash dividends declared per common share (b) ($ in millions, except per share data; shares in thousands) Approximate dollar value Number of shares Beginning of period End of period 2016 Third quarter $ 159 8,298 483,753 475,470 $ 0.08 Fourth quarter 167 8,745 475,470 467,000 0.08 2017 First quarter $ 169 8,097 467,000 462,193 $ 0.08 Second quarter 204 10,485 462,193 452,292 0.08 Third quarter 190 8,507 452,292 443,796 0.12 Fourth quarter 190 7,033 443,796 437,054 0.12 2018 First quarter $ 185 6,473 437,054 432,691 $ 0.13 Second quarter 195 7,280 432,691 425,752 0.13 Third quarter 250 9,194 425,752 416,591 0.15 Fourth quarter 309 12,121 416,591 404,900 0.15 (a) Includes shares of common stock withheld to cover income taxes owed by participants in our share-based incentive plans. (b) On January 14, 2019 , the Ally Board of Directors (the Board) declared a quarterly cash dividend of $0.17 per share on all common stock, payable on February 15, 2019 . Refer to Note 31 for further information regarding this common stock dividend.

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position	The following table summarizes the amounts of derivative instruments reported on our Consolidated Balance Sheet . The amounts are presented on a gross basis, are segregated by derivatives that are designated and qualifying as hedging instruments or those that are not, and are further segregated by type of contract within those two categories. Derivative contracts in a receivable and payable position exclude open trade equity on derivatives cleared through central clearing counterparties. Any associated collateral exchanged with our central clearing counterparties are treated as settlements of the derivative exposure, rather than collateral. Such payments are recognized as settlements of the derivatives contracts in a receivable and payable position on our Consolidated Balance Sheet . Notional amounts are reference amounts from which contractual obligations are derived and are not recorded on the balance sheet. In our view, derivative notional is not an accurate measure of our derivative exposure when viewed in isolation from other factors, such as market rate fluctuations and counterparty credit risk. 2018 2017 Derivative contracts in a Notional amount Derivative contracts in a Notional amount December 31, ($ in millions) receivable position payable position receivable position payable position Derivatives designated as accounting hedges Interest rate contracts Swaps $ — $ — $ 24,203 $ — $ — $ 6,915 Foreign exchange contracts Forwards 1 — 136 — 1 136 Total derivatives designated as accounting hedges 1 — 24,339 — 1 7,051 Derivatives not designated as accounting hedges Interest rate contracts Futures and forwards — — 11 — — 23 Written options — 37 6,793 1 39 8,327 Purchased options 37 — 6,742 38 — 8,237 Total interest rate risk 37 37 13,546 39 39 16,587 Foreign exchange contracts Futures and forwards 3 — 181 — 1 124 Total foreign exchange risk 3 — 181 — 1 124 Total derivatives not designated as accounting hedges 40 37 13,727 39 40 16,711 Total derivatives $ 41 $ 37 $ 38,066 $ 39 $ 41 $ 23,762
Schedule of Fair Value Hedging Instruments, Statements of Financial Performance and Financial Position, Location	The following table presents amounts recorded on our Consolidated Balance Sheet related to cumulative basis adjustments for fair value hedges. December 31, ($ in millions) Carrying amount of the hedged items Cumulative amount of fair value hedging adjustment included in the carrying amount of the hedged items Total Discontinued (a) 2018 2017 2018 2017 2018 2017 Assets Available-for-sale securities (b) (c) $ 1,485 $ 173 $ — $ 2 $ (5 ) $ 2 Finance receivables and loans, net (d) 40,850 2,305 24 18 5 19 Liabilities Long-term debt $ 13,001 $ 14,640 $ 67 $ 208 $ 67 $ 235 (a) Represents the fair value hedging adjustment on qualifying hedges for which the hedging relationship was discontinued. This represents a subset of the amounts reported in the total hedging adjustment. (b) The carrying amount of hedged available-for-sale securities is presented above using amortized cost. Refer to Note 8 for a reconciliation of the amortized cost and fair value of available-for-sale securities. (c) Includes the amortized cost basis of closed portfolios used to designate hedging relationships in which the hedged item is the last layer expected to be remaining at the end of the hedging relationship. At December 31, 2018, the amortized cost basis of the closed portfolios used in these hedging relationships was $47 million , there was no basis adjustment associated with the last-of-layer relationships, and the amount identified as the last of layer in the hedge relationship was $28 million . A last-of-layer hedge strategy did not exist at December 31, 2017 . (d) The hedged item represents the carrying value of the hedged portfolio of assets. The amount identified as the last of layer in the hedge relationship was $21.4 billion as of December 31, 2018 . The basis adjustment associated with the last-of-layer relationship was a $19 million asset as of December 31, 2018 , which would be allocated across the entire remaining closed pool upon termination or maturity of the hedge relationship. A last-of-layer hedge strategy did not exist at December 31, 2017 .
Derivative Instruments, Gain (Loss)	The following table summarizes the location and amounts of gains and losses on derivative instruments not designated as accounting hedges reported in our Consolidated Statement of Income . Year ended December 31, ($ in millions) 2018 2017 2016 Gain (loss) recognized in earnings Interest rate contracts Gain on mortgage and automotive loans, net $ — $ 1 $ — Other income, net of losses — (3 ) — Total interest rate contracts — (2 ) — Foreign exchange contracts Interest on long-term debt — — (2 ) Other income, net of losses 13 (7 ) 1 Total foreign exchange contracts 13 (7 ) (1 ) Gain (loss) recognized in earnings $ 13 $ (9 ) $ (1 )
Derivative Instruments Designated as FV Hedges, Gain (Loss)	The following table summarizes the location and amounts of gains and losses on derivative instruments designated as fair value and cash flow hedges reported in our Consolidated Statement of Income . Interest and fees on finance receivables and loans Interest and dividends on investment securities and other earning assets Interest on deposits Interest on long-term debt Year ended December 31, ($ in millions) 2018 2017 2016 2018 2017 2016 2018 2017 2016 2018 2017 2016 Gain (loss) on fair value hedging relationships Interest rate contracts Hedged fixed-rate unsecured debt $ — $ — $ — $ — $ — $ — $ — $ — $ — $ 62 $ 8 $ (78 ) Derivatives designated as hedging instruments on fixed-rate unsecured debt — — — — — — — — — (61 ) (3 ) 73 Hedged fixed-rate FHLB advances — — — — — — — — — 47 22 8 Derivatives designated as hedging instruments on fixed-rate FHLB advances — — — — — — — — — (47 ) (22 ) (8 ) Hedged available-for-sale securities — — — (3 ) (1 ) — — — — — — — Derivatives designated as hedging instruments on available-for-sale securities — — — 3 1 — — — — — — — Hedged fixed-rate consumer automotive loans 19 (3 ) — — — — — — — — — — Derivatives designated as hedging instruments on fixed-rate consumer automotive loans (19 ) 1 (2 ) — — — — — — — — — Total (loss) gain on fair value hedging relationships — (2 ) (2 ) — — — — — — 1 5 (5 ) Gain on cash flow hedging relationships Interest rate contracts Hedged deposit liabilities Reclassified from accumulated other comprehensive income into income — — — — — — 1 — — — — — Hedged variable-rate borrowings Reclassified from accumulated other comprehensive income into income — — — — — — — — — 1 — — Total gain on cash flow hedging relationships $ — $ — $ — $ — $ — $ — $ 1 $ — $ — $ 1 $ — $ — Total amounts presented in the Consolidated Statement of Income $ 6,688 $ 5,819 $ 5,162 $ 788 $ 599 $ 418 1,735 $ 1,077 $ 830 $ 1,753 $ 1,653 $ 1,742
Schedule of Derivative Instruments	The following table summarizes the location and amounts of gains and losses related to interest and amortization on derivative instruments designated as fair value and cash flow hedges reported in our Consolidated Statement of Income . Interest and fees on finance receivables and loans Interest and dividends on investment securities and other earning assets Interest on deposits Interest on long-term debt Year ended December 31, ($ in millions) 2018 2017 2016 2018 2017 2016 2018 2017 2016 2018 2017 2016 Gain (loss) on fair value hedging relationships Interest rate contracts Amortization of deferred unsecured debt basis adjustments $ — $ — $ — $ — $ — $ — $ — $ — $ — $ 51 $ 77 $ 84 Interest for qualifying accounting hedges of unsecured debt — — — — — — — — — 8 24 40 Amortization of deferred secured debt basis adjustments FHLB advances) — — — — — — — — — (17 ) (2 ) — Interest for qualifying accounting hedges of secured debt (FHLB advances) — — — — — — — — — 6 3 5 Interest for qualifying accounting hedges of available-for-sale securities — — — (1 ) — — — — — — — — Amortization of deferred loan basis adjustments (14 ) (21 ) (20 ) — — — — — — — — — Interest for qualifying accounting hedges of consumer automotive loans held-for-investment 16 (1 ) (18 ) — — — — — — — — — Total gain (loss) on fair value hedging relationships 2 (22 ) (38 ) (1 ) — — — — — 48 102 129 Gain (loss) on cash flow hedging relationships Interest rate contracts Interest for qualifying accounting hedges of variable-rate borrowings — — — — — — — — — 8 (1 ) — Interest for qualifying accounting hedges of deposit liabilities — — — — — — 3 — — — — — Total gain (loss) on cash flow hedging relationships $ — $ — $ — $ — $ — $ — $ 3 $ — $ — $ 8 $ (1 ) $ —
Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss)	The following table summarizes the effect of cash flow hedges on accumulated other comprehensive loss. Year ended December 31, ($ in millions) 2018 2017 2016 Interest rate contracts Gain recognized in other comprehensive loss $ 10 $ 5 $ —
Schedule of Net Investment Hedges in Accumulated Other Comprehensive Income (Loss)	The following table summarizes the effect of net investment hedges on accumulated other comprehensive loss and the Consolidated Statement of Comprehensive Income . Year ended December 31, ($ in millions) 2018 2017 2016 Foreign exchange contracts (a) (b) Gain (loss) recognized in other comprehensive loss $ 12 $ (10 ) $ 1 (a) There were no amounts excluded from effectiveness testing for the years ended December 31, 2018 , 2017 , or 2016. (b) Gains and losses reclassified from accumulated other comprehensive loss are reported as other income, net of losses, in the Consolidated Statement of Income. There were no amounts reclassified for the years ended December 31, 2018 , 2017 , or 2016.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	The significant components of income tax expense from continuing operations were as follows. Year ended December 31, ($ in millions) 2018 2017 2016 Current income tax (benefit) expense U.S. federal $ (12 ) $ (17 ) $ — Foreign 5 6 8 State and local 35 53 9 Total current expense 28 42 17 Deferred income tax expense (benefit) U.S. federal 328 566 423 State and local 3 (27 ) 30 Total deferred expense 331 539 453 Total income tax expense from continuing operations $ 359 $ 581 $ 470
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of income tax expense from continuing operations with the amounts at the statutory U.S. federal income tax rate is shown in the following table. Year ended December 31, ($ in millions) 2018 2017 2016 Statutory U.S. federal tax expense (a) $ 340 $ 527 $ 553 Change in tax resulting from Nondeductible expenses 28 4 7 State and local income taxes, net of federal income tax benefit (b) 26 7 35 Tax law enactment (23 ) 119 — Changes in unrecognized tax benefits (c) 22 1 (161 ) Tax credits, excluding expirations (20 ) (12 ) (15 ) Valuation allowance change, excluding expirations (8 ) (49 ) 51 Other, net (6 ) (16 ) — Total income tax expense from continuing operations $ 359 $ 581 $ 470 (a) The statutory U.S. federal tax rate was 21% for 2018 and 35% for both 2017 and 2016. (b) Amount for 2017 includes state deferred tax adjustments primarily offset in the valuation allowance change caption. (c) Amount for 2016 is primarily the result of a U.S. tax reserve release in the second quarter of 2016 related to a prior-year federal return.
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	The significant components of deferred tax assets and liabilities are reflected in the following table. December 31, ($ in millions) 2018 2017 Deferred tax assets Tax credit carryforwards $ 1,796 $ 2,002 Adjustments to loan value 366 450 State and local taxes 168 200 Unearned insurance premiums 90 85 Hedging transactions 27 49 Tax loss carryforwards 8 302 Other 222 108 Gross deferred tax assets 2,677 3,196 Valuation allowance (1,057 ) (1,123 ) Deferred tax assets, net of valuation allowance 1,620 2,073 Deferred tax liabilities Lease transactions 850 1,212 Deferred acquisition costs 321 269 Debt transactions 93 95 Other 56 44 Gross deferred tax liabilities 1,320 1,620 Net deferred tax assets (a) $ 300 $ 453 (a) Amounts include $317 million and $461 million of net deferred tax assets included in other assets on our Consolidated Balance Sheet for tax jurisdictions in a total net deferred tax asset position at December 31, 2018 , and 2017 , respectively, and $17 million and $8 million included in accrued expenses and other liabilities on our Consolidated Balance Sheet for tax jurisdictions in a total net deferred tax liability position.
Schedule of Deferred Tax Assets and Related Valuation Allowances	The following table summarizes net deferred tax assets including related valuation allowances at December 31, 2018 . ($ in millions) Deferred tax asset (liability) Valuation allowance Net deferred tax asset (liability) Years of expiration Tax credit carryforwards Foreign tax credits $ 1,522 $ (963 ) $ 559 2022–2028 General business credits 274 — 274 2025–2038 Total tax credit carryforwards 1,796 (963 ) 833 Tax loss carryforwards Net operating losses — federal 8 — 8 2027–2036 Net operating losses — state 198 (a) (94 ) 104 2019–2038 Total federal and state tax loss carryforwards 206 (94 ) 112 Other net deferred tax liabilities (645 ) — (645 ) n/a Net deferred tax assets $ 1,357 $ (1,057 ) $ 300 (a) State net operating loss carryforwards are included in the state and local taxes and other liabilities totals disclosed in our deferred inventory table above.
Schedule of Unrecognized Tax Benefits Roll Forward	The following table provides a reconciliation of the beginning and ending amount of unrecognized tax benefits. ($ in millions) 2018 2017 2016 Balance at January 1, $ 15 $ 14 $ 185 Additions based on tax positions related to the current year — — — Additions for tax positions of prior years 29 3 12 Reductions for tax positions of prior years — (1 ) — Settlements — — (182 ) Expiration of statute of limitations — (1 ) (1 ) Balance at December 31, $ 44 $ 15 $ 14

Share-based Compensation Plans

Share-based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2018
Share-based Compensation Plans [Abstract]
Share-based Compensation Arrangements by Share-based Payment Award, Performance-based Units and Restricted Stock Units	The following table presents the changes in outstanding non-vested PSUs and RSUs activity during 2018 . (in thousands, except per share data) Number of units Weighted-average grant date fair value per share RSUs and PSUs Outstanding non-vested at January 1, 2018 5,592 $ 19.89 Granted 2,577 29.41 Vested (3,167 ) 21.61 Forfeited (138 ) 23.54 Outstanding non-vested at December 31, 2018 4,864 23.71

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on a Recurring Basis	The following tables display the assets and liabilities measured at fair value on a recurring basis including financial instruments elected for the fair value option. We often economically hedge the fair value change of our assets or liabilities with derivatives and other financial instruments. The tables below display the hedges separately from the hedged items; therefore, they do not directly display the impact of our risk-management activities. Recurring fair value measurements December 31, 2018 ($ in millions) Level 1 Level 2 Level 3 Total Assets Investment securities Equity securities (a) $ 766 $ — $ 7 $ 773 Available-for-sale securities Debt securities U.S. Treasury and federal agencies 1,850 1 — 1,851 U.S. States and political subdivisions — 802 — 802 Foreign government 7 138 — 145 Agency mortgage-backed residential — 17,138 — 17,138 Mortgage-backed residential — 2,686 — 2,686 Mortgage-backed commercial — 717 — 717 Asset-backed — 723 — 723 Corporate debt — 1,241 — 1,241 Total available-for-sale securities 1,857 23,446 — 25,303 Mortgage loans held-for-sale (b) — — 8 8 Interests retained in financial asset sales — — 4 4 Derivative contracts in a receivable position Interest rate — 37 — 37 Foreign currency — 4 — 4 Total derivative contracts in a receivable position — 41 — 41 Total assets $ 2,623 $ 23,487 $ 19 $ 26,129 Liabilities Accrued expenses and other liabilities Derivative contracts in a payable position Interest rate $ — $ 37 $ — $ 37 Total derivative contracts in a payable position — 37 — 37 Total liabilities $ — $ 37 $ — $ 37 (a) Our investment in any one industry did not exceed 9% . (b) Carried at fair value due to fair value option elections. Recurring fair value measurements December 31, 2017 ($ in millions) Level 1 Level 2 Level 3 Total Assets Investment securities Equity securities (a) $ 518 $ — $ — $ 518 Available-for-sale securities Debt securities U.S. Treasury 1,777 — — 1,777 U.S. States and political subdivisions — 854 — 854 Foreign government 8 146 — 154 Agency mortgage-backed residential — 14,291 — 14,291 Mortgage-backed residential — 2,494 — 2,494 Mortgage-backed commercial — 541 — 541 Asset-backed — 936 — 936 Corporate debt — 1,256 — 1,256 Total available-for-sale securities 1,785 20,518 — 22,303 Mortgage loans held-for-sale (b) — — 13 13 Interests retained in financial asset sales — — 5 5 Derivative contracts in a receivable position Interest rate — 38 1 39 Total derivative contracts in a receivable position — 38 1 39 Total assets $ 2,303 $ 20,556 $ 19 $ 22,878 Liabilities Accrued expenses and other liabilities Derivative contracts in a payable position Interest rate $ — $ 39 $ — $ 39 Foreign currency — 2 — 2 Total derivative contracts in a payable position — 41 — 41 Total liabilities $ — $ 41 $ — $ 41 (a) Our investment in any one industry did not exceed 14% . (b) Carried at fair value due to fair value option elections.
Fair Value, Assets Measured on a Recurring Basis, Unobservable Input Reconciliation	The following tables present the reconciliation for all Level 3 assets and liabilities measured at fair value on a recurring basis. There were no transfers into or out of Level 3 in the periods presented. We often economically hedge the fair value change of our assets or liabilities with derivatives and other financial instruments. The Level 3 items presented below may be hedged by derivatives and other financial instruments that are classified as Level 1 or Level 2. Thus, the following tables do not fully reflect the impact of our risk-management activities. Level 3 recurring fair value measurements Net realized/unrealized (losses) gains Fair value at Dec. 31, 2018 Net unrealized losses still held at December 31, 2018 ($ in millions) Fair value at Jan. 1, 2018 included in earnings included in OCI Purchases Sales Issuances Settlements included in earnings included in OCI Assets Equity securities (a) $ 19 $ (7 ) (b) $ — $ — $ — $ — $ (5 ) $ 7 $ (10 ) $ — Mortgage loans held-for-sale (c) 13 5 (d) — 303 (313 ) — — 8 — — Other assets Interests retained in financial asset sales 5 — — — — — (1 ) 4 — — Derivative assets 1 (1 ) (d) — — — — — — — — Total assets $ 38 $ (3 ) $ — $ 303 $ (313 ) $ — $ (6 ) $ 19 $ (10 ) $ — (a) In connection with our adoption of ASU 2016-01 on January 1, 2018, certain of our equity securities previously measured using the cost method of accounting are now measured at fair value on a recurring basis, and have been categorized as Level 3 within the fair value hierarchy. Accordingly, the fair value of such investments has been included in the opening balance of the reconciliation above. (b) Reported as other gain on investments, net, in the Consolidated Statement of Income. (c) Carried at fair value due to fair value option elections. (d) Reported as gain on mortgage and automotive loans, net, in the Consolidated Statement of Income. Level 3 recurring fair value measurements Fair value at Jan. 1, 2017 Net realized/unrealized gains Purchases Sales Issuances Settlements Fair value at Dec. 31, 2017 Net unrealized gains included in earnings still held at Dec. 31, 2017 ($ in millions) included in earnings included in OCI Assets Mortgage loans held-for-sale (a) $ — $ 2 (b) $ — $ 137 $ (126 ) $ — $ — $ 13 $ — Other assets Interests retained in financial asset sales 29 1 (c) — — 8 — (33 ) 5 — Derivative assets — 1 (b) — — — — — 1 1 Total assets $ 29 $ 4 $ — $ 137 $ (118 ) $ — $ (33 ) $ 19 $ 1 (a) Carried at fair value due to fair value option elections. (b) Reported as gain on mortgage and automotive loans, net, in the Consolidated Statement of Income. (c) Reported as other income, net of losses, in the Consolidated Statement of Income
Fair Value Measurements - Nonrecurring Basis	The following tables display assets and liabilities measured at fair value on a nonrecurring basis and still held at December 31, 2018 , and 2017, respectively. The amounts are as of the end of each period presented, which approximate the fair value measurements that occurred during each period. Nonrecurring fair value measurements Lower-of-cost or fair value or valuation reserve allowance Total gain (loss) included in earnings December 31, 2018 ($ in millions) Level 1 Level 2 Level 3 Total Assets Loans held-for-sale, net Automotive (a) $ — $ — $ 210 $ 210 $ (2 ) n/m (b) Other — — 96 96 — n/m (b) Total loans held-for-sale, net — — 306 306 (2 ) n/m (b) Commercial finance receivables and loans, net (c) Automotive — — 84 84 (10 ) n/m (b) Other — — 55 55 (46 ) n/m (b) Total commercial finance receivables and loans, net — — 139 139 (56 ) n/m (b) Other assets Nonmarketable equity investments — — 1 1 (1 ) n/m (b) Equity-method investments — — 3 3 — n/m (b) Repossessed and foreclosed assets (d) — — 13 13 (1 ) n/m (b) Total assets $ — $ — $ 462 $ 462 $ (60 ) n/m n/m = not meaningful (a) Represents loans within our commercial automotive portfolio. Of this amount, $104 million was valued based upon a sales price for a transaction that closed in January 2019, and $106 million was valued using a discounted cash flow analysis, with a spread over forward interest rates as a significant unobservable input utilizing a range of 0.08 – 1.09 % and weighted average of 0.72 %. (b) We consider the applicable valuation or loan loss allowance to be the most relevant indicator of the impact on earnings caused by the fair value measurement. Accordingly, the table above excludes total gains and losses included in earnings for these items. The carrying values are inclusive of the respective valuation or loan loss allowance. (c) Represents the portion of the portfolio specifically impaired during 2018 . The related valuation allowance represents the cumulative adjustment to fair value of those specific receivables. (d) The allowance provided for repossessed and foreclosed assets represents any cumulative valuation adjustment recognized to adjust the assets to fair value. Nonrecurring fair value measurements Lower-of-cost or fair value or valuation reserve allowance Total gain (loss) included in earnings December 31, 2017 ($ in millions) Level 1 Level 2 Level 3 Total Assets Loans held-for-sale, net $ — $ — $ 77 $ 77 $ — n/m (a) Commercial finance receivables and loans, net (b) Automotive — — 20 20 (3 ) n/m (a) Other — — 22 22 (12 ) n/m (a) Total commercial finance receivables and loans, net — — 42 42 (15 ) n/m (a) Other assets Repossessed and foreclosed assets (c) — — 14 14 (1 ) n/m (a) Other — — 3 3 — n/m (a) Total assets $ — $ — $ 136 $ 136 $ (16 ) n/m n/m = not meaningful (a) We consider the applicable valuation or loan loss allowance to be the most relevant indicator of the impact on earnings caused by the fair value measurement. Accordingly, the table above excludes total gains and losses included in earnings for these items. The carrying values are inclusive of the respective valuation or loan loss allowance. (b) Represents the portion of the portfolio specifically impaired during 2017 . The related valuation allowance represents the cumulative adjustment to fair value of those specific receivables. (c) The allowance provided for repossessed and foreclosed assets represents any cumulative valuation adjustment recognized to adjust the assets to fair value.
Financial Instruments Disclosure	The following table presents the carrying and estimated fair value of financial instruments, except for those recorded at fair value on a recurring basis presented in the previous section of this note titled Recurring Fair Value. When possible, we use quoted market prices to determine fair value. Where quoted market prices are not available, the fair value is internally derived based on appropriate valuation methodologies with respect to the amount and timing of future cash flows and estimated discount rates. However, considerable judgment is required in interpreting current market data to develop the market assumptions and inputs necessary to estimate fair value. As such, the actual amount received to sell an asset or the amount paid to settle a liability could differ from our estimates. Fair value information presented herein was based on information available at December 31, 2018 , and December 31, 2017 . Estimated fair value ($ in millions) Carrying value Level 1 Level 2 Level 3 Total December 31, 2018 Financial assets Held-to-maturity securities $ 2,362 $ — $ 2,307 $ — $ 2,307 Loans held-for-sale, net 306 — — 306 306 Finance receivables and loans, net 128,684 — — 130,878 130,878 FHLB/FRB stock (a) 1,351 — 1,351 — 1,351 Financial liabilities Deposit liabilities (b) $ 51,985 $ — $ — $ 51,997 $ 51,997 Short-term borrowings 9,987 — — 9,992 9,992 Long-term debt 44,193 — 23,846 21,800 45,646 December 31, 2017 Financial assets Held-to-maturity securities $ 1,899 $ — $ 1,865 $ — $ 1,865 Loans held-for-sale, net 95 — — 95 95 Finance receivables and loans, net 121,617 — — 123,302 123,302 Nonmarketable equity investments 1,233 — 1,190 49 1,239 Financial liabilities Deposit liabilities (b) $ 45,869 $ — $ — $ 45,827 $ 45,827 Short-term borrowings 11,413 — — 11,417 11,417 Long-term debt 44,226 — 27,807 18,817 46,624 (a) Included in other assets (nonmarketable equity investments) on our Consolidated Balance Sheet. (b) In connection with our adoption of ASU 2016-01 on January 1, 2018, deposit liabilities with no defined or contractual maturities are no longer included in the table above. Amounts for December 31, 2017, have been adjusted to conform to the current presentation and exclude $47.4 billion and $45.2 billion of deposit liabilities with no defined or contractual maturities from the carrying value and Level 3 fair value, respectively. Refer to Note 14 for information regarding the composition of our deposits portfolio, and Note 1 for further information regarding recently adopted accounting standards.

Offsetting Assets and Liabili_2

Offsetting Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2018
Offsetting Assets and Liabilities [Abstract]
Offsetting Assets and Liabilities	The composition of offsetting derivative instruments, financial assets, and financial liabilities was as follows. Gross amounts of recognized assets/liabilities Gross amounts offset on the Consolidated Balance Sheet Net amounts of assets/liabilities presented on the Consolidated Balance Sheet Gross amounts not offset on the Consolidated Balance Sheet December 31, 2018 ($ in millions) Financial instruments Collateral (a) (b) (c) Net amount Assets Derivative assets in net asset positions (d) $ 41 $ — $ 41 $ — $ (4 ) $ 37 Total assets $ 41 $ — $ 41 $ — $ (4 ) $ 37 Liabilities Derivative liabilities in net liability positions (d) $ 37 $ — $ 37 $ — $ — $ 37 Securities sold under agreements to repurchase (e) 685 — 685 — (685 ) — Total liabilities $ 722 $ — $ 722 $ — $ (685 ) $ 37 (a) Financial collateral received/pledged shown as a balance based on the sum of all net asset and liability positions between Ally and each individual derivative counterparty. (b) Amounts disclosed are limited to the financial asset or liability balance and, accordingly, exclude excess collateral received or pledged and noncash collateral received. There was $3 million of noncash derivative collateral, and $4 million of noncash collateral associated with our repurchase agreements, pledged to us that was excluded at December 31, 2018 . We do not record such collateral received on our Consolidated Balance Sheet unless certain conditions are met. (c) Certain agreements grant us the right to sell or pledge the noncash assets we receive as collateral. Noncash collateral pledged to us where the agreement grants us the right to sell or pledge the underlying assets had a fair value of $7 million at December 31, 2018 . We have not sold or pledged any of the noncash collateral received under these agreements as of December 31, 2018 . (d) For additional information on derivative instruments and hedging activities, refer to Note 21 . (e) For additional information on securities sold under agreements to repurchase, refer to Note 15 . Gross amounts of recognized assets/liabilities Gross amounts offset on the Consolidated Balance Sheet Net amounts of assets/liabilities presented on the Consolidated Balance Sheet Gross amounts not offset on the Consolidated Balance Sheet December 31, 2017 ($ in millions) Financial instruments Collateral (a) (b) (c) Net amount Assets Derivative assets in net asset positions $ 38 $ — $ 38 $ — $ — $ 38 Derivative assets with no offsetting arrangements 1 — 1 — — 1 Total assets (d) $ 39 $ — $ 39 $ — $ — $ 39 Liabilities Derivative liabilities in net liability positions (d) $ 41 $ — $ 41 $ — $ (1 ) $ 40 Securities sold under agreements to repurchase (e) 892 — 892 — (892 ) — Total liabilities $ 933 $ — $ 933 $ — $ (893 ) $ 40 (a) Financial collateral received/pledged shown as a balance based on the sum of all net asset and liability positions between Ally and each individual derivative counterparty. (b) Amounts disclosed are limited to the financial asset or liability balance and, accordingly, exclude excess collateral received or pledged and noncash collateral received. There was $2 million of noncash derivative collateral pledged to us that was excluded at December 31, 2017 . We do not record such collateral received on our Consolidated Balance Sheet unless certain conditions are met. (c) Certain agreements grant us the right to sell or pledge the noncash assets we receive as collateral. Noncash collateral pledged to us where the agreement grants us the right to sell or pledge the underlying assets had a fair value of $2 million at December 31, 2017 . We have not sold or pledged any of the noncash collateral received under these agreements as of December 31, 2017 . (d) For additional information on derivative instruments and hedging activities, refer to Note 21 . (e) For additional information on securities sold under agreements to repurchase, refer to Note 15 .

