Ally Financial (ALLY) 10-Q 6 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	3 Months Ended
	Mar. 31, 2019	May 02, 2019	Jun. 29, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	Ally Financial Inc.
Entity Central Index Key	0000040729
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		397,159,456
Entity Current Reporting Status	Yes
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Public Float			$ 11.2

Condensed Consolidated Statemen

Condensed Consolidated Statement of Comprehensive Income Condensed Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Financing Revenue and Other Income [Line Items]
Interest and fees on finance receivables and loans	$ 1,807	$ 1,543
Interest on loans held-for-sale	2	0
Interest and dividends on investment securities and other earning assets	240	176
Interest on cash and cash equivalents	23	15
Operating leases	361	382
Total financing revenue and other interest income	2,433	2,116
Interest Expense [Abstract]
Interest on deposits	592	351
Interest on short-term borrowings	44	32
Interest on long-term debt	419	411
Total interest expense	1,055	794
Net depreciation expense on operating lease assets	246	273
Net financing revenue and other interest income	1,132	1,049
Other revenue [Abstract]
Insurance premiums and service revenue earned	261	256
Gain on mortgage and automotive loans, net	10	1
Other (loss) gain on investments, net	108	(12)
Other income, net of losses	87	109
Total other revenue	466	354
Total net revenue	1,598	1,403
Provision for loan losses	282	261
Noninterest Expense [Abstract]
Compensation and benefits expense	318	306
Insurance losses and loss adjustment expenses	59	63
Other operating expenses	453	445
Total noninterest expense	830	814
Income from continuing operations before income tax expense	486	328
Income tax expense from continuing operations	111	76
Net income from continuing operations	375	252
Net income	374	250
Other comprehensive income (loss), net of tax	306	(328)
Comprehensive income	680	(78)
Income (loss) from discontinued operations, net of tax	$ (1)	$ (2)
Earnings Per Share, Basic [Abstract]
Net income from continuing operations, basic earnings per common share	$ 0.93	$ 0.58
Income (loss) from discontinued operations, net of tax, basic earnings per common share	0	(0.01)
Net income, basic earnings per common share	0.93	0.57
Earnings Per Share, Diluted [Abstract]
Net income from continuing operations, diluted earnings per common share	0.92	0.57
Income (loss) from discontinued operations, net of tax, diluted earnings per common share	0	(0.01)
Net income, diluted earnings per common share	0.92	0.57
Cash dividends declared per common share	$ 0.17	$ 0.13
Retained earnings
Net income	$ 374	$ 250

Condensed Consolidated Balance

Condensed Consolidated Balance Sheet & Mini Balance Sheet - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Assets [Abstract]
Cash and cash equivalents, noninterest-bearing	$ 946	$ 810
Cash and cash equivalents, interest-bearing	3,011	3,727
Total cash and cash equivalents	3,957	4,537
Equity securities	536	773
Available-for-sale securities	27,630	25,303
Held-to-maturity securities	2,387	2,362
Loans held-for-sale, net	107	314
Finance receivables and loans, net [Abstract]
Finance receivables and loans, net of unearned income	130,055	129,926
Allowance for loan losses	1,288	1,242
Total finance receivables and loans, net	128,767	128,684
Investment in operating leases, net	8,339	8,417
Premiums receivable and other insurance assets	2,401	2,326
Other assets	5,993	6,153
Total assets	180,117	178,869
Liabilities and Equity [Abstract]
Deposit liabilities, noninterest-bearing	141	142
Deposit liabilities, interest-bearing	113,158	106,036
Total deposit liabilities	113,299	106,178
Short-term borrowings	6,115	9,987
Long-term debt	41,490	44,193
Interest payable	696	523
Unearned insurance premiums and service revenue	3,096	3,044
Accrued expenses and other liabilities	1,722	1,676
Total liabilities	166,418	165,601
Equity [Abstract]
Common stock and paid-in capital	21,379	21,345
Accumulated deficit	(5,195)	(5,489)
Accumulated other comprehensive loss	(225)	(539)
Treasury stock, at cost	(2,260)	(2,049)
Total equity	13,699	13,268
Total liabilities and equity	180,117	178,869
Variable interest entity
Finance receivables and loans, net [Abstract]
Finance receivables and loans, net of unearned income	16,772	18,086
Allowance for loan losses	99	114
Total finance receivables and loans, net	16,673	17,972
Investment in operating leases, net	123	164
Other assets	636	767
Total assets	17,432	18,903
Liabilities and Equity [Abstract]
Long-term debt	9,742	10,482
Accrued expenses and other liabilities	11	12
Total liabilities	$ 9,753	$ 10,494

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheet & Mini Balance Sheet (Paranthetical) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
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	495,771,320	492,797,409
Common stock, shares outstanding	399,760,804	404,899,599
Treasury stock, shares	96,010,516	87,897,810
Held-to-maturity securities, fair value	$ 2,374	$ 2,307

Condensed Consolidated Statem_2

Condensed Consolidated Statement of Changes in Equity - USD ($) $ in Millions	Total	Common stock and paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)	Treasury stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity	$ 13,494	$ 21,245	$ (6,406)		$ (1,110)
Accumulated other comprehensive loss	$ (235)			$ (235)
Common stock dividends, amount per share	$ 0.13
Net income	$ 250		250
Share-based compensation	28	28
Other comprehensive income (loss)	(328)			(328)
Common stock repurchases	(185)				(185)
Common stock dividends	(58)		(58)
Equity	13,082	21,273	(6,318)		(1,295)
Accumulated other comprehensive loss	(578)			(578)
Equity	13,268	21,345	(5,489)		(2,049)
Accumulated other comprehensive loss	$ (539)			(539)
Common stock dividends, amount per share	$ 0.17
Net income	$ 374		374
Share-based compensation	34	34
Other comprehensive income (loss)	306			306
Common stock repurchases	(211)				(211)
Common stock dividends	(70)		(70)
Equity	13,699	$ 21,379	$ (5,195)		$ (2,260)
Accumulated other comprehensive loss	$ (225)			$ (225)

Condensed Consolidated Statem_3

Condensed Consolidated Statement of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income	$ 374	$ 250
Depreciation and amortization	369	434
Provision for loan losses	282	261
Gain (Loss) on Sales of Loans, Net	(10)	(1)
Gain (Loss) on Investments	(108)	12
Originations and purchases of loans held-for-sale	(134)	(248)
Proceeds from sales and repayments of loans held-for-sale	111	230
Increase (decrease) in deferred income taxes	100	83
Increase (decrease) in interest payable	173	120
Increase (decrease) in other operating assets	(40)	29
Increase (decrease) in other operating liabilities	37	(106)
Increase (decrease) in other operating assets and liabilities, net	(73)	33
Net cash provided by (used in) operating activities	1,081	1,097
Net Cash (Used in) Provided by Investing Activities [Abstract]
Purchases of equity securities	(48)	(374)
Proceeds from sales of equity securities	383	220
Purchases of available-for-sale securities	(3,401)	(2,360)
Proceeds from sale of available-for-sale securities	656	328
Proceeds from repayments of available-for-sale securities	694	795
Purchases of held-to-maturity securities	(131)	(155)
Proceeds from repayments of held-to-maturity securities	44	35
Purchases of finance receivables and loans held-for-investment	(1,452)	(1,497)
Proceeds from sales of finance receivables and loans initially held-for-investment	157	0
Originations and repayments of finance receivables and loans held-for-investment and other, net	1,149	(1,300)
Purchases of operating lease assets	(792)	(969)
Disposals of operating lease assets	624	976
Net change in nonmarketable equity investments	171	(19)
Payments for (proceeds from) other, net	(95)	(82)
Net cash provided by investing activities	(2,041)	(4,402)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Net change in short-term borrowings	(3,872)	(1,848)
Net increase in deposits	7,114	4,173
Proceeds from issuance of long-term debt	1,766	6,665
Repayments of long-term debt	(4,490)	(5,771)
Repurchase of common stock	(211)	(185)
Dividends paid	(70)	(58)
Net cash provided by (used in) financing activities	237	2,976
Effect of exchange-rate changes on cash and cash equivalents and restricted cash	1	(2)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Net increase (decrease) in cash and cash equivalents and restricted cash	(722)	(331)
Cash and cash equivalents and restricted cash	4,904	4,938
Cash and cash equivalents as disclosed on the Condensed Consolidated Balance Sheet	3,957	3,721
Restricted cash included in other assets on the Condensed Consolidated Balance Sheet	947	1,217
Supplemental Cash Flow Information [Abstract]
Cash paid for interest	862	667
Cash paid for income taxes	12	5
Loans held-for-sale transferred to finance receivables and loans held-for-investment	63	0
Finance receivables and loans transferred to loans held-for-sale, noncash	20	0
Proceeds from repayments of mortgage loans held-for-investment originally designated as held-for-sale	$ 3	$ 11