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Financial information for our reportable operating segments is summarized as follows. Year ended December 31, ($ in millions) Automotive Finance operations Insurance operations Mortgage Finance operations Corporate Finance operations Corporate and Other Consolidated (a) 2018 Net financing revenue and other interest income $ 3,769 $ 54 $ 179 $ 204 $ 184 $ 4,390 Other revenue 269 981 7 38 119 1,414 Total net revenue 4,038 1,035 186 242 303 5,804 Provision for loan losses 920 — 1 12 (15 ) 918 Total noninterest expense 1,750 955 140 86 333 3,264 Income (loss) from continuing operations before income tax expense $ 1,368 $ 80 $ 45 $ 144 $ (15 ) $ 1,622 Total assets $ 117,304 $ 7,734 $ 15,211 $ 4,670 $ 33,950 $ 178,869 2017 Net financing revenue and other interest income $ 3,713 $ 59 $ 132 $ 167 $ 150 $ 4,221 Other revenue 355 1,059 4 45 81 1,544 Total net revenue 4,068 1,118 136 212 231 5,765 Provision for loan losses 1,134 — 8 22 (16 ) 1,148 Total noninterest expense 1,714 950 108 76 262 3,110 Income (loss) from continuing operations before income tax expense $ 1,220 $ 168 $ 20 $ 114 $ (15 ) $ 1,507 Total assets $ 114,089 $ 7,464 $ 11,708 $ 3,979 $ 29,908 $ 167,148 2016 Net financing revenue and other interest income (loss) $ 3,665 $ 61 $ 97 $ 121 $ (37 ) $ 3,907 Other revenue 306 1,036 — 26 162 1,530 Total net revenue 3,971 1,097 97 147 125 5,437 Provision for loan losses 924 — (4 ) 10 (13 ) 917 Total noninterest expense 1,667 940 67 66 199 2,939 Income (loss) from continuing operations before income tax expense $ 1,380 $ 157 $ 34 $ 71 $ (61 ) $ 1,581 Total assets $ 116,347 $ 7,172 $ 8,307 $ 3,183 $ 28,719 $ 163,728 (a) Net financing revenue and other interest income after the provision for loan losses totaled $3.5 billion , $3.1 billion , and $3.0 billion for the years ended December 31, 2018 , 2017 , and 2016 , respectively.

Parent and Guarantor Condense_2

Parent and Guarantor Condensed Consolidating Financial Statements (Tables)	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Income Statement	Condensed Consolidating Statements of Comprehensive Income Year ended December 31, 2018 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing revenue and other interest income Interest and fees on finance receivables and loans $ (40 ) $ — $ 6,728 $ — $ 6,688 Interest and fees on finance receivables and loans — intercompany 12 — 5 (17 ) — Interest on loans held-for-sale — — 15 — 15 Interest and dividends on investment securities and other earning assets — — 789 (1 ) 788 Interest on cash and cash equivalents 8 — 64 — 72 Interest-bearing cash — intercompany 8 — 9 (17 ) — Operating leases 5 — 1,484 — 1,489 Total financing (loss) revenue and other interest income (7 ) — 9,094 (35 ) 9,052 Interest expense Interest on deposits — — 1,735 — 1,735 Interest on short-term borrowings 44 — 105 — 149 Interest on long-term debt 1,009 — 744 — 1,753 Interest on intercompany debt 15 — 20 (35 ) — Total interest expense 1,068 — 2,604 (35 ) 3,637 Net depreciation expense on operating lease assets 8 — 1,017 — 1,025 Net financing (loss) revenue (1,083 ) — 5,473 — 4,390 Cash dividends from subsidiaries Bank subsidiary 2,600 2,600 — (5,200 ) — Nonbank subsidiaries 443 — — (443 ) — Other revenue Insurance premiums and service revenue earned — — 1,022 — 1,022 Gain on mortgage and automotive loans, net 70 — 9 (54 ) 25 Other gain on investments, net — — (50 ) — (50 ) Other income, net of losses 411 — 770 (764 ) 417 Total other revenue 481 — 1,751 (818 ) 1,414 Total net revenue 2,441 2,600 7,224 (6,461 ) 5,804 Provision for loan losses 176 — 796 (54 ) 918 Noninterest expense Compensation and benefits expense 83 — 1,072 — 1,155 Insurance losses and loss adjustment expenses — — 295 — 295 Other operating expenses 681 — 1,897 (764 ) 1,814 Total noninterest expense 764 — 3,264 (764 ) 3,264 Income from continuing operations before income tax (benefit) expense and undistributed (loss) income of subsidiaries 1,501 2,600 3,164 (5,643 ) 1,622 Income tax (benefit) expense from continuing operations (300 ) — 659 — 359 Net income from continuing operations 1,801 2,600 2,505 (5,643 ) 1,263 (Loss) income from discontinued operations, net of tax (2 ) — 2 — — Undistributed (loss) income of subsidiaries Bank subsidiary (614 ) (614 ) — 1,228 — Nonbank subsidiaries 78 — — (78 ) — Net income 1,263 1,986 2,507 (4,493 ) 1,263 Other comprehensive loss, net of tax (289 ) (243 ) (308 ) 551 (289 ) Comprehensive income $ 974 $ 1,743 $ 2,199 $ (3,942 ) $ 974 Year ended December 31, 2017 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing revenue and other interest income Interest and fees on finance receivables and loans $ (27 ) $ — $ 5,846 $ — $ 5,819 Interest and fees on finance receivables and loans — intercompany 12 — 6 (18 ) — Interest and dividends on investment securities and other earning assets — — 601 (2 ) 599 Interest on cash and cash equivalents 7 — 30 — 37 Interest-bearing cash — intercompany 4 — 7 (11 ) — Operating leases 11 — 1,856 — 1,867 Total financing revenue and other interest income 7 — 8,346 (31 ) 8,322 Interest expense Interest on deposits 3 — 1,078 (4 ) 1,077 Interest on short-term borrowings 60 — 67 — 127 Interest on long-term debt 1,101 — 552 — 1,653 Interest on intercompany debt 15 — 12 (27 ) — Total interest expense 1,179 — 1,709 (31 ) 2,857 Net depreciation expense on operating lease assets 11 — 1,233 — 1,244 Net financing (loss) revenue (1,183 ) — 5,404 — 4,221 Cash dividends from subsidiaries Bank subsidiary 3,300 3,300 — (6,600 ) — Nonbank subsidiaries 752 — — (752 ) — Other revenue Insurance premiums and service revenue earned — — 973 — 973 Gain on mortgage and automotive loans, net 40 — 28 — 68 Other gain on investments, net — — 102 — 102 Other income, net of losses 675 — 834 (1,108 ) 401 Total other revenue 715 — 1,937 (1,108 ) 1,544 Total net revenue 3,584 3,300 7,341 (8,460 ) 5,765 Provision for loan losses 465 — 683 — 1,148 Noninterest expense Compensation and benefits expense 180 — 915 — 1,095 Insurance losses and loss adjustment expenses — — 332 — 332 Other operating expenses 899 — 1,892 (1,108 ) 1,683 Total noninterest expense 1,079 — 3,139 (1,108 ) 3,110 Income from continuing operations before income tax expense and undistributed (loss) income of subsidiaries 2,040 3,300 3,519 (7,352 ) 1,507 Income tax expense from continuing operations 337 — 244 — 581 Net income from continuing operations 1,703 3,300 3,275 (7,352 ) 926 Income (loss) from discontinued operations, net of tax 7 — (4 ) — 3 Undistributed (loss) income of subsidiaries Bank subsidiary (1,168 ) (1,168 ) — 2,336 — Nonbank subsidiaries 387 — — (387 ) — Net income 929 2,132 3,271 (5,403 ) 929 Other comprehensive income, net of tax 106 65 104 (169 ) 106 Comprehensive income $ 1,035 $ 2,197 $ 3,375 $ (5,572 ) $ 1,035 Year ended December 31, 2016 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing revenue and other interest income Interest and fees on finance receivables and loans $ (104 ) $ — $ 5,266 $ — $ 5,162 Interest and fees on finance receivables and loans — intercompany 11 — 8 (19 ) — Interest and dividends on investment securities and other earning assets — — 421 (3 ) 418 Interest on cash and cash equivalents 5 — 9 — 14 Interest-bearing cash — intercompany — — 9 (9 ) — Operating leases 17 — 2,694 — 2,711 Total financing (loss) revenue and other interest income (71 ) — 8,407 (31 ) 8,305 Interest expense Interest on deposits 8 — 822 — 830 Interest on short-term borrowings 40 — 17 — 57 Interest on long-term debt 1,161 — 581 — 1,742 Interest on intercompany debt 20 — 11 (31 ) — Total interest expense 1,229 — 1,431 (31 ) 2,629 Net depreciation expense on operating lease assets 14 — 1,755 — 1,769 Net financing (loss) revenue (1,314 ) — 5,221 — 3,907 Cash dividends from subsidiaries Nonbank subsidiaries 965 — — (965 ) — Other revenue Insurance premiums and service revenue earned — — 945 — 945 (Loss) gain on mortgage and automotive loans, net (11 ) — 22 — 11 Other gain on investments, net — — 176 9 185 Other income, net of losses 1,250 — 935 (1,796 ) 389 Total other revenue 1,239 — 2,078 (1,787 ) 1,530 Total net revenue 890 — 7,299 (2,752 ) 5,437 Provision for loan losses 408 — 509 — 917 Noninterest expense Compensation and benefits expense 573 — 419 — 992 Insurance losses and loss adjustment expenses — — 342 — 342 Other operating expenses 1,261 — 2,130 (1,786 ) 1,605 Total noninterest expense 1,834 — 2,891 (1,786 ) 2,939 (Loss) income from continuing operations before income tax (benefit) expense and undistributed income (loss) of subsidiaries (1,352 ) — 3,899 (966 ) 1,581 Income tax (benefit) expense from continuing operations (279 ) (82 ) 831 — 470 Net (loss) income from continuing operations (1,073 ) 82 3,068 (966 ) 1,111 Loss from discontinued operations, net of tax (39 ) — (5 ) — (44 ) Undistributed income (loss) of subsidiaries Bank subsidiary 1,273 1,273 — (2,546 ) — Nonbank subsidiaries 906 (2 ) — (904 ) — Net income 1,067 1,353 3,063 (4,416 ) 1,067 Other comprehensive loss, net of tax (110 ) (63 ) (106 ) 169 (110 ) Comprehensive income $ 957 $ 1,290 $ 2,957 $ (4,247 ) $ 957
Condensed Balance Sheet	Condensed Consolidating Balance Sheet December 31, 2018 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Assets Cash and cash equivalents Noninterest-bearing $ 55 $ — $ 755 $ — $ 810 Interest-bearing 5 — 3,722 — 3,727 Interest-bearing — intercompany 1,249 — 521 (1,770 ) — Total cash and cash equivalents 1,309 — 4,998 (1,770 ) 4,537 Equity securities — — 773 — 773 Available-for-sale securities — — 25,303 — 25,303 Held-to-maturity securities — — 2,382 (20 ) 2,362 Loans held-for-sale, net — — 314 — 314 Finance receivables and loans, net Finance receivables and loans, net 2,349 — 127,577 — 129,926 Intercompany loans to Nonbank subsidiaries 882 — 397 (1,279 ) — Allowance for loan losses (55 ) — (1,187 ) — (1,242 ) Total finance receivables and loans, net 3,176 — 126,787 (1,279 ) 128,684 Investment in operating leases, net 5 — 8,412 — 8,417 Intercompany receivables from Bank subsidiary 158 — — (158 ) — Nonbank subsidiaries 45 — 129 (174 ) — Investment in subsidiaries Bank subsidiary 16,213 16,213 — (32,426 ) — Nonbank subsidiaries 6,928 — — (6,928 ) — Premiums receivable and other insurance assets — — 2,326 — 2,326 Other assets 2,226 — 5,453 (1,526 ) 6,153 Total assets $ 30,060 $ 16,213 $ 176,877 $ (44,281 ) $ 178,869 Liabilities and equity Deposit liabilities Noninterest-bearing $ — $ — $ 142 $ — $ 142 Interest-bearing 1 — 106,035 — 106,036 Interest-bearing — intercompany — — 1,249 (1,249 ) — Total deposit liabilities 1 — 107,426 (1,249 ) 106,178 Short-term borrowings 2,477 — 7,510 — 9,987 Long-term debt 12,774 — 31,419 — 44,193 Intercompany debt to Bank subsidiary 20 — — (20 ) — Nonbank subsidiaries 918 — 882 (1,800 ) — Intercompany payables to Bank subsidiary 45 — — (45 ) — Nonbank subsidiaries 124 — 129 (253 ) — Interest payable 159 — 364 — 523 Unearned insurance premiums and service revenue — — 3,044 — 3,044 Accrued expenses and other liabilities 274 — 2,962 (1,560 ) 1,676 Total liabilities 16,792 — 153,736 (4,927 ) 165,601 Total equity 13,268 16,213 23,141 (39,354 ) 13,268 Total liabilities and equity $ 30,060 $ 16,213 $ 176,877 $ (44,281 ) $ 178,869 December 31, 2017 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Assets Cash and cash equivalents Noninterest-bearing $ 74 $ — $ 770 $ — $ 844 Interest-bearing 5 — 3,403 — 3,408 Interest-bearing — intercompany 1,138 — 695 (1,833 ) — Total cash and cash equivalents 1,217 — 4,868 (1,833 ) 4,252 Equity securities — — 518 — 518 Available-for-sale securities — — 22,303 — 22,303 Held-to-maturity securities — — 1,973 (74 ) 1,899 Loans held-for-sale, net — — 108 — 108 Finance receivables and loans, net Finance receivables and loans, net 7,434 — 115,459 — 122,893 Intercompany loans to Nonbank subsidiaries 879 — 408 (1,287 ) — Allowance for loan losses (185 ) — (1,091 ) — (1,276 ) Total finance receivables and loans, net 8,128 — 114,776 (1,287 ) 121,617 Investment in operating leases, net 19 — 8,722 — 8,741 Intercompany receivables from Bank subsidiary 80 — — (80 ) — Nonbank subsidiaries 71 — 77 (148 ) — Investment in subsidiaries Bank subsidiary 16,962 16,962 — (33,924 ) — Nonbank subsidiaries 8,111 — — (8,111 ) — Premiums receivable and other insurance assets — — 2,082 (35 ) 2,047 Other assets 2,207 — 5,105 (1,649 ) 5,663 Total assets $ 36,795 $ 16,962 $ 160,532 $ (47,141 ) $ 167,148 Liabilities and equity Deposit liabilities Noninterest-bearing $ — $ — $ 108 $ — $ 108 Interest-bearing 12 — 93,136 — 93,148 Interest-bearing — intercompany — — 1,139 (1,139 ) — Total deposit liabilities 12 — 94,383 (1,139 ) 93,256 Short-term borrowings 3,171 — 8,242 — 11,413 Long-term debt 17,966 — 26,260 — 44,226 Intercompany debt to Bank subsidiary 74 — — (74 ) — Nonbank subsidiaries 1,103 — 879 (1,982 ) — Intercompany payables to Bank subsidiary 4 — — (4 ) — Nonbank subsidiaries 132 — 127 (259 ) — Interest payable 200 — 175 — 375 Unearned insurance premiums and service revenue — — 2,604 — 2,604 Accrued expenses and other liabilities 639 — 2,790 (1,649 ) 1,780 Total liabilities 23,301 — 135,460 (5,107 ) 153,654 Total equity 13,494 16,962 25,072 (42,034 ) 13,494 Total liabilities and equity $ 36,795 $ 16,962 $ 160,532 $ (47,141 ) $ 167,148
Condensed Cash Flow Statement	Condensed Consolidating Statement of Cash Flows Year ended December 31, 2018 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 1,659 $ 2,600 $ 5,536 $ (5,645 ) $ 4,150 Investing activities Purchases of equity securities — — (1,076 ) — (1,076 ) Proceeds from sales of equity securities — — 787 — 787 Purchases of available-for-sale securities — — (7,868 ) — (7,868 ) Proceeds from sales of available-for-sale securities — — 852 — 852 Proceeds from repayments of available-for-sale securities — — 3,215 — 3,215 Purchases of held-to-maturity securities — — (578 ) — (578 ) Proceeds from repayments of held-to-maturity securities — — 147 — 147 Net change in investment securities — intercompany — — 54 (54 ) — Purchases of finance receivables and loans held-for-investment (131 ) — (7,101 ) 1,539 (5,693 ) Proceeds from sales of finance receivables and loans initially held-for-investment 1,596 — 34 (1,539 ) 91 Originations and repayments of finance receivables and loans held-for-investment and other, net 3,489 — (6,734 ) — (3,245 ) Net change in loans — intercompany (20 ) — (2 ) 22 — Purchases of operating lease assets — — (3,709 ) — (3,709 ) Disposals of operating lease assets 10 — 3,079 — 3,089 Capital contributions to subsidiaries (61 ) (6 ) — 67 — Returns of contributed capital 266 — — (266 ) — Net change in nonmarketable equity investments (16 ) — (165 ) — (181 ) Other, net — — (340 ) — (340 ) Net cash provided by (used in) investing activities 5,133 (6 ) (19,405 ) (231 ) (14,509 ) Financing activities Net change in short-term borrowings — third party (694 ) — (732 ) — (1,426 ) Net (decrease) increase in deposits (11 ) — 12,989 (111 ) 12,867 Proceeds from issuance of long-term debt — third party 69 — 18,332 — 18,401 Repayments of long-term debt — third party (4,774 ) — (13,166 ) — (17,940 ) Net change in debt — intercompany (198 ) — (10 ) 208 — Repurchase of common stock (939 ) — — — (939 ) Dividends paid — third party (242 ) — — — (242 ) Dividends paid and returns of contributed capital — intercompany — (2,600 ) (3,309 ) 5,909 — Capital contributions from parent — 6 61 (67 ) — Net cash (used in) provided by financing activities (6,789 ) (2,594 ) 14,165 5,939 10,721 Effect of exchange-rate changes on cash and cash equivalents and restricted cash — — (5 ) — (5 ) Net increase in cash and cash equivalents and restricted cash 3 — 291 63 357 Cash and cash equivalents and restricted cash at beginning of year 1,395 — 5,707 (1,833 ) 5,269 Cash and cash equivalents and restricted cash at end of year $ 1,398 $ — $ 5,998 $ (1,770 ) $ 5,626 The following table provides a reconciliation of cash and cash equivalents and restricted cash from the Condensed Consolidated Balance Sheet to the Condensed Consolidated Statement of Cash Flows. December 31, 2018 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Cash and cash equivalents on the Consolidated Balance Sheet $ 1,309 $ — $ 4,998 $ (1,770 ) $ 4,537 Restricted cash included in other assets on the Consolidated Balance Sheet (a) 89 — 1,000 — 1,089 Total cash and cash equivalents and restricted cash in the Consolidated Statement of Cash Flows $ 1,398 $ — $ 5,998 $ (1,770 ) $ 5,626 (a) Restricted cash balances relate primarily to Ally securitization arrangements. Refer to Note 13 for additional details describing the nature of restricted cash balances. Year ended December 31, 2017 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 4,591 $ 3,300 $ 3,466 $ (7,278 ) $ 4,079 Investing activities Purchases of equity securities — — (899 ) — (899 ) Proceeds from sales of equity securities — — 1,049 — 1,049 Purchases of available-for-sale securities — — (10,335 ) — (10,335 ) Proceeds from sales of available-for-sale securities — — 3,584 — 3,584 Proceeds from repayments of available-for-sale securities — — 2,899 — 2,899 Purchases of held-to-maturity securities — — (1,026 ) — (1,026 ) Proceeds from repayments of held-to-maturity securities — — 68 — 68 Net change in investment securities — intercompany 7 — 291 (298 ) — Purchases of finance receivables and loans held-for-investment (35 ) — (5,417 ) — (5,452 ) Proceeds from sales of finance receivables and loans initially held-for-investment 106 — 1,233 — 1,339 Originations and repayments of finance receivables and loans held-for-investment and other, net 860 — 33 (1,956 ) (1,063 ) Net change in loans — intercompany 2,068 — 217 (2,285 ) — Purchases of operating lease assets — — (4,052 ) — (4,052 ) Disposals of operating lease assets 13 — 5,554 — 5,567 Capital contributions to subsidiaries (1,212 ) (5 ) — 1,217 — Returns of contributed capital 1,567 — — (1,567 ) — Net change in nonmarketable equity investments — — (187 ) — (187 ) Other, net (31 ) — (99 ) (89 ) (219 ) Net cash provided by (used in) investing activities 3,343 (5 ) (7,087 ) (4,978 ) (8,727 ) Financing activities Net change in short-term borrowings — third party (453 ) — (810 ) — (1,263 ) Net (decrease) increase in deposits (156 ) — 15,466 (1,138 ) 14,172 Proceeds from issuance of long-term debt — third party 354 — 15,654 1,961 17,969 Repayments of long-term debt — third party (6,111 ) — (21,797 ) — (27,908 ) Net change in debt — intercompany (225 ) — (2,074 ) 2,299 — Repurchase of common stock (753 ) — — — (753 ) Dividends paid — third party (184 ) — — — (184 ) Dividends paid and returns of contributed capital — intercompany — (3,300 ) (5,619 ) 8,919 — Capital contributions from parent — 5 1,212 (1,217 ) — Net cash (used in) provided by financing activities (7,528 ) (3,295 ) 2,032 10,824 2,033 Effect of exchange-rate changes on cash and cash equivalents — — 3 — 3 Net increase (decrease) in cash and cash equivalents and restricted cash 406 — (1,586 ) (1,432 ) (2,612 ) Cash and cash equivalents and restricted cash at beginning of year 989 — 7,293 (401 ) 7,881 Cash and cash equivalents and restricted cash at end of year $ 1,395 $ — $ 5,707 $ (1,833 ) $ 5,269 The following table provides a reconciliation of cash and cash equivalents and restricted cash from the Condensed Consolidated Balance Sheet to the Condensed Consolidated Statement of Cash Flows. December 31, 2017 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Cash and cash equivalents on the Consolidated Balance Sheet $ 1,217 $ — $ 4,868 $ (1,833 ) $ 4,252 Restricted cash included in other assets on the Consolidated Balance Sheet (a) 178 — 839 — 1,017 Total cash and cash equivalents and restricted cash in the Consolidated Statement of Cash Flows $ 1,395 $ — $ 5,707 $ (1,833 ) $ 5,269 (a) Restricted cash balances relate primarily to Ally securitization arrangements. Refer to Note 13 for additional details describing the nature of restricted cash balances. Year ended December 31, 2016 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 241 $ 6 $ 5,383 $ (1,063 ) $ 4,567 Investing activities Purchases of equity securities — — (470 ) — (470 ) Proceeds from sales of equity securities — — 680 — 680 Purchases of available-for-sale securities — — (15,561 ) — (15,561 ) Proceeds from sales of available-for-sale securities — — 10,356 — 10,356 Proceeds from repayments of available-for-sale securities — — 3,379 — 3,379 Purchases of held-to-maturity securities — — (841 ) — (841 ) Purchases of finance receivables and loans held-for-investment (4 ) — (3,855 ) — (3,859 ) Proceeds from sales of finance receivables and loans initially held-for-investment — — 4,285 — 4,285 Originations and repayments of finance receivables and loans held-for-investment and other, net 2,013 — (10,839 ) — (8,826 ) Net change in loans — intercompany 877 — (67 ) (810 ) — Purchases of operating lease assets — — (3,274 ) — (3,274 ) Disposals of operating lease assets 25 — 6,279 — 6,304 Acquisitions, net of cash acquired (309 ) — — — (309 ) Capital contributions to subsidiaries (3,908 ) — — 3,908 — Returns of contributed capital 3,678 8 — (3,686 ) — Net change in nonmarketable equity investments — — (628 ) — (628 ) Other, net (206 ) — (191 ) 91 (306 ) Net cash provided by (used in) investing activities 2,166 8 (10,747 ) (497 ) (9,070 ) Financing activities Net change in short-term borrowings — third party 169 — 4,395 — 4,564 Net (decrease) increase in deposits (61 ) — 12,569 — 12,508 Proceeds from issuance of long-term debt — third party 979 — 13,176 — 14,155 Repayments of long-term debt — third party (2,662 ) — (23,750 ) — (26,412 ) Net change in debt — intercompany (382 ) — (877 ) 1,259 — Redemption of preferred stock (696 ) — — — (696 ) Repurchase of common stock (341 ) — — — (341 ) Dividends paid — third party (108 ) — — — (108 ) Dividends paid and returns of contributed capital — intercompany — (14 ) (4,644 ) 4,658 — Capital contributions from parent — — 3,908 (3,908 ) — Net cash (used in) provided by financing activities (3,102 ) (14 ) 4,777 2,009 3,670 Effect of exchange-rate changes on cash and cash equivalents — — 1 — 1 Net decrease in cash and cash equivalents and restricted cash (695 ) — (586 ) 449 (832 ) Cash and cash equivalents and restricted cash at beginning of year 1,684 — 7,879 (850 ) 8,713 Cash and cash equivalents and restricted cash at end of year $ 989 $ — $ 7,293 $ (401 ) $ 7,881

Guarantees and Commitments Guar

Guarantees and Commitments Guarantees and Commitments (Tables)	12 Months Ended
	Dec. 31, 2018
Guarantees and Commitments [Abstract]
Schedule of Guarantor Obligations	Guarantees are defined as contracts or indemnification agreements that contingently require us to make payments to third parties based on changes in the underlying agreements with the guaranteed parties. The following summarizes our outstanding guarantees, including those of our discontinued operations, made to third parties on our Consolidated Balance Sheet , for the periods shown. 2018 2017 December 31, ($ in millions) Maximum liability Carrying value of liability Maximum liability Carrying value of liability Standby letters of credit and other guarantees $ 218 $ 7 $ 227 $ 8
Financing Commitments	The contractual commitments were as follows. December 31, ($ in millions) 2018 2017 Unused revolving credit line commitments and other (a) $ 3,435 $ 2,341 Commitments to provide capital to investees (b) 394 283 Home equity lines of credit (c) 253 318 Mortgage loan origination commitments (d) 171 95 Construction-lending commitments (e) 85 144 (a) The unused portion of revolving lines of credit reset at prevailing market rates and, as such, approximate market value. (b) We are committed to contribute capital to certain investees. (c) We are committed to fund the remaining unused balances on home equity lines of credit. (d) Commitments with mortgage loan applicants in which the loan terms, including interest rate and price, are guaranteed for a designated period of time subject to the completion of underwriting procedures. (e) We are committed to fund the remaining unused balance while loans are in the construction period.
Schedule of Future Minimum Rental Payments for Operating Leases	Future minimum rental payments required under operating leases, primarily for real property, with noncancelable lease terms expiring after December 31, 2018 , are as follows. Year ended December 31, ($ in millions) 2019 $ 48 2020 47 2021 46 2022 37 2023 31 2024 and thereafter 294 Total minimum payment required $ 503
Long-term Purchase Commitment	We have entered into multiple agreements for information technology, voice and communication technology, and related maintenance. Many of the agreements are subject to variable price provisions, fixed or minimum price provisions, and termination or renewal provisions. Year ended December 31, ($ in millions) 2019 $ 70 2020 and 2021 47 2022 and thereafter — Total future payment obligations $ 117

Quarterly Financial Statement_2

Quarterly Financial Statements (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information (unaudited) [Abstract]
Quarterly Financial Information	($ in millions) First quarter Second quarter Third quarter Fourth quarter 2018 Net financing revenue and other interest income $ 1,049 $ 1,094 $ 1,107 $ 1,140 Other revenue 354 364 398 298 Total net revenue 1,403 1,458 1,505 1,438 Provision for loan losses 261 158 233 266 Total noninterest expense 814 839 807 804 Income from continuing operations before income tax expense 328 461 465 368 Income tax expense from continuing operations 76 113 91 79 Net income from continuing operations 252 348 374 289 (Loss) income from discontinued operations, net of tax (2 ) 1 — 1 Net income $ 250 $ 349 $ 374 $ 290 Basic earnings per common share (a) Net income from continuing operations $ 0.58 $ 0.81 $ 0.89 $ 0.70 Net income 0.57 0.81 0.89 0.70 Diluted earnings per common share (a) Net income from continuing operations $ 0.57 $ 0.80 $ 0.88 $ 0.70 Net income 0.57 0.81 0.88 0.70 Cash dividends declared per common share $ 0.13 $ 0.13 $ 0.15 $ 0.15 2017 Net financing revenue and other interest income $ 979 $ 1,067 $ 1,081 $ 1,094 Other revenue 396 388 381 379 Total net revenue 1,375 1,455 1,462 1,473 Provision for loan losses 271 269 314 294 Total noninterest expense 778 810 753 769 Income from continuing operations before income tax expense 326 376 395 410 Income tax expense from continuing operations (b) 113 122 115 231 Net income from continuing operations 213 254 280 179 Income (loss) from discontinued operations, net of tax 1 (2 ) 2 2 Net income $ 214 $ 252 $ 282 $ 181 Basic earnings per common share (a) Net income from continuing operations $ 0.46 $ 0.55 $ 0.62 $ 0.40 Net income 0.46 0.55 0.63 0.41 Diluted earnings per common share (a) Net income from continuing operations $ 0.46 $ 0.55 $ 0.62 $ 0.40 Net income 0.46 0.55 0.63 0.41 Cash dividends declared per common share $ 0.08 $ 0.08 $ 0.12 $ 0.12 (a) Earnings per share is calculated quarterly on an independent basis, therefore the total of the amounts presented for each year above may not reconcile to the annual amounts presented in Note 19 . (b) Amount for the fourth quarter of 2017 includes $119 million of tax expense attributable to tax reform enacted on December 22, 2017.

Description of Business, Basi_3

Description of Business, Basis of Presentation, and Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Jan. 01, 2018
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of changes in accounting principles, net of tax	$ 126	$ 126
Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of changes in accounting principles, net of tax	20	(7)
Accounting Standards Update 2018-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of changes in accounting principles, net of tax	42	$ 0
Right-of-use asset | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	161
Accrued expenses and other liabilities | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	29
Lease liability | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	190
Retained earnings | Accounting Standards Update 2017-08
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(10)
AOCI Attributable to Parent | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 8

Discontinued Operations (Detail

Discontinued Operations (Details) - 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
Discontinued Operations [Abstract]
Income (loss) from discontinued operations, before tax									$ 1	$ 2	$ 43
Income (loss) from discontinued operations, net of tax	$ (1)	$ 0	$ (1)	$ 2	$ (2)	$ (2)	$ 2	$ (1)	$ 0	$ (3)	$ 44

Revenue from Contracts with C_3

Revenue from Contracts with Customers (Contract with Customer, Asset and Liability) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Premiums receivable and other insurance assets	$ 2,326		$ 2,047
Other assets	6,153		5,663
Assets	178,869		167,148	$ 163,728
Unearned insurance premiums and service revenue	3,044		2,604
Liabilities	165,601		153,654
Accumulated deficit	(5,489)		(6,406)
Equity	13,268	$ 13,375	13,494	$ 13,317	$ 13,439
Liabilities and equity	$ 178,869		$ 167,148
Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Premiums receivable and other insurance assets		122
Other assets		41
Assets		163
Unearned insurance premiums and service revenue		289
Liabilities		289
Accumulated deficit		(126)
Equity		(126)
Liabilities and equity		163
Day one balance
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Premiums receivable and other insurance assets		2,169
Other assets		5,704
Assets		167,311
Unearned insurance premiums and service revenue		2,893
Liabilities		153,943
Accumulated deficit		(6,532)
Equity		13,368
Liabilities and equity		$ 167,311

Revenue from Contracts with C_4

Revenue from Contracts with Customers (Impact of ASU 2014-09 on Balance Sheet and Income Statement) (Details) - 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	Jan. 01, 2018	Dec. 31, 2015
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Insurance premiums and service revenue earned									$ 1,022	$ 973	$ 945
Other revenue	$ 298	$ 398	$ 364	$ 354	$ 379	$ 381	$ 388	$ 396	1,414	1,544	1,530
Net revenue									5,804	5,765	5,437
Compensation and benefits expense									1,155	1,095	992
Other operating expenses									1,814	1,683	1,605
Noninterest expense	804	807	839	814	769	753	810	778	3,264	3,110	2,939
Income from continuing operations before income tax expense	368	465	461	328	410	395	376	326	1,622	1,507	1,581
Income tax expense from continuing operations	79	91	113	76	231	115	122	113	359	581	470
Net income from continuing operations	289	374	348	252	179	280	254	213	1,263	926	1,111
Net income	290	$ 374	$ 349	$ 250	181	$ 282	$ 252	$ 214	1,263	929	1,067
Comprehensive income									974	1,035	957
Premiums receivable and other insurance assets	2,326				2,047				2,326	2,047
Other assets	6,153				5,663				6,153	5,663
Assets	178,869				167,148				178,869	167,148	163,728
Unearned insurance premiums and service revenue	3,044				2,604				3,044	2,604
Liabilities	165,601				153,654				165,601	153,654
Accumulated deficit	(5,489)				(6,406)				(5,489)	(6,406)
Equity	13,268				13,494				13,268	13,494	$ 13,317	$ 13,375	$ 13,439
Liabilities and equity	178,869				$ 167,148				178,869	$ 167,148
Effect of adopting the amendments to Topic 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Insurance premiums and service revenue earned									(26)
Other revenue									(26)
Net revenue									(26)
Compensation and benefits expense									(1)
Other operating expenses									(12)
Noninterest expense									(13)
Income from continuing operations before income tax expense									(13)
Income tax expense from continuing operations									(3)
Net income from continuing operations									(10)
Net income									(10)
Comprehensive income									(10)
Premiums receivable and other insurance assets	135								135
Other assets	44								44
Assets	179								179
Unearned insurance premiums and service revenue	315								315
Liabilities	315								315
Accumulated deficit	(136)								(136)
Equity	(136)								(136)
Liabilities and equity	$ 179								$ 179

Revenue from Contracts with C_5

Revenue from Contracts with Customers (Disaggregation of Revenue) (Details) - 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
Disaggregation of Revenue [Line Items]
Insurance commissions									$ 440	$ 415	$ 389
Revenue from contracts with customers									689
Other revenue	$ 298	$ 398	$ 364	$ 354	$ 379	$ 381	$ 388	$ 396	1,414	1,544	1,530
Noninsurance contracts
Disaggregation of Revenue [Line Items]
Contract with customer, unearned revenue	289								289
Unearned revenue, revenue recognized									91
Unearned revenue, remaining performance obligation, amount	2,600								2,600
Deferred commissions	1,500								1,500
Insurance commissions									427
Revenue from contracts with customers									506
Remarketing fee income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									79
Brokerage commissions and other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									62
Brokered/agent commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									15
Deposit account and other banking fees
Disaggregation of Revenue [Line Items]
Gross interchange fee income									12
Interchange expense									10
Revenue from contracts with customers									13
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									14
Automotive Finance operations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									92
Other revenue									269	355	306
Automotive Finance operations | Noninsurance contracts
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Automotive Finance operations | Remarketing fee income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									79
Automotive Finance operations | Brokerage commissions and other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Automotive Finance operations | Brokered/agent commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Automotive Finance operations | Deposit account and other banking fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Automotive Finance operations | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									13
Automotive Finance operations | Sale of off-lease vehicles
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									90
Insurance operations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									522
Other revenue									981	1,059	1,036
Insurance operations | Noninsurance contracts
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									506
Insurance operations | Remarketing fee income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Insurance operations | Brokerage commissions and other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Insurance operations | Brokered/agent commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									15
Insurance operations | Deposit account and other banking fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Insurance operations | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									1
Mortgage Finance operations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Other revenue									7	4	0
Mortgage Finance operations | Noninsurance contracts
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Mortgage Finance operations | Remarketing fee income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Mortgage Finance operations | Brokerage commissions and other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Mortgage Finance operations | Brokered/agent commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Mortgage Finance operations | Deposit account and other banking fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Mortgage Finance operations | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Corporate Finance operations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Other revenue									38	45	26
Corporate Finance operations | Noninsurance contracts
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Corporate Finance operations | Remarketing fee income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Corporate Finance operations | Brokerage commissions and other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Corporate Finance operations | Brokered/agent commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Corporate Finance operations | Deposit account and other banking fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Corporate Finance operations | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
2019 | Noninsurance contracts
Disaggregation of Revenue [Line Items]
Unearned revenue, remaining performance obligation, amount	721								721
2020 | Noninsurance contracts
Disaggregation of Revenue [Line Items]
Unearned revenue, remaining performance obligation, amount	639								639
2021 | Noninsurance contracts
Disaggregation of Revenue [Line Items]
Unearned revenue, remaining performance obligation, amount	519								519
2022 | Noninsurance contracts
Disaggregation of Revenue [Line Items]
Unearned revenue, remaining performance obligation, amount	379								379
2023 and thereafter | Noninsurance contracts
Disaggregation of Revenue [Line Items]
Unearned revenue, remaining performance obligation, amount	$ 386								386
Corporate and Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									75
Other revenue									119	$ 81	$ 162
Corporate and Other | Noninsurance contracts
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Corporate and Other | Remarketing fee income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Corporate and Other | Brokerage commissions and other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									62
Corporate and Other | Brokered/agent commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Corporate and Other | Deposit account and other banking fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									13
Corporate and Other | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									0
Out of scope of Topic 606
Disaggregation of Revenue [Line Items]
Other revenue									725
Out of scope of Topic 606 | Automotive Finance operations
Disaggregation of Revenue [Line Items]
Other revenue									177
Out of scope of Topic 606 | Insurance operations
Disaggregation of Revenue [Line Items]
Other revenue									459
Out of scope of Topic 606 | Mortgage Finance operations
Disaggregation of Revenue [Line Items]
Other revenue									7
Out of scope of Topic 606 | Corporate Finance operations
Disaggregation of Revenue [Line Items]
Other revenue									38
Out of scope of Topic 606 | Corporate and Other
Disaggregation of Revenue [Line Items]
Other revenue									$ 44

Insurance Premiums and Servic_3

Insurance Premiums and Service Revenue Earned (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Insurance Premiums and Service Revenue [Line Items]
Service revenue	$ 1,022	$ 973	$ 945
Insurance premiums written
Insurance Premiums and Service Revenue [Line Items]
Direct insurance premiums written	420	384	317
Assumed insurance premiums written	0	2	3
Insurance premiums, gross	420	386	320
Ceded insurance premiums written	(219)	(254)	(198)
Insurance premiums written, net	201	132	122
Service revenue	973	864	826
Insurance premiums and service revenue written and earned	1,174	996	948
Insurance premiums earned
Insurance Premiums and Service Revenue [Line Items]
Direct insurance premiums earned	414	364	318
Assumed insurance premiums earned	4	5	5
Insurance premiums, gross	418	369	323
Ceded insurance premiums earned	(197)	(188)	(141)
Insurance premiums earned, net	221	181	182
Service revenue	801	792	763
Insurance premiums and service revenue written and earned	$ 1,022	$ 973	$ 945

Other Income, Net of Losses (Sc

Other Income, Net of Losses (Schedule of Other Income, Net of Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Nonoperating Income (Expense) [Abstract]
Late charges and other administrative fees	$ 110	$ 102	$ 98
Remarketing fees	79	104	103
Income from equity method investments	46	14	18
Servicing fees	27	51	64
Other income, net	155	130	106
Total other income, net of losses	$ 417	$ 401	$ 389

Reserves for Insurance Losses_3

Reserves for Insurance Losses and Loss Adjustment Expenses (Short-duration Insurance Contracts, Claims Development) (Details) $ in Millions	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)
Claims Development [Line Items]
Incurred claims and allocated loss adjustment expenses, net of reinsurance	$ 2,363
Cumulative paid claims and allocated adjustment expenses, net of insurance, separately presented	2,337
All outstanding liabilities for loss and allocated loss adjustment expenses before 2012, net of reinsurance	9
Reserves for insurance losses and allocated loss adjustment expenses, net of reinsurance	35	$ 30	$ 38
Accident year 2012
Claims Development [Line Items]
Incurred claims and allocated loss adjustment expenses, net of reinsurance	422	422	423	$ 423	$ 423	$ 430	$ 435
Incurred but not reported (IBNR) claims plus expected development on reported claims	$ 0
Cumulative number of reported claims	772,549
Cumulative paid claims and allocated loss adjustment expenses, net of reinsurance	$ 421	421	419	418	416	412	$ 391
Accident year 2013
Claims Development [Line Items]
Incurred claims and allocated loss adjustment expenses, net of reinsurance	368	369	370	370	365	376
Incurred but not reported (IBNR) claims plus expected development on reported claims	$ 0
Cumulative number of reported claims	672,273
Cumulative paid claims and allocated loss adjustment expenses, net of reinsurance	$ 368	368	368	366	364	$ 347
Accident year 2014
Claims Development [Line Items]
Incurred claims and allocated loss adjustment expenses, net of reinsurance	388	388	388	389	390
Incurred but not reported (IBNR) claims plus expected development on reported claims	$ 0
Cumulative number of reported claims	525,297
Cumulative paid claims and allocated loss adjustment expenses, net of reinsurance	$ 388	388	388	388	$ 369
Accident year 2015
Claims Development [Line Items]
Incurred claims and allocated loss adjustment expenses, net of reinsurance	272	272	271	274
Incurred but not reported (IBNR) claims plus expected development on reported claims	$ 0
Cumulative number of reported claims	342,261
Cumulative paid claims and allocated loss adjustment expenses, net of reinsurance	$ 272	272	272	$ 252
Accident year 2016
Claims Development [Line Items]
Incurred claims and allocated loss adjustment expenses, net of reinsurance	328	327	326
Incurred but not reported (IBNR) claims plus expected development on reported claims	$ 0
Cumulative number of reported claims	475,973
Cumulative paid claims and allocated loss adjustment expenses, net of reinsurance	$ 328	327	$ 302
Accident year 2017
Claims Development [Line Items]
Incurred claims and allocated loss adjustment expenses, net of reinsurance	314	310
Incurred but not reported (IBNR) claims plus expected development on reported claims	$ 0
Cumulative number of reported claims	481,319
Cumulative paid claims and allocated loss adjustment expenses, net of reinsurance	$ 315	$ 289
Accident year 2018
Claims Development [Line Items]
Incurred claims and allocated loss adjustment expenses, net of reinsurance	271
Incurred but not reported (IBNR) claims plus expected development on reported claims	$ 19
Cumulative number of reported claims	482,605
Cumulative paid claims and allocated loss adjustment expenses, net of reinsurance	$ 245

Reserves for Insurance Losses_4

Reserves for Insurance Losses and Loss Adjustment Expenses (Short-duration Contracts, Schedule of Historical Claims Duration) (Details)	Dec. 31, 2018
Reserves for Insurance Losses and Loss Adjustment Expenses (Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability) [Abstract]
Percentage payout of incurred claims, year one	92.80%
Percentage payout of incurred claims, year two	6.10%
Percentage payout of incurred claims, year three	0.40%
Percentage payout of incurred claims, year four	0.30%
Percentage payout of incurred claims, year five	0.10%
Percentage payout of incurred claims, year six	0.20%
Percentage payout of incurred claims, year seven	0.10%

Reserves for Insurance Losses_5

Reserves for Insurance Losses and Loss Adjustment Expenses (Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reserves for Insurance Losses and Loss Adjustment Expenses (Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability) [Abstract]
Reserves for insurance losses and loss adjustment expenses, net of reinsurance	$ 35	$ 30	$ 38
Reinsurance recoverable on unpaid claims	96	108	108	$ 120
Unallocated loss adjustment expenses	3	2	3
Reserves for insurance losses and loss adjustment expenses	$ 134	$ 140	$ 149	$ 169

Reserves for Insurance Losses_6

Reserves for Insurance Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Gross reserves for insurance losses and loss adjustment expenses	$ 140	$ 149	$ 169
Reinsurance recoverable	108	108	120
Net reserves for insurance losses and loss adjustment expenses	32	41	49
Net insurance losses and loss adjustment expenses, current year	291	332	345
Net insurance losses and loss adjustment expenses, prior years	4	0	(3)
Net insurance losses and loss adjustment expenses incurred	295	332	342
Net insurance losses and loss adjustment expenses paid or payable, current year	(263)	(309)	(320)
Net insurance losses and loss adjustment expenses paid or payable, prior years	(26)	(32)	(30)
Total net insurance losses and loss adjustment expenses paid or payable	(289)	(341)	(350)
Net reserves for insurance losses and loss adjustment expenses	38	32	41
Reinsurance recoverable	96	108	108
Gross reserves for insurance losses and loss adjustment expenses	$ 134	$ 140	$ 149

Other Operating Expenses (Sched

Other Operating Expenses (Schedule Of Other Operating Expenses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Expenses [Abstract]
Insurance commissions	$ 440	$ 415	$ 389
Technology and communications	299	284	274
Advertising and marketing	172	133	112
Lease and loan administration	164	159	136
Professional services	133	113	103
Regulatory and licensing fees	121	113	94
Vehicle remarketing and repossession	111	110	95
Premises and equipment depreciation	87	89	84
Occupancy	45	46	51
Non-income taxes	29	21	25
Amortization of intangible assets	11	11	6
Other operating expenses	202	189	236
Total other operating expenses	$ 1,814	$ 1,683	$ 1,605

Investment Securities (Investme

Investment Securities (Investment Table) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	$ 2,362	$ 1,899
Held-to-maturity securities, fair value	2,307	1,865
Securities, amount eligible to be repledged or sold by counterparty	821	1,000
US Treasury | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	1,911	1,831
Debt securities, available-for-sale, unrealized gains	0	0
Debt securities, available-for-sale, unrealized losses	(60)	(54)
Debt securities, available-for-sale, fair value	1,851	1,777
US States and political subdivisions | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	816	850
Debt securities, available-for-sale, unrealized gains	3	11
Debt securities, available-for-sale, unrealized losses	(17)	(7)
Debt securities, available-for-sale, fair value	802	854
Foreign government | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	145	153
Debt securities, available-for-sale, unrealized gains	1	2
Debt securities, available-for-sale, unrealized losses	(1)	(1)
Debt securities, available-for-sale, fair value	145	154
Agency mortgage-backed residential | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	17,486	14,412
Debt securities, available-for-sale, unrealized gains	47	35
Debt securities, available-for-sale, unrealized losses	(395)	(156)
Debt securities, available-for-sale, fair value	17,138	14,291
Agency mortgage-backed residential | Held-to-maturity securities
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	2,319	1,863
Debt securities, held-to-maturity, unrecognized gain	6	3
Debt securities, held-to-maturity, unrecognized loss	61	37
Held-to-maturity securities, fair value	2,264	1,829
Mortgage-backed residential | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	2,796	2,517
Debt securities, available-for-sale, unrealized gains	1	11
Debt securities, available-for-sale, unrealized losses	(111)	(34)
Debt securities, available-for-sale, fair value	2,686	2,494
Mortgage-backed commercial | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	718	541
Debt securities, available-for-sale, unrealized gains	1	1
Debt securities, available-for-sale, unrealized losses	(2)	(1)
Debt securities, available-for-sale, fair value	717	541
Asset-backed | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	723	933
Debt securities, available-for-sale, unrealized gains	2	4
Debt securities, available-for-sale, unrealized losses	(2)	(1)
Debt securities, available-for-sale, fair value	723	936
Asset-backed | Held-to-maturity securities
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	43	36
Debt securities, held-to-maturity, unrecognized gain	0	0
Debt securities, held-to-maturity, unrecognized loss	0	0
Held-to-maturity securities, fair value	43	36
Corporate debt | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	1,286	1,262
Debt securities, available-for-sale, unrealized gains	1	5
Debt securities, available-for-sale, unrealized losses	(46)	(11)
Debt securities, available-for-sale, fair value	1,241	1,256
Available-for-sale debt securities | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	25,881	22,499
Debt securities, available-for-sale, unrealized gains	56	69
Debt securities, available-for-sale, unrealized losses	(634)	(265)
Debt securities, available-for-sale, fair value	25,303	22,303
Held-to-maturity securities
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	2,362	1,899
Debt securities, held-to-maturity, unrecognized gain	6	3
Debt securities, held-to-maturity, unrecognized loss	61	37
Held-to-maturity securities, fair value	2,307	1,865
Federal Home Loan Bank certificates and obligations | Available-for-sale securities
Schedule of Investments [Line Items]
Securities pledged for Federal Home Loan Bank, at fair value	9,200	7,800
Federal Home Loan Bank certificates and obligations | Held-to-maturity securities
Schedule of Investments [Line Items]
Securities pledged for Federal Home Loan Bank, at fair value	1,200	664
Insurance operations
Schedule of Investments [Line Items]
Deposit securities	$ 12	$ 12

Investment Securities (Invest_2

Investment Securities (Investments Classified by Contractual Maturity Date) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Schedule of Investments [Line Items]
Cash equivalents	$ 35	$ 10
Held-to-maturity securities
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost, before other-than-temporary impairment	$ 2,362	$ 1,899
Debt securities, held-to-maturity, yield	3.20%	3.10%
Debt securities, held-to-maturity, maturity, within one year, amortized Cost	$ 0	$ 0
Debt securities, held-to-maturity, due in one year or less, yield	0.00%	0.00%
Debt securities, held-to-maturity, maturity, after one through five years, amortized cost	$ 42	$ 35
Debt securities, held-to-maturity, due after one year through five years, yield	2.00%	1.70%
Debt securities, held-to-maturity, maturity, after five through ten years, amortized cost	$ 1	$ 1
Debt securities, held-to-maturity, due after five years through ten years, yield	3.30%	3.00%
Debt securities, held-to-maturity, maturity, after 10 Years, amortized cost	$ 2,319	$ 1,863
Debt securities, held-to-maturity, due after ten years, yield	3.20%	3.10%
Available-for-sale securities | US Treasury
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 1,851	$ 1,777
Debt securities, available-for-sale, yield	1.90%	1.70%
Debt securities, available-for-sale, due in one year or less	$ 12	$ 0
Debt securities, available-for-sale, due in one year or less, yield	1.00%	0.00%
Debt securities, available-for-sale, due after one year through five years	$ 1,277	$ 487
Debt securities, available-for-sale, due after one year through five years, yield	1.80%	1.70%
Debt securities, available-for-sale, due after five years through ten years	$ 562	$ 1,290
Debt securities, available-for-sale, due after five years through ten years, yield	2.00%	1.80%
Debt securities, available-for-sale, due after ten years	$ 0	$ 0
Debt securities, available-for-sale, due after ten years, yield	0.00%	0.00%
Debt securities, available-for-sale, amortized cost	$ 1,911	$ 1,831
Available-for-sale securities | US States and political subdivisions
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 802	$ 854
Debt securities, available-for-sale, yield	3.00%	2.90%
Debt securities, available-for-sale, due in one year or less	$ 49	$ 76
Debt securities, available-for-sale, due in one year or less, yield	1.90%	1.80%
Debt securities, available-for-sale, due after one year through five years	$ 43	$ 36
Debt securities, available-for-sale, due after one year through five years, yield	2.30%	2.30%
Debt securities, available-for-sale, due after five years through ten years	$ 252	$ 203
Debt securities, available-for-sale, due after five years through ten years, yield	2.60%	2.50%
Debt securities, available-for-sale, due after ten years	$ 458	$ 539
Debt securities, available-for-sale, due after ten years, yield	3.40%	3.30%
Debt securities, available-for-sale, amortized cost	$ 816	$ 850
Available-for-sale securities | Foreign government
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 145	$ 154
Debt securities, available-for-sale, yield	2.40%	2.50%
Debt securities, available-for-sale, due in one year or less	$ 18	$ 0
Debt securities, available-for-sale, due in one year or less, yield	3.10%	0.00%
Debt securities, available-for-sale, due after one year through five years	$ 60	$ 80
Debt securities, available-for-sale, due after one year through five years, yield	2.30%	2.50%
Debt securities, available-for-sale, due after five years through ten years	$ 67	$ 74
Debt securities, available-for-sale, due after five years through ten years, yield	2.40%	2.40%
Debt securities, available-for-sale, due after ten years	$ 0	$ 0
Debt securities, available-for-sale, due after ten years, yield	0.00%	0.00%
Debt securities, available-for-sale, amortized cost	$ 145	$ 153
Available-for-sale securities | Agency mortgage-backed residential
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 17,138	$ 14,291
Debt securities, available-for-sale, yield	3.30%	3.10%
Debt securities, available-for-sale, due in one year or less	$ 0	$ 0
Debt securities, available-for-sale, due in one year or less, yield	0.00%	0.00%
Debt securities, available-for-sale, due after one year through five years	$ 0	$ 0
Debt securities, available-for-sale, due after one year through five years, yield	0.00%	0.00%
Debt securities, available-for-sale, due after five years through ten years	$ 54	$ 3
Debt securities, available-for-sale, due after five years through ten years, yield	1.90%	2.90%
Debt securities, available-for-sale, due after ten years	$ 17,084	$ 14,288
Debt securities, available-for-sale, due after ten years, yield	3.30%	3.10%
Debt securities, available-for-sale, amortized cost	$ 17,486	$ 14,412
Available-for-sale securities | Mortgage-backed residential
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 2,686	$ 2,494
Debt securities, available-for-sale, yield	3.30%	3.10%
Debt securities, available-for-sale, due in one year or less	$ 0	$ 0
Debt securities, available-for-sale, due in one year or less, yield	0.00%	0.00%
Debt securities, available-for-sale, due after one year through five years	$ 0	$ 0
Debt securities, available-for-sale, due after one year through five years, yield	0.00%	0.00%
Debt securities, available-for-sale, due after five years through ten years	$ 0	$ 0
Debt securities, available-for-sale, due after five years through ten years, yield	0.00%	0.00%
Debt securities, available-for-sale, due after ten years	$ 2,686	$ 2,494
Debt securities, available-for-sale, due after ten years, yield	3.30%	3.10%
Debt securities, available-for-sale, amortized cost	$ 2,796	$ 2,517
Available-for-sale securities | Mortgage-backed commercial
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 717	$ 541
Debt securities, available-for-sale, yield	3.80%	3.20%
Debt securities, available-for-sale, due in one year or less	$ 0	$ 0
Debt securities, available-for-sale, due in one year or less, yield	0.00%	0.00%
Debt securities, available-for-sale, due after one year through five years	$ 3	$ 30
Debt securities, available-for-sale, due after one year through five years, yield	3.10%	3.10%
Debt securities, available-for-sale, due after five years through ten years	$ 46	$ 31
Debt securities, available-for-sale, due after five years through ten years, yield	3.90%	3.10%
Debt securities, available-for-sale, due after ten years	$ 668	$ 480
Debt securities, available-for-sale, due after ten years, yield	3.80%	3.20%
Debt securities, available-for-sale, amortized cost	$ 718	$ 541
Available-for-sale securities | Asset-backed
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 723	$ 936
Debt securities, available-for-sale, yield	3.50%	3.10%
Debt securities, available-for-sale, due in one year or less	$ 0	$ 0
Debt securities, available-for-sale, due in one year or less, yield	0.00%	0.00%
Debt securities, available-for-sale, due after one year through five years	$ 478	$ 698
Debt securities, available-for-sale, due after one year through five years, yield	3.40%	3.10%
Debt securities, available-for-sale, due after five years through ten years	$ 121	$ 106
Debt securities, available-for-sale, due after five years through ten years, yield	4.00%	3.10%
Debt securities, available-for-sale, due after ten years	$ 124	$ 132
Debt securities, available-for-sale, due after ten years, yield	3.30%	2.80%
Debt securities, available-for-sale, amortized cost	$ 723	$ 933
Available-for-sale securities | Corporate debt
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 1,241	$ 1,256
Debt securities, available-for-sale, yield	3.10%	2.90%
Debt securities, available-for-sale, due in one year or less	$ 144	$ 140
Debt securities, available-for-sale, due in one year or less, yield	2.80%	2.60%
Debt securities, available-for-sale, due after one year through five years	$ 496	$ 513
Debt securities, available-for-sale, due after one year through five years, yield	2.90%	2.60%
Debt securities, available-for-sale, due after five years through ten years	$ 581	$ 564
Debt securities, available-for-sale, due after five years through ten years, yield	3.30%	3.20%
Debt securities, available-for-sale, due after ten years	$ 20	$ 39
Debt securities, available-for-sale, due after ten years, yield	5.50%	4.70%
Debt securities, available-for-sale, amortized cost	$ 1,286	$ 1,262
Available-for-sale securities | Available-for-sale debt securities
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 25,303	$ 22,303
Debt securities, available-for-sale, yield	3.20%	3.00%
Debt securities, available-for-sale, due in one year or less	$ 223	$ 216
Debt securities, available-for-sale, due in one year or less, yield	2.60%	2.30%
Debt securities, available-for-sale, due after one year through five years	$ 2,357	$ 1,844
Debt securities, available-for-sale, due after one year through five years, yield	2.40%	2.50%
Debt securities, available-for-sale, due after five years through ten years	$ 1,683	$ 2,271
Debt securities, available-for-sale, due after five years through ten years, yield	2.80%	2.30%
Debt securities, available-for-sale, due after ten years	$ 21,040	$ 17,972
Debt securities, available-for-sale, due after ten years, yield	3.30%	3.10%
Debt securities, available-for-sale, amortized cost	$ 25,881	$ 22,499
Debt securities, available-for-sale, maturity, within one year, amortized cost	224	217
Debt securities, available-for-sale, maturity, after one through five years, amortized cost	2,405	1,852
Debt securities, available-for-sale, maturity, after five through ten years, amortized cost	1,743	2,314
Debt securities, available-for-sale, maturity, after 10 Years, amortized cost	21,509	18,116
Held-to-maturity securities | Agency mortgage-backed residential
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost, before other-than-temporary impairment	$ 2,319	$ 1,863
Debt securities, held-to-maturity, yield	3.20%	3.10%
Debt securities, held-to-maturity, maturity, within one year, amortized Cost	$ 0	$ 0
Debt securities, held-to-maturity, due in one year or less, yield	0.00%	0.00%
Debt securities, held-to-maturity, maturity, after one through five years, amortized cost	$ 0	$ 0
Debt securities, held-to-maturity, due after one year through five years, yield	0.00%	0.00%
Debt securities, held-to-maturity, maturity, after five through ten years, amortized cost	$ 0	$ 0
Debt securities, held-to-maturity, due after five years through ten years, yield	0.00%	0.00%
Debt securities, held-to-maturity, maturity, after 10 Years, amortized cost	$ 2,319	$ 1,863
Debt securities, held-to-maturity, due after ten years, yield	3.20%	3.10%
Held-to-maturity securities | Asset-backed
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost, before other-than-temporary impairment	$ 43	$ 36
Debt securities, held-to-maturity, yield	2.00%	1.70%
Debt securities, held-to-maturity, maturity, within one year, amortized Cost	$ 0	$ 0
Debt securities, held-to-maturity, due in one year or less, yield	0.00%	0.00%
Debt securities, held-to-maturity, maturity, after one through five years, amortized cost	$ 42	$ 35
Debt securities, held-to-maturity, due after one year through five years, yield	2.00%	1.70%
Debt securities, held-to-maturity, maturity, after five through ten years, amortized cost	$ 1	$ 1
Debt securities, held-to-maturity, due after five years through ten years, yield	3.30%	3.00%
Debt securities, held-to-maturity, maturity, after 10 Years, amortized cost	$ 0	$ 0
Debt securities, held-to-maturity, due after ten years, yield	0.00%	0.00%