Description of Business, Basis

Description of Business, Basis of Presentation, and Changes in Significant Accounting Policies Description of Business, Basis of Presentation, and Changes in Significant Accounting Policies	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block]	Description of Business, Basis of Presentation, and Changes in 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 . 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. 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 lease assets and residuals, fair value of financial instruments, and the determination of the provision for income taxes. The Condensed Consolidated Financial Statements at March 31, 2019 , and for the three months ended March 31, 2019 , and 2018 , are unaudited but reflect all adjustments that are, in management’s opinion, necessary for the fair presentation of the results for the interim periods presented. All such adjustments are of a normal recurring nature. These unaudited Condensed Consolidated Financial Statements should be read in conjunction with the audited Consolidated Financial Statements (and the related Notes) included in our Annual Report on Form 10-K for the year ended December 31, 2018 , as filed on February 20, 2019, with the U.S. Securities and Exchange Commission (SEC). Significant Accounting Policies Lease Accounting At contract inception, we determine whether the contract is or contains a lease based on the terms and conditions of the contract. Lease contracts are recognized on our Condensed Consolidated Balance Sheet as right-of-use (ROU) assets and lease liabilities; however, we have elected not to recognize ROU assets and lease liabilities on real estate leases with terms of one year or less. Lease liabilities and their corresponding ROU assets are recorded based on the present value of the future lease payments over the expected lease term. As the interest rate implicit in the lease contract is typically not readily determinable, we utilize our incremental borrowing rate, which is the rate we would incur to borrow on a collateralized basis over a similar term on an amount equal to the lease payments in a similar economic environment. The ROU asset also includes initial direct costs paid less lease incentives received from the lessor. Our lease contracts are generally classified as operating and, as a result, we recognize a single lease cost within other operating expenses on the income statement on a straight-line basis over the lease term. This update to our accounting policy resulted from our adoption of Accounting Standards Update (ASU) 2016-02 on January 1, 2019, as further described within the section below titled Recently Adopted Accounting Standards . Investments Premiums on debt securities that have noncontingent call features that are callable at fixed prices on preset dates are amortized to the earliest call date as an adjustment to investment yield. All other premiums and discounts on debt securities are amortized over the stated maturity of the security as an adjustment to investment yield. This method of amortization differs from that described in Note 1 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K , which describes our full accounting policy for Investments. This update to our amortization methodology resulted from the adoption of ASU 2017-08 on January 1, 2019, as further described within the section below titled Recently Adopted Accounting Standards . Income Taxes In calculating the provision for interim income taxes, in accordance with Accounting Standards Codification (ASC) 740, Income Taxes , we apply an estimated annual effective tax rate to year-to-date ordinary income. At the end of each interim period, we estimate the effective tax rate expected to be applicable for the full fiscal year. This method differs from that described in Note 1 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K, which describes our annual significant income tax accounting policy and related methodology. Refer to Note 1 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K regarding additional significant accounting policies. Recently Adopted Accounting Standards Leases (ASU 2016-02) In February 2016, the Financial Accounting Standards Board (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 (previously referred to as capital leases) and lessor accounting requirements for operating leases and sales type and direct financing 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 ROU asset and lease liability equal to the present value of the lease payments. The ROU 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 issued additional ASUs to clarify the guidance and provide certain practical expedients and an additional transition option. We adopted ASU 2016-02 and the subsequent ASUs that modified ASU 2016-02 (collectively, the amendments) on January 1, 2019. This includes the early adoption of ASU 2019-01, which was issued in March 2019 to amend certain provisions included in ASU 2016-02. We adopted this guidance using the modified retrospective approach on January 1, 2019, and have not adjusted prior period comparative information and will continue to disclose prior period financial information in accordance with the previous lease accounting guidance. We have elected certain practical expedients permitted within the amendments 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. We made an accounting policy election to calculate the impact of adoption using the remaining minimum lease payments and remaining lease term for each contract that was identified as a lease, discounted at our incremental borrowing rate as of the adoption date. The adoption of the amendments resulted in a ROU asset of approximately $161 million from operating leases 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 . The adoption did not change our previously reported Condensed Consolidated Statements of Comprehensive Income and did not result in a cumulative catch-up adjustment to opening retained earnings. Receivables—Nonrefundable Fees and Other Costs: Premium Amortization on Purchased Callable Debt Securities (ASU 2017-08) 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. We adopted the amendments on January 1, 2019, on a modified retrospective basis, which resulted in an increase to our accumulated deficit of $10 million , net of income taxes, partially offset by an $8 million decrease to accumulated other comprehensive loss, net of income taxes. Recently Issued Accounting Standards Financial Instruments—Credit Losses (ASU 2016-13) In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (CECL). 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. We plan to adopt these amendments on January 1, 2020, and expect to utilize the modified retrospective approach as required. The new accounting model for credit losses represents a significant departure from existing GAAP, and will materially increase the allowance for credit losses on our finance receivables and loans, with a resulting negative adjustment to retained earnings. We expect that our consumer automotive loan portfolio will generate the majority of this increase. 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. We performed a limited parallel run during the first quarter of 2019, and will continue to refine and enhance our estimation process with additional parallel testing throughout 2019. Additionally, we do not expect a material allowance for credit losses on our debt securities as a result of the standard based upon the current composition of our portfolio.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	3 Months Ended
	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer	Revenue from Contracts with Customers Our primary revenue sources, which include financing revenue and other interest income, are addressed by other GAAP and are not in the scope of ASC 606, Revenue from Contracts with Customers. 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 this standard. 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 this standard. 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 amortized over the terms of the related policies and service contracts on the same basis as premiums and service revenue are earned, and all advertising costs are recognized as expense when incurred. 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 revenue recognition principles of ASC 606, Revenue from Contracts with Customers . For further information regarding our revenue recognition policies and details about the nature of our respective revenue streams, refer to Note 1 and Note 3 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K . Three months ended March 31, ($ in millions) Automotive Finance operations Insurance operations Mortgage Finance operations Corporate Finance operations Corporate and Other Consolidated 2019 Revenue from contracts with customers Noninsurance contracts (a) (b) (c) $ — $ 131 $ — $ — $ — $ 131 Remarketing fee income 18 — — — — 18 Brokerage commissions and other revenue — — — — 17 17 Deposit account and other banking fees — — — — 5 5 Brokered/agent commissions — 3 — — — 3 Other 5 — — — — 5 Total revenue from contracts with customers 23 134 — — 22 179 All other revenue 45 226 2 11 3 287 Total other revenue (d) $ 68 $ 360 $ 2 $ 11 $ 25 $ 466 2018 Revenue from contracts with customers Noninsurance contracts (a) (b) (c) $ — $ 123 $ — $ — $ — $ 123 Remarketing fee income 23 — — — — 23 Brokerage commissions and other revenue — — — — 16 16 Deposit account and other banking fees — — — — 3 3 Brokered/agent commissions — 4 — — — 4 Other 2 1 — — — 3 Total revenue from contracts with customers 25 128 — — 19 172 All other revenue 41 118 1 8 14 182 Total other revenue (d) $ 66 $ 246 $ 1 $ 8 $ 33 $ 354 (a) We had $2.6 billion and $2.5 billion in unearned revenue associated with outstanding contracts at January 1, 2019, and January 1, 2018, respectively, and $199 million and $194 million of these balances were recognized as insurance premiums and service revenue earned in our Condensed Consolidated Statement of Comprehensive Income during the three months ended March 31, 2019 , and March 31, 2018 , respectively. (b) At March 31, 2019 , we had unearned revenue of $2.7 billion associated with outstanding contracts, and with respect to this balance we expect to recognize revenue of $554 million during the remainder of 2019 , $672 million in 2020 , $562 million in 2021 , $424 million in 2022 , and $477 million thereafter. At March 31, 2018, we had unearned revenue of $2.5 billion associated with outstanding contracts. (c) We had opening and closing balances of deferred insurance assets of $1.5 billion and $1.6 billion at January 1, 2019, and March 31, 2019 , respectively, and recognized $111 million of expense during the three months ended March 31, 2019 . We had opening and closing balances of deferred insurance assets of $1.4 billion at both January 1, 2018, and March 31, 2018, and recognized $103 million of expense during the three months ended March 31, 2018 . (d) Represents a component of total net revenue. Refer to Note 21 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 $15 million and $18 million for the three months ended March 31, 2019 , and March 31, 2018, respectively, on the sale of off-lease vehicles. These gains are included in depreciation expense on operating lease assets in our Condensed Consolidated Statement of Comprehensive Income .

Other Income, Net of Losses

Other Income, Net of Losses	3 Months Ended
	Mar. 31, 2019
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. Three months ended March 31, ($ in millions) 2019 2018 Late charges and other administrative fees $ 29 $ 29 Remarketing fees 18 23 Servicing fees 6 8 Income from equity-method investments 4 6 Other, net 30 43 Total other income, net of losses $ 87 $ 109

Reserves for Insurance Losses a

Reserves for Insurance Losses and Loss Adjustment Expenses Reserves for Insurance Losses and Loss Adjustment Expenses	3 Months Ended
	Mar. 31, 2019
Reserves for Insurance Losses and Loss Adjustment Expenses [Abstract]
Reserves for Insurance Losses and Loss Adjustment Expenses	Reserves for Insurance Losses and Loss Adjustment Expenses The following table shows a rollforward of our reserves for insurance losses and loss adjustment expenses. ($ in millions) 2019 2018 Total gross reserves for insurance losses and loss adjustment expenses at January 1, $ 134 $ 140 Less: Reinsurance recoverable 96 108 Net reserves for insurance losses and loss adjustment expenses at January 1, 38 32 Net insurance losses and loss adjustment expenses incurred related to: Current year 59 60 Prior years (a) — 3 Total net insurance losses and loss adjustment expenses incurred 59 63 Net insurance losses and loss adjustment expenses paid or payable related to: Current year (33 ) (31 ) Prior years (23 ) (19 ) Total net insurance losses and loss adjustment expenses paid or payable (56 ) (50 ) Net reserves for insurance losses and loss adjustment expenses at March 31, 41 45 Plus: Reinsurance recoverable 94 112 Total gross reserves for insurance losses and loss adjustment expenses at March 31, $ 135 $ 157 (a) There have been no material adverse changes to the reserve for prior years.