Investment Securities (Invest_3

Investment Securities (Investment Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Taxable interest	$ 690	$ 534	$ 375
Taxable dividends	14	12	17
Interest and dividends exempt from U.S. federal income tax	25	22	19
Interest and dividends on investment securities	788	599	418
Excludes other earning assets
Interest and dividends on investment securities	$ 729	$ 568	$ 411

Investment Securities (Schedule

Investment Securities (Schedule Of Realized Gain (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Securities, Available-for-sale [Abstract]
Other-than-temporary impairments of available-for-sale securities	$ 0	$ 0	$ 0
Available-for-sale securities, gross realized gains	12	106	187
Available-for-sale securities, gross realized losses	(1)	(4)	(2)
Net realized gains (losses) on available-for-sale securities	11	102	185
Net realized gain (loss) on equity securities	60
Net unrealized gain (loss) on equity securities	(121)
Other (loss) gain on investments, net	$ (50)	$ 102	$ 185

Investment Securities (Schedu_2

Investment Securities (Schedule of Unrealized Loss on Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	$ 8,074	$ 6,541
Debt securities, available-for-sale, unrealized loss, less than 12 months	(138)	(38)
Debt securities, available-for-sale, fair value, 12 months or longer	12,046	8,242
Debt securities, available-for-sale, unrealized loss, 12 months or longer	(496)	(227)
Debt Securities, held-to-maturity, less than 12 Months, fair value	473	808
Debt securities, held-to-maturity, unrealized loss, less than 12 Months	6	5
Debt Securities, held-to-maturity, 12 Months or Longer, fair value	1,395	687
Debt securities, held-to-maturity, unrealized loss, 12 months or longer	55	32
US Treasury
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	31	471
Debt securities, available-for-sale, unrealized loss, less than 12 months	0	(8)
Debt securities, available-for-sale, fair value, 12 months or longer	1,758	1,305
Debt securities, available-for-sale, unrealized loss, 12 months or longer	(60)	(46)
US States and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	259	242
Debt securities, available-for-sale, unrealized loss, less than 12 months	(3)	(2)
Debt securities, available-for-sale, fair value, 12 months or longer	317	183
Debt securities, available-for-sale, unrealized loss, 12 months or longer	(14)	(5)
Foreign government
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	6	80
Debt securities, available-for-sale, unrealized loss, less than 12 months	0	(1)
Debt securities, available-for-sale, fair value, 12 months or longer	74	4
Debt securities, available-for-sale, unrealized loss, 12 months or longer	(1)	0
Agency mortgage-backed residential
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	5,537	4,066
Debt securities, available-for-sale, unrealized loss, less than 12 months	(94)	(19)
Debt securities, available-for-sale, fair value, 12 months or longer	7,808	5,671
Debt securities, available-for-sale, unrealized loss, 12 months or longer	(301)	(137)
Debt Securities, held-to-maturity, less than 12 Months, fair value	457	773
Debt securities, held-to-maturity, unrealized loss, less than 12 Months	6	5
Debt Securities, held-to-maturity, 12 Months or Longer, fair value	1,376	687
Debt securities, held-to-maturity, unrealized loss, 12 months or longer	55	32
Mortgage-backed residential
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	1,024	857
Debt securities, available-for-sale, unrealized loss, less than 12 months	(20)	(2)
Debt securities, available-for-sale, fair value, 12 months or longer	1,360	773
Debt securities, available-for-sale, unrealized loss, 12 months or longer	(91)	(32)
Mortgage-backed commercial
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	347	76
Debt securities, available-for-sale, unrealized loss, less than 12 months	(1)	(1)
Debt securities, available-for-sale, fair value, 12 months or longer	36	21
Debt securities, available-for-sale, unrealized loss, 12 months or longer	(1)	0
Asset-backed
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	294	220
Debt securities, available-for-sale, unrealized loss, less than 12 months	(1)	(1)
Debt securities, available-for-sale, fair value, 12 months or longer	124	91
Debt securities, available-for-sale, unrealized loss, 12 months or longer	(1)	0
Debt Securities, held-to-maturity, less than 12 Months, fair value	16	35
Debt securities, held-to-maturity, unrealized loss, less than 12 Months	0	0
Debt Securities, held-to-maturity, 12 Months or Longer, fair value	19	0
Debt securities, held-to-maturity, unrealized loss, 12 months or longer	0	0
Corporate debt
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	576	529
Debt securities, available-for-sale, unrealized loss, less than 12 months	(19)	(4)
Debt securities, available-for-sale, fair value, 12 months or longer	569	194
Debt securities, available-for-sale, unrealized loss, 12 months or longer	$ (27)	$ (7)

Finance Receivables and Loans_3

Finance Receivables and Loans, Net (Schedule of Accounts, Notes, Loans and Financing Receivables) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 129,926	$ 122,893
Loans and finance receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unamortized premiums and discounts and deferred fees and costs	587	551
Consumer portfolio segment | Consumer loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	87,240	81,821
Consumer portfolio segment | Automobile loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	70,539	68,071
Consumer portfolio segment | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	16,701	13,750
Consumer portfolio segment | Mortgage Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	15,155	11,657
Interest-only mortgage loans	$ 18	20
Consumer portfolio segment | Mortgage Finance | 2019, or sooner
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	34.00%
Consumer portfolio segment | Mortgage Finance | 2020, or sooner
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	41.00%
Consumer portfolio segment | Mortgage - Legacy
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 1,546	2,093
Interest-only mortgage loans	$ 341	496
Interest-only mortgage loans having exited the interest-only period	99.00%
Commercial portfolio segment | Commercial loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 42,686	41,072
Commercial portfolio segment | Commercial and industrial automotive
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	33,672	33,025
Commercial portfolio segment | Commercial and industrial other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	4,205	3,887
Commercial portfolio segment | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 4,809	$ 4,160

Finance Receivables and Loans_4

Finance Receivables and Loans, Net (Allowance for Credit Losses on Financing Receivables) (Details) - 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
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan losses				$ 1,276				$ 1,144	$ 1,276	$ 1,144
Allowance for loan and lease losses, charge-offs									(1,433)	(1,392)
Allowance for loan and lease losses, recoveries									488	382
Allowance for loan and lease losses, net charge-offs									(945)	(1,010)
Provision for loan losses	$ 266	$ 233	$ 158	261	$ 294	$ 314	$ 269	271	918	1,148	$ 917
Allowance for loan and lease losses, other									7	6
Allowance for loan losses	1,242				1,276				1,242	1,276	1,144
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses, individually evaluated for impairment	123				77				123	77
Allowance for loan losses, collectively evaluated for impairment	1,119				1,199				1,119	1,199
Finance receivables and loans, net	129,926				122,893				129,926	122,893
Finance receivables and loans, individually evaluated for impairment	1,075				733				1,075	733
Finance receivables and loans, collectively evaluated for impairment	128,851				122,160				128,851	122,160
Consumer portfolio segment | Automobile loan
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan losses				1,066				932	1,066	932
Allowance for loan and lease losses, charge-offs									(1,383)	(1,344)
Allowance for loan and lease losses, recoveries									456	358
Allowance for loan and lease losses, net charge-offs									(927)	(986)
Provision for loan losses									911	1,127
Allowance for loan and lease losses, other									2	7
Allowance for loan losses	1,048				1,066				1,048	1,066	932
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses, individually evaluated for impairment	44				36				44	36
Allowance for loan losses, collectively evaluated for impairment	1,004				1,030				1,004	1,030
Finance receivables and loans, net	70,539				68,071				70,539	68,071
Finance receivables and loans, individually evaluated for impairment	495				430				495	430
Finance receivables and loans, collectively evaluated for impairment	70,044				67,641				70,044	67,641
Consumer portfolio segment | Residential mortgage
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan losses				79				91	79	91
Allowance for loan and lease losses, charge-offs									(35)	(30)
Allowance for loan and lease losses, recoveries									25	24
Allowance for loan and lease losses, net charge-offs									(10)	(6)
Provision for loan losses									(15)	(7)
Allowance for loan and lease losses, other									1	(1)
Allowance for loan losses	53				79				53	79	91
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses, individually evaluated for impairment	23				27				23	27
Allowance for loan losses, collectively evaluated for impairment	30				52				30	52
Finance receivables and loans, net	16,701				13,750				16,701	13,750
Finance receivables and loans, individually evaluated for impairment	231				231				231	231
Finance receivables and loans, collectively evaluated for impairment	16,470				13,519				16,470	13,519
Commercial portfolio segment | Commercial loan
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan losses				$ 131				$ 121	131	121
Allowance for loan and lease losses, charge-offs									(15)	(18)
Allowance for loan and lease losses, recoveries									7	0
Allowance for loan and lease losses, net charge-offs									(8)	(18)
Provision for loan losses									22	28
Allowance for loan and lease losses, other									4	0
Allowance for loan losses	141				131				141	131	$ 121
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses, individually evaluated for impairment	56				14				56	14
Allowance for loan losses, collectively evaluated for impairment	85				117				85	117
Finance receivables and loans, net	42,686				41,072				42,686	41,072
Finance receivables and loans, individually evaluated for impairment	349				72				349	72
Finance receivables and loans, collectively evaluated for impairment	$ 42,337				$ 41,000				$ 42,337	$ 41,000

Finance Receivables and Loans_5

Finance Receivables and Loans, Net (Schedule of Sales of Financing Receivables and Loans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, significant sales and transfers	$ 826	$ 1,348
Consumer portfolio segment | Automobile loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, significant sales and transfers	578	1,339
Consumer portfolio segment | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, significant sales and transfers	10	9
Commercial portfolio segment | Commercial loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, significant sales and transfers	$ 238	$ 0

Finance Receivables and Loans_6

Finance Receivables and Loans, Net (Schedule of Purchases of Financing Receivables and Loans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables and loans, significant purchases	$ 5,357	$ 5,346
Consumer portfolio segment | Automobile loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables and loans, significant purchases	896	865
Consumer portfolio segment | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables and loans, significant purchases	4,446	4,481
Commercial portfolio segment | Commercial loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables and loans, significant purchases	$ 15	$ 0

Finance Receivables and Loans_7

Finance Receivables and Loans, Net (Past Due Financing Receivables and Loans) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	$ 3,151	$ 2,967
Financing receivable, recorded investment, current	126,775	119,926
Total finance receivables and loans	129,926	122,893
Consumer portfolio segment | Consumer loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	3,098	2,959
Financing receivable, recorded investment, current	84,142	78,862
Total finance receivables and loans	87,240	81,821
Consumer portfolio segment | Automobile loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	2,940	2,740
Financing receivable, recorded investment, current	67,599	65,331
Total finance receivables and loans	70,539	68,071
Consumer portfolio segment | Residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	158	219
Financing receivable, recorded investment, current	16,543	13,531
Total finance receivables and loans	16,701	13,750
Consumer portfolio segment | Mortgage Finance
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	76	89
Financing receivable, recorded investment, current	15,079	11,568
Total finance receivables and loans	15,155	11,657
Consumer portfolio segment | Mortgage - Legacy
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	82	130
Financing receivable, recorded investment, current	1,464	1,963
Total finance receivables and loans	1,546	2,093
Commercial portfolio segment | Commercial loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	53	8
Financing receivable, recorded investment, current	42,633	41,064
Total finance receivables and loans	42,686	41,072
Commercial portfolio segment | Commercial and industrial automotive
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	32	8
Financing receivable, recorded investment, current	33,640	33,017
Total finance receivables and loans	33,672	33,025
Commercial portfolio segment | Commercial and industrial other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	20	0
Financing receivable, recorded investment, current	4,185	3,887
Total finance receivables and loans	4,205	3,887
Commercial portfolio segment | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	1	0
Financing receivable, recorded investment, current	4,808	4,160
Total finance receivables and loans	4,809	4,160
Financing receivables, 30 to 59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	2,204	2,102
Financing receivables, 30 to 59 days past due | Consumer portfolio segment | Consumer loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	2,204	2,097
Financing receivables, 30 to 59 days past due | Consumer portfolio segment | Automobile loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	2,107	1,994
Financing receivables, 30 to 59 days past due | Consumer portfolio segment | Residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	97	103
Financing receivables, 30 to 59 days past due | Consumer portfolio segment | Mortgage Finance
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	67	60
Financing receivables, 30 to 59 days past due | Consumer portfolio segment | Mortgage - Legacy
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	30	43
Financing receivables, 30 to 59 days past due | Commercial portfolio segment | Commercial loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	5
Financing receivables, 30 to 59 days past due | Commercial portfolio segment | Commercial and industrial automotive
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	5
Financing receivables, 30 to 59 days past due | Commercial portfolio segment | Commercial and industrial other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	0
Financing receivables, 30 to 59 days past due | Commercial portfolio segment | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	0
Financing receivables, 60 to 89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	557	514
Financing receivables, 60 to 89 days past due | Consumer portfolio segment | Consumer loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	552	514
Financing receivables, 60 to 89 days past due | Consumer portfolio segment | Automobile loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	537	478
Financing receivables, 60 to 89 days past due | Consumer portfolio segment | Residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	15	36
Financing receivables, 60 to 89 days past due | Consumer portfolio segment | Mortgage Finance
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	5	11
Financing receivables, 60 to 89 days past due | Consumer portfolio segment | Mortgage - Legacy
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	10	25
Financing receivables, 60 to 89 days past due | Commercial portfolio segment | Commercial loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	5	0
Financing receivables, 60 to 89 days past due | Commercial portfolio segment | Commercial and industrial automotive
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	1	0
Financing receivables, 60 to 89 days past due | Commercial portfolio segment | Commercial and industrial other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	4	0
Financing receivables, 60 to 89 days past due | Commercial portfolio segment | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	0
Financing receivables, equal to greater than 90 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	390	351
Financing receivables, equal to greater than 90 days past due | Consumer portfolio segment | Consumer loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	342	348
Financing receivables, equal to greater than 90 days past due | Consumer portfolio segment | Automobile loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	296	268
Financing receivables, equal to greater than 90 days past due | Consumer portfolio segment | Residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	46	80
Financing receivables, equal to greater than 90 days past due | Consumer portfolio segment | Mortgage Finance
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	4	18
Financing receivables, equal to greater than 90 days past due | Consumer portfolio segment | Mortgage - Legacy
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	42	62
Financing receivables, equal to greater than 90 days past due | Commercial portfolio segment | Commercial loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	48	3
Financing receivables, equal to greater than 90 days past due | Commercial portfolio segment | Commercial and industrial automotive
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	31	3
Financing receivables, equal to greater than 90 days past due | Commercial portfolio segment | Commercial and industrial other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	16	0
Financing receivables, equal to greater than 90 days past due | Commercial portfolio segment | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	$ 1	$ 0

Finance Receivables and Loans_8

Finance Receivables and Loans, Net (Schedule of Financing Receivables, Non Accrual Status) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	$ 1,092	$ 792
Consumer portfolio segment | Consumer loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	743	720
Consumer portfolio segment | Automobile loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	664	603
Consumer portfolio segment | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	79	117
Consumer portfolio segment | Mortgage Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	9	25
Consumer portfolio segment | Mortgage - Legacy
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	70	92
Commercial portfolio segment | Commercial loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	349	72
Commercial portfolio segment | Commercial and industrial automotive
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	203	27
Commercial portfolio segment | Commercial and industrial other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	142	44
Commercial portfolio segment | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	$ 4	$ 1

Finance Receivables and Loans_9

Finance Receivables and Loans, Net (Financing Receivable Credit Quality Indicators) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 129,926	$ 122,893
Consumer portfolio segment | Consumer loan
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	87,240	81,821
Consumer portfolio segment | Consumer loan | Performing financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	86,497	81,101
Consumer portfolio segment | Consumer loan | Nonperforming financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	743	720
Consumer portfolio segment | Automobile loan
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	70,539	68,071
Consumer portfolio segment | Automobile loan | Performing financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	69,875	67,468
Consumer portfolio segment | Automobile loan | Nonperforming financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	664	603
Consumer portfolio segment | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	16,701	13,750
Consumer portfolio segment | Residential mortgage | Performing financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	16,622	13,633
Consumer portfolio segment | Residential mortgage | Nonperforming financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	79	117
Consumer portfolio segment | Mortgage Finance
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	15,155	11,657
Consumer portfolio segment | Mortgage Finance | Performing financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	15,146	11,632
Consumer portfolio segment | Mortgage Finance | Nonperforming financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	9	25
Consumer portfolio segment | Mortgage - Legacy
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	1,546	2,093
Consumer portfolio segment | Mortgage - Legacy | Performing financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	1,476	2,001
Consumer portfolio segment | Mortgage - Legacy | Nonperforming financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 70	$ 92

Finance Receivables and Loan_10

Finance Receivables and Loans, Net (Schedule of Pass And Criticized Credit Quality Indicators of Finance Receivables) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 129,926	$ 122,893
Commercial portfolio segment | Commercial loan
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	42,686	41,072
Commercial portfolio segment | Commercial loan | Pass
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	38,710	37,991
Commercial portfolio segment | Commercial loan | Criticized
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	3,976	3,081
Commercial portfolio segment | Commercial and industrial automotive
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	33,672	33,025
Commercial portfolio segment | Commercial and industrial automotive | Pass
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	30,799	30,982
Commercial portfolio segment | Commercial and industrial automotive | Criticized
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	2,873	2,043
Commercial portfolio segment | Commercial and industrial other
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	4,205	3,887
Commercial portfolio segment | Commercial and industrial other | Pass
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	3,373	2,986
Commercial portfolio segment | Commercial and industrial other | Criticized
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	832	901
Commercial portfolio segment | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	4,809	4,160
Commercial portfolio segment | Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	4,538	4,023
Commercial portfolio segment | Commercial real estate | Criticized
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 271	$ 137

Finance Receivables and Loan_11

Finance Receivables and Loans, Net (Impaired Financing Receivables) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	$ 1,105	$ 756
Financing receivable, impaired, gross carrying value	1,075	733
Financing receivable, impaired, with no allowance	332	172
Financing receivable, impaired, with related allowance	743	561
Financing receivable, impaired, allowance for impaired loans	123	77
Consumer portfolio segment | Consumer loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	739	674
Financing receivable, impaired, gross carrying value	726	661
Financing receivable, impaired, with no allowance	176	153
Financing receivable, impaired, with related allowance	550	508
Financing receivable, impaired, allowance for impaired loans	67	63
Consumer portfolio segment | Automobile loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	503	438
Financing receivable, impaired, gross carrying value	495	430
Financing receivable, impaired, with no allowance	105	91
Financing receivable, impaired, with related allowance	390	339
Financing receivable, impaired, allowance for impaired loans	44	36
Consumer portfolio segment | Residential mortgage
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	236	236
Financing receivable, impaired, gross carrying value	231	231
Financing receivable, impaired, with no allowance	71	62
Financing receivable, impaired, with related allowance	160	169
Financing receivable, impaired, allowance for impaired loans	23	27
Consumer portfolio segment | Mortgage Finance
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	15	8
Financing receivable, impaired, gross carrying value	15	8
Financing receivable, impaired, with no allowance	6	4
Financing receivable, impaired, with related allowance	9	4
Financing receivable, impaired, allowance for impaired loans	1	0
Consumer portfolio segment | Mortgage - Legacy
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	221	228
Financing receivable, impaired, gross carrying value	216	223
Financing receivable, impaired, with no allowance	65	58
Financing receivable, impaired, with related allowance	151	165
Financing receivable, impaired, allowance for impaired loans	22	27
Commercial portfolio segment | Commercial loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	366	82
Financing receivable, impaired, gross carrying value	349	72
Financing receivable, impaired, with no allowance	156	19
Financing receivable, impaired, with related allowance	193	53
Financing receivable, impaired, allowance for impaired loans	56	14
Commercial portfolio segment | Commercial and industrial automotive
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	203	27
Financing receivable, impaired, gross carrying value	203	27
Financing receivable, impaired, with no allowance	112	9
Financing receivable, impaired, with related allowance	91	18
Financing receivable, impaired, allowance for impaired loans	10	3
Commercial portfolio segment | Commercial and industrial other
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	159	54
Financing receivable, impaired, gross carrying value	142	44
Financing receivable, impaired, with no allowance	40	10
Financing receivable, impaired, with related allowance	102	34
Financing receivable, impaired, allowance for impaired loans	46	11
Commercial portfolio segment | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	4	1
Financing receivable, impaired, gross carrying value	4	1
Financing receivable, impaired, with no allowance	4	0
Financing receivable, impaired, with related allowance	0	1
Financing receivable, impaired, allowance for impaired loans	$ 0	$ 0

Finance Receivables and Loan_12

Finance Receivables and Loans, Net (Schedule of Average Balance and Interest Income of Impaired Finance Receivables) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	$ 889	$ 756	$ 701
Financing receivable, impaired, interest income	44	42	28
Consumer portfolio segment | Consumer loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	707	633	600
Financing receivable, impaired, interest income	39	31	26
Consumer portfolio segment | Automobile loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	478	391	344
Financing receivable, impaired, interest income	28	21	17
Consumer portfolio segment | Residential mortgage
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	229	242	256
Financing receivable, impaired, interest income	11	10	9
Consumer portfolio segment | Mortgage Finance
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	11	8	8
Financing receivable, impaired, interest income	1	0	0
Consumer portfolio segment | Mortgage - Legacy
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	218	234	248
Financing receivable, impaired, interest income	10	10	9
Commercial portfolio segment | Commercial loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	182	123	101
Financing receivable, impaired, interest income	5	11	2
Commercial portfolio segment | Commercial and industrial automotive
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	93	49	35
Financing receivable, impaired, interest income	4	2	1
Commercial portfolio segment | Commercial and industrial other
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	84	69	60
Financing receivable, impaired, interest income	0	9	1
Commercial portfolio segment | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	5	5	6
Financing receivable, impaired, interest income	$ 1	$ 0	$ 0

Finance Receivables and Loan_13

Finance Receivables and Loans, Net (Troubled Debt Restructurings) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, gross carrying value	$ 812	$ 712	$ 663
Loans and leases receivable, impaired, commitment to lend	$ 4	$ 6	$ 2
Consumer portfolio segment | Consumer loan
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, number of loans	26,975	26,282	20,354
Financing receivable, modifications, pre-modification gross carrying value	$ 465	$ 402	$ 368
Financing receivable, modifications, post-modification gross carrying value	$ 416	$ 355	$ 314
Consumer portfolio segment | Automobile loan
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, number of loans	26,748	26,156	20,227
Financing receivable, modifications, pre-modification gross carrying value	$ 426	$ 380	$ 347
Financing receivable, modifications, post-modification gross carrying value	$ 378	$ 333	$ 293
Consumer portfolio segment | Residential mortgage
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, number of loans	227	126	127
Financing receivable, modifications, pre-modification gross carrying value	$ 39	$ 22	$ 21
Financing receivable, modifications, post-modification gross carrying value	$ 38	$ 22	$ 21
Consumer portfolio segment | Mortgage Finance
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, number of loans	23	4	7
Financing receivable, modifications, pre-modification gross carrying value	$ 9	$ 1	$ 3
Financing receivable, modifications, post-modification gross carrying value	$ 9	$ 1	$ 3
Consumer portfolio segment | Mortgage - Legacy
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, number of loans	204	122	120
Financing receivable, modifications, pre-modification gross carrying value	$ 30	$ 21	$ 18
Financing receivable, modifications, post-modification gross carrying value	$ 29	$ 21	$ 18
Commercial portfolio segment | Commercial loan
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, number of loans	6	6	1
Financing receivable, modifications, pre-modification gross carrying value	$ 89	$ 63	$ 7
Financing receivable, modifications, post-modification gross carrying value	$ 86	$ 62	$ 7
Commercial portfolio segment | Commercial and industrial other
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, number of loans	3	0
Financing receivable, modifications, pre-modification gross carrying value	$ 85	$ 44
Financing receivable, modifications, post-modification gross carrying value	$ 82	$ 44
Commercial portfolio segment | Commercial and industrial automotive
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, number of loans	3	4	1
Financing receivable, modifications, pre-modification gross carrying value	$ 4	$ 16	$ 7
Financing receivable, modifications, post-modification gross carrying value	$ 4	$ 15	$ 7
Commercial portfolio segment | Commercial real estate
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, number of loans		2
Financing receivable, modifications, pre-modification gross carrying value		$ 3
Financing receivable, modifications, post-modification gross carrying value		$ 3

Finance Receivables and Loan_14

Finance Receivables and Loans, Net (Finance receivables and loans redefaulted during the period) (Details) - Consumer portfolio segment $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Consumer loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, modifications, subsequent default, number of loans	9,713	8,832	7,804
Financing receivable, modifications, subsequent default, gross carrying value	$ 111	$ 103	$ 94
Financing receivables, impaired, troubled debt restructuring, charge-off amount	$ 73	$ 71	$ 56
Automobile loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, modifications, subsequent default, number of loans	9,711	8,829	7,800
Financing receivable, modifications, subsequent default, gross carrying value	$ 111	$ 102	$ 94
Financing receivables, impaired, troubled debt restructuring, charge-off amount	$ 73	$ 71	$ 56
Mortgage Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, modifications, subsequent default, number of loans		1
Financing receivable, modifications, subsequent default, gross carrying value		$ 1
Financing receivables, impaired, troubled debt restructuring, charge-off amount		$ 0
Mortgage - Legacy
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, modifications, subsequent default, number of loans	2	2	4
Financing receivable, modifications, subsequent default, gross carrying value	$ 0	$ 0	$ 0
Financing receivables, impaired, troubled debt restructuring, charge-off amount	$ 0	$ 0	$ 0

Finance Receivables and Loan_15

Finance Receivables and Loans, Net Finance Receivables and Loans, Net (Consumer Concentration Risk by State and Foreign Geographic) (Details) - Consumer portfolio segment	Dec. 31, 2018	Dec. 31, 2017
Automobile loan
Concentration Risk [Line Items]
Consumer Concentration Risk	100.00%	100.00%
Residential mortgage
Concentration Risk [Line Items]
Consumer Concentration Risk	100.00%	100.00%
California and Texas
Concentration Risk [Line Items]
Consumer Concentration Risk	25.40%	24.70%
California | Automobile loan
Concentration Risk [Line Items]
Consumer Concentration Risk	8.40%	8.20%
California | Residential mortgage
Concentration Risk [Line Items]
Consumer Concentration Risk	36.90%	34.60%
Texas | Automobile loan
Concentration Risk [Line Items]
Consumer Concentration Risk	12.80%	13.20%
Texas | Residential mortgage
Concentration Risk [Line Items]
Consumer Concentration Risk	6.20%	6.50%
Florida | Automobile loan
Concentration Risk [Line Items]
Consumer Concentration Risk	8.80%	8.50%
Florida | Residential mortgage
Concentration Risk [Line Items]
Consumer Concentration Risk	4.70%	4.80%
Pennsylvania | Automobile loan
Concentration Risk [Line Items]
Consumer Concentration Risk	4.50%	4.60%
Pennsylvania | Residential mortgage
Concentration Risk [Line Items]
Consumer Concentration Risk	1.40%	1.50%
Illinois | Automobile loan
Concentration Risk [Line Items]
Consumer Concentration Risk	4.10%	4.20%
Illinois | Residential mortgage
Concentration Risk [Line Items]
Consumer Concentration Risk	3.00%	3.20%
Georgia | Automobile loan
Concentration Risk [Line Items]
Consumer Concentration Risk	4.10%	4.20%
Georgia | Residential mortgage
Concentration Risk [Line Items]
Consumer Concentration Risk	2.80%	2.50%
North Carolina | Automobile loan
Concentration Risk [Line Items]
Consumer Concentration Risk	3.90%	3.70%
North Carolina | Residential mortgage
Concentration Risk [Line Items]
Consumer Concentration Risk	1.70%	1.80%
New York | Automobile loan
Concentration Risk [Line Items]
Consumer Concentration Risk	3.10%	3.00%
New York | Residential mortgage
Concentration Risk [Line Items]
Consumer Concentration Risk	2.40%	2.20%
Ohio | Automobile loan
Concentration Risk [Line Items]
Consumer Concentration Risk	3.50%	3.40%
Ohio | Residential mortgage
Concentration Risk [Line Items]
Consumer Concentration Risk	0.40%	0.50%
New Jersey | Automobile loan
Concentration Risk [Line Items]
Consumer Concentration Risk	2.70%	2.60%
New Jersey | Residential mortgage
Concentration Risk [Line Items]
Consumer Concentration Risk	2.10%	2.10%
United States, Other | Automobile loan
Concentration Risk [Line Items]
Consumer Concentration Risk	44.10%	44.40%
United States, Other | Residential mortgage
Concentration Risk [Line Items]
Consumer Concentration Risk	38.40%	40.30%

Finance Receivables and Loan_16

Finance Receivables and Loans, Net Finance Receivables and Loans, Net (Commercial Concentration Risk) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Concentration Risk [Line Items]
Commercial Concentration Risk	100.00%	100.00%
Texas
Concentration Risk [Line Items]
Commercial Concentration Risk	15.50%	15.70%
Florida
Concentration Risk [Line Items]
Commercial Concentration Risk	11.60%	10.30%
California
Concentration Risk [Line Items]
Commercial Concentration Risk	8.30%	8.20%
Michigan
Concentration Risk [Line Items]
Commercial Concentration Risk	6.80%	7.70%
New York
Concentration Risk [Line Items]
Commercial Concentration Risk	4.80%	2.10%
Georgia
Concentration Risk [Line Items]
Commercial Concentration Risk	4.00%	4.60%
North Carolina
Concentration Risk [Line Items]
Commercial Concentration Risk	3.60%	3.60%
South Carolina
Concentration Risk [Line Items]
Commercial Concentration Risk	3.40%	3.50%
New Jersey
Concentration Risk [Line Items]
Commercial Concentration Risk	3.10%	3.60%
Utah
Concentration Risk [Line Items]
Commercial Concentration Risk	2.60%	1.60%
United States, Other
Concentration Risk [Line Items]
Commercial Concentration Risk	36.30%	39.10%

Finance Receivables and Loan_17

Finance Receivables and Loans, Net Finance Receivables and Loans, Net (Commercial Criticized Exposure) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Concentration Risk [Line Items]
Commercial criticized finance receivables and loans	100.00%	100.00%
5500 Retail, Auto Dealers and Gasoline Stations [Member]
Concentration Risk [Line Items]
Commercial criticized finance receivables and loans	80.60%	76.30%
7380 Services, Miscellaneous Business Services [Member]
Concentration Risk [Line Items]
Commercial criticized finance receivables and loans	5.00%	6.70%
8071 Services, Medical Laboratories [Member]
Concentration Risk [Line Items]
Commercial criticized finance receivables and loans	3.70%	4.90%
810000 to 819999 Other Services (except Public Administration) [Member]
Concentration Risk [Line Items]
Commercial criticized finance receivables and loans	10.70%	12.10%

Investment in Operating Lease_3

Investment in Operating Leases, Net (Investments In Operating Leases) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Leases, Operating [Abstract]
Vehicles subject to or available for operating lease	$ 9,995	$ 10,556
Accumulated depreciation on vehicles subject to or available for operating lease	(1,578)	(1,815)
Investment in operating leases, net	$ 8,417	$ 8,741

Investment in Operating Lease_4

Investment in Operating Leases, Net (Schedule Of Depreciation Expense On Operating Lease Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Leases, Operating [Abstract]
Depreciation expense on operating lease assets (excluding remarketing gains)	$ 1,115	$ 1,368	$ 1,982
Remarketing gains, net	(90)	(124)	(213)
Net depreciation expense on operating lease assets	$ 1,025	$ 1,244	$ 1,769

Investment in Operating Lease_5

Investment in Operating Leases, Net Investment in Operating Leases, Net (Future Lease Nonresidual Rental Payments) (Details) $ in Millions	Dec. 31, 2018USD ($)
Future Lease Nonresidual Rental Payments [Abstract]
Operating leases, future payments receivable, current	$ 1,308
Operating leases, future payments receivable, due in two years	830
Operating leases, future payments receivable, due in three years	297
Operating leases, future payments receivable, due in four years	27
Operating leases, future payments receivable, thereafter	3
Operating leases, future payments receivable	$ 2,465

Securitizations and Variable _3

Securitizations and Variable Interest Entities (Schedule of Variable Interest Entities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Securitization or asset-backed financing arrangement, financial asset for which transfer is accounted as sale, gain on sale	$ 1	$ 2	$ 0
Variable interest entity, assets deconsolidated	(1,235)	(1,964)
Variable interest entity, carrying value of assets for which we have continuing involvement	28,195	30,776
Variable interest entity, carrying value of liabilities for which we have continuing involvement	10,845	10,483
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	2,334	2,791
Commercial portfolio segment
Variable Interest Entity [Line Items]
Variable interest entity, nonconsolidated, carrying amount, assets	806	592
Variable Interest Entity, nonconsolidated, carrying amount, liabilities	326	248
Variable interest entity, assets deconsolidated	0	0
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	1,054	790
Automobile loan | Consumer portfolio segment
Variable Interest Entity [Line Items]
Variable interest entity, consolidated, carrying amount, assets	16,255	17,597
Variable interest entity, consolidated, carrying amount, liabilities	6,573	7,677
Variable interest entity, nonconsolidated, carrying amount, assets	45	37
Variable Interest Entity, nonconsolidated, carrying amount, liabilities	0	0
Variable interest entity, assets deconsolidated	(1,235)	(1,964)
Cash flows between transferor and transferee, proceeds from transfers completed during the period	24	1,187	$ 1,715
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	1,280	2,001
Automobile loan | Consumer portfolio segment | Held-to-maturity securities
Variable Interest Entity [Line Items]
Variable interest entity, consolidated, carrying amount, assets	43	36
Automobile loan | Consumer portfolio segment | Other assets
Variable Interest Entity [Line Items]
Variable interest entity, consolidated, carrying amount, assets	2	1
Automobile loan | Commercial portfolio segment
Variable Interest Entity [Line Items]
Variable interest entity, consolidated, carrying amount, assets	11,089	12,550
Variable interest entity, consolidated, carrying amount, liabilities	3,946	2,558
Unencumbered | Automobile loan | Consumer portfolio segment
Variable Interest Entity [Line Items]
Variable interest entity, consolidated, carrying amount, assets	8,400	8,500
Variable interest entity, consolidated, carrying amount, liabilities	25	$ 29
Amount deconsolidated during the period | Automobile loan | Consumer portfolio segment
Variable Interest Entity [Line Items]
Variable interest entity, assets deconsolidated	(545)
Variable interest entity, liabilities deconsolidated	$ (497)

Securitizations and Variable _4

Securitizations and Variable Interest Entities (On-balance Sheet Variable Interest Entities) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Securitization and Variable Interest Entities On-balance Sheet Variable Interest Entities [Line Items]
Finance receivables and loans	$ 129,926	$ 122,893
Finance receivables and loans, net	128,684	121,617
Investment in operating leases, net	8,417	8,741
Other assets	6,153	5,663
Assets	178,869	167,148	$ 163,728
Long-term debt	44,193	44,226
Liabilities	165,601	153,654
Variable interest entity
Securitization and Variable Interest Entities On-balance Sheet Variable Interest Entities [Line Items]
Allowance for loan losses	(114)	(136)
Finance receivables and loans, net	17,972	20,487
Investment in operating leases, net	164	444
Other assets	767	689
Assets	18,903	21,620
Long-term debt	10,482	10,197
Accrued expenses and other liabilities, noncurrent	12	9
Liabilities	10,494	10,206
Variable interest entity | Consumer portfolio segment
Securitization and Variable Interest Entities On-balance Sheet Variable Interest Entities [Line Items]
Finance receivables and loans	7,282	8,186
Variable interest entity | Commercial portfolio segment
Securitization and Variable Interest Entities On-balance Sheet Variable Interest Entities [Line Items]
Finance receivables and loans	$ 10,804	$ 12,437

Securitizations and Variable _5

Securitizations and Variable Interest Entities (Schedule of Cash Flow Received from and Paid to Nonconsolidated Securitization Entities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash Flow Received and Paid to Nonconsolidated Securitization Entities [Line Items]
Cash flows between transferor and transferee, disbursement for repurchases during the period	$ (4)
Consumer portfolio segment | Automobile loan
Cash Flow Received and Paid to Nonconsolidated Securitization Entities [Line Items]
Cash flows between transferor and transferee, proceeds from transfers completed during the period	24	$ 1,187	$ 1,715
Cash flows between transferor and transferee, cash flows received on retained interests in securitization entities	20	21
Cash flows between transferor and transferee, servicing fees	18	31	35
Cash flows between transferor and transferee, disbursement for repurchases during the period		(491)
Cash flows between transferor and transferee, representations and warranty recoveries	0
Cash flows between transferor and transferee, other cash flows		4	8
Consumer portfolio segment | Residential mortgage
Cash Flow Received and Paid to Nonconsolidated Securitization Entities [Line Items]
Cash flows between transferor and transferee, proceeds from transfers completed during the period	0	0	0
Cash flows between transferor and transferee, cash flows received on retained interests in securitization entities	0	0
Cash flows between transferor and transferee, servicing fees	0	0	0
Cash flows between transferor and transferee, disbursement for repurchases during the period	0	0
Cash flows between transferor and transferee, representations and warranty recoveries	$ 2
Cash flows between transferor and transferee, other cash flows		$ 0	$ 0

Securitizations and Variable _6

Securitizations and Variable Interest Entities (Schedule of Quantitative Information and Net Credit Losses about Securitized and Other Financial Assets Managed Together) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Loans managed and securitized, principal amount outstanding	$ 1,869	$ 3,363
Loans managed and securitized, delinquent amount at end of period	16	20
Loans managed and securitized, net credit losses	12	16
Off-balance sheet loans | Consumer portfolio segment | Automobile loan
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Loans managed and securitized, principal amount outstanding	1,235	1,964
Loans managed and securitized, delinquent amount at end of period	13	16
Loans managed and securitized, net credit losses	10	13
Whole-loan sales
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Loans managed and securitized, principal amount outstanding	634	1,399
Loans managed and securitized, delinquent amount at end of period	3	4
Loans managed and securitized, net credit losses	$ 2	$ 3

Premiums Receivable and Other_3

Premiums Receivable and Other Insurance Assets Premiums Receivable and Other Insurance Assets (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Premiums Receivable and Other Insurance Assets [Abstract]
Prepaid reinsurance premiums	$ 527	$ 507
Reinsurance recoverables on unpaid losses	96	108
Reinsurance recoverable on paid losses	22	19
Premiums receivable	88	84
Deferred policy acquisition costs	1,593	1,329
Total premiums receivable and other insurance assets	$ 2,326	$ 2,047

Other Assets (Schedule of Other

Other Assets (Schedule of Other Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Other Assets [Abstract]
Property and equipment at cost	$ 1,250	$ 1,064
Accumulated depreciation, property and equipment	(686)	(608)
Property and equipment, net	564	456
Nonmarketable equity securities	1,410	1,233
Restricted cash collections for securitization trusts	965	923
Investments in qualified affordable housing projects	649	472
Accrued interest, late fees, and rent receivables	599	550
Deferred tax assets, net	317	461
Equity method investments	262	220
Goodwill	240	240
Other accounts receivable	203	116
Restricted cash and cash equivalents	124	94
Derivative contracts in a receivable position, fair value	41	39
Cash collateral placed with counterparties	26	29
Other assets, other	753	830
Total other assets	6,153	5,663
Federal Home Loan Bank stock	903	745
Federal Reserve Bank stock	448	445
Equity securities without a readily determinable fair value	59
Impairment related to equity securities without a readily determinable fair value	2
Investments in qualified affordable housing projects, unfunded commitment	319	240
Goodwill [Line Items]
Goodwill	240	240
Insurance operations
Other Assets [Abstract]
Goodwill	27	27
Goodwill [Line Items]
Goodwill	27	27
Automotive Finance operations
Other Assets [Abstract]
Goodwill	20	20
Goodwill [Line Items]
Goodwill	20	20
Corporate and Other
Other Assets [Abstract]
Goodwill	193	193
Goodwill [Line Items]
Goodwill	$ 193	$ 193

Deposit Liabilities (Schedule o

Deposit Liabilities (Schedule of Deposit Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deposits [Abstract]
Noninterest-bearing deposits	$ 142	$ 108
Interest-bearing Deposit Liabilities, by Component [Abstract]
Interest-bearing deposits, savings and money market checking accounts	56,050	49,267
Interest-bearing deposits, certificates of deposits	49,985	43,869
Interest-bearing deposits, dealer deposits	1	12
Total deposit liabilities	106,178	93,256
Certificates of deposit, $100,000 or more	21,000	18,900
Certificates of deposit, in excess of $250,000 federal insurance limit	$ 6,100	$ 5,300

Deposit Liabilities (Time Depos

Deposit Liabilities (Time Deposit Maturities) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Schedule of Maturities for Total Time Deposits [Line Items]
Certificates of deposit	$ 49,985	$ 43,869
One year, or less
Schedule of Maturities for Total Time Deposits [Line Items]
Certificates of deposit	31,518
Two years, or less
Schedule of Maturities for Total Time Deposits [Line Items]
Certificates of deposit	11,687
Three years, or less
Schedule of Maturities for Total Time Deposits [Line Items]
Certificates of deposit	4,569
Four years, or less
Schedule of Maturities for Total Time Deposits [Line Items]
Certificates of deposit	1,493
Five years, or less
Schedule of Maturities for Total Time Deposits [Line Items]
Certificates of deposit	718
Total deposits
Schedule of Maturities for Total Time Deposits [Line Items]
Certificates of deposit	$ 49,985

Debt (Schedule of Short-term De

Debt (Schedule of Short-term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Short-term Debt [Line Items]
Demand notes	$ 2,477	$ 3,171
Federal Home Loan Bank, advances	6,825	7,350
Financial instruments sold under agreements to repurchase	685	892
Total short-term borrowings	$ 9,987	$ 11,413
Weighted average interest rate	2.50%	1.50%
Non-derivative cash collateral received from counterparties associated with repurchase agreements	$ 8	$ 1
Non-derivative noncash collateral received from counterparties associated with repurchase agreements	4
Non-derivative cash collateral placed with counterparties associated with repurchase agreements	0	10
Unsecured debt
Short-term Debt [Line Items]
Demand notes	2,477	3,171
Federal Home Loan Bank, advances	0	0
Financial instruments sold under agreements to repurchase	0	0
Total short-term borrowings	2,477	3,171
Secured debt
Short-term Debt [Line Items]
Demand notes	0	0
Federal Home Loan Bank, advances	6,825	7,350
Financial instruments sold under agreements to repurchase	685	892
Total short-term borrowings	7,510	$ 8,242
Maturity within 30 days | Secured debt
Short-term Debt [Line Items]
Financial instruments sold under agreements to repurchase	575
Maturity within 31 to 60 days | Secured debt
Short-term Debt [Line Items]
Financial instruments sold under agreements to repurchase	110
US Treasury | Secured debt
Short-term Debt [Line Items]
Financial instruments sold under agreements to repurchase	436
Agency mortgage-backed residential | Secured debt
Short-term Debt [Line Items]
Financial instruments sold under agreements to repurchase	$ 249

Debt (Long-term Debt) (Details)

Debt (Long-term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Stated interest rate	8.125%
Total secured debt	$ 39,596	$ 36,837
Long-term debt	44,193	44,226
Subordinated debt	1,000	1,400
Variable interest entity debt	10,500	10,200
Long-term debt, due after one year	35,217	33,189
Unsecured debt
Debt Instrument [Line Items]
Long-term debt, fixed interest rate, amount	9,406	12,820
Long-term debt, variable interest rate, amount	1	1
Trust preferred securities	2,572	2,570
Fair value adjustment	128	240
Total unsecured debt	$ 12,107	$ 15,631
Weighted-average stated interest rate	6.29%	5.68%
Long-term debt	$ 12,107	$ 15,631
Long-term debt, due after one year	10,444	12,091
Secured debt
Debt Instrument [Line Items]
Long-term debt, fixed interest rate, amount	23,514	18,845
Long-term debt, variable interest rate, amount	8,633	9,782
Fair value adjustment	$ (61)	$ (32)
Weighted-average stated interest rate	2.54%	1.96%
Total secured debt	$ 32,086	$ 28,595
Long-term debt	32,086	28,595
Long-term debt without a stated interest rate	5	8
Long-term debt, due after one year	24,773	21,098
Revolving credit facilities
Debt Instrument [Line Items]
Long-term debt, due after one year	6,700	8,100
Federal Home Loan Bank advances
Debt Instrument [Line Items]
Total secured debt	$ 14,900	$ 10,300
Minimum | Unsecured debt
Debt Instrument [Line Items]
Stated interest rate	2.42%	1.48%
Minimum | Secured debt
Debt Instrument [Line Items]
Stated interest rate	1.26%	0.63%
Maximum | Unsecured debt
Debt Instrument [Line Items]
Stated interest rate	8.40%	8.00%
Maximum | Secured debt
Debt Instrument [Line Items]
Stated interest rate	4.50%	4.50%

Debt (Schedule of Debt) (Detail

Debt (Schedule of Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term debt, due within one year	$ 8,976	$ 11,037
Long-term debt, due after one year	35,217	33,189
Total long-term debt	44,193	44,226
Derivative instrument converting variable-rate debt into fixed-rate obligations	0	3,400
Derivative instrument converting fixed rate debt into variable rate debt	0	3,800
Revolving credit facilities
Debt Instrument [Line Items]
Long-term debt, due after one year	6,700	8,100
Unsecured debt
Debt Instrument [Line Items]
Long-term debt, due within one year	1,663	3,540
Long-term debt, due after one year	10,444	12,091
Total long-term debt	12,107	15,631
Secured debt
Debt Instrument [Line Items]
Long-term debt, due within one year	7,313	7,497
Long-term debt, due after one year	24,773	21,098
Total long-term debt	$ 32,086	$ 28,595

Debt (Scheduled Remaining Matur

Debt (Scheduled Remaining Maturity of Long-term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term debt, maturities, repayments of principal in next 12 months	$ 8,976
Long-term debt, maturities, repayments of principal in year two	9,579
Long-term debt, maturities, repayments of principal in year three	10,848
Long-term debt, maturities, repayments of principal in year four	6,341
Long-term debt, maturities, repayments of principal in year five	1,186
Long-term debt, maturities, repayments of principal after year five	7,263
Total long-term debt	44,193	$ 44,226
Unsecured debt
Debt Instrument [Line Items]
Long-term debt, maturities, repayments of principal in next 12 months	1,663
Long-term debt, maturities, repayments of principal in year two	2,216
Long-term debt, maturities, repayments of principal in year three	653
Long-term debt, maturities, repayments of principal in year four	1,020
Long-term debt, maturities, repayments of principal in year five	(44)
Long-term debt, maturities, repayments of principal after year five	6,599
Total long-term debt	12,107	15,631
Secured debt
Debt Instrument [Line Items]
Total long-term debt	32,086	$ 28,595
Long-term debt | Unsecured debt
Debt Instrument [Line Items]
Long-term debt, maturities, repayments of principal in next 12 months	1,704
Long-term debt, maturities, repayments of principal in year two	2,257
Long-term debt, maturities, repayments of principal in year three	698
Long-term debt, maturities, repayments of principal in year four	1,069
Long-term debt, maturities, repayments of principal in year five	12
Long-term debt, maturities, repayments of principal after year five	7,502
Total long-term debt	13,242
Long-term debt | Secured debt
Debt Instrument [Line Items]
Long-term debt, maturities, repayments of principal in next 12 months	7,313
Long-term debt, maturities, repayments of principal in year two	7,363
Long-term debt, maturities, repayments of principal in year three	10,195
Long-term debt, maturities, repayments of principal in year four	5,321
Long-term debt, maturities, repayments of principal in year five	1,230
Long-term debt, maturities, repayments of principal after year five	664
Total long-term debt	32,086
Original issue discount | Unsecured debt
Debt Instrument [Line Items]
Debt instrument, unamortized discount, current	(41)
Debt instrument, unamortized discount	(1,135)
Original issue discount | Unsecured debt | Debt instrument, redemption, period two
Debt Instrument [Line Items]
Debt instrument, unamortized discount, noncurrent	(41)
Original issue discount | Unsecured debt | Debt instrument, redemption, period three
Debt Instrument [Line Items]
Debt instrument, unamortized discount, noncurrent	(45)
Original issue discount | Unsecured debt | Debt Instrument, redemption, period four
Debt Instrument [Line Items]
Debt instrument, unamortized discount, noncurrent	(49)
Original issue discount | Unsecured debt | Debt Instrument, redemption, period five
Debt Instrument [Line Items]
Debt instrument, unamortized discount, noncurrent	(56)
Original issue discount | Unsecured debt | Debt instrument, redemption, period six
Debt Instrument [Line Items]
Debt instrument, unamortized discount, noncurrent	$ (903)

Debt (Pledged Assets Related to

Debt (Pledged Assets Related to Secured Borrowings and Repurchase Agreement) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Pledged Assets related to secured borrowings [Line Items]
Pledged financial instruments, investment securities	$ 10,280	$ 8,371
Pledged assets, mortgage assets held-for-investment and lending receivables	16,498	13,579
Pledged assets,operating leases	170	457
Pledged assets, restricted as collateral	59,526	58,761
Secured debt	39,596	36,837
Ally Bank
Pledged Assets related to secured borrowings [Line Items]
Pledged financial instruments, investment securities	9,564	7,443
Pledged assets, mortgage assets held-for-investment and lending receivables	16,498	13,579
Pledged assets,operating leases	0	0
Pledged assets, restricted as collateral	51,340	43,694
Secured debt	32,072	23,278
Pledged assets for Federal Home Loan Bank | Ally Bank
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	30,800	25,200
Pledged assets for Federal Reserve Bank | Ally Bank
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	2,400	2,300
Short-term borrowings
Pledged Assets related to secured borrowings [Line Items]
Secured debt	7,500	8,200
Consumer portfolio segment | Automobile loan
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, finance receivables	17,015	19,787
Consumer portfolio segment | Automobile loan | Ally Bank
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, finance receivables	9,715	6,200
Commercial portfolio segment | Automobile loan
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, finance receivables	15,563	16,567
Commercial portfolio segment | Automobile loan | Ally Bank
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, finance receivables	$ 15,563	$ 16,472

Debt (Narrative - Trust Preferr

Debt (Narrative - Trust Preferred Securities) (Details) $ / shares in Units, $ in Billions	Dec. 31, 2018USD ($)$ / shares
Narrative - Trust Preferred Securities [Line Items]
Trust preferred securities, fixed rate, floating rate, percentage	8.125%
Preferred stock, liquidation amount per share | $ / shares	$ 25
Distribution payable in addition to annual rate equal to three-month London interbank offer rate, percentage	5.785%
Period of consecutive quarters for which Ally has right to defer interest payments, maximum	20
Redemption price, percentage of principal debt, plus accrued and unpaid interest	100.00%
Fixed income interest rate
Narrative - Trust Preferred Securities [Line Items]
Trust preferred securities | $	$ 2.6

Debt (Committed Funding Facilit

Debt (Committed Funding Facilities) (Details) - Committed funding facilities - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term line of credit	$ 6,665	$ 8,115
Line of credit facility, remaining borrowing capacity	1,935	3,810
Line of credit facility, maximum borrowing capacity	8,600	11,925
Ally Bank | Secured debt
Debt Instrument [Line Items]
Long-term line of credit	3,500	1,785
Line of credit facility, remaining borrowing capacity	1,300	890
Line of credit facility, maximum borrowing capacity	4,800	2,675
Secured funding facilities, revolving, one year or greater
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	7,000
Nonbank funding | Secured debt
Debt Instrument [Line Items]
Long-term line of credit	3,165	6,330
Line of credit facility, remaining borrowing capacity	635	2,920
Line of credit facility, maximum borrowing capacity	$ 3,800	$ 9,250

Accrued Expenses and Other Li_3

Accrued Expenses and Other Liabilities (Schedule of Accrued Expenses and Other Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounts Payable and Accrued Liabilities [Abstract]
Accounts payable	$ 516	$ 746
Unfunded commitments for investment in qualified affordable housing projects	319	240
Employee compensation and benefits	255	248
Reserves for insurance losses and loss adjustment expenses	134	140	$ 149	$ 169
Cash collateral received from counterparties	41	17
Fair value of derivative contracts in a payable position	37	41
Deferred revenue	27	32
Other liabilities	347	316
Total accrued expenses and other liabilities	$ 1,676	$ 1,780

Equity (Common Stock) (Details)

Equity (Common Stock) (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity [Abstract]
Common stock, shares issued	489,883,553	485,708,000	482,791,000	492,797,409	489,883,553	485,708,000
New issuances, common stock, employee benefits and compensation plans	2,914,000	4,176,000	2,917,000
Common stock, shares issued	492,797,409	489,883,553	485,708,000
Treasury stock, shares	(52,829,617)	(18,707,000)	(811,000)
Repurchase of common stock	(35,068,000)	(34,122,000)	(17,897,000)
Treasury stock, shares	(87,897,810)	(52,829,617)	(18,707,000)
Common stock, shares issued	489,883,553	485,708,000	482,791,000
Common stock, shares outstanding				404,899,599	437,053,936	467,000,000

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss (Rollforward) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018	Dec. 31, 2015
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax [Abstract]
Accumulated other comprehensive income (loss), investment securities, adjustment, after tax	$ (481)	$ (173)	$ (273)	$ (186)	$ (159)
Other comprehensive income (loss), investment securities, net change, after tax	(295)	100	(114)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Accumulated other comprehensive income (loss), translation adjustment, net of tax	18	16	14	20	9
Other comprehensive income (loss), foreign currency translation adjustment, net of tax	(2)	2	5
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract]
Accumulated other comprehensive income (loss), cumulative changes in net gain (loss) from cash flow hedges, net of tax	19	11	8	11	8
Other comprehensive income (loss), cash flow hedges, net change, after tax	8	3	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Net of Tax [Abstract]
Accumulated other comprehensive income (loss), defined benefit pension plans, after tax	(95)	(89)	(90)	(95)	(89)
Other comprehensive (income) loss, defined benefit plan, after reclassification adjustment, after tax	0	(1)	1
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Total accumulated other comprehensive loss, net of tax	539	235	341	250	$ 231
Other comprehensive income (loss), net of tax	$ (289)	$ 106	$ (110)
Accounting Standards Update 2016-01
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax [Abstract]
Accumulated other comprehensive income (loss), investment securities, adjustment, after tax				27
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Accumulated other comprehensive income (loss), translation adjustment, net of tax				0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract]
Accumulated other comprehensive income (loss), cumulative changes in net gain (loss) from cash flow hedges, net of tax				0
Other Comprehensive Income (Loss), Defined Benefit Plan, Net of Tax [Abstract]
Accumulated other comprehensive income (loss), defined benefit pension plans, after tax				0
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Total accumulated other comprehensive loss, net of tax				(27)
Accounting Standards Update 2018-02
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax [Abstract]
Accumulated other comprehensive income (loss), investment securities, adjustment, after tax				(40)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Accumulated other comprehensive income (loss), translation adjustment, net of tax				4
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract]
Accumulated other comprehensive income (loss), cumulative changes in net gain (loss) from cash flow hedges, net of tax				0
Other Comprehensive Income (Loss), Defined Benefit Plan, Net of Tax [Abstract]
Accumulated other comprehensive income (loss), defined benefit pension plans, after tax				(6)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Total accumulated other comprehensive loss, net of tax				$ 42

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Loss (Before and After Tax) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax [Abstract]
Other compehrensive income (loss), investment securities, net unrealized gains (losses) arising during the period, before tax	$ (375)	$ 237	$ 13
Other compehrensive income (loss), investement securities, net realized gains reclassified to income from continuing operations, before tax	11	105	185
Other comprehensive income, investment securities, net change, before tax	(386)	132	(172)
Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax [Abstract]
Other comprehensive income (loss), investment securities, unrealized holding gains (losses) arising during the period, tax	88	(45)	20
Other comprehensive income (loss), investment securities, net realized gains reclassified to income from continuing operations, tax effect	(3)	(13)	(38)
Other comprehensive income (loss), investment securities, net change, tax effect	91	(32)	58
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax [Abstract]
Other comprehensive income (loss), investment securities, net unrealized gains (losses) arising during the period, after tax	(287)	192	33
Other comprehensive income (loss), investment securities, net realized gains reclassified to income from continuing operations, after tax	8	92	147
Other comprehensive income (loss), investment securities, net change, after tax	(295)	100	(114)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax [Abstract]
Other comprehensive income (loss), translation adjustments, before tax and reclassification adjustments			5
Other comprehensive income (loss), translation adjustments, reclassification adjustment, before tax			(1)
Other comprehensive income (loss), translation adjustments, net change, before tax	(14)	12	6
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax [Abstract]
Other comprehensive income (loss), translation adjustments before reclassification adjustments, tax			2
Other comprehensive income (loss), translation reclassification adjustment, tax			0
Other comprehensive income (loss), translation adjustments, net unrealized gains (losses) arising during the period, tax effect	3	(4)	(2)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Other comprehensive income (loss), foreign currency transaction and translation gain (loss) arising during the period before reclassification adjustments, net of tax			3
Other comprehensive income (loss), translation reclassification adjustment, net of tax	0	0	(1)
Other comprehensive income (loss), translation adjustments, net unrealized gains (losses) arising during the period, after tax	(11)	8	4
Other Comprehensive Income (Loss), Net investment hedges, before Tax [Abstract]
Other comprehensive income (loss), net investment hedges, unrealized gains (losses) arising during the period, before tax	12	(10)	1
Other Comprehensive Income (Loss), Net investment hedges, Tax [Abstract]
Other comprehensive income (loss), net investment hedges, net unrealized gains arising during the period, tax effect	(3)	4	0
Other Comprehensive Income (Loss), Net investment hedges, Net of Tax [Abstract]
Net investment hedges, unrealized gains (losses) arising during the period, after tax	9	(6)	1
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax [Abstract]
Other comprehensive income (loss), cash flow hedges, net unrealized gains (losses) arising during the period before tax	12	5
Other comprehensive income (loss), cash flow hedge, gain (loss), reclassification, before tax	2
Other comprehensive income (loss), cash flow hedge, gain (loss), after reclassification, before tax	10
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax [Abstract]
Other comprehensive income (loss), cash flow hedges, net unrealized gains arising during the period, tax	(2)	(2)
Other comprehensive income (loss), cash flow hedge, gain (loss), reclassification, tax	0
Other comprehensive income (loss), cash flow hedge, gain (loss), after reclassification, tax	(2)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract]
Other comprehensive income (loss), cash flow hedges, net unrealized gains (losses) arising during the period	10	3	0
Other comprehensive income (loss), cash flow hedge, gain (loss), reclassification, after tax	2	0	0
Other comprehensive income (loss), cash flow hedge, gain (loss), after reclassification and tax	8	3	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Tax [Abstract]
Other comprehensive income (loss), defined benefit pension plans, net unrealized gains (losses) arising during period, before tax	1	1	(5)
Other comprehensive income (loss), defined benefit plan, gain (loss), reclassification adjustment from AOCI, before tax			(4)
Other comprehensive (income) loss, defined benefit plan, after reclassification adjustment, before tax			1
Other Comprehensive (Income) Loss, Defined Benefit Plan, Tax [Abstract]
Other comprehensive income (loss), defined benefit pension plans, net unrealized gains (losses) arising during period, tax	(1)	0	2
Other comprehensive (income) loss, defined benefit plan, reclassification adjustment, tax			2
Other comprehensive (income) loss, defined benefit plan, after reclassification adjustment, tax			0
Other Comprehensive Income (Loss), Defined Benefit Plan, Net of Tax [Abstract]
Other comprehensive (income) loss, defined benefit plan, before reclassification adjustment, after tax	0	(1)	3
Other Comprehensive Income (loss), defined benefit plan, gain (loss), reclassification adjustment, after tax	0	0	(2)
Other comprehensive (income), defined benefit pension plans, net unrealized gains (losses) arising during period, after tax	0	1	(1)
Other Comprehensive Income (Loss), before Tax [Abstract]
Other comprehensive income (loss), before tax	(377)	140	(166)
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income (loss), tax effect	88	(34)	56
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other comprehensive income (loss), net of tax	$ (289)	$ 106	$ (110)