Other Operating Expenses

Other Operating Expenses	3 Months Ended
	Mar. 31, 2019
Operating Expenses [Abstract]
Other Operating Income and Expense	Other Operating Expenses Details of other operating expenses were as follows. Three months ended March 31, ($ in millions) 2019 2018 Insurance commissions $ 114 $ 110 Technology and communications 77 71 Advertising and marketing 48 39 Lease and loan administration 39 42 Professional services 29 32 Regulatory and licensing fees 28 30 Vehicle remarketing and repossession 27 32 Premises and equipment depreciation 22 20 Occupancy 13 11 Non-income taxes 9 8 Amortization of intangible assets 3 3 Other 44 47 Total other operating expenses $ 453 $ 445

Investment Securities

Investment Securities	3 Months Ended
	Mar. 31, 2019
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. March 31, 2019 December 31, 2018 Amortized cost Gross unrealized Fair value Amortized cost Gross unrealized Fair value ($ in millions) gains losses gains losses Available-for-sale securities Debt securities U.S. Treasury and federal agencies $ 1,990 $ 1 $ (49 ) $ 1,942 $ 1,911 $ — $ (60 ) $ 1,851 U.S. States and political subdivisions 771 13 (3 ) 781 816 3 (17 ) 802 Foreign government 170 2 — 172 145 1 (1 ) 145 Agency mortgage-backed residential 18,939 98 (193 ) 18,844 17,486 47 (395 ) 17,138 Agency mortgage-backed commercial 316 4 — 320 3 — — 3 Mortgage-backed residential 2,912 7 (33 ) 2,886 2,796 1 (111 ) 2,686 Mortgage-backed commercial 725 — (2 ) 723 715 1 (2 ) 714 Asset-backed 665 4 (1 ) 668 723 2 (2 ) 723 Corporate debt 1,301 7 (14 ) 1,294 1,286 1 (46 ) 1,241 Total available-for-sale securities (a) (b) (c) $ 27,789 $ 136 $ (295 ) $ 27,630 $ 25,881 $ 56 $ (634 ) $ 25,303 Held-to-maturity securities Debt securities Agency mortgage-backed residential (d) $ 2,351 $ 15 $ (28 ) $ 2,338 $ 2,319 $ 6 $ (61 ) $ 2,264 Asset-backed retained notes 36 — — 36 43 — — 43 Total held-to-maturity securities $ 2,387 $ 15 $ (28 ) $ 2,374 $ 2,362 $ 6 $ (61 ) $ 2,307 (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 March 31, 2019 , and December 31, 2018 . (b) Certain available-for-sale securities are included in fair value hedging relationships. Refer to Note 17 for additional information. (c) Available-for-sale securities with a fair value of $4.1 billion and $9.2 billion at March 31, 2019 , and December 31, 2018 , respectively, were pledged to secure advances from the Federal Home Loan Bank (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 $985 million and $821 million of the underlying investment securities at March 31, 2019 , and December 31, 2018 , respectively. (d) Held-to-maturity securities with a fair value of $1.3 billion and $1.2 billion at March 31, 2019 , and December 31, 2018, respectively, were pledged to secure advances from the FHLB. The maturity distribution of debt securities outstanding is summarized in the following tables. Call or prepayment options may cause actual maturities to differ from contractual maturities. Total Due in one year or less Due after one year through five years Due after five years through ten years Due after ten years ($ in millions) Amount Yield Amount Yield Amount Yield Amount Yield Amount Yield March 31, 2019 Fair value of available-for-sale securities (a) U.S. Treasury and federal agencies $ 1,942 1.7 % $ 28 1.7 % $ 1,341 1.6 % $ 573 1.9 % $ — — % U.S. States and political subdivisions 781 3.2 52 2.7 43 2.5 212 2.7 474 3.5 Foreign government 172 2.3 41 2.1 55 2.3 73 2.4 3 2.7 Agency mortgage-backed residential 18,844 3.4 — — — — 52 1.9 18,792 3.4 Agency mortgage-backed commercial 320 3.2 — — 3 3.1 83 3.3 234 3.2 Mortgage-backed residential 2,886 3.3 — — — — — — 2,886 3.3 Mortgage-backed commercial 723 3.8 — — — — 36 4.0 687 3.8 Asset-backed 668 3.5 — — 390 3.4 165 4.0 113 3.3 Corporate debt 1,294 3.2 152 3.1 512 2.9 606 3.4 24 5.9 Total available-for-sale securities $ 27,630 3.3 $ 273 2.7 $ 2,344 2.2 $ 1,800 2.8 $ 23,213 3.4 Amortized cost of available-for-sale securities $ 27,789 $ 273 $ 2,376 $ 1,814 $ 23,326 Amortized cost of held-to-maturity securities Agency mortgage-backed residential $ 2,351 3.2 % $ — — % $ — — % $ — — % $ 2,351 3.2 % Asset-backed retained notes 36 2.1 — — 36 2.1 — — — — Total held-to-maturity securities $ 2,387 3.2 $ — — $ 36 2.1 $ — — $ 2,351 3.2 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 Agency mortgage-backed commercial 3 3.1 — — 3 3.1 — — — — Mortgage-backed residential 2,686 3.3 — — — — — — 2,686 3.3 Mortgage-backed commercial 714 3.8 — — — — 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 (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 $56 million and $35 million at March 31, 2019 , and December 31, 2018 , respectively, and were composed primarily of money-market accounts and short-term securities, including U.S. Treasury bills. The following table presents interest and dividends on investment securities. Three months ended March 31, ($ in millions) 2019 2018 Taxable interest $ 214 $ 154 Taxable dividends 3 3 Interest and dividends exempt from U.S. federal income tax 5 6 Interest and dividends on investment securities $ 222 $ 163 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. Three months ended March 31, ($ in millions) 2019 2018 Available-for-sale securities Gross realized gains $ 10 $ 6 Gross realized losses (a) (1 ) — Net realized gains on available-for-sale securities 9 6 Net realized gain on equity securities 29 22 Net unrealized gain (loss) on equity securities 70 (40 ) Other gain (loss) on investments, net $ 108 $ (12 ) (a) Certain available-for-sale securities were sold at a loss during the three months ended March 31, 2019 , as a result of market conditions within these 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. 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. For additional information on our methodology, refer to Note 1 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K. As of March 31, 2019 , 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 March 31, 2019 . March 31, 2019 December 31, 2018 Less than 12 months 12 months or longer Less than 12 months 12 months or longer ($ 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 $ 42 $ — $ 1,749 $ (49 ) $ 31 $ — $ 1,758 $ (60 ) U.S. States and political subdivisions 23 — 189 (3 ) 259 (3 ) 317 (14 ) Foreign government 4 — 22 — 6 — 74 (1 ) Agency mortgage-backed residential 510 (1 ) 11,145 (192 ) 5,537 (94 ) 7,808 (301 ) Agency mortgage-backed commercial 30 — — — — — — — Mortgage-backed residential 131 — 1,676 (33 ) 1,024 (20 ) 1,360 (91 ) Mortgage-backed commercial 517 (2 ) 41 — 347 (1 ) 36 (1 ) Asset-backed 6 — 214 (1 ) 294 (1 ) 124 (1 ) Corporate debt 105 — 764 (14 ) 576 (19 ) 569 (27 ) Total temporarily impaired available-for-sale securities $ 1,368 $ (3 ) $ 15,800 $ (292 ) $ 8,074 $ (138 ) $ 12,046 $ (496 ) Held-to-maturity securities Debt securities Agency mortgage-backed residential $ 86 $ — $ 1,376 $ (28 ) $ 457 $ (6 ) $ 1,376 $ (55 ) Asset-backed retained notes — — 16 — 16 — 19 — Total held-to-maturity debt securities $ 86 $ — $ 1,392 $ (28 ) $ 473 $ (6 ) $ 1,395 $ (55 )