Earnings per Common Share (Sche

Earnings per Common Share (Schedule of Basic and Diluted Earnings per Common Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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
Earnings Per Share [Abstract]
Net income from continuing operations	$ 289	$ 374	$ 348	$ 252	$ 179	$ 280	$ 254	$ 213	$ 1,263	$ 926	$ 1,111
Preferred stock dividends									0	0	(30)
Net income from continuing operations attributable to common shareholders									1,263	926	1,081
Income (loss) from discontinued operations, net of tax	$ 1	$ 0	$ 1	$ (2)	$ 2	$ 2	$ (2)	$ 1	0	3	(44)
Net income (loss) attributable to common stockholders									$ 1,263	$ 929	$ 1,037
Basic weighted-average common shares outstanding									425,165	453,704	481,105
Diluted weighted-average common shares outstanding									427,680	455,350	482,182
Earnings Per Share, Basic [Abstract]
Net income from continuing operations, basic earnings per common share	$ 0.70	$ 0.89	$ 0.81	$ 0.58	$ 0.40	$ 0.62	$ 0.55	$ 0.46	$ 2.97	$ 2.04	$ 2.25
Income (loss) from discontinued operations, net of tax, basic earnings per common share									0	0.01	(0.09)
Net income, basic earnings per common share	0.70	0.89	0.81	0.57	0.41	0.63	0.55	0.46	2.97	2.05	2.15
Earnings Per Share, Diluted [Abstract]
Net income from continuing operations, diluted earnings per common share	0.70	0.88	0.80	0.57	0.40	0.62	0.55	0.46	2.95	2.03	2.24
Income (loss) from discontinued operations, net of tax, diluted earnings per common share									0	0.01	(0.09)
Net income, diluted earnings per common share	$ 0.70	$ 0.88	$ 0.81	$ 0.57	$ 0.41	$ 0.63	$ 0.55	$ 0.46	$ 2.95	$ 2.04	$ 2.15

Regulatory Capital and Other _3

Regulatory Capital and Other Regulatory Matters (Schedule of Regulatory Capital Amount and Ratios) (Details) - USD ($) $ / shares in Units, $ in Millions	Jan. 14, 2019	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, 2016	Sep. 30, 2016
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier one capital to risk-weighted assets, required minimum		4.50%
Tier one capital to risk-weighted assets, required minimum		6.00%
Capital to risk-weighted assets, required minimum		8.00%
Common equity tier one capital conservation buffer		2.50%
Tier one leverage ratio, minimum		4.00%
BHC enhanced prudential standards, minimum		$ 100,000
BHC enhanced prudential standards, maximum		250,000
BHC stress test threshold		$ 50,000
BHC capital requirement, dividend payout ratio		30.00%
Minimum capital conservation buffer		1.875%				1.25%
Minimum capital conservation buffer, increased percentage		2.50%
Increase (decrease) in share repurchase program		32.00%
Common stock repurchase program, authorized amount		$ 1,000
Dividends declared, amount per common share		$ 0.15	$ 0.15	$ 0.13	$ 0.13	$ 0.12	$ 0.12	$ 0.08	$ 0.08	$ 0.08	$ 0.08
Parent company
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier one capital to risk-weighted assets, required minimum		4.50%
Tier one capital to risk-weighted assets, required minimum		6.00%
Capital to risk-weighted assets, required minimum		8.00%
Tier one leverage ratio, minimum		4.00%
Common equity tier one capital to risk-weighted assets, amount		$ 13,397				$ 13,237
Common equity tier one capital to risk-weighted assets, ratio		9.14%				9.53%
Tier one capital to risk-weighted assets, amount		$ 15,831				$ 15,628
Tier one capital to risk-weighted assets, ratio		10.80%				11.25%
Tier one capital to risk-weighted assets, well-capitalized minimum		6.00%
Capital to risk-weighted assets, amount		$ 18,046				$ 17,974
Capital to risk-weighted assets, ratio		12.31%				12.94%
Capital to risk weighted assets, well-capitalzed minimum		10.00%
Tier one leverage to adjusted quarterly average assets, amount		$ 15,831				$ 15,628
Tier one leverage to adjusted quarterly average assets, ratio		9.00%				9.53%
Subsidiaries
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier one capital to risk-weighted assets, required minimum		4.50%
Tier one capital to risk-weighted assets, required minimum		6.00%
Capital to risk-weighted assets, required minimum		8.00%
Tier one leverage ratio, minimum		4.00%
Common equity tier one capital to risk-weighted assets, amount		$ 16,552				$ 17,059
Common equity tier one capital to risk-weighted assets, ratio		12.61%				15.04%
Common equity tier one capital to risk-weighted assets, well-capitalized minimum		6.50%
Tier one capital to risk-weighted assets, amount		$ 16,552				$ 17,059
Tier one capital to risk-weighted assets, ratio		12.61%				15.04%
Tier one capital to risk-weighted assets, well-capitalized minimum		8.00%
Capital to risk-weighted assets, amount		$ 17,620				$ 17,886
Capital to risk-weighted assets, ratio		13.42%				15.77%
Capital to risk weighted assets, well-capitalzed minimum		10.00%
Tier one leverage to adjusted quarterly average assets, amount		$ 16,552				$ 17,059
Tier one leverage to adjusted quarterly average assets, ratio		10.69%				12.87%
Tier one leverage to adjusted quarterly average assets, well-capitalized minimum		5.00%
Subsequent event
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Dividends declared, amount per common share	$ 0.17

Regulatory Capital and Other _4

Regulatory Capital and Other Regulatory Matters (Common Share Repurchases) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Jan. 14, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016
Accelerated Share Repurchases [Line Items]
Treasury stock, common, amount	$ 309	$ 190		$ 250	$ 195	$ 185	$ 190	$ 204	$ 169	$ 167	$ 159
Treasury stock, common, shares	12,121,000	7,033,000		9,194,000	7,280,000	6,473,000	8,507,000	10,485,000	8,097,000	8,745,000	8,298,000
Common stock, shares outstanding	404,899,599	437,053,936								467,000,000
Dividends declared, amount per common share	$ 0.15	$ 0.12		$ 0.15	$ 0.13	$ 0.13	$ 0.12	$ 0.08	$ 0.08	$ 0.08	$ 0.08
BHC enhanced prudential standards, minimum	$ 100,000
BHC enhanced prudential standards, maximum	250,000
Assets	178,869	$ 167,148								$ 163,728
Dividends paid to Parent	2,600	3,300
FRB required reserve balance	279	$ 370
Statutory amount available for dividend payments	$ 134
Beginning of period
Accelerated Share Repurchases [Line Items]
Common stock, shares outstanding		437,054,000		416,591,000	425,752,000	432,691,000	443,796,000	452,292,000	462,193,000	467,000,000	475,470,000	483,753,000
End of period
Accelerated Share Repurchases [Line Items]
Common stock, shares outstanding	404,900,000	437,054,000		416,591,000	425,752,000	432,691,000	443,796,000	452,292,000	462,193,000	467,000,000	475,470,000
Subsequent event
Accelerated Share Repurchases [Line Items]
Dividends declared, amount per common share			$ 0.17
Subsidiaries
Accelerated Share Repurchases [Line Items]
Assets	$ 159,000	$ 137,400

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Cash collateral placed with counterparties	$ 26	$ 20
Noncash collateral placed with counterparties	105	97
Cash collateral received from counterparties	30	17
Noncash collateral received from counterparties	$ 3	$ 2

Derivative Instruments and He_4

Derivative Instruments and Hedging Activities (Fair Value Amounts of Derivative Instruments Reported on our Condensed Consolidated Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	$ 41	$ 39
Fair value of derivative contracts in a payable position	37	41
Derivative, notional amount	38,066	23,762
Designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	1	0
Fair value of derivative contracts in a payable position	0	1
Derivative, notional amount	24,339	7,051
Not designated as hedging instrument | Other trading
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	40	39
Fair value of derivative contracts in a payable position	37	40
Derivative, notional amount	13,727	16,711
Interest rate swaps | Designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	0	0
Fair value of derivative contracts in a payable position	0	0
Derivative, notional amount	24,203	6,915
Foreign exchange forwards | Designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	1	0
Fair value of derivative contracts in a payable position	0	1
Derivative, notional amount	136	136
Interest rate contracts | Not designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	37	39
Fair value of derivative contracts in a payable position	37	39
Derivative, notional amount	13,546	16,587
Interest rate contracts | Not designated as hedging instrument | Futures and forwards
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	0	0
Fair value of derivative contracts in a payable position	0	0
Derivative, notional amount	11	23
Interest rate contracts | Not designated as hedging instrument | Written options
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	0	1
Fair value of derivative contracts in a payable position	37	39
Derivative, notional amount	6,793	8,327
Interest rate contracts | Not designated as hedging instrument | Purchased options
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	37	38
Fair value of derivative contracts in a payable position	0	0
Derivative, notional amount	6,742	8,237
Foreign exchange contracts | Not designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	3	0
Fair value of derivative contracts in a payable position	0	1
Derivative, notional amount	181	124
Foreign exchange contracts | Not designated as hedging instrument | Foreign exchange forwards
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	3	0
Fair value of derivative contracts in a payable position	0	1
Derivative, notional amount	$ 181	$ 124

Derivative Instruments and He_5

Derivative Instruments and Hedging Activities (Schedule of Fair Value Hedging Instruments, Statements of Financial Performance and Financial Position, Location) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Long-term debt	$ 44,193	$ 44,226
Amortized cost basis of the closed portfolios used in hedging relationships	47
Hedged asset, last-of-layer, amount	21,400
Hedge basis adjustment, last-of-layer	19
Carrying amount
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Available-for-sale debt securities	1,485	173
Finance receivables and loans, net	40,850	2,305
Long-term debt	13,001	14,640
Available-for-sale securities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustments for fair value hedges included in the carrying amount of hedged items	0	2
Hedged asset, last-of-layer, amount	28
Hedge basis adjustment, last-of-layer	0
Available-for-sale securities | Discontinued hedge
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustments for fair value hedges included in the carrying amount of hedged items	(5)	2
Finance receivables and loans, net
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustments for fair value hedges included in the carrying amount of hedged items	24	18
Finance receivables and loans, net | Discontinued hedge
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustments for fair value hedges included in the carrying amount of hedged items	5	19
Long-term debt
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustments for fair value hedges included in the carrying amount of hedged items	67	208
Long-term debt | Discontinued hedge
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustments for fair value hedges included in the carrying amount of hedged items	$ 67	$ 235

Derivative Instruments and He_6

Derivative Instruments and Hedging Activities (Statement of Gains and Losses on Derivative Instruments Reported in Statement of Comprehensive Income) (Details) - Not designated as hedging instrument - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments, net, pretax	$ 13	$ (9)	$ (1)
Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest rate derivative instruments	0	(2)	0
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on foreign currency derivative instruments	13	(7)	(1)
Gains on mortgage and automotive loans | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest rate derivative instruments	0	1	0
Other income | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest rate derivative instruments	0	(3)	0
Other income | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on foreign currency derivative instruments	13	(7)	1
Interest expense | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on foreign currency derivative instruments	$ 0	$ 0	$ (2)

Derivative Instruments and He_7

Derivative Instruments and Hedging Activities (Derivative Instruments Designated as Fair Value Hedges, Gain (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Interest and fees on finance receivables and loans	$ 6,688	$ 5,819	$ 5,162
Interest and dividends on investment securities and other earning assets	788	599	418
Interest on deposits	1,735	1,077	830
Interest on long-term debt	1,753	1,653	1,742
Designated as hedging instrument | Interest and fees on finance receivables and loans | Fair value hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on fair value hedges	0	(2)	(2)
Designated as hedging instrument | Interest and dividends on investment securities and other earning assets | Fair value hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on fair value hedges	0	0	0
Designated as hedging instrument | Interest on deposits | Fair value hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on fair value hedges	0	0	0
Designated as hedging instrument | Interest on long-term debt | Fair value hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on fair value hedges	1	5	(5)
Designated as hedging instrument | Unsecured debt | Interest and fees on finance receivables and loans | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	0	0	0
Change in unrealized gain (loss) on fair value hedging instruments	0	0	0
Designated as hedging instrument | Unsecured debt | Interest and dividends on investment securities and other earning assets | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	0	0	0
Change in unrealized gain (loss) on fair value hedging instruments	0	0	0
Designated as hedging instrument | Unsecured debt | Interest on deposits | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	0	0	0
Change in unrealized gain (loss) on fair value hedging instruments	0	0	0
Designated as hedging instrument | Unsecured debt | Interest on long-term debt | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	62	8	(78)
Change in unrealized gain (loss) on fair value hedging instruments	(61)	(3)	73
Designated as hedging instrument | Federal Home Loan Bank certificates and obligations | Interest and fees on finance receivables and loans | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	0	0	0
Change in unrealized gain (loss) on fair value hedging instruments	0	0	0
Designated as hedging instrument | Federal Home Loan Bank certificates and obligations | Interest and dividends on investment securities and other earning assets | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	0	0	0
Change in unrealized gain (loss) on fair value hedging instruments	0	0	0
Designated as hedging instrument | Federal Home Loan Bank certificates and obligations | Interest on deposits | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	0	0	0
Change in unrealized gain (loss) on fair value hedging instruments	0	0	0
Designated as hedging instrument | Federal Home Loan Bank certificates and obligations | Interest on long-term debt | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	47	22	8
Change in unrealized gain (loss) on fair value hedging instruments	(47)	(22)	(8)
Designated as hedging instrument | Available-for-sale securities | Interest and fees on finance receivables and loans | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	0	0	0
Change in unrealized gain (loss) on fair value hedging instruments	0	0	0
Designated as hedging instrument | Available-for-sale securities | Interest and dividends on investment securities and other earning assets | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	(3)	(1)	0
Change in unrealized gain (loss) on fair value hedging instruments	3	1	0
Designated as hedging instrument | Available-for-sale securities | Interest on deposits | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	0	0	0
Change in unrealized gain (loss) on fair value hedging instruments	0	0	0
Designated as hedging instrument | Available-for-sale securities | Interest on long-term debt | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	0	0	0
Change in unrealized gain (loss) on fair value hedging instruments	0	0	0
Designated as hedging instrument | Fixed-rate automotive loans | Interest and fees on finance receivables and loans | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	19	(3)	0
Change in unrealized gain (loss) on fair value hedging instruments	(19)	1	(2)
Designated as hedging instrument | Fixed-rate automotive loans | Interest and dividends on investment securities and other earning assets | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	0	0	0
Change in unrealized gain (loss) on fair value hedging instruments	0	0	0
Designated as hedging instrument | Fixed-rate automotive loans | Interest on deposits | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	0	0	0
Change in unrealized gain (loss) on fair value hedging instruments	0	0	0
Designated as hedging instrument | Fixed-rate automotive loans | Interest on long-term debt | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	0	0	0
Change in unrealized gain (loss) on fair value hedging instruments	0	0	0
Deposit liabilities | Designated as hedging instrument | Interest and fees on finance receivables and loans | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedges, reclassified to earnings, net	0	0	0
Deposit liabilities | Designated as hedging instrument | Interest and dividends on investment securities and other earning assets | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedges, reclassified to earnings, net	0	0	0
Deposit liabilities | Designated as hedging instrument | Interest on deposits | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedges, reclassified to earnings, net	1	0	0
Deposit liabilities | Designated as hedging instrument | Interest on long-term debt | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedges, reclassified to earnings, net	0	0	0
Variable-rate borrowings | Designated as hedging instrument | Interest and fees on finance receivables and loans | Cash flow hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedging relationships	0	0	0
Variable-rate borrowings | Designated as hedging instrument | Interest and fees on finance receivables and loans | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedges, reclassified to earnings, net	0	0	0
Variable-rate borrowings | Designated as hedging instrument | Interest and dividends on investment securities and other earning assets | Cash flow hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedging relationships	0	0	0
Variable-rate borrowings | Designated as hedging instrument | Interest and dividends on investment securities and other earning assets | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedges, reclassified to earnings, net	0	0	0
Variable-rate borrowings | Designated as hedging instrument | Interest on deposits | Cash flow hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedging relationships	1	0	0
Variable-rate borrowings | Designated as hedging instrument | Interest on deposits | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedges, reclassified to earnings, net	0	0	0
Variable-rate borrowings | Designated as hedging instrument | Interest on long-term debt | Cash flow hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedging relationships	1	0	0
Variable-rate borrowings | Designated as hedging instrument | Interest on long-term debt | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedges, reclassified to earnings, net	$ 1	$ 0	$ 0

Derivative Instruments and He_8

Derivative Instruments and Hedging Activities (Interest and Amortization on Derivative Instruments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Interest and dividends on investment securities and other earning assets	$ 788	$ 599	$ 418
Interest on long-term debt	1,753	1,653	1,742
Earnings on cash flow hedges to be recognized within twelve months	15
Designated as hedging instrument | Interest and fees on finance receivables and loans | Fair value hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on fair value hedges	0	(2)	(2)
Designated as hedging instrument | Interest and fees on finance receivables and loans | Amortization and interest | Fair value hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on fair value hedges	2	(22)	(38)
Designated as hedging instrument | Interest and fees on finance receivables and loans | Amortization and interest | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedging relationships	0	0	0
Designated as hedging instrument | Interest and dividends on investment securities and other earning assets | Fair value hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on fair value hedges	0	0	0
Designated as hedging instrument | Interest and dividends on investment securities and other earning assets | Amortization and interest | Fair value hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on fair value hedges	(1)	0	0
Designated as hedging instrument | Interest and dividends on investment securities and other earning assets | Amortization and interest | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedging relationships	0	0	0
Designated as hedging instrument | Interest on deposits | Fair value hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on fair value hedges	0	0	0
Designated as hedging instrument | Interest on deposits | Amortization and interest | Fair value hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on fair value hedges	0	0	0
Designated as hedging instrument | Interest on deposits | Amortization and interest | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedging relationships	3	0	0
Designated as hedging instrument | Interest on long-term debt | Fair value hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on fair value hedges	1	5	(5)
Designated as hedging instrument | Interest on long-term debt | Amortization and interest | Fair value hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on fair value hedges	48	102	129
Designated as hedging instrument | Interest on long-term debt | Amortization and interest | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedging relationships	8	(1)	0
Designated as hedging instrument | Unsecured debt | Interest and fees on finance receivables and loans | Amortization and interest | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on amortization of deferred basis adjustments	0	0	0
Gain (loss) on interest for qualifying hedge	0	0	0
Designated as hedging instrument | Unsecured debt | Interest and dividends on investment securities and other earning assets | Amortization and interest | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on amortization of deferred basis adjustments	0	0	0
Gain (loss) on interest for qualifying hedge	0	0	0
Designated as hedging instrument | Unsecured debt | Interest on deposits | Amortization and interest | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on amortization of deferred basis adjustments	0	0	0
Gain (loss) on interest for qualifying hedge	0	0	0
Designated as hedging instrument | Unsecured debt | Interest on long-term debt | Amortization and interest | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on amortization of deferred basis adjustments	51	77	84
Gain (loss) on interest for qualifying hedge	8	24	40
Designated as hedging instrument | Federal Home Loan Bank certificates and obligations | Interest and fees on finance receivables and loans | Amortization and interest | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on amortization of deferred basis adjustments	0	0	0
Gain (loss) on interest for qualifying hedge	0	0	0
Designated as hedging instrument | Federal Home Loan Bank certificates and obligations | Interest and dividends on investment securities and other earning assets | Amortization and interest | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on amortization of deferred basis adjustments	0	0	0
Gain (loss) on interest for qualifying hedge	0	0	0
Designated as hedging instrument | Federal Home Loan Bank certificates and obligations | Interest on deposits | Amortization and interest | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on amortization of deferred basis adjustments	0	0	0
Gain (loss) on interest for qualifying hedge	0	0	0
Designated as hedging instrument | Federal Home Loan Bank certificates and obligations | Interest on long-term debt | Amortization and interest | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on amortization of deferred basis adjustments	(17)	(2)	0
Gain (loss) on interest for qualifying hedge	6	3	5
Designated as hedging instrument | Available-for-sale securities | Interest and fees on finance receivables and loans | Amortization and interest | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest for qualifying hedge	0	0	0
Designated as hedging instrument | Available-for-sale securities | Interest and dividends on investment securities and other earning assets | Amortization and interest | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest for qualifying hedge	(1)	0	0
Designated as hedging instrument | Available-for-sale securities | Interest on deposits | Amortization and interest | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest for qualifying hedge	0	0	0
Designated as hedging instrument | Available-for-sale securities | Interest on long-term debt | Amortization and interest | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest for qualifying hedge	0	0	0
Designated as hedging instrument | Fixed-rate automotive loans | Interest and fees on finance receivables and loans | Amortization and interest | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on amortization of deferred basis adjustments	(14)	(21)	(20)
Gain (loss) on interest for qualifying hedge	16	(1)	(18)
Designated as hedging instrument | Fixed-rate automotive loans | Interest and dividends on investment securities and other earning assets | Amortization and interest | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on amortization of deferred basis adjustments	0	0	0
Gain (loss) on interest for qualifying hedge	0	0	0
Designated as hedging instrument | Fixed-rate automotive loans | Interest on deposits | Amortization and interest | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on amortization of deferred basis adjustments	0	0	0
Gain (loss) on interest for qualifying hedge	0	0	0
Designated as hedging instrument | Fixed-rate automotive loans | Interest on long-term debt | Amortization and interest | Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on amortization of deferred basis adjustments	0	0	0
Gain (loss) on interest for qualifying hedge	0	0	0
Variable-rate borrowings | Designated as hedging instrument | Interest and fees on finance receivables and loans | Cash flow hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedging relationships	0	0	0
Variable-rate borrowings | Designated as hedging instrument | Interest and fees on finance receivables and loans | Amortization and interest | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest for qualifying hedge	0	0	0
Variable-rate borrowings | Designated as hedging instrument | Interest and dividends on investment securities and other earning assets | Cash flow hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedging relationships	0	0	0
Variable-rate borrowings | Designated as hedging instrument | Interest and dividends on investment securities and other earning assets | Amortization and interest | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest for qualifying hedge	0	0	0
Variable-rate borrowings | Designated as hedging instrument | Interest on deposits | Cash flow hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedging relationships	1	0	0
Variable-rate borrowings | Designated as hedging instrument | Interest on deposits | Amortization and interest | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest for qualifying hedge	0	0	0
Variable-rate borrowings | Designated as hedging instrument | Interest on long-term debt | Cash flow hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedging relationships	1	0	0
Variable-rate borrowings | Designated as hedging instrument | Interest on long-term debt | Amortization and interest | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest for qualifying hedge	8	(1)	0
Deposit liabilities | Designated as hedging instrument | Interest and fees on finance receivables and loans | Amortization and interest | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest for qualifying hedge	0	0	0
Deposit liabilities | Designated as hedging instrument | Interest and dividends on investment securities and other earning assets | Amortization and interest | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest for qualifying hedge	0	0	0
Deposit liabilities | Designated as hedging instrument | Interest on deposits | Amortization and interest | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest for qualifying hedge	3	0	0
Deposit liabilities | Designated as hedging instrument | Interest on long-term debt | Amortization and interest | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest for qualifying hedge	$ 0	$ 0	$ 0

Derivative Instruments and He_9

Derivative Instruments and Hedging Activities (Derivative Instruments Used in Net Investment Hedge Accounting Relationships) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, amounts excluded from effectiveness testing, net	$ 0	$ 0	$ 0
Derivatives used in net Investment hedge, gain (loss), reclassified to earnings, net of tax	0	0	0
Interest rate contracts | Cash flow hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in other comprehensive income (loss), cash flow hedge, interest rate contracts	10	5	0
Foreign exchange contracts | Net investment hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in other comprehensive income (loss), net investment hedge, foreign exchange contracts	$ 12	$ (10)	$ 1

Income Taxes (Schedule of Signi

Income Taxes (Schedule of Significant Components of Income Tax Expense) (Details) - 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
Income Tax Disclosure [Abstract]
Current U.S. federal tax expense (benefit)									$ (12)	$ (17)	$ 0
Current foreign tax expense (benefit)									5	6	8
Current state and local tax expense (benefit)									35	53	9
Total current tax expense (benefit)									28	42	17
Deferred U.S. federal income tax expense (benefit)									328	566	423
Deferred state and local income tax expense (benefit)									3	(27)	30
Total deferred expense (benefit)									331	539	453
Income tax expense from continuing operations	$ 79	$ 91	$ 113	$ 76	$ 231	$ 115	$ 122	$ 113	$ 359	$ 581	$ 470

Income Taxes (Schedule of Effec

Income Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Details) - 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
Income Tax Disclosure [Abstract]
Statutory U.S. federal tax expense									$ 340	$ 527	$ 553
Nondeductible expenses									28	4	7
State and local income taxes, net of federal income tax benefit									26	7	35
Change in enacted tax rate, amount									(23)	119	0
Changes in unrecognized tax expenses (benefits)									22	1	(161)
Tax credits, excluding expirations									(20)	(12)	(15)
Valuation allowance change, excluding expirations									(8)	(49)	51
Other tax adjustments, net									(6)	(16)	0
Income tax expense from continuing operations	$ 79	$ 91	$ 113	$ 76	$ 231	$ 115	$ 122	$ 113	$ 359	$ 581	$ 470
Federal statutory income tax rate									21.00%	35.00%	35.00%

Income Taxes (Schedule of Defer

Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Tax Credit Carryforward [Line Items]
Deferred tax assets, tax credit carryforwards	$ 1,796
Deferred tax assets, valuation allowance	(1,057)
Deferred tax assets, net	317	$ 461
Other assets	6,153	5,663
Accrued expenses and other liabilities	1,676	1,780
Deferred tax asset
Tax Credit Carryforward [Line Items]
Deferred tax assets, tax credit carryforwards	1,796	2,002
Deferred tax assets, adjustment to loan value	366	450
Deferred tax assets, state and local taxes	168	200
Deferred tax assets, unearned insurance premiums	90	85
Deferred tax assets, hedging transactions	27	49
Deferred tax assets, tax loss carryforward	8	302
Deferred tax assets, other	222	108
Deferred tax assets, gross	2,677	3,196
Deferred tax assets, valuation allowance	(1,057)	(1,123)
Deferred tax assets, net of valuation allowance	1,620	2,073
Other assets	317	461
Deferred tax liability
Tax Credit Carryforward [Line Items]
Deferred tax liabilities, lease transactions	850	1,212
Deferred tax liabilities, deferred acquisition cost	321	269
Deferred tax liabilities, debt transactions	93	95
Deferred tax liabilities, other	56	44
Deferred tax liabilities, gross	1,320	1,620
Deferred tax assets, net	300	453
Accrued expenses and other liabilities	$ 17	$ 8

Income Taxes (Schedule of Def_2

Income Taxes (Schedule of Deferred Tax Assets and Related Valuation Allowance Recognized for Net Operating and Other Loss Carryforwards and Tax Carryforwards) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Deferred tax assets, tax credit carryforwards	$ 1,796
Valuation allowance, tax credit carryforwards	(963)
Net deferred tax assets, tax credit carryforwards	833
Deferred tax assets, operating loss carryforwards	8
Operating Loss Carryforwards, Valuation Allowance	0
Net deferred tax assets, operating loss carryforwards	8
Deferred tax assets, state and local tax carryforwards	206
State and local tax carryforwards, valuation allowance	(94)
Net deferred tax assets, state and local tax carryforwards	112
Deferred tax assets, other non-attribute	(645)
Other non-attribute, valuation allowance	0
Deferred tax assets, gross, net of deferred tax liabilities	1,357
Deferred tax assets, valuation allowance	(1,057)
Deferred tax assets, net	317	$ 461
Foreign tax credits
Operating Loss Carryforwards [Line Items]
Deferred tax assets, tax credit carryforwards	1,522
Valuation allowance, tax credit carryforwards	(963)
Net deferred tax assets, tax credit carryforwards	559
General business credits
Operating Loss Carryforwards [Line Items]
Deferred tax assets, tax credit carryforwards	274
Valuation allowance, tax credit carryforwards	0
Net deferred tax assets, tax credit carryforwards	274
State and local jurisdiction
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards	198
Operating Loss Carryforwards, Valuation Allowance	(94)
Net deferred tax assets, operating loss carryforwards	104
Deferred tax liability
Operating Loss Carryforwards [Line Items]
Deferred tax assets, net	$ 300	$ 453

Income Taxes (Schedule of Unrec

Income Taxes (Schedule of Unrecognized Tax Benefits Roll Forward) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 15	$ 14	$ 185
Unrecognized tax benefits, additions based on current period tax positions	0	0	0
Unrecognized tax benefits, additions for prior period tax positions	29	3	12
Unrecognized tax benefits, reductions for prior period tax positions	0	(1)	0
Unrecognized tax benefits, decrease resulting from settlements	0	0	(182)
Unrecognized tax benefits, reduction resulting from expiration of statue of limitations	0	(1)	(1)
Unrecognized tax benefits	$ 44	$ 15	$ 14

Income Taxes (Narrative - Unrec

Income Taxes (Narrative - Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Unrecognized tax benefits that would impact effective tax rate	$ 34	$ 12	$ 9
Unrecognized tax benefits, interest and penalties accrued	1	1	1
Unrecognized tax benefits, interest and penalties	1	$ 1	$ 1
Change in unrecognized tax benefits that is reasonably possible, amount	$ 41

Share-based Compensation Plan_2

Share-based Compensation Plans (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
RSUs and PSUs [Line Items]
Incentive compensation plan, shares available for future grants of equity-based awards	34,864,368
Minimum range for PSU awards payable upon vest	0.00%
Maximum range for PSU awards payable upon vest	150.00%
Share-based compensation, RSUs and PSUs, outstanding, non-vested, weighted-average grant date fair value per share	$ 23.71	$ 19.89
Share-based compensation, RSUs and PSUs, granted, weighted-average grant date fair value per share	29.41
Share-based compensation, RSUs and PSUs, vested, weighted-average grant date fair value per share	21.61
Share-based compensation, RSUs and PSUs, forfeited, weighted-average grant date fair value per share	$ 23.54
Restricted stock units and performance share units	$ 72	$ 60	$ 54
Number of RSU and PSU shares
RSUs and PSUs [Line Items]
Share-based compensation, RSUs and PSUs, outstanding, non-vested, number	4,864,000	5,592,000
Share-based compensation, RSUs and PSUs, granted	2,577,000
Share-based compensation, RSUs and PSUs, vested, number	(3,167,000)
Share-based compensation, RSUs and PSUs, forfeited, number	(138,000)

Fair Value (Fair Value Measurem

Fair Value (Fair Value Measurements - Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	$ 773	$ 518
Available-for-sale securities	$ 25,303	$ 22,303
Investment in any one industry did not exceed percentage	9.00%	14.00%
Fair value, measurements, recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 25,303	$ 22,303
Derivative assets	41	39
Assets, fair value	26,129	22,878
Derivative liabilities	(37)	(41)
Liabilities, fair value	37	41
Fair value, measurements, recurring | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	(37)	(39)
Fair value, measurements, recurring | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities		(2)
Fair value, measurements, recurring | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	773	518
Fair value, measurements, recurring | US Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,851	1,777
Fair value, measurements, recurring | US States and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	802	854
Fair value, measurements, recurring | Foreign government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	145	154
Fair value, measurements, recurring | Agency mortgage-backed residential
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	17,138	14,291
Fair value, measurements, recurring | Mortgage-backed residential
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,686	2,494
Fair value, measurements, recurring | Mortgage-backed commercial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	717	541
Fair value, measurements, recurring | Asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	723	936
Fair value, measurements, recurring | Corporate debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,241	1,256
Fair value, measurements, recurring | Loans held-for-sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held-for-sale, fair value	8	13
Fair value, measurements, recurring | Retained interest
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Retained interest, fair value	4	5
Fair value, measurements, recurring | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	37	39
Fair value, measurements, recurring | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	4
Fair value, measurements, recurring | Fair value, inputs, level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,857	1,785
Derivative assets	0	0
Assets, fair value	2,623	2,303
Derivative liabilities	0	0
Liabilities, fair value	0	0
Fair value, measurements, recurring | Fair value, inputs, level 1 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 1 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities		0
Fair value, measurements, recurring | Fair value, inputs, level 1 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	766	518
Fair value, measurements, recurring | Fair value, inputs, level 1 | US Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,850	1,777
Fair value, measurements, recurring | Fair value, inputs, level 1 | US States and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 1 | Foreign government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	7	8
Fair value, measurements, recurring | Fair value, inputs, level 1 | Agency mortgage-backed residential
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 1 | Mortgage-backed residential
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 1 | Mortgage-backed commercial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 1 | Asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 1 | Corporate debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 1 | Loans held-for-sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held-for-sale, fair value	0	0
Fair value, measurements, recurring | Fair value, inputs, level 1 | Retained interest
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Retained interest, fair value	0	0
Fair value, measurements, recurring | Fair value, inputs, level 1 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Fair value, measurements, recurring | Fair value, inputs, level 1 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0
Fair value, measurements, recurring | Fair value, inputs, level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	23,446	20,518
Derivative assets	41	38
Assets, fair value	23,487	20,556
Derivative liabilities	(37)	(41)
Liabilities, fair value	37	41
Fair value, measurements, recurring | Fair value, inputs, level 2 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	(37)	(39)
Fair value, measurements, recurring | Fair value, inputs, level 2 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities		(2)
Fair value, measurements, recurring | Fair value, inputs, level 2 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 2 | US Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1	0
Fair value, measurements, recurring | Fair value, inputs, level 2 | US States and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	802	854
Fair value, measurements, recurring | Fair value, inputs, level 2 | Foreign government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	138	146
Fair value, measurements, recurring | Fair value, inputs, level 2 | Agency mortgage-backed residential
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	17,138	14,291
Fair value, measurements, recurring | Fair value, inputs, level 2 | Mortgage-backed residential
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,686	2,494
Fair value, measurements, recurring | Fair value, inputs, level 2 | Mortgage-backed commercial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	717	541
Fair value, measurements, recurring | Fair value, inputs, level 2 | Asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	723	936
Fair value, measurements, recurring | Fair value, inputs, level 2 | Corporate debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,241	1,256
Fair value, measurements, recurring | Fair value, inputs, level 2 | Loans held-for-sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held-for-sale, fair value	0	0
Fair value, measurements, recurring | Fair value, inputs, level 2 | Retained interest
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Retained interest, fair value	0	0
Fair value, measurements, recurring | Fair value, inputs, level 2 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	37	38
Fair value, measurements, recurring | Fair value, inputs, level 2 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	4
Fair value, measurements, recurring | Fair value, inputs, level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Derivative assets	0	1
Assets, fair value	19	19
Derivative liabilities	0	0
Liabilities, fair value	0	0
Fair value, measurements, recurring | Fair value, inputs, level 3 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 3 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities		0
Fair value, measurements, recurring | Fair value, inputs, level 3 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	7	0
Fair value, measurements, recurring | Fair value, inputs, level 3 | US Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 3 | US States and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 3 | Foreign government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 3 | Agency mortgage-backed residential
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 3 | Mortgage-backed residential
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 3 | Mortgage-backed commercial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 3 | Asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 3 | Corporate debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair value, measurements, recurring | Fair value, inputs, level 3 | Loans held-for-sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held-for-sale, fair value	8	13
Fair value, measurements, recurring | Fair value, inputs, level 3 | Retained interest
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Retained interest, fair value	4	5
Fair value, measurements, recurring | Fair value, inputs, level 3 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	$ 1
Fair value, measurements, recurring | Fair value, inputs, level 3 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	$ 0

Fair Value (Fair Value Measur_2

Fair Value (Fair Value Measurements - Reconciliation of Level 3 Assets And Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, measurement, recurring, asset value, beginning balance		$ 29
Fair value, measurement, recurring, asset, gain (loss) included in earnings	$ (3)	4
Fair value, measurement, recurring, asset, gain (loss) included in other comprehensive income (loss)	0	0
Fair value, measurement, recurring, asset, purchases	303	137
Fair value, measurement, recurring, asset, sales	(313)	(118)
Fair value, measurement , recurring, asset, issuances	0	0
Fair value, measurement, recurring, asset, settlements	(6)	(33)
Fair value, measurement, recurring, asset value, ending balance	19
Fair value, assets, recurring, net unrealized gains (losses)	(10)	1
Fair value, assets measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	0
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, measurement, recurring, asset value, beginning balance	19
Fair value, measurement, recurring, asset, gain (loss) included in earnings	(7)
Fair value, measurement, recurring, asset, gain (loss) included in other comprehensive income (loss)	0
Fair value, measurement, recurring, asset, purchases	0
Fair value, measurement, recurring, asset, sales	0
Fair value, measurement , recurring, asset, issuances	0
Fair value, measurement, recurring, asset, settlements	(5)
Fair value, measurement, recurring, asset value, ending balance	7	19
Fair value, assets, recurring, net unrealized gains (losses)	(10)
Fair value, assets measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	0
Loans held-for-sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, measurement, recurring, asset value, beginning balance	13	0
Fair value, measurement, recurring, asset, gain (loss) included in earnings	5	2
Fair value, measurement, recurring, asset, gain (loss) included in other comprehensive income (loss)	0	0
Fair value, measurement, recurring, asset, purchases	303	137
Fair value, measurement, recurring, asset, sales	(313)	(126)
Fair value, measurement , recurring, asset, issuances	0	0
Fair value, measurement, recurring, asset, settlements	0	0
Fair value, measurement, recurring, asset value, ending balance	8	13
Fair value, assets, recurring, net unrealized gains (losses)	0	0
Fair value, assets measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	0
Retained interest
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, measurement, recurring, asset value, beginning balance	5	29
Fair value, measurement, recurring, asset, gain (loss) included in earnings	0	1
Fair value, measurement, recurring, asset, gain (loss) included in other comprehensive income (loss)	0	0
Fair value, measurement, recurring, asset, purchases	0	0
Fair value, measurement, recurring, asset, sales	0	8
Fair value, measurement , recurring, asset, issuances	0	0
Fair value, measurement, recurring, asset, settlements	(1)	(33)
Fair value, measurement, recurring, asset value, ending balance	4	5
Fair value, assets, recurring, net unrealized gains (losses)	0	0
Fair value, assets measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	0
Derivative
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, measurement, recurring, asset value, beginning balance	1	0
Fair value, measurement, recurring, asset, gain (loss) included in earnings	(1)	1
Fair value, measurement, recurring, asset, gain (loss) included in other comprehensive income (loss)	0	0
Fair value, measurement, recurring, asset, purchases	0	0
Fair value, measurement, recurring, asset, sales	0	0
Fair value, measurement , recurring, asset, issuances	0	0
Fair value, measurement, recurring, asset, settlements	0	0
Fair value, measurement, recurring, asset value, ending balance	0	1
Fair value, assets, recurring, net unrealized gains (losses)	0	1
Fair value, assets measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	0
Total assets after adoption of ASU 2016-01
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, measurement, recurring, asset value, beginning balance	38
Fair value, measurement, recurring, asset value, ending balance		38
Total assets prior to adoption of ASU 2016-01
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, measurement, recurring, asset value, beginning balance	$ 19
Fair value, measurement, recurring, asset value, ending balance		$ 19

Fair Value (Fair Value Measur_3

Fair Value (Fair Value Measurements - Nonrecurring Basis) (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	$ 314,000,000	$ 108,000,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	19,000,000		$ 29,000,000
Loans held-for-sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	8,000,000	13,000,000	$ 0
Fair Value, measurements, nonrecurring | Automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	210,000,000
Lower of cost or fair value or valuation reserve allowance	(2,000,000)
Fair Value, measurements, nonrecurring | Loans held-for-sale, Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	96,000,000
Lower of cost or fair value or valuation reserve allowance	0
Fair Value, measurements, nonrecurring | Loans held-for-sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	306,000,000	77,000,000
Lower of cost or fair value or valuation reserve allowance	(2,000,000)	0
Fair Value, measurements, nonrecurring | Commercial finance receivables and loans, automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial finance receivables and loans, net, fair value	84,000,000	20,000,000
Lower of cost or fair value or valuation reserve allowance	(10,000,000)	(3,000,000)
Fair Value, measurements, nonrecurring | Commercial finance receivables and loans, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial finance receivables and loans, net, fair value	55,000,000	22,000,000
Lower of cost or fair value or valuation reserve allowance	(46,000,000)	(12,000,000)
Fair Value, measurements, nonrecurring | Commercial loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial finance receivables and loans, net, fair value	139,000,000	42,000,000
Lower of cost or fair value or valuation reserve allowance	(56,000,000)	(15,000,000)
Fair Value, measurements, nonrecurring | Nonmarketable equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value	1,000,000
Lower of cost or fair value or valuation reserve allowance	(1,000,000)
Fair Value, measurements, nonrecurring | Equity method investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value	3,000,000
Lower of cost or fair value or valuation reserve allowance	0
Fair Value, measurements, nonrecurring | Repossessed and foreclosed assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value	13,000,000	14,000,000
Lower of cost or fair value or valuation reserve allowance	(1,000,000)	(1,000,000)
Fair Value, measurements, nonrecurring | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value		3,000,000
Lower of cost or fair value or valuation reserve allowance		0
Fair Value, measurements, nonrecurring | Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	462,000,000	136,000,000
Lower of cost or fair value or valuation reserve allowance	(60,000,000)	(16,000,000)
Fair Value, measurements, nonrecurring | Fair value, inputs, level 1 | Automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 1 | Loans held-for-sale, Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 1 | Loans held-for-sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	0	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 1 | Commercial finance receivables and loans, automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial finance receivables and loans, net, fair value	0	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 1 | Commercial finance receivables and loans, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial finance receivables and loans, net, fair value	0	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 1 | Commercial loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial finance receivables and loans, net, fair value	0	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 1 | Nonmarketable equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 1 | Equity method investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 1 | Repossessed and foreclosed assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value	0	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 1 | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value		0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 1 | Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	0	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 2 | Automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 2 | Loans held-for-sale, Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 2 | Loans held-for-sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	0	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 2 | Commercial finance receivables and loans, automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial finance receivables and loans, net, fair value	0	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 2 | Commercial finance receivables and loans, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial finance receivables and loans, net, fair value	0	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 2 | Commercial loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial finance receivables and loans, net, fair value	0	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 2 | Nonmarketable equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 2 | Equity method investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 2 | Repossessed and foreclosed assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value	0	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 2 | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value		0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 2 | Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	0	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 3 | Automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	210,000,000
Fair Value, measurements, nonrecurring | Fair value, inputs, level 3 | Loans held-for-sale, Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	96,000,000
Fair Value, measurements, nonrecurring | Fair value, inputs, level 3 | Loans held-for-sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	306,000,000	77,000,000
Fair Value, measurements, nonrecurring | Fair value, inputs, level 3 | Commercial finance receivables and loans, automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial finance receivables and loans, net, fair value	84,000,000	20,000,000
Fair Value, measurements, nonrecurring | Fair value, inputs, level 3 | Commercial finance receivables and loans, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial finance receivables and loans, net, fair value	55,000,000	22,000,000
Fair Value, measurements, nonrecurring | Fair value, inputs, level 3 | Commercial loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial finance receivables and loans, net, fair value	139,000,000	42,000,000
Fair Value, measurements, nonrecurring | Fair value, inputs, level 3 | Nonmarketable equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value	1,000,000
Fair Value, measurements, nonrecurring | Fair value, inputs, level 3 | Equity method investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value	3,000,000
Fair Value, measurements, nonrecurring | Fair value, inputs, level 3 | Repossessed and foreclosed assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value	13,000,000	14,000,000
Fair Value, measurements, nonrecurring | Fair value, inputs, level 3 | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value		3,000,000
Fair Value, measurements, nonrecurring | Fair value, inputs, level 3 | Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	462,000,000	$ 136,000,000
Valuation Technique, Market Approach [Member] | Fair Value, measurements, nonrecurring | Automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	104,000,000
Valuation Technique, Discounted Cash Flow [Member] | Fair Value, measurements, nonrecurring | Automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	106,000,000
Minimum | Valuation Technique, Discounted Cash Flow [Member] | Fair Value, measurements, nonrecurring | Automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	0.08
Maximum | Valuation Technique, Discounted Cash Flow [Member] | Fair Value, measurements, nonrecurring | Automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	1.09
Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member] | Fair Value, measurements, nonrecurring | Automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 0.72

Fair Value (Fair Value of Finan

Fair Value (Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	$ 2,362	$ 1,899
Loans held-for-sale, net	314	108
Finance receivables and loans, net	128,684	121,617
Nonmarketable equity securities	1,410	1,233
Deposit liabilities	106,178	93,256
Short-term borrowings	9,987	11,413
Long-term debt	44,193	44,226
Deposit liabilities with no defined contractual maturities, carrying value		47,400
Deposit liabilities with no defined contractual maturities, fair value		45,200
Reported value measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	2,362	1,899
Loans held-for-sale, net	306	95
Finance receivables and loans, net	128,684	121,617
Nonmarketable equity securities	1,351	1,233
Deposit liabilities	51,985	45,869
Short-term borrowings	9,987	11,413
Long-term debt	44,193	44,226
Estimate of fair value measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	2,307	1,865
Loans held-for-sale, net	306	95
Finance receivables and loans, net	130,878	123,302
Nonmarketable equity securities	1,351	1,239
Deposit liabilities	51,997	45,827
Short-term borrowings	9,992	11,417
Long-term debt	45,646	46,624
Estimate of fair value measurement | Fair value, inputs, level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	0	0
Loans held-for-sale, net	0	0
Finance receivables and loans, net	0	0
Nonmarketable equity securities	0	0
Deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Estimate of fair value measurement | Fair value, inputs, level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	2,307	1,865
Loans held-for-sale, net	0	0
Finance receivables and loans, net	0	0
Nonmarketable equity securities	1,351	1,190
Deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	23,846	27,807
Estimate of fair value measurement | Fair value, inputs, level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	0	0
Loans held-for-sale, net	306	95
Finance receivables and loans, net	130,878	123,302
Nonmarketable equity securities	0	49
Deposit liabilities	51,997	45,827
Short-term borrowings	9,992	11,417
Long-term debt	$ 21,800	$ 18,817

Offsetting Assets and Liabili_3

Offsetting Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Offsetting Assets and Liabilities [Line Items]
Derivative asset, gross amount of recognized assets	$ 41	$ 39
Derivative liability, gross amounts of recognized liabilities	37	41
Noncash Derivative Collateral Pledged to Ally	3	2
Noncash Repurchase Collateral pledged to Ally	4
Customer securities, entity has right to sell or repledge, fair value	7	2
Derivative assets in net asset positions
Offsetting Assets and Liabilities [Line Items]
Derivative asset, gross amount of recognized assets	41	38
Derivative assets and liabilities, gross amounts offset	0	0
Derivative asset, fair value, net amounts offset against collateral	41	38
Derivative asset, gross amounts not offset	0	0
Derivative assets, collateral	(4)	0
Derivative assets, net	37	38
Derivative assets with no offsetting arrangements
Offsetting Assets and Liabilities [Line Items]
Derivative asset, gross amount of recognized assets		1
Derivative assets and liabilities, gross amounts offset		0
Derivative asset, fair value, net amounts offset against collateral		1
Derivative asset, gross amounts not offset		0
Derivative assets, collateral		0
Derivative assets, net		1
Derivative assets
Offsetting Assets and Liabilities [Line Items]
Derivative asset, gross amount of recognized assets	41	39
Derivative assets and liabilities, gross amounts offset	0	0
Derivative asset, fair value, net amounts offset against collateral	41	39
Derivative asset, gross amounts not offset	0	0
Derivative assets, collateral	(4)	0
Derivative assets, net	37	39
Derivative liabilities in net liability positions
Offsetting Assets and Liabilities [Line Items]
Derivative assets and liabilities, gross amounts offset	0	0
Derivative liability, gross amounts of recognized liabilities	37	41
Derivative liability, fair value, net amounts offset against collateral	37	41
Derivative liability, gross amounts not offset	0	0
Derivative liabilities, collateral	0	(1)
Derivative liabilities, net	37	40
Securities sold under agreements to repurchase
Offsetting Assets and Liabilities [Line Items]
Derivative assets and liabilities, gross amounts offset	0	0
Derivative liability, gross amounts of recognized liabilities	685	892
Derivative liability, fair value, net amounts offset against collateral	685	892
Derivative liability, gross amounts not offset	0	0
Derivative liabilities, collateral	(685)	(892)
Derivative liabilities, net	0	0
Derivative liabilities
Offsetting Assets and Liabilities [Line Items]
Derivative assets and liabilities, gross amounts offset	0	0
Derivative liability, gross amounts of recognized liabilities	722	933
Derivative liability, fair value, net amounts offset against collateral	722	933
Derivative liability, gross amounts not offset	0	0
Derivative liabilities, collateral	(685)	(893)
Derivative liabilities, net	$ 37	$ 40

Segment Information (Details)

Segment Information (Details) $ 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 ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Segment Reporting Information [Line Items]
Number of operating segments									4
Net financing revenue and other interest income	$ 1,140	$ 1,107	$ 1,094	$ 1,049	$ 1,094	$ 1,081	$ 1,067	$ 979	$ 4,390	$ 4,221	$ 3,907
Other revenue	298	398	364	354	379	381	388	396	1,414	1,544	1,530
Net revenue									5,804	5,765	5,437
Provision for loan losses	266	233	158	261	294	314	269	271	918	1,148	917
Noninterest expense	804	807	839	814	769	753	810	778	3,264	3,110	2,939
Income from continuing operations before income tax expense	368	$ 465	$ 461	$ 328	410	$ 395	$ 376	$ 326	1,622	1,507	1,581
Assets	178,869				167,148				178,869	167,148	163,728
Net financing revenue and other interest income after provision for loan losses									3,500	3,100	3,000
Corporate and Other
Segment Reporting Information [Line Items]
Net financing revenue and other interest income									184	150	(37)
Other revenue									119	81	162
Net revenue									303	231	125
Provision for loan losses									(15)	(16)	(13)
Noninterest expense									333	262	199
Income from continuing operations before income tax expense									(15)	(15)	(61)
Assets	33,950				29,908				33,950	29,908	28,719
Automotive Finance operations
Segment Reporting Information [Line Items]
Net financing revenue and other interest income									3,769	3,713	3,665
Other revenue									269	355	306
Net revenue									4,038	4,068	3,971
Provision for loan losses									920	1,134	924
Noninterest expense									1,750	1,714	1,667
Income from continuing operations before income tax expense									1,368	1,220	1,380
Assets	117,304				114,089				117,304	114,089	116,347
Insurance operations
Segment Reporting Information [Line Items]
Net financing revenue and other interest income									54	59	61
Other revenue									981	1,059	1,036
Net revenue									1,035	1,118	1,097
Provision for loan losses									0	0	0
Noninterest expense									955	950	940
Income from continuing operations before income tax expense									80	168	157
Assets	7,734				7,464				7,734	7,464	7,172
Mortgage Finance operations
Segment Reporting Information [Line Items]
Net financing revenue and other interest income									179	132	97
Other revenue									7	4	0
Net revenue									186	136	97
Provision for loan losses									1	8	(4)
Noninterest expense									140	108	67
Income from continuing operations before income tax expense									45	20	34
Assets	15,211				11,708				15,211	11,708	8,307
Corporate Finance operations
Segment Reporting Information [Line Items]
Net financing revenue and other interest income									204	167	121
Other revenue									38	45	26
Net revenue									242	212	147
Provision for loan losses									12	22	10
Noninterest expense									86	76	66
Income from continuing operations before income tax expense									144	114	71
Assets	$ 4,670				$ 3,979				$ 4,670	$ 3,979	$ 3,183

Parent and Guarantor Condense_3

Parent and Guarantor Condensed Consolidating Financial Statements (Schedule of Condensed Consolidating Statement of Income) (Details) - 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
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									$ 6,688	$ 5,819	$ 5,162
Interest on loans held-for-sale									15	0	0
Interest and dividends on investment securities and other earning assets									788	599	418
Interest on cash and cash equivalents									72	37	14
Operating leases									1,489	1,867	2,711
Financing revenue and other interest income									9,052	8,322	8,305
Interest on deposits									1,735	1,077	830
Interest on short-term borrowings									149	127	57
Interest on long-term debt									1,753	1,653	1,742
Interest on intercompany debt									0	0	0
Interest expense									3,637	2,857	2,629
Net depreciation expense on operating lease assets									1,025	1,244	1,769
Net financing (loss) revenue	$ 1,140	$ 1,107	$ 1,094	$ 1,049	$ 1,094	$ 1,081	$ 1,067	$ 979	4,390	4,221	3,907
Cash dividends from bank subsidiaries									0	0
Cash dividends from nonbank subsidiaries									0	0	0
Insurance premiums and service revenue earned									1,022	973	945
Gain on mortgage and automotive loans, net									25	68	11
Other (loss) gain on investments, net									(50)	102	185
Other income, net of losses									417	401	389
Other revenue	298	398	364	354	379	381	388	396	1,414	1,544	1,530
Net revenue									5,804	5,765	5,437
Provision for loan losses	266	233	158	261	294	314	269	271	918	1,148	917
Compensation and benefits expense									1,155	1,095	992
Insurance losses and loss adjustment expenses									295	332	342
Other operating expenses									1,814	1,683	1,605
Noninterest expense	804	807	839	814	769	753	810	778	3,264	3,110	2,939
Income from continuing operations before tax	368	465	461	328	410	395	376	326	1,622	1,507	1,581
Income tax expense from continuing operations	79	91	113	76	231	115	122	113	359	581	470
Net (loss) income from continuing operations	289	374	348	252	179	280	254	213	1,263	926	1,111
Income (loss) from discontinued operations, net of tax	1	0	1	(2)	2	2	(2)	1	0	3	(44)
Undistributed income of bank subsidiary									0	0	0
Undistributed income of nonbank subsidiaries									0	0	0
Net Income (Loss) Attributable to Parent	$ 290	$ 374	$ 349	$ 250	$ 181	$ 282	$ 252	$ 214	1,263	929	1,067
Other comprehensive income (loss), attributable to parent									(289)	106	(110)
Comprehensive income									974	1,035	957
Parent
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									(40)	(27)	(104)
Interest on loans held-for-sale									0
Interest and dividends on investment securities and other earning assets									0	0	0
Interest on cash and cash equivalents									8	7	5
Operating leases									5	11	17
Financing revenue and other interest income									(7)	7	(71)
Interest on deposits									0	3	8
Interest on short-term borrowings									44	60	40
Interest on long-term debt									1,009	1,101	1,161
Interest on intercompany debt									15	15	20
Interest expense									1,068	1,179	1,229
Net depreciation expense on operating lease assets									8	11	14
Net financing (loss) revenue									(1,083)	(1,183)	(1,314)
Cash dividends from bank subsidiaries									2,600	3,300
Cash dividends from nonbank subsidiaries									443	752	965
Insurance premiums and service revenue earned									0	0	0
Gain on mortgage and automotive loans, net									70	40	(11)
Other (loss) gain on investments, net									0	0	0
Other income, net of losses									411	675	1,250
Other revenue									481	715	1,239
Net revenue									2,441	3,584	890
Provision for loan losses									176	465	408
Compensation and benefits expense									83	180	573
Insurance losses and loss adjustment expenses									0	0	0
Other operating expenses									681	899	1,261
Noninterest expense									764	1,079	1,834
Income from continuing operations before tax									1,501	2,040	(1,352)
Income tax expense from continuing operations									(300)	337	(279)
Net (loss) income from continuing operations									1,801	1,703	(1,073)
Income (loss) from discontinued operations, net of tax									(2)	7	(39)
Undistributed income of bank subsidiary									(614)	(1,168)	1,273
Undistributed income of nonbank subsidiaries									78	387	906
Net Income (Loss) Attributable to Parent									1,263	929	1,067
Other comprehensive income (loss), attributable to parent									(289)	106	(110)
Comprehensive income									974	1,035	957
Guarantors
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									0	0	0
Interest on loans held-for-sale									0
Interest and dividends on investment securities and other earning assets									0	0	0
Interest on cash and cash equivalents									0	0	0
Operating leases									0	0	0
Financing revenue and other interest income									0	0	0
Interest on deposits									0	0	0
Interest on short-term borrowings									0	0	0
Interest on long-term debt									0	0	0
Interest on intercompany debt									0	0	0
Interest expense									0	0	0
Net depreciation expense on operating lease assets									0	0	0
Net financing (loss) revenue									0	0	0
Cash dividends from bank subsidiaries									2,600	3,300
Cash dividends from nonbank subsidiaries									0	0	0
Insurance premiums and service revenue earned									0	0	0
Gain on mortgage and automotive loans, net									0	0	0
Other (loss) gain on investments, net									0	0	0
Other income, net of losses									0	0	0
Other revenue									0	0	0
Net revenue									2,600	3,300	0
Provision for loan losses									0	0	0
Compensation and benefits expense									0	0	0
Insurance losses and loss adjustment expenses									0	0	0
Other operating expenses									0	0	0
Noninterest expense									0	0	0
Income from continuing operations before tax									2,600	3,300	0
Income tax expense from continuing operations									0	0	(82)
Net (loss) income from continuing operations									2,600	3,300	82
Income (loss) from discontinued operations, net of tax									0	0	0
Undistributed income of bank subsidiary									(614)	(1,168)	1,273
Undistributed income of nonbank subsidiaries									0	0	(2)
Net Income (Loss) Attributable to Parent									1,986	2,132	1,353
Other comprehensive income (loss), attributable to parent									(243)	65	(63)
Comprehensive income									1,743	2,197	1,290
Nonguarantors
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									6,728	5,846	5,266
Interest on loans held-for-sale									15
Interest and dividends on investment securities and other earning assets									789	601	421
Interest on cash and cash equivalents									64	30	9
Operating leases									1,484	1,856	2,694
Financing revenue and other interest income									9,094	8,346	8,407
Interest on deposits									1,735	1,078	822
Interest on short-term borrowings									105	67	17
Interest on long-term debt									744	552	581
Interest on intercompany debt									20	12	11
Interest expense									2,604	1,709	1,431
Net depreciation expense on operating lease assets									1,017	1,233	1,755
Net financing (loss) revenue									5,473	5,404	5,221
Cash dividends from bank subsidiaries									0	0
Cash dividends from nonbank subsidiaries									0	0	0
Insurance premiums and service revenue earned									1,022	973	945
Gain on mortgage and automotive loans, net									9	28	22
Other (loss) gain on investments, net									(50)	102	176
Other income, net of losses									770	834	935
Other revenue									1,751	1,937	2,078
Net revenue									7,224	7,341	7,299
Provision for loan losses									796	683	509
Compensation and benefits expense									1,072	915	419
Insurance losses and loss adjustment expenses									295	332	342
Other operating expenses									1,897	1,892	2,130
Noninterest expense									3,264	3,139	2,891
Income from continuing operations before tax									3,164	3,519	3,899
Income tax expense from continuing operations									659	244	831
Net (loss) income from continuing operations									2,505	3,275	3,068
Income (loss) from discontinued operations, net of tax									2	(4)	(5)
Undistributed income of bank subsidiary									0	0	0
Undistributed income of nonbank subsidiaries									0	0	0
Net Income (Loss) Attributable to Parent									2,507	3,271	3,063
Other comprehensive income (loss), attributable to parent									(308)	104	(106)
Comprehensive income									2,199	3,375	2,957
Affiliated entity
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									0	0	0
Interest on cash and cash equivalents									0	0	0
Gain on mortgage and automotive loans, net									0	0	0
Affiliated entity | Parent
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									12	12	11
Interest on cash and cash equivalents									8	4	0
Gain on mortgage and automotive loans, net									(20)	2,068	877
Affiliated entity | Guarantors
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									0	0	0
Interest on cash and cash equivalents									0	0	0
Gain on mortgage and automotive loans, net									0	0
Affiliated entity | Nonguarantors
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									5	6	8
Interest on cash and cash equivalents									9	7	9
Gain on mortgage and automotive loans, net									(2)	217	(67)
Consolidating adjustments
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									0	0	0
Interest on loans held-for-sale									0
Interest and dividends on investment securities and other earning assets									(1)	(2)	(3)
Interest on cash and cash equivalents									0	0	0
Operating leases									0	0	0
Financing revenue and other interest income									(35)	(31)	(31)
Interest on deposits									0	(4)	0
Interest on short-term borrowings									0	0	0
Interest on long-term debt									0	0	0
Interest on intercompany debt									(35)	(27)	(31)
Interest expense									(35)	(31)	(31)
Net depreciation expense on operating lease assets									0	0	0
Net financing (loss) revenue									0	0	0
Cash dividends from bank subsidiaries									(5,200)	(6,600)
Cash dividends from nonbank subsidiaries									(443)	(752)	(965)
Insurance premiums and service revenue earned									0	0	0
Gain on mortgage and automotive loans, net									(54)	0	0
Other (loss) gain on investments, net									0	0	9
Other income, net of losses									(764)	(1,108)	(1,796)
Other revenue									(818)	(1,108)	(1,787)
Net revenue									(6,461)	(8,460)	(2,752)
Provision for loan losses									(54)	0	0
Compensation and benefits expense									0	0	0
Insurance losses and loss adjustment expenses									0	0	0
Other operating expenses									(764)	(1,108)	(1,786)
Noninterest expense									(764)	(1,108)	(1,786)
Income from continuing operations before tax									(5,643)	(7,352)	(966)
Income tax expense from continuing operations									0	0	0
Net (loss) income from continuing operations									(5,643)	(7,352)	(966)
Income (loss) from discontinued operations, net of tax									0	0	0
Undistributed income of bank subsidiary									1,228	2,336	(2,546)
Undistributed income of nonbank subsidiaries									(78)	(387)	(904)
Net Income (Loss) Attributable to Parent									(4,493)	(5,403)	(4,416)
Other comprehensive income (loss), attributable to parent									551	(169)	169
Comprehensive income									(3,942)	(5,572)	(4,247)
Consolidating adjustments | Affiliated entity
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									(17)	(18)	(19)
Interest on cash and cash equivalents									(17)	(11)	(9)
Gain on mortgage and automotive loans, net									$ 22	$ (2,285)	$ (810)