Finance Receivables and Loans,

Finance Receivables and Loans, Net	3 Months Ended
	Mar. 31, 2019
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. ($ in millions) March 31, 2019 December 31, 2018 Consumer automotive (a) $ 71,553 $ 70,539 Consumer mortgage Mortgage Finance (b) 16,225 15,155 Mortgage — Legacy (c) 1,433 1,546 Total consumer mortgage 17,658 16,701 Total consumer 89,211 87,240 Commercial Commercial and industrial Automotive 31,559 33,672 Other 4,516 4,205 Commercial real estate 4,769 4,809 Total commercial 40,844 42,686 Total finance receivables and loans (d) $ 130,055 $ 129,926 (a) Certain finance receivables and loans are included in fair value hedging relationships. Refer to Note 17 for additional information. (b) Includes loans originated as interest-only mortgage loans of $17 million and $18 million at March 31, 2019 , and December 31, 2018 , respectively, 33% of which are expected to start principal amortization in 2019, and 40% in 2020 . The remainder of these loans have exited the interest-only period. (c) Includes loans originated as interest-only mortgage loans of $305 million and $341 million at March 31, 2019 , and December 31, 2018 , 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 $584 million and $587 million at March 31, 2019 , and December 31, 2018 , respectively. The following tables present an analysis of the activity in the allowance for loan losses on finance receivables and loans. Three months ended March 31, 2019 ($ in millions) Consumer automotive Consumer mortgage Commercial Total Allowance at January 1, 2019 $ 1,048 $ 53 $ 141 $ 1,242 Charge-offs (a) (352 ) (3 ) (5 ) (360 ) Recoveries 118 5 — 123 Net charge-offs (234 ) 2 (5 ) (237 ) Provision for loan losses 257 (3 ) 28 282 Other (b) (1 ) — 2 1 Allowance at March 31, 2019 $ 1,070 $ 52 $ 166 $ 1,288 Allowance for loan losses at March 31, 2019 Individually evaluated for impairment $ 46 $ 22 $ 58 $ 126 Collectively evaluated for impairment 1,024 30 108 1,162 Finance receivables and loans at gross carrying value Ending balance $ 71,553 $ 17,658 $ 40,844 $ 130,055 Individually evaluated for impairment 501 227 269 997 Collectively evaluated for impairment 71,052 17,431 40,575 129,058 (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 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K for more information regarding our charge-off policies. (b) Primarily related to the transfer of finance receivables and loans from held-for-sale to held-for-investment. Three months ended March 31, 2018 ($ in millions) Consumer automotive Consumer mortgage Commercial Total Allowance at January 1, 2018 $ 1,066 $ 79 $ 131 $ 1,276 Charge-offs (a) (365 ) (12 ) — (377 ) Recoveries 112 6 — 118 Net charge-offs (253 ) (6 ) — (259 ) Provision for loan losses 253 1 7 261 Allowance at March 31, 2018 $ 1,066 $ 74 $ 138 $ 1,278 Allowance for loan losses at March 31, 2018 Individually evaluated for impairment $ 40 $ 27 $ 21 $ 88 Collectively evaluated for impairment 1,026 47 117 1,190 Finance receivables and loans at gross carrying value Ending balance $ 69,318 $ 14,683 $ 41,326 $ 125,327 Individually evaluated for impairment 463 230 147 840 Collectively evaluated for impairment 68,855 14,453 41,179 124,487 (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 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K for more information regarding our charge-off policies. 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. Three months ended March 31, ($ in millions) 2019 2018 Consumer automotive $ 20 $ — Consumer mortgage — 1 Total sales and transfers (a) $ 20 $ 1 (a) During the three months ended March 31, 2019 , we also sold $128 million of finance receivables that were classified as held-for-sale and transferred $63 million of finance receivables from held-for-sale to held-for-investment as of March 31, 2019 , both relating to equipment finance receivables from our commercial automotive business. The following table presents information about significant purchases of finance receivables and loans based on unpaid principal balance at the time of purchase. Three months ended March 31, ($ in millions) 2019 2018 Consumer automotive $ 99 $ 168 Consumer mortgage 1,235 1,295 Total purchases of finance receivables and loans $ 1,334 $ 1,463 The following table presents an analysis of our past-due finance receivables and loans recorded at gross carrying value. ($ 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 March 31, 2019 Consumer automotive $ 1,575 $ 379 $ 260 $ 2,214 $ 69,339 $ 71,553 Consumer mortgage Mortgage Finance 52 8 9 69 16,156 16,225 Mortgage — Legacy 31 11 36 78 1,355 1,433 Total consumer mortgage 83 19 45 147 17,511 17,658 Total consumer 1,658 398 305 2,361 86,850 89,211 Commercial Commercial and industrial Automotive 1 8 78 87 31,472 31,559 Other — — 2 2 4,514 4,516 Commercial real estate — — 2 2 4,767 4,769 Total commercial 1 8 82 91 40,753 40,844 Total consumer and commercial $ 1,659 $ 406 $ 387 $ 2,452 $ 127,603 $ 130,055 December 31, 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 The following table presents the gross carrying value of our finance receivables and loans on nonaccrual status. ($ in millions) March 31, 2019 December 31, 2018 Consumer automotive $ 643 $ 664 Consumer mortgage Mortgage Finance 13 9 Mortgage — Legacy 62 70 Total consumer mortgage 75 79 Total consumer 718 743 Commercial Commercial and industrial Automotive 138 203 Other 125 142 Commercial real estate 6 4 Total commercial 269 349 Total consumer and commercial finance receivables and loans $ 987 $ 1,092 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 90 days or more, or when full collection is not expected. Refer to Note 1 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K for additional information. March 31, 2019 December 31, 2018 ($ in millions) Performing Nonperforming Total Performing Nonperforming Total Consumer automotive $ 70,910 $ 643 $ 71,553 $ 69,875 $ 664 $ 70,539 Consumer mortgage Mortgage Finance 16,212 13 16,225 15,146 9 15,155 Mortgage — Legacy 1,371 62 1,433 1,476 70 1,546 Total consumer mortgage 17,583 75 17,658 16,622 79 16,701 Total consumer $ 88,493 $ 718 $ 89,211 $ 86,497 $ 743 $ 87,240 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. March 31, 2019 December 31, 2018 ($ in millions) Pass Criticized (a) Total Pass Criticized (a) Total Commercial and industrial Automotive $ 28,774 $ 2,785 $ 31,559 $ 30,799 $ 2,873 $ 33,672 Other 3,711 805 4,516 3,373 832 4,205 Commercial real estate 4,526 243 4,769 4,538 271 4,809 Total commercial $ 37,011 $ 3,833 $ 40,844 $ 38,710 $ 3,976 $ 42,686 (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 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K. The following table presents information about our impaired finance receivables and loans. ($ in millions) Unpaid principal balance (a) Gross carrying value Impaired with no allowance Impaired with an allowance Allowance for impaired loans March 31, 2019 Consumer automotive $ 509 $ 501 $ 99 $ 402 $ 46 Consumer mortgage Mortgage Finance 15 15 6 9 1 Mortgage — Legacy 216 212 65 147 21 Total consumer mortgage 231 227 71 156 22 Total consumer 740 728 170 558 68 Commercial Commercial and industrial Automotive 138 138 41 97 18 Other 144 125 56 69 40 Commercial real estate 6 6 3 3 — Total commercial 288 269 100 169 58 Total consumer and commercial finance receivables and loans $ 1,028 $ 997 $ 270 $ 727 $ 126 December 31, 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 (a) Adjusted for charge-offs. The following table presents average balance and interest income for our impaired finance receivables and loans. 2019 2018 Three months ended March 31, ($ in millions) Average balance Interest income Average balance Interest income Consumer automotive $ 499 $ 8 $ 444 $ 7 Consumer mortgage Mortgage Finance 15 — 9 — Mortgage — Legacy 214 3 221 2 Total consumer mortgage 229 3 230 2 Total consumer 728 11 674 9 Commercial Commercial and industrial Automotive 170 1 47 1 Other 130 — 52 — Commercial real estate 5 — 3 — Total commercial 305 1 102 1 Total consumer and commercial finance receivables and loans $ 1,033 $ 12 $ 776 $ 10 Troubled Debt Restructurings 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 $837 million and $812 million at March 31, 2019 , and December 31, 2018, respectively. Total commitments to lend additional funds to borrowers whose terms had been modified in a TDR were $13 million and $4 million at March 31, 2019 , and December 31, 2018, respectively. Refer to Note 1 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K for additional information. The following table presents information related to finance receivables and loans recorded at gross carrying value modified in connection with a TDR during the period. 2019 2018 Three months ended March 31, ($ in millions) Number of loans Pre-modification gross carrying value Post-modification gross carrying value Number of loans Pre-modification gross carrying value Post-modification gross carrying value Consumer automotive 7,427 $ 129 $ 111 7,042 $ 128 $ 110 Consumer mortgage Mortgage Finance 1 — — 1 1 1 Mortgage — Legacy 20 3 3 62 10 9 Total consumer mortgage 21 3 3 63 11 10 Total consumer finance receivables and loans 7,448 132 114 7,105 139 120 Commercial Commercial and Industrial Automotive 6 41 41 — — — Total commercial 6 41 41 — — — Total consumer and commercial finance receivables and loans 7,454 $ 173 $ 155 7,105 $ 139 $ 120 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 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K for additional information) except for commercial finance receivables and loans, where redefault is defined as 90 days past due. 2019 2018 Three months ended March 31, ($ in millions) Number of loans Gross carrying value Charge-off amount Number of loans Gross carrying value Charge-off amount Consumer automotive 2,209 $ 26 $ 16 2,326 $ 28 $ 18 Total consumer finance receivables and loans 2,209 $ 26 $ 16 2,326 $ 28 $ 18

Leasing

Leasing	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Leases	Leasing On January 1, 2019, we adopted the amendments to the lease accounting principles. Refer to the section titled Recently Adopted Accounting Standards in Note 1 for additional information. Ally as the Lessee We have operating leases for our corporate facilities, which have remaining lease terms of 6 months to 13 years. Most of the property leases have fixed payment terms with annual fixed-escalation clauses and include options to extend the leases for periods that range from 1 to 15 years. Some of those lease agreements also include options to terminate the leases in periods that range from 2 to 5 years after the commencement of the leases. We have not included any of these term extensions or termination provisions in our estimates of the lease term, as we do not consider it reasonably certain that the options will be exercised. Our property-lease agreements contain a lease component, which includes the right to use the real estate, and non-lease components, which include utilities and common area maintenance services. Lease components are accounted for under the ASC Topic on Leases, while non-lease components are accounted for under other GAAP Topics. We elected the practical expedient to account for the lease and non-lease components for property leases as a single lease component. Additional variable-rent payments made during the lease term are not based on a rate or index and are excluded from the calculations of ROU assets and lease liabilities and recognized as a component of variable lease expense as incurred. We also have operating leases for a fleet of vehicles that is used by our sales force for business purposes, with noncancellable lease terms of 367 days. Thereafter, the leases are month-to-month, up to a maximum of 48 months from inception. In addition to lease costs related to the vehicles, the lease contracts include non-lease components such as maintenance, fuel, and administrative services. We elected to account for the lease and non-lease components separately. As a result, the non-lease components are excluded from the calculation of the ROU asset and lease liability and are recognized as other operating expenses as incurred. The following table details our total investment in operating leases. ($ in millions) March 31, 2019 January 1, 2019 (a) Assets Operating lease right-of-use assets (b) $ 177 $ 161 Liabilities Operating lease liabilities (c) $ 206 $ 190 (a) Date of adoption. (b) Included in other assets on our Condensed Consolidated Balance Sheet . (c) Included in accrued expenses and other liabilities on our Condensed Consolidated Balance Sheet . During the three months ended March 31, 2019 , we paid $12 million in cash for amounts included in the measurement of lease liabilities at March 31, 2019 . This amount is included in net cash provided by operating activities in the Condensed Consolidated Statement of Cash Flows . During the three months ended March 31, 2019 , we obtained $27 million of ROU assets in exchange for new operating lease liabilities. As of March 31, 2019 , the weighted-average remaining lease term of our operating lease portfolio was 7 years, and the weighted-average discount rate was 2.98% . The following table presents future minimum rental payments we are required to make under operating leases that have commenced as of March 31, 2019 , and that have noncancellable lease terms expiring after March 31, 2019 . ($ in millions) 2019 $ 36 2020 46 2021 36 2022 24 2023 16 2024 and thereafter 71 Total undiscounted cash flows 229 Difference between undiscounted cash flows and discounted cash flows (23 ) Total lease liability $ 206 In addition to the above, we entered into a forward-starting lease agreement in September 2017, for a new corporate facility in Charlotte, North Carolina, where we plan to consolidate several existing facilities into that location. The lessor and their agents are currently constructing the facilities at this location, with the lease scheduled to commence in April 2021 after construction is completed. The lease agreement will have a total of $290 million in undiscounted future lease payments over the 15 year term of the lease. Future minimum rental payments required under operating leases as of December 31, 2018, prior to the date of adoption and as defined by the previous lease accounting guidance, with noncancellable lease terms expiring after December 31, 2018, were as follows. Year ended December 31, ($ in millions) 2019 $ 48 2020 47 2021 46 2022 37 2023 31 2024 and thereafter 294 Total minimum payments required $ 503 The following table details the components of total net operating lease expense. Three months ended March 31, ($ in millions) 2019 2018 Operating lease expense $ 11 $ 10 Variable lease expense 2 2 Total lease expense, net (a) $ 13 $ 12 (a) Included in other operating expenses in our Condensed Consolidated Statement of Comprehensive Income . Ally as the Lessor Investment in Operating Leases We purchase consumer operating lease contracts and the associated vehicles from dealerships after those contracts are executed by the dealers and the consumers. The amount we pay a dealer for an operating lease contract is based on the negotiated price for the vehicle less vehicle trade-in, down payment from the consumer, and available automotive manufacturer incentives. Under the operating lease, the consumer is obligated to make payments in amounts equal to the amount by which the negotiated purchase price of the vehicle (less any trade-in value, down payment, or available manufacturer incentives) exceeds the contract residual value (including residual support) of the vehicle at lease termination, plus operating lease rental charges. The customer can terminate the lease at any point after commencement, subject to additional charges and fees. Both the consumer and the dealership have the option to purchase the vehicle at the end of the lease term, which can range from 24 to 60 months, at the residual value of the vehicle, however it is not reasonably certain this option will be exercised and as such our consumer leases are classified as operating leases. We have made an accounting policy election to exclude the sales taxes we collect from consideration in the lease contract and from variable lease payments not included in contract consideration. In addition to the charges described above, the consumer is generally responsible for certain charges related to excess mileage or excessive wear and tear on the vehicle. These charges are deemed variable lease payments and, as these payments are not based on a rate or index, they are recognized as net depreciation expense on operating lease assets in our Condensed Consolidated Statement of Comprehensive Income as incurred. When we acquire a consumer operating lease, we assume ownership of the vehicle from the dealer. We require that property damage, bodily injury, collision, and comprehensive insurance be obtained by the lessee on all consumer operating leases. Neither the consumer nor the dealer is responsible for the value of the vehicle at the time of lease termination. When vehicles are not purchased by customers or the receiving dealer at scheduled lease termination, the vehicle is returned to us for remarketing. We generally bear the risk of loss to the extent the value of a leased vehicle upon remarketing is below the expected residual value. 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. Periodically, we revise the projected value of the leased vehicle at termination based on current market conditions and adjust depreciation expense if necessary over the remaining life of the contract. At termination, 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, which is included in net depreciation expense on operating lease assets in our Condensed Consolidated Statement of Comprehensive Income . Excessive mileage or excessive wear and tear on the vehicle during the lease may impact the sales proceeds received upon remarketing. As of March 31, 2019 , consumer operating leases with a carrying value, net of accumulated depreciation, of $394 million were covered by a residual value guarantee of 15% of the manufacturer’s suggested retail price. The following table details our investment in operating leases. ($ in millions) March 31, 2019 December 31, 2018 Vehicles $ 9,903 $ 9,995 Accumulated depreciation (1,564 ) (1,578 ) Investment in operating leases, net $ 8,339 $ 8,417 The following table presents future minimum rental payments we have the right to receive under operating leases with noncancellable lease terms expiring after March 31, 2019 . ($ in millions) 2019 $ 1,024 2020 933 2021 402 2022 57 2023 5 2024 and thereafter — Total lease payments from operating leases $ 2,421 We recognized $361 million and $382 million in operating lease revenue for the three months ended March 31, 2019 , and March 31, 2018 , respectively. Depreciation expense on operating lease assets includes remarketing gains and losses recognized on the sale of operating lease assets. The following table summarizes the components of depreciation expense on operating lease assets. Three months ended March 31, ($ in millions) 2019 2018 Depreciation expense on operating lease assets (excluding remarketing gains) $ 261 $ 291 Remarketing gains, net (15 ) (18 ) Net depreciation expense on operating lease assets $ 246 $ 273 Finance Leases Our total gross investment in finance leases, which is included in finance receivables and loans, net, on our Condensed Consolidated Balance Sheet was $481 million and $439 million as of March 31, 2019 , and December 31, 2018 , respectively. This includes lease payment receivables of $465 million and $425 million and unguaranteed residual assets of $16 million and $14 million , respectively, as of March 31, 2019 , and December 31, 2018 . Interest income on finance lease receivables was $6 million for both the three months ended March 31, 2019 , and March 31, 2018 , and is included in interest and fees on finance receivables and loans in our Condensed Consolidated Statement of Comprehensive Income . The following table presents future minimum rental payments we have the right to receive under finance leases with noncancellable lease terms expiring after March 31, 2019 . ($ in millions) 2019 $ 110 2020 139 2021 134 2022 67 2023 38 2024 and thereafter 29 Total undiscounted cash flows 517 Difference between undiscounted cash flows and discounted cash flows (52 ) Present value of lease payments recorded as lease receivable $ 465