Parent and Guarantor Condense_4

Parent and Guarantor Condensed Consolidating Financial Statements (Schedule of Condensed Consolidating Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents, noninterest-bearing	$ 810		$ 844
Cash and cash equivalents, interest-bearing	3,727		3,408
Cash and cash equivalents	4,537		4,252
Equity securities	773		518
Available-for-sale securities	25,303		22,303
Held-to-maturity securities	2,362		1,899
Loans held-for-sale, net	314		108
Finance receivables and loans, net	129,926		122,893
Intercompany loans to nonbank subsidiary	0		0
Allowance for loan losses	1,242		1,276	$ 1,144
Total finance receivables and loans, net	128,684		121,617
Investment in operating leases, net	8,417		8,741
Intercompany receivables from bank subsidiary	0		0
Intercompany receivables from nonbank subsidiary	0		0
Investment in bank subsidiaries	0		0
Investment in nonbank subsidiaries	0		0
Premiums receivable and other insurance assets	2,326		2,047
Other assets	6,153		5,663
Assets	178,869		167,148	163,728
Deposit liabilities, noninterest-bearing	142		108
Deposit liabilities, interest-bearing	106,036		93,148
Deposit liabilities	106,178		93,256
Short-term borrowings	9,987		11,413
Long-term debt	44,193		44,226
Intercompany debt payable to bank subsidiaries	0		0
Intercompany debt payable to nonbank subsidiaries	0		0
Intercompany payables to bank subsidiary	0		0
Intercompany payables to nonbank subsidiaries	0		0
Interest payable	523		375
Unearned insurance premiums and service revenue	3,044		2,604
Accrued expenses and other liabilities	1,676		1,780
Total liabilities	165,601		153,654
Equity	13,268	$ 13,375	13,494	$ 13,317	$ 13,439
Total liabilities and equity	178,869		167,148
Parent
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents, noninterest-bearing	55		74
Cash and cash equivalents, interest-bearing	5		5
Cash and cash equivalents	1,309		1,217
Equity securities	0		0
Available-for-sale securities	0		0
Held-to-maturity securities	0		0
Loans held-for-sale, net	0		0
Finance receivables and loans, net	2,349		7,434
Intercompany loans to nonbank subsidiary	882		879
Allowance for loan losses	55		185
Total finance receivables and loans, net	3,176		8,128
Investment in operating leases, net	5		19
Intercompany receivables from bank subsidiary	158		80
Intercompany receivables from nonbank subsidiary	45		71
Investment in bank subsidiaries	16,213		16,962
Investment in nonbank subsidiaries	6,928		8,111
Premiums receivable and other insurance assets	0		0
Other assets	2,226		2,207
Assets	30,060		36,795
Deposit liabilities, noninterest-bearing	0		0
Deposit liabilities, interest-bearing	1		12
Deposit liabilities	1		12
Short-term borrowings	2,477		3,171
Long-term debt	12,774		17,966
Intercompany debt payable to bank subsidiaries	20		74
Intercompany debt payable to nonbank subsidiaries	918		1,103
Intercompany payables to bank subsidiary	45		4
Intercompany payables to nonbank subsidiaries	124		132
Interest payable	159		200
Unearned insurance premiums and service revenue	0		0
Accrued expenses and other liabilities	274		639
Total liabilities	16,792		23,301
Equity	13,268		13,494
Total liabilities and equity	30,060		36,795
Guarantors
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents, noninterest-bearing	0		0
Cash and cash equivalents, interest-bearing	0		0
Cash and cash equivalents	0		0
Equity securities	0		0
Available-for-sale securities	0		0
Held-to-maturity securities	0		0
Loans held-for-sale, net	0		0
Finance receivables and loans, net	0		0
Intercompany loans to nonbank subsidiary	0		0
Allowance for loan losses	0		0
Total finance receivables and loans, net	0		0
Investment in operating leases, net	0		0
Intercompany receivables from bank subsidiary	0		0
Intercompany receivables from nonbank subsidiary	0		0
Investment in bank subsidiaries	16,213		16,962
Investment in nonbank subsidiaries	0		0
Premiums receivable and other insurance assets	0		0
Other assets	0		0
Assets	16,213		16,962
Deposit liabilities, noninterest-bearing	0		0
Deposit liabilities, interest-bearing	0		0
Deposit liabilities	0		0
Short-term borrowings	0		0
Long-term debt	0		0
Intercompany debt payable to bank subsidiaries	0		0
Intercompany debt payable to nonbank subsidiaries	0		0
Intercompany payables to bank subsidiary	0		0
Intercompany payables to nonbank subsidiaries	0		0
Interest payable	0		0
Unearned insurance premiums and service revenue	0		0
Accrued expenses and other liabilities	0		0
Total liabilities	0		0
Equity	16,213		16,962
Total liabilities and equity	16,213		16,962
Nonguarantors
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents, noninterest-bearing	755		770
Cash and cash equivalents, interest-bearing	3,722		3,403
Cash and cash equivalents	4,998		4,868
Equity securities	773		518
Available-for-sale securities	25,303		22,303
Held-to-maturity securities	2,382		1,973
Loans held-for-sale, net	314		108
Finance receivables and loans, net	127,577		115,459
Intercompany loans to nonbank subsidiary	397		408
Allowance for loan losses	1,187		1,091
Total finance receivables and loans, net	126,787		114,776
Investment in operating leases, net	8,412		8,722
Intercompany receivables from bank subsidiary	0		0
Intercompany receivables from nonbank subsidiary	129		77
Investment in bank subsidiaries	0		0
Investment in nonbank subsidiaries	0		0
Premiums receivable and other insurance assets	2,326		2,082
Other assets	5,453		5,105
Assets	176,877		160,532
Deposit liabilities, noninterest-bearing	142		108
Deposit liabilities, interest-bearing	106,035		93,136
Deposit liabilities	107,426		94,383
Short-term borrowings	7,510		8,242
Long-term debt	31,419		26,260
Intercompany debt payable to bank subsidiaries	0		0
Intercompany debt payable to nonbank subsidiaries	882		879
Intercompany payables to bank subsidiary	0		0
Intercompany payables to nonbank subsidiaries	129		127
Interest payable	364		175
Unearned insurance premiums and service revenue	3,044		2,604
Accrued expenses and other liabilities	2,962		2,790
Total liabilities	153,736		135,460
Equity	23,141		25,072
Total liabilities and equity	176,877		160,532
Affiliated entity
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents, interest-bearing	0		0
Deposit liabilities, interest-bearing	0		0
Affiliated entity | Parent
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents, interest-bearing	1,249		1,138
Deposit liabilities, interest-bearing	0		0
Affiliated entity | Guarantors
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents, interest-bearing	0		0
Deposit liabilities, interest-bearing	0		0
Affiliated entity | Nonguarantors
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents, interest-bearing	521		695
Deposit liabilities, interest-bearing	1,249		1,139
Consolidating adjustments
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents, noninterest-bearing	0		0
Cash and cash equivalents, interest-bearing	0		0
Cash and cash equivalents	(1,770)		(1,833)
Equity securities	0		0
Available-for-sale securities	0		0
Held-to-maturity securities	(20)		(74)
Loans held-for-sale, net	0		0
Finance receivables and loans, net	0		0
Intercompany loans to nonbank subsidiary	(1,279)		(1,287)
Allowance for loan losses	0		0
Total finance receivables and loans, net	(1,279)		(1,287)
Investment in operating leases, net	0		0
Intercompany receivables from bank subsidiary	(158)		(80)
Intercompany receivables from nonbank subsidiary	(174)		(148)
Investment in bank subsidiaries	(32,426)		(33,924)
Investment in nonbank subsidiaries	(6,928)		(8,111)
Premiums receivable and other insurance assets	0		(35)
Other assets	(1,526)		(1,649)
Assets	(44,281)		(47,141)
Deposit liabilities, noninterest-bearing	0		0
Deposit liabilities, interest-bearing	0		0
Deposit liabilities	(1,249)		(1,139)
Short-term borrowings	0		0
Long-term debt	0		0
Intercompany debt payable to bank subsidiaries	(20)		(74)
Intercompany debt payable to nonbank subsidiaries	(1,800)		(1,982)
Intercompany payables to bank subsidiary	(45)		(4)
Intercompany payables to nonbank subsidiaries	(253)		(259)
Interest payable	0		0
Unearned insurance premiums and service revenue	0		0
Accrued expenses and other liabilities	(1,560)		(1,649)
Total liabilities	(4,927)		(5,107)
Equity	(39,354)		(42,034)
Total liabilities and equity	(44,281)		(47,141)
Consolidating adjustments | Affiliated entity
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents, interest-bearing	(1,770)		(1,833)
Deposit liabilities, interest-bearing	$ (1,249)		$ (1,139)

Parent and Guarantor Condense_5

Parent and Guarantor Condensed Consolidating Financial Statements (Statement of Cash Flows) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net cash provided by (used in) operating activities	$ 4,150	$ 4,079	$ 4,567
Purchases of equity securities	(1,076)	(899)	(470)
Proceeds from sales of equity securities	787	1,049	680
Purchases of available-for-sale securities	(7,868)	(10,335)	(15,561)
Proceeds from sale of available-for-sale securities	852	3,584	10,356
Proceeds from repayments of available-for-sale securities	3,215	2,899	3,379
Purchases of held-to-maturity securities	(578)	(1,026)	(841)
Proceeds from repayments of held-to-maturity securities	147	68	0
Purchases of finance receivables and loans held-for-investment	(5,693)	(5,452)	(3,859)
Proceeds from sales of finance receivables and loans initially held-for-investment	91	1,339	4,285
Originations and repayments of finance receivables and loans held-for-investment and other, net	(3,245)	(1,063)	(8,826)
Net change in intercompany loans	25	68	11
Purchases of operating lease assets	(3,709)	(4,052)	(3,274)
Disposals of operating lease assets	3,089	5,567	6,304
Acquisitions, net of cash acquired	0	0	(309)
Capital contributions to subsidiaries	0	0	0
Returns of contributed capital	0	0	0
Net change in nonmarketable equity investments	(181)	(187)	(628)
Payments for (proceeds from) other, net	(340)	(219)	(306)
Net cash provided by investing activities	(14,509)	(8,727)	(9,070)
Net change in short-term borrowings	(1,426)	(1,263)	4,564
Net (decrease) increase in deposits	12,867	14,172	12,508
Proceeds from issuance of long-term debt	18,401	17,969	14,155
Repayments of long-term debt	(17,940)	(27,908)	(26,412)
Redemption of preferred stock			(696)
Repurchase of common stock	(939)	(753)	(341)
Dividends paid	(242)	(184)	(108)
Capital contributions from parent	0	0	0
Net cash provided by (used in) financing activities	10,721	2,033	3,670
Effect of exchange-rate changes on cash and cash equivalents and restricted cash	(5)	3	1
Net increase (decrease) in cash and cash equivalents and restricted cash	357	(2,612)	(832)
Cash and cash equivalents and restricted cash	5,626	5,269	7,881	$ 8,713
Cash and cash equivalents	4,537	4,252
Restricted cash included in other assets on the Consolidated Balance Sheet	1,089	1,017
Parent
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net cash provided by (used in) operating activities	1,659	4,591	241
Purchases of equity securities	0	0	0
Proceeds from sales of equity securities	0	0	0
Purchases of available-for-sale securities	0	0	0
Proceeds from sale of available-for-sale securities	0	0	0
Proceeds from repayments of available-for-sale securities	0	0	0
Purchases of held-to-maturity securities	0	0	0
Proceeds from repayments of held-to-maturity securities	0	0
Purchases of finance receivables and loans held-for-investment	(131)	(35)	(4)
Proceeds from sales of finance receivables and loans initially held-for-investment	1,596	106	0
Originations and repayments of finance receivables and loans held-for-investment and other, net	3,489	860	2,013
Net change in intercompany loans	70	40	(11)
Purchases of operating lease assets	0	0	0
Disposals of operating lease assets	10	13	25
Acquisitions, net of cash acquired			(309)
Capital contributions to subsidiaries	(61)	(1,212)	(3,908)
Returns of contributed capital	266	1,567	3,678
Net change in nonmarketable equity investments	(16)	0	0
Payments for (proceeds from) other, net	0	(31)	(206)
Net cash provided by investing activities	5,133	3,343	2,166
Net change in short-term borrowings	(694)	(453)	169
Net (decrease) increase in deposits	(11)	(156)	(61)
Proceeds from issuance of long-term debt	69	354	979
Repayments of long-term debt	(4,774)	(6,111)	(2,662)
Redemption of preferred stock			(696)
Repurchase of common stock	(939)	(753)	(341)
Dividends paid	(242)	(184)	(108)
Capital contributions from parent	0	0	0
Net cash provided by (used in) financing activities	(6,789)	(7,528)	(3,102)
Effect of exchange-rate changes on cash and cash equivalents and restricted cash	0	0	0
Net increase (decrease) in cash and cash equivalents and restricted cash	3	406	(695)
Cash and cash equivalents and restricted cash	1,398	1,395	989	1,684
Cash and cash equivalents	1,309	1,217
Restricted cash included in other assets on the Consolidated Balance Sheet	89	178
Guarantors
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net cash provided by (used in) operating activities	2,600	3,300	6
Purchases of equity securities	0	0	0
Proceeds from sales of equity securities	0	0	0
Purchases of available-for-sale securities	0	0	0
Proceeds from sale of available-for-sale securities	0	0	0
Proceeds from repayments of available-for-sale securities	0	0	0
Purchases of held-to-maturity securities	0	0	0
Proceeds from repayments of held-to-maturity securities	0	0
Purchases of finance receivables and loans held-for-investment	0	0	0
Proceeds from sales of finance receivables and loans initially held-for-investment	0	0	0
Originations and repayments of finance receivables and loans held-for-investment and other, net	0	0	0
Net change in intercompany loans	0	0	0
Purchases of operating lease assets	0	0	0
Disposals of operating lease assets	0	0	0
Acquisitions, net of cash acquired			0
Capital contributions to subsidiaries	(6)	(5)	0
Returns of contributed capital	0	0	8
Net change in nonmarketable equity investments	0	0	0
Payments for (proceeds from) other, net	0	0	0
Net cash provided by investing activities	(6)	(5)	8
Net change in short-term borrowings	0	0	0
Net (decrease) increase in deposits	0	0	0
Proceeds from issuance of long-term debt	0	0	0
Repayments of long-term debt	0	0	0
Redemption of preferred stock			0
Repurchase of common stock	0	0	0
Dividends paid	0	0	0
Capital contributions from parent	6	5	0
Net cash provided by (used in) financing activities	(2,594)	(3,295)	(14)
Effect of exchange-rate changes on cash and cash equivalents and restricted cash	0	0	0
Net increase (decrease) in cash and cash equivalents and restricted cash	0	0	0
Cash and cash equivalents and restricted cash	0	0	0	0
Cash and cash equivalents	0	0
Restricted cash included in other assets on the Consolidated Balance Sheet	0	0
Nonguarantors
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net cash provided by (used in) operating activities	5,536	3,466	5,383
Purchases of equity securities	(1,076)	(899)	(470)
Proceeds from sales of equity securities	787	1,049	680
Purchases of available-for-sale securities	(7,868)	(10,335)	(15,561)
Proceeds from sale of available-for-sale securities	852	3,584	10,356
Proceeds from repayments of available-for-sale securities	3,215	2,899	3,379
Purchases of held-to-maturity securities	(578)	(1,026)	(841)
Proceeds from repayments of held-to-maturity securities	147	68
Purchases of finance receivables and loans held-for-investment	(7,101)	(5,417)	(3,855)
Proceeds from sales of finance receivables and loans initially held-for-investment	34	1,233	4,285
Originations and repayments of finance receivables and loans held-for-investment and other, net	(6,734)	33	(10,839)
Net change in intercompany loans	9	28	22
Purchases of operating lease assets	(3,709)	(4,052)	(3,274)
Disposals of operating lease assets	3,079	5,554	6,279
Acquisitions, net of cash acquired			0
Capital contributions to subsidiaries	0	0	0
Returns of contributed capital	0	0	0
Net change in nonmarketable equity investments	(165)	(187)	(628)
Payments for (proceeds from) other, net	(340)	(99)	(191)
Net cash provided by investing activities	(19,405)	(7,087)	(10,747)
Net change in short-term borrowings	(732)	(810)	4,395
Net (decrease) increase in deposits	12,989	15,466	12,569
Proceeds from issuance of long-term debt	18,332	15,654	13,176
Repayments of long-term debt	(13,166)	(21,797)	(23,750)
Redemption of preferred stock			0
Repurchase of common stock	0	0	0
Dividends paid	0	0	0
Capital contributions from parent	61	1,212	3,908
Net cash provided by (used in) financing activities	14,165	2,032	4,777
Effect of exchange-rate changes on cash and cash equivalents and restricted cash	(5)	3	1
Net increase (decrease) in cash and cash equivalents and restricted cash	291	(1,586)	(586)
Cash and cash equivalents and restricted cash	5,998	5,707	7,293	7,879
Cash and cash equivalents	4,998	4,868
Restricted cash included in other assets on the Consolidated Balance Sheet	1,000	839
Consolidating adjustments
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net cash provided by (used in) operating activities	(5,645)	(7,278)	(1,063)
Purchases of equity securities	0	0	0
Proceeds from sales of equity securities	0	0	0
Purchases of available-for-sale securities	0	0	0
Proceeds from sale of available-for-sale securities	0	0	0
Proceeds from repayments of available-for-sale securities	0	0	0
Purchases of held-to-maturity securities	0	0	0
Proceeds from repayments of held-to-maturity securities	0	0
Purchases of finance receivables and loans held-for-investment	1,539	0	0
Proceeds from sales of finance receivables and loans initially held-for-investment	(1,539)	0	0
Originations and repayments of finance receivables and loans held-for-investment and other, net	0	(1,956)	0
Net change in intercompany loans	(54)	0	0
Purchases of operating lease assets	0	0	0
Disposals of operating lease assets	0	0	0
Acquisitions, net of cash acquired			0
Capital contributions to subsidiaries	67	1,217	3,908
Returns of contributed capital	(266)	(1,567)	(3,686)
Net change in nonmarketable equity investments	0	0	0
Payments for (proceeds from) other, net	0	(89)	91
Net cash provided by investing activities	(231)	(4,978)	(497)
Net change in short-term borrowings	0	0	0
Net (decrease) increase in deposits	(111)	(1,138)	0
Proceeds from issuance of long-term debt	0	1,961	0
Repayments of long-term debt	0	0	0
Redemption of preferred stock			0
Repurchase of common stock	0	0	0
Dividends paid	0	0	0
Capital contributions from parent	(67)	(1,217)	(3,908)
Net cash provided by (used in) financing activities	5,939	10,824	2,009
Effect of exchange-rate changes on cash and cash equivalents and restricted cash	0	0	0
Net increase (decrease) in cash and cash equivalents and restricted cash	63	(1,432)	449
Cash and cash equivalents and restricted cash	(1,770)	(1,833)	(401)	$ (850)
Cash and cash equivalents	(1,770)	(1,833)
Restricted cash included in other assets on the Consolidated Balance Sheet	0	0
Affiliated entity
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net change in intercompany investment securities	0	0
Net change in intercompany loans	0	0	0
Net change in intercompany debt	0	0	0
Dividends paid and returns of contributed capital, intercompany	0	0	0
Affiliated entity | Parent
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net change in intercompany investment securities	0	7
Net change in intercompany loans	(20)	2,068	877
Net change in intercompany debt	(198)	(225)	(382)
Dividends paid and returns of contributed capital, intercompany	0	0	0
Affiliated entity | Guarantors
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net change in intercompany investment securities	0	0
Net change in intercompany loans	0	0
Net change in intercompany debt	0	0	0
Dividends paid and returns of contributed capital, intercompany	(2,600)	(3,300)	(14)
Affiliated entity | Nonguarantors
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net change in intercompany investment securities	54	291
Net change in intercompany loans	(2)	217	(67)
Net change in intercompany debt	(10)	(2,074)	(877)
Dividends paid and returns of contributed capital, intercompany	(3,309)	(5,619)	(4,644)
Affiliated entity | Consolidating adjustments
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net change in intercompany investment securities	(54)	(298)
Net change in intercompany loans	22	(2,285)	(810)
Net change in intercompany debt	208	2,299	1,259
Dividends paid and returns of contributed capital, intercompany	$ 5,909	$ 8,919	$ 4,658

Guarantees and Commitments (Gua

Guarantees and Commitments (Guarantees to third parties) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Guarantor Obligations [Line Items]
Standby letters of credit and other guarantees	$ 7	$ 8
Standby letters of credit, cash collateral received	2
Maximum
Guarantor Obligations [Line Items]
Standby letters of credit and other guarantees	$ 218	$ 227

Guarantees and Commitments (Con

Guarantees and Commitments (Contractual Financing Commitments) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Guarantees and Commitments [Abstract]
Unused revolving credit line commitments and other	$ 3,435	$ 2,341
Commitments to provide capital to investees	394	283
Commitment to fund remaining unused balances on home equity lines of credit	253	318
Mortgage loan origination commitments	171	95
Construction-lending commitments	$ 85	$ 144

Guarantees and Commitments (Sch

Guarantees and Commitments (Schedule of Lease Commitments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Guarantees and Commitments [Abstract]
Operating leases, future minimum payments due, next twelve months	$ 48
Operating leases, future minimum payments, due in two years	47
Operating leases, future minimum payments, due in three years	46
Operating leases, future minimum payments, due in four years	37
Operating leases, future minimum payments, due in five years	31
Operating leases, future minimum payments, due thereafter	294
Total future minimum payments due, operating leases	503
Operating leases, rent expense	$ 45	$ 46	$ 51

Guarantees and Commitments (Oth

Guarantees and Commitments (Other Purchase Commitments) (Details) $ in Millions	Dec. 31, 2018USD ($)
Guarantees and Commitments [Abstract]
Other commitment, due in next twelve months	$ 70
Other commitment, due in second and third year	47
Other commitment, due in fourth year	0
Total future payment obligations, other commitment	$ 117

Quarterly Financial Information

Quarterly Financial Information (unaudited) (Details) - 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 Statements [Abstract]
Net financing revenue and other interest income	$ 1,140	$ 1,107	$ 1,094	$ 1,049	$ 1,094	$ 1,081	$ 1,067	$ 979	$ 4,390	$ 4,221	$ 3,907
Other revenue	298	398	364	354	379	381	388	396	1,414	1,544	1,530
Total net revenue	1,438	1,505	1,458	1,403	1,473	1,462	1,455	1,375
Provision for loan losses	266	233	158	261	294	314	269	271	918	1,148	917
Noninterest expense	804	807	839	814	769	753	810	778	3,264	3,110	2,939
Income from continuing operations before income tax expense	368	465	461	328	410	395	376	326	1,622	1,507	1,581
Income tax expense from continuing operations	79	91	113	76	231	115	122	113	359	581	470
Net income from continuing operations	289	374	348	252	179	280	254	213	1,263	926	1,111
Income (loss) from discontinued operations, net of tax	1	0	1	(2)	2	2	(2)	1	0	3	(44)
Net income	$ 290	$ 374	$ 349	$ 250	$ 181	$ 282	$ 252	$ 214	$ 1,263	$ 929	$ 1,067
Net income from continuing operations, basic earnings per common share	$ 0.70	$ 0.89	$ 0.81	$ 0.58	$ 0.40	$ 0.62	$ 0.55	$ 0.46	$ 2.97	$ 2.04	$ 2.25
Net income, basic earnings per common share	0.70	0.89	0.81	0.57	0.41	0.63	0.55	0.46	2.97	2.05	2.15
Net income from continuing operations, diluted earnings per common share	0.70	0.88	0.80	0.57	0.40	0.62	0.55	0.46	2.95	2.03	2.24
Net income, diluted earnings per common share	0.70	0.88	0.81	0.57	0.41	0.63	0.55	0.46	2.95	2.04	2.15
Cash dividends declared per common share	$ 0.15	$ 0.15	$ 0.13	$ 0.13	$ 0.12	$ 0.12	$ 0.08	$ 0.08	$ 0.56	$ 0.40	$ 0.16
Tax Act Impacts [Line Items]
Change in enacted tax rate, amount									$ (23)	$ 119	$ 0
Net impacts as a result of the Tax Act
Tax Act Impacts [Line Items]
Change in enacted tax rate, amount										$ 119

Subsequent Events (Details)

Subsequent Events (Details) - $ / shares	Jan. 14, 2019	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, 2016	Sep. 30, 2016
Subsequent Event [Line Items]
Dividends declared, amount per common share		$ 0.15	$ 0.15	$ 0.13	$ 0.13	$ 0.12	$ 0.12	$ 0.08	$ 0.08	$ 0.08	$ 0.08
Subsequent event
Subsequent Event [Line Items]
Dividends declared, amount per common share	$ 0.17
Increase (decrease) in dividends payable, per share	$ 0.02

Uncategorized Items - ally-2018

Label	Element	Value
Preferred Stock [Member]
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	$ 0
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax	(250,000,000)
Retained Earnings [Member]
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	(6,510,000,000)
Common Stock Including Additional Paid in Capital [Member]
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	21,245,000,000
Treasury Stock [Member]
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	(1,110,000,000)
Accounting Standards Update 2016-01 [Member] | AOCI Attributable to Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	27,000,000
Accounting Standards Update 2016-01 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(20,000,000)
Accounting Standards Update 2014-09 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(126,000,000)
Accounting Standards Update 2018-02 [Member] | AOCI Attributable to Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(42,000,000)
Accounting Standards Update 2018-02 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 42,000,000