Securitizations and Variable In

Securitizations and Variable Interest Entities	3 Months Ended
	Mar. 31, 2019
Securitizations And Variable Interest Entities [Abstract]
Variable Interest Entity Disclosure	Securitizations and Variable Interest Entities 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). An SPE is a legal entity that is designed to fulfill a specified limited need of the sponsor. Our principal use of SPEs is to obtain liquidity by securitizing certain of our financial assets. SPEs are often variable interest entities (VIEs) and may or may not be included on our Condensed Consolidated Balance Sheet . 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 the equity investment at risk lack the ability to control 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. The VIEs included on the Condensed Consolidated Balance Sheet represent SPEs 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. 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 Condensed 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. There were no sales of financial assets into nonconsolidated VIEs for both the three months ended March 31, 2019 , and March 31, 2018 . 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. Refer to Note 1 and Note 11 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K for further description of our securitization activities and our involvement with VIEs. 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 Condensed Consolidated Balance Sheet . ($ 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 March 31, 2019 On-balance sheet variable interest entities Consumer automotive $ 16,226 (b) $ 6,480 (c) Commercial automotive 9,620 3,297 Off-balance sheet variable interest entities Consumer automotive 38 (d) — $ 957 $ 995 (e) Commercial other 867 (f) 343 (g) — 1,115 (h) Total $ 26,751 $ 10,120 $ 957 $ 2,110 December 31, 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 45 (d) — $ 1,235 $ 1,280 (e) Commercial other 806 (f) 326 (g) — 1,054 (h) Total $ 28,195 $ 10,845 $ 1,235 $ 2,334 (a) Asset values represent the current unpaid principal balance of outstanding consumer finance receivables and loans within the VIEs. (b) Includes $8.4 billion of assets that were not encumbered by VIE beneficial interests held by third parties at both March 31, 2019 , and December 31, 2018 . Ally or consolidated affiliates hold the interests in these assets. (c) Includes $24 million and $25 million of liabilities that were not obligations to third-party beneficial interest holders at March 31, 2019 , and December 31, 2018 , respectively. (d) Represents retained notes and certificated residual interests, of which $36 million and $43 million were classified as held-to-maturity securities at March 31, 2019 , and December 31, 2018 , respectively, and $2 million were classified as other assets at both March 31, 2019 , and December 31, 2018 . These assets represent our five percent interest in the credit risk of the assets underlying asset-backed securitizations. (e) 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. (f) Amounts are classified as other assets. (g) Amounts are classified as accrued expenses and other liabilities. (h) 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. 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 three months ended March 31, 2019 , and 2018 . Additionally, this table contains information regarding cash flows received from and paid to nonconsolidated SPEs that existed during each period. Three months ended March 31, ($ in millions) Consumer automotive 2019 Cash flows received on retained interests in securitization entities $ 7 Servicing fees 3 Cash disbursements for repurchases during the period (1 ) 2018 Cash flows received on retained interests in securitization entities $ 5 Servicing fees 5 Cash disbursements for repurchases during the period (1 ) 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 ($ in millions) March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018 Off-balance sheet securitization entities Consumer automotive $ 957 $ 1,235 $ 8 $ 13 Whole-loan sales (a) Consumer automotive 503 634 2 3 Total $ 1,460 $ 1,869 $ 10 $ 16 (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 Three months ended March 31, ($ in millions) 2019 2018 Off-balance sheet securitization entities Consumer automotive $ 2 $ 3 Whole-loan sales (a) Consumer automotive — 1 Total $ 2 $ 4 (a) Whole-loan sales are not part of a securitization transaction, but represent consumer automotive pools of loans sold to third-party investors.

Other Assets

Other Assets	3 Months Ended
	Mar. 31, 2019
Other Assets [Abstract]
Other Assets Disclosure	Other Assets The components of other assets were as follows. ($ in millions) March 31, 2019 December 31, 2018 Property and equipment at cost $ 1,286 $ 1,250 Accumulated depreciation (708 ) (686 ) Net property and equipment 578 564 Nonmarketable equity investments (a) 1,240 1,410 Restricted cash held for securitization trusts (b) 838 965 Investment in qualified affordable housing projects (c) 687 649 Accrued interest, fees, and rent receivables 624 599 Equity-method investments (d) 289 262 Other accounts receivable 269 203 Goodwill (e) 240 240 Net deferred tax assets 137 317 Restricted cash and cash equivalents (f) 109 124 Fair value of derivative contracts in receivable position (g) 22 41 Cash collateral placed with counterparties 20 26 Other assets 940 753 Total other assets $ 5,993 $ 6,153 (a) Includes investments in FHLB stock of $732 million and $903 million at March 31, 2019 , and December 31, 2018 , respectively; Federal Reserve Bank (FRB) stock of $448 million at both March 31, 2019 , and December 31, 2018 ; and equity securities without a readily determinable fair value of $60 million and $59 million at March 31, 2019 , and December 31, 2018 , respectively, measured at cost with adjustments for impairment and observable changes in price. Through March 31, 2019 , we recorded $3 million of cumulative impairments and downward adjustments 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 $336 million and $319 million of unfunded commitments to provide additional capital contributions to investees at March 31, 2019 , and December 31, 2018 , respectively. Substantially all of the unfunded commitments at March 31, 2019 , are expected to be paid out over the next five years. (d) Primarily relates to investments made in connection with our Community Reinvestment Act (CRA) program. (e) Includes goodwill of $27 million within our Insurance operations at both March 31, 2019 , and December 31, 2018 ; $193 million within Corporate and Other at both March 31, 2019 , and December 31, 2018 ; and $20 million within Automotive Finance operations at both March 31, 2019 , and December 31, 2018 . No changes to the carrying amount of goodwill were recorded during the three months ended March 31, 2019 . (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 17 .

Deposit Liabilities

Deposit Liabilities	3 Months Ended
	Mar. 31, 2019
Deposits [Abstract]
Deposit Liabilities Disclosures	Deposit Liabilities Deposit liabilities consisted of the following. ($ in millions) March 31, 2019 December 31, 2018 Noninterest-bearing deposits $ 141 $ 142 Interest-bearing deposits Savings and money-market checking accounts 60,258 56,050 Certificates of deposit 52,899 49,985 Other deposits 1 1 Total deposit liabilities $ 113,299 $ 106,178 At March 31, 2019 , and December 31, 2018 , certificates of deposit included $22.1 billion and $21.0 billion , respectively, of those in denominations of $100 thousand or more. At March 31, 2019 , and December 31, 2018 , certificates of deposit included $6.6 billion and $6.1 billion , respectively, of those in denominations in excess of $250 thousand federal insurance limits.

Debt

Debt	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Debt Disclosure	Debt Short-term Borrowings The following table presents the composition of our short-term borrowings portfolio. March 31, 2019 December 31, 2018 ($ in millions) Unsecured Secured (a) Total Unsecured Secured (a) Total Demand notes $ 2,486 $ — $ 2,486 $ 2,477 $ — $ 2,477 Federal Home Loan Bank — 2,775 2,775 — 6,825 6,825 Securities sold under agreements to repurchase — 854 854 — 685 685 Total short-term borrowings $ 2,486 $ 3,629 $ 6,115 $ 2,477 $ 7,510 $ 9,987 (a) Refer to the section below titled Long-term Debt for further details on assets restricted as collateral for payment of the related debt. 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 March 31, 2019 , the securities sold under agreements to repurchase consisted of $448 million of U.S. Treasury securities and $406 million of agency mortgage-backed residential debt securities set to mature as follows: $513 million within 30 days, $268 million within 31 to 60 days , and $73 million within 61 to 90 days. Refer to Note 6 and Note 20 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 March 31, 2019 , we did not place any collateral, and we received cash collateral totaling $8 million and noncash collateral totaling $3 million . At December 31, 2018 , we did not place any collateral, and we received cash collateral totaling $8 million and noncash collateral totaling $4 million . Long-term Debt The following table presents the composition of our long-term debt portfolio. March 31, 2019 December 31, 2018 ($ in millions) Unsecured Secured Total Unsecured Secured Total Long-term debt (a) Due within one year $ 2,630 $ 6,948 $ 9,578 $ 1,663 $ 7,313 $ 8,976 Due after one year 8,708 23,204 31,912 10,444 24,773 35,217 Total long-term debt (b) (c) $ 11,338 $ 30,152 $ 41,490 $ 12,107 $ 32,086 $ 44,193 (a) Includes basis adjustments related to the application of hedge accounting. Refer to Note 17 for additional information. (b) Includes $2.6 billion of trust preferred securities at both March 31, 2019 , and December 31, 2018 . (c) Includes advances net of hedge basis adjustment from the FHLB of Pittsburgh of $14.7 billion and $14.9 billion at March 31, 2019 , and December 31, 2018 , respectively. The following table presents the scheduled remaining maturity of long-term debt at March 31, 2019 , assuming no early redemptions will occur. The amounts below include adjustments to the carrying value resulting from the application of hedge accounting. The actual payment of secured debt may vary based on the payment activity of the related pledged assets. ($ in millions) 2019 2020 2021 2022 2023 2024 and thereafter Total Unsecured Long-term debt $ 917 $ 2,258 $ 697 $ 1,075 $ 12 $ 7,504 $ 12,463 Original issue discount (31 ) (41 ) (45 ) (49 ) (56 ) (903 ) (1,125 ) Total unsecured 886 2,217 652 1,026 (44 ) 6,601 11,338 Secured Long-term debt 4,998 6,909 10,185 6,008 1,236 816 30,152 Total long-term debt $ 5,884 $ 9,126 $ 10,837 $ 7,034 $ 1,192 $ 7,417 $ 41,490 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. March 31, 2019 December 31, 2018 ($ in millions) Total (a) Ally Bank Total (a) Ally Bank Investment securities (b) $ 5,243 $ 4,357 $ 10,280 $ 9,564 Mortgage assets held-for-investment and lending receivables 17,447 17,447 16,498 16,498 Consumer automotive finance receivables 15,882 9,777 17,015 9,715 Commercial automotive finance receivables 14,269 14,269 15,563 15,563 Operating leases 132 — 170 — Total assets restricted as collateral (c) (d) $ 52,973 $ 45,850 $ 59,526 $ 51,340 Secured debt $ 33,781 (e) $ 27,233 $ 39,596 (e) $ 32,072 (a) Ally Bank is a component of the total column. (b) A portion of the restricted investment securities at March 31, 2019 , and December 31, 2018 , 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 $26.6 billion and $30.8 billion at March 31, 2019 , and December 31, 2018 , 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 at both March 31, 2019 , and December 31, 2018 . 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 Condensed Consolidated Balance Sheet . Refer to Note 10 for additional information. (e) Includes $3.6 billion and $7.5 billion of short-term borrowings at March 31, 2019 , and December 31, 2018 , respectively. Trust Preferred Securities At both March 31, 2019 , and December 31, 2018 , we had 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 offered 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. 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 Condensed Consolidated Balance Sheet . As of March 31, 2019 , Ally Bank had exclusive access to $3.8 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 March 31, 2019 , all of our $7.6 billion of capacity was revolving and of this balance, $6.0 billion was from facilities with a remaining tenor greater than 364 days. Committed Secured Credit Facilities Outstanding Unused capacity (a) Total capacity ($ in millions) March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018 Bank funding Secured $ 3,050 $ 3,500 $ 700 $ 1,300 $ 3,750 $ 4,800 Parent funding Secured 2,666 3,165 1,134 635 3,800 3,800 Total committed secured credit facilities $ 5,716 $ 6,665 $ 1,834 $ 1,935 $ 7,550 $ 8,600 (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	3 Months Ended
	Mar. 31, 2019
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. ($ in millions) March 31, 2019 December 31, 2018 Accounts payable $ 347 $ 516 Unfunded commitments for investment in qualified affordable housing projects 336 319 Employee compensation and benefits 165 255 Reserves for insurance losses and loss adjustment expenses 135 134 Deferred revenue 28 27 Cash collateral received from counterparties 27 41 Fair value of derivative contracts in payable position (a) 21 37 Other liabilities 663 347 Total accrued expenses and other liabilities $ 1,722 $ 1,676 (a) For additional information on derivative instruments and hedging activities, refer to Note 17 .

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	3 Months Ended
	Mar. 31, 2019
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 December 31, 2017 $ (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 (186 ) 20 11 (95 ) (250 ) 2018 net change (338 ) (1 ) 14 (3 ) (328 ) Balance at March 31, 2018 $ (524 ) $ 19 $ 25 $ (98 ) $ (578 ) Balance at December 31, 2018 $ (481 ) $ 18 $ 19 $ (95 ) $ (539 ) Cumulative effect of changes in accounting principles, net of tax (c) Adoption of Accounting Standards Update 2017-08 8 — — — 8 Balance at January 1, 2019 (473 ) 18 19 (95 ) (531 ) 2019 net change 315 — (8 ) (1 ) 306 Balance at March 31, 2019 $ (158 ) $ 18 $ 11 $ (96 ) $ (225 ) (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 17 . (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. Three months ended March 31, 2019 ($ in millions) Before tax Tax effect After tax Investment securities Net unrealized gains arising during the period $ 421 $ (99 ) $ 322 Less: Net realized gains reclassified to income from continuing operations 9 (a) (2 ) (b) 7 Net change 412 (97 ) 315 Translation adjustments Net unrealized gains arising during the period 2 (1 ) 1 Net investment hedges (c) Net unrealized losses arising during the period (2 ) 1 (1 ) Cash flow hedges (c) Net unrealized losses arising during the period (5 ) 1 (4 ) Less: Net realized gains reclassified to income from continuing operations 5 (1 ) 4 Net change (10 ) 2 (8 ) Defined benefit pension plans Net unrealized losses arising during the period (1 ) — (1 ) Other comprehensive loss $ 401 $ (95 ) $ 306 (a) Includes gains reclassified to other gain (loss) on investments, net in our Condensed Consolidated Statement of Comprehensive Income . (b) Includes amounts reclassified to income tax expense from continuing operations in our Condensed Consolidated Statement of Comprehensive Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 17 . Three months ended March 31, 2018 ($ in millions) Before tax Tax effect After tax Investment securities Net unrealized losses arising during the period $ (436 ) $ 103 $ (333 ) Less: Net realized gains reclassified to income from continuing operations 6 (a) (1 ) (b) 5 Net change (442 ) 104 (338 ) Translation adjustments Net unrealized losses arising during the period (5 ) 1 (4 ) Net investment hedges (c) Net unrealized gains arising during the period 4 (1 ) 3 Cash flow hedges (c) Net unrealized gains arising during the period 18 (4 ) 14 Defined benefit pension plans Net unrealized losses arising during the period (3 ) — (3 ) Other comprehensive loss $ (428 ) $ 100 $ (328 ) (a) Includes gains reclassified to other (loss) gain on investments, net in our Condensed Consolidated Statement of Comprehensive Income . (b) Includes amounts reclassified to income tax expense from continuing operations in our Condensed Consolidated Statement of Comprehensive Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 17 .

Earnings per Common Share

Earnings per Common Share	3 Months Ended
	Mar. 31, 2019
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. Three months ended March 31, ($ in millions, except per share data; shares in thousands) (a) 2019 2018 Net income from continuing operations attributable to common stockholders $ 375 $ 252 Loss from discontinued operations, net of tax (1 ) (2 ) Net income attributable to common stockholders $ 374 $ 250 Basic weighted-average common shares outstanding (b) 404,129 436,213 Diluted weighted-average common shares outstanding (b) 405,959 438,931 Basic earnings per common share Net income from continuing operations $ 0.93 $ 0.58 Loss from discontinued operations, net of tax — (0.01 ) Net income $ 0.93 $ 0.57 Diluted earnings per common share Net income from continuing operations $ 0.92 $ 0.57 Loss from discontinued operations, net of tax — (0.01 ) Net income $ 0.92 $ 0.57 (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	3 Months Ended
	Mar. 31, 2019
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 Condensed 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 subject to a capital conservation buffer of more than 2.5% . 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 address the impact of CECL on regulatory capital by allowing BHCs and banks, including Ally, the option 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, in order to reduce uncertainty, the FRB 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. Following the issuance of this proposed rule, during 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. 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 $50 billion or more in total consolidated assets. The proposal would introduce a stress capital buffer based on firm-specific stress test performance, which would effectively replace the non-stress capital conservation buffer. The proposal would also make several changes to the CCAR process, such as eliminating the CCAR quantitative objection, narrowing the set of planned capital actions assumed to occur in the stress scenario, and eliminating the 30% dividend payout ratio as a criterion for heightened scrutiny of a firm’s capital plan. In December 2017, the Basel Committee approved revisions to the global Basel III capital framework (commonly known as Basel IV), many of which—if adopted in the United States—could heighten regulatory capital standards even more. At this time, how all of these proposals and revisions will be harmonized and finalized in the United States is not clear or predictable and we continue to evaluate the impacts these proposals and revisions may have on us. Compliance with capital requirements is a strategic priority for Ally. We expect to be in compliance with all applicable requirements within the established timeframes. The following table summarizes our capital ratios under the U.S. Basel III capital framework. March 31, 2019 December 31, 2018 Required minimum (a) Well-capitalized minimum ($ in millions) Amount Ratio Amount Ratio Capital ratios Common Equity Tier 1 (to risk-weighted assets) Ally Financial Inc. $ 13,603 9.33 % $ 13,397 9.14 % 4.50 % (b) Ally Bank 16,609 12.55 16,552 12.61 4.50 6.50 % Tier 1 (to risk-weighted assets) Ally Financial Inc. $ 16,035 10.99 % $ 15,831 10.80 % 6.00 % 6.00 % Ally Bank 16,609 12.55 16,552 12.61 6.00 8.00 Total (to risk-weighted assets) Ally Financial Inc. $ 18,292 12.54 % $ 18,046 12.31 % 8.00 % 10.00 % Ally Bank 17,802 13.46 17,620 13.42 8.00 10.00 Tier 1 leverage (to adjusted quarterly average assets) (c) Ally Financial Inc. $ 16,035 9.02 % $ 15,831 9.00 % 4.00 % (b) Ally Bank 16,609 10.45 16,552 10.69 4.00 5.00 % (a) In addition to the minimum risk-based capital requirements for the 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 2.5% and 1.875% at March 31, 2019 , and December 31, 2018 , respectively. (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 March 31, 2019 , 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 and distributions to our common stockholders over the last five quarters. 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 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 2019 First quarter $ 211 8,113 404,900 399,761 $ 0.17 (a) Includes shares of common stock withheld to cover income taxes owed by participants in our share-based incentive plans. (b) On April 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 May 15, 2019 . Refer to Note 24 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 increases 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 April 14, 2019, the Board declared a quarterly cash dividend of $0.17 per share of our common stock. Refer to Note 24 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. As described earlier in this note, Ally’s capital actions during this cycle will be largely based on the results from its 2018 supervisory stress test. On April 1, 2019, the Board authorized an increase in our stock-repurchase program, permitting us to repurchase up to $1.25 billion of our common stock from time to time from the third quarter of 2019 through the second quarter of 2020, representing a 25% increase over our previously announced program. 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 and approval by the Board. The amount and size of any future dividends and share repurchases also will be subject to various factors, including Ally’s capital and liquidity positions, regulatory considerations, any accounting standards that affect capital or liquidity (including CECL), financial and operational performance, alternative uses of capital, common-stock price, and general market conditions, and may be suspended at any time.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	3 Months Ended
	Mar. 31, 2019
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, as well as interest rate floor contracts designated as cash flow hedges of the expected future cash flows in the form of interest receipts on a portion of our dealer floorplan commercial loans. 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. We execute certain over-the-counter (OTC) derivatives such as interest rate caps using bilateral agreements with financial counterparties. Bilateral 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. Payments related to the exchange of collateral for OTC derivatives are recognized as collateral. We also 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 three months ended March 31, 2019 , or 2018 . We placed cash collateral totaling $19 million and noncash collateral totaling $99 million supporting our derivative positions at March 31, 2019 , and $26 million and $105 million at December 31, 2018 , respectively, in accounts maintained by counterparties. These amounts include collateral placed at clearinghouses and exclude cash and noncash collateral pledged under repurchase agreements. Refer to Note 12 for details on the repurchase agreements. The receivables for cash collateral placed are included on our Condensed Consolidated Balance Sheet in other assets. We received cash collateral from counterparties totaling $12 million at March 31, 2019 , and we received $30 million and $3 million of cash and noncash collateral, respectively, at December 31, 2018 , in accounts maintained by counterparties. These amounts include collateral received from clearinghouses and exclude cash and noncash collateral pledged under repurchase agreements. Refer to Note 12 for details on repurchase agreements. The payables for cash collateral received are included on our Condensed Consolidated Balance Sheet in accrued expenses and other liabilities. Included in these amounts is noncash collateral where we have been granted the right to sell or pledge the underlying assets. We have not sold or pledged any of the noncash collateral received under these agreements. Balance Sheet Presentation The following table summarizes the amounts of derivative instruments reported on our Condensed Consolidated Balance Sheet . The amounts are presented on a gross basis, are segregated by derivatives that are designated and qualifying as hedging instruments or those that are not, and are further segregated by type of contract within those two categories. Derivative contracts in a receivable and payable position exclude open trade equity on derivatives cleared through central clearing counterparties. Any associated collateral exchanged with our central clearing counterparties are treated as settlements of the derivative exposure, rather than collateral. Such payments are recognized as settlements of the derivatives contracts in a receivable and payable position on our Condensed Consolidated Balance Sheet . Notional amounts are reference amounts from which contractual obligations are derived and are not recorded on the balance sheet. In our view, derivative notional is not an accurate measure of our derivative exposure when viewed in isolation from other factors, such as market rate fluctuations and counterparty credit risk. March 31, 2019 December 31, 2018 Derivative contracts in a Notional amount Derivative contracts in a Notional amount ($ in millions) receivable position payable position receivable position payable position Derivatives designated as accounting hedges Interest rate contracts Swaps $ — $ — $ 12,085 $ — $ — $ 24,203 Purchased options 1 — 100 — — — Foreign exchange contracts Forwards — 1 134 1 — 136 Total derivatives designated as accounting hedges 1 1 12,319 1 — 24,339 Derivatives not designated as accounting hedges Interest rate contracts Futures and forwards — — 11 — — 11 Written options 2 19 6,180 — 37 6,793 Purchased options 19 — 6,081 37 — 6,742 Total interest rate risk 21 19 12,272 37 37 13,546 Foreign exchange contracts Futures and forwards — — 124 3 — 181 Total foreign exchange risk — — 124 3 — 181 Equity contracts Written options — 1 1 — — — Total equity risk — 1 1 — — — Total derivatives not designated as accounting hedges 21 20 12,397 40 37 13,727 Total derivatives $ 22 $ 21 $ 24,716 $ 41 $ 37 $ 38,066 The following table presents amounts recorded on our Condensed Consolidated Balance Sheet related to cumulative basis adjustments for fair value hedges. ($ 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) March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018 Assets Available-for-sale securities (b) (c) $ 1,495 $ 1,485 $ 10 $ — $ 8 $ (5 ) Finance receivables and loans, net (d) 36,433 40,850 63 24 68 5 Liabilities Long-term debt $ 12,263 $ 13,001 $ 66 $ 67 $ 66 $ 67 (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 6 for a reconciliation of the amortized cost and fair value of available-for-sale securities. (c) The amount identified as the last of layer in the hedge relationship was $28 million at both March 31, 2019 , and December 31, 2018 , but the hedge relationship was discontinued during the three months ended March 31, 2019 . The carrying amount associated with the last-of-layer relationship was $46 million and $47 million , respectively. There was no basis adjustment associated with the last-of-layer relationships for either period. (d) The hedged item represents the carrying value of the hedged portfolio of assets. The amount identified as the last of layer in the open hedge relationship was $9.6 billion as of March 31, 2019 , and $21.4 billion as of December 31, 2018 . The basis adjustment associated with the open last-of-layer relationship was a $5 million liability as of March 31, 2019 , and 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. The amount that is identified as the last of layer in the discontinued hedge relationship was $11.2 billion for the three months ended March 31, 2019 . The basis adjustment associated with the discontinued last-of-layer relationship was a $65 million asset for the three months ended March 31, 2019 , which was allocated across the entire remaining pool upon termination of the hedge relationship. Statement of Comprehensive Income Presentation The following table summarizes the location and amounts of gains and losses on derivative instruments not designated as accounting hedges reported in our Condensed Consolidated Statement of Comprehensive Income . Three months ended March 31, ($ in millions) 2019 2018 Gain (loss) recognized in earnings Interest rate contracts Gain on mortgage and automotive loans, net $ 1 $ — Other income, net of losses (5 ) 2 Total interest rate contracts (4 ) 2 Foreign exchange contracts Other income, net of losses (1 ) — Total foreign exchange contracts (1 ) — (Loss) gain recognized in earnings $ (5 ) $ 2 The following table summarizes the location and amounts of gains and losses on derivative instruments designated as fair value hedges reported in our Condensed Consolidated Statement of Comprehensive 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 Three months ended March 31, ($ in millions) 2019 2018 2019 2018 2019 2018 2019 2018 Gain (loss) on fair value hedging relationships Interest rate contracts Hedged fixed-rate unsecured debt $ — $ — $ — $ — $ — $ — $ — $ 36 Derivatives designated as hedging instruments on fixed-rate unsecured debt — — — — — — — (35 ) Hedged fixed-rate FHLB advances — — — — — — — 33 Derivatives designated as hedging instruments on fixed-rate FHLB advances — — — — — — — (33 ) Hedged available-for-sale securities — — 10 (3 ) — — — — Derivatives designated as hedging instruments on available-for-sale securities — — (10 ) 3 — — — — Hedged fixed-rate consumer automotive loans 43 (45 ) — — — — — — Derivatives designated as hedging instruments on fixed-rate consumer automotive loans (43 ) 45 — — — — — — Total gain on fair value hedging relationships — — — — — — — 1 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 — — — — — — 4 — Total gain on cash flow hedging relationships $ — $ — $ — $ — $ 1 $ — $ 4 $ — Total amounts presented in the Condensed Consolidated Statement of Comprehensive Income $ 1,807 $ 1,543 $ 240 $ 176 $ 592 $ 351 $ 419 $ 411 During the next twelve months, we estimate $7 million will be reclassified into pretax earnings from derivatives designated as cash flow hedges. The following table summarizes the location and amounts of gains and losses related to interest and amortization on derivative instruments designated as fair value and cash flow hedges reported in our Condensed Consolidated Statement of Comprehensive Income . Interest and fees on finance receivables and loans Interest and dividends on investment securities and other earning assets Interest on long-term debt Three months ended March 31, ($ in millions) 2019 2018 2019 2018 2019 2018 Gain (loss) on fair value hedging relationships Interest rate contracts Amortization of deferred unsecured debt basis adjustments $ — $ — $ — $ — $ 6 $ 15 Interest for qualifying accounting hedges of unsecured debt — — — — — 3 Amortization of deferred secured debt basis adjustments (FHLB advances) — — — — (6 ) (1 ) Interest for qualifying accounting hedges of secured debt (FHLB advances) — — — — — 2 Interest for qualifying accounting hedges of available-for-sale securities — — — (1 ) — — Amortization of deferred loan basis adjustments (4 ) (4 ) — — — — Interest for qualifying accounting hedges of consumer automotive loans held-for-investment 6 (7 ) — — — — Total gain (loss) on fair value hedging relationships 2 (11 ) — (1 ) — 19 Gain on cash flow hedging relationships Interest rate contracts Interest for qualifying accounting hedges of variable-rate borrowings — — — — — 1 Total gain on cash flow hedging relationships $ — $ — $ — $ — $ — $ 1 The following table summarizes the effect of cash flow hedges on accumulated other comprehensive loss. Three months ended March 31, ($ in millions) 2019 2018 Interest rate contracts (Loss) gain recognized in other comprehensive loss $ (10 ) $ 18 The following table summarizes the effect of net investment hedges on accumulated other comprehensive loss and the Condensed Consolidated Statement of Comprehensive Income . Three months ended March 31, ($ in millions) 2019 2018 Foreign exchange contracts (a) (b) (Loss) gain recognized in other comprehensive loss $ (2 ) $ 4 (a) There were no amounts excluded from effectiveness testing for the three months ended March 31, 2019 , or 2018 . (b) Gains and losses reclassified from accumulated other comprehensive loss are reported as other income, net of losses, in the Condensed Consolidated Statement of Comprehensive Income. There were no amounts reclassified for the three months ended March 31, 2019 , or 2018 .

Income Taxes Income Taxes

Income Taxes Income Taxes	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Tax Disclosure	Income Taxes We recognized total income tax expense from continuing operations of $111 million for the three months ended March 31, 2019 , compared to income tax expense of $76 million for the same period in 2018 . The increase in income tax expense for the three months ended March 31, 2019 , compared to the same period in 2018 , was primarily driven by the tax effects of an increase in pretax earnings. 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.

Fair Value

Fair Value	3 Months Ended
	Mar. 31, 2019
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 Condensed 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 March 31, 2019 ($ in millions) Level 1 Level 2 Level 3 Total Assets Investment securities Equity securities (a) $ 525 $ — $ 11 $ 536 Available-for-sale securities Debt securities U.S. Treasury and federal agencies 1,941 1 — 1,942 U.S. States and political subdivisions — 781 — 781 Foreign government 7 165 — 172 Agency mortgage-backed residential — 18,844 — 18,844 Agency mortgage-backed commercial — 320 — 320 Mortgage-backed residential — 2,886 — 2,886 Mortgage-backed commercial — 723 — 723 Asset-backed — 668 — 668 Corporate debt — 1,294 — 1,294 Total available-for-sale securities 1,948 25,682 — 27,630 Mortgage loans held-for-sale (b) — — 15 15 Interests retained in financial asset sales — — 4 4 Derivative contracts in a receivable position Interest rate — 20 2 22 Total derivative contracts in a receivable position — 20 2 22 Total assets $ 2,473 $ 25,702 $ 32 $ 28,207 Liabilities Accrued expenses and other liabilities Derivative contracts in a payable position Interest rate $ — $ 19 $ — $ 19 Foreign currency — 1 — 1 Other 1 — — 1 Total derivative contracts in a payable position 1 20 — 21 Total liabilities $ 1 $ 20 $ — $ 21 (a) Our investment in any one industry did not exceed 15% . (b) Carried at fair value due to fair value option elections. 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 Agency mortgage-backed commercial — 3 — 3 Mortgage-backed residential — 2,686 — 2,686 Mortgage-backed commercial — 714 — 714 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. 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 gains Fair value at March 31, 2019 Net unrealized gains still held at March 31, 2019 ($ in millions) Fair value at Jan. 1, 2019 included in earnings included in OCI Purchases Sales Issuances Settlements included in earnings included in OCI Assets Equity securities $ 7 $ 4 (a) $ — $ — $ — $ — $ — $ 11 $ 4 $ — Mortgage loans held-for-sale (b) 8 1 (c) — 90 (84 ) — — 15 — — Other assets Interests retained in financial asset sales 4 — — — — — — 4 — — Derivative assets — 2 (c) — — — — — 2 2 — Total assets $ 19 $ 7 $ — $ 90 $ (84 ) $ — $ — $ 32 $ 6 $ — (a) Reported as other gain on investments, net, in the Condensed Consolidated Statement of Comprehensive Income . (b) Carried at fair value due to fair value option elections. (c) Reported as gain on mortgage and automotive loans, net, in the Condensed Consolidated Statement of Comprehensive Income . Level 3 recurring fair value measurements Fair value at Jan. 1, 2018 Net realized/unrealized (losses) gains Purchases Sales Issuances Settlements Fair value at March 31, 2018 Net unrealized losses included in earnings still held at March 31, 2018 ($ in millions) included in earnings included in OCI Assets Equity securities $ 19 $ (4 ) (a) $ — $ — $ — $ — $ (3 ) $ 12 $ (5 ) Mortgage loans held-for-sale (b) 13 1 (c) — 59 (66 ) — — 7 — Other assets Interests retained in financial asset sales 5 — — — — — — 5 — Derivative assets 1 — — — — — — 1 — Total assets $ 38 $ (3 ) $ — $ 59 $ (66 ) $ — $ (3 ) $ 25 $ (5 ) (a) Reported as other loss on investments, net, in the Condensed Consolidated Statement of Comprehensive Income . (b) Carried at fair value due to fair value option elections. (c) Reported as gain on mortgage and automotive loans, net, in the Condensed Consolidated Statement of Comprehensive 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 March 31, 2019 , and December 31, 2018 , 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 reserve, valuation reserve, or cumulative impairment Total gain (loss) included in earnings March 31, 2019 ($ in millions) Level 1 Level 2 Level 3 Total Assets Loans held-for-sale, net Automotive $ — $ — $ 18 $ 18 $ — n/m (a) Other — — 74 74 — n/m (a) Total loans held-for-sale, net — — 92 92 — n/m (a) Commercial finance receivables and loans, net (b) Automotive — — 83 83 (18 ) n/m (a) Other — — 30 30 (40 ) n/m (a) Total commercial finance receivables and loans, net — — 113 113 (58 ) n/m (a) Other assets Repossessed and foreclosed assets (c) — — 12 12 (1 ) n/m (a) Nonmarketable equity investments — — 2 2 — n/m (a) Equity-method investments — — 1 1 (3 ) n/m (a) Total assets $ — $ — $ 220 $ 220 $ (62 ) n/m n/m = not meaningful (a) We consider the applicable valuation allowance, loan loss allowance, or cumulative impairment 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 allowance, loan loss allowance, or cumulative impairment. (b) Represents the portion of the portfolio specifically impaired during 2019 . 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. Nonrecurring fair value measurements Lower-of-cost or fair value reserve, valuation reserve, or cumulative impairment 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 allowance, loan loss allowance, or cumulative impairment 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 allowance, loan loss allowance, or cumulative impairment. (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. 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 March 31, 2019 , and December 31, 2018 . Estimated fair value ($ in millions) Carrying value Level 1 Level 2 Level 3 Total March 31, 2019 Financial assets Held-to-maturity securities $ 2,387 $ — $ 2,374 $ — $ 2,374 Loans held-for-sale, net 92 — — 92 92 Finance receivables and loans, net 128,767 — — 131,541 131,541 FHLB/FRB stock (a) 1,180 — 1,180 — 1,180 Financial liabilities Deposit liabilities $ 54,899 $ — $ — $ 55,106 $ 55,106 Short-term borrowings 6,115 — — 6,119 6,119 Long-term debt 41,490 — 23,038 20,661 43,699 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 $ 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 (a) Included in other assets on our Condensed Consolidated Balance Sheet .

Offsetting Assets and Liabiliti

Offsetting Assets and Liabilities	3 Months Ended
	Mar. 31, 2019
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 March 31, 2019 , these instruments are reported as gross assets and gross liabilities on the Condensed 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 Condensed Consolidated Balance Sheet Net amounts of assets/liabilities presented on the Condensed Consolidated Balance Sheet Gross amounts not offset on the Condensed Consolidated Balance Sheet March 31, 2019 ($ in millions) Financial instruments Collateral (a) (b) (c) Net amount Assets Derivative assets in net asset positions (d) $ 20 $ — $ 20 $ (1 ) $ (1 ) $ 18 Derivative assets with no offsetting arrangements 2 — 2 — — 2 Total assets $ 22 $ — $ 22 $ (1 ) $ (1 ) $ 20 Liabilities Derivative liabilities in net liability positions (d) $ 20 $ — $ 20 $ — $ (1 ) $ 19 Derivative liabilities in net asset positions 1 — 1 (1 ) — — Total derivative liabilities (d) 21 — 21 (1 ) (1 ) 19 Securities sold under agreements to repurchase (e) 854 — 854 — (854 ) — Total liabilities $ 875 $ — $ 875 $ (1 ) $ (855 ) $ 19 (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 collateral associated with our repurchase agreements pledged to us that was excluded at March 31, 2019 . We do not record such collateral received on our Condensed 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 $3 million at March 31, 2019 . We have not sold or pledged any of the noncash collateral received under these agreements as of March 31, 2019 . (d) For additional information on derivative instruments and hedging activities, refer to Note 17 . (e) For additional information on securities sold under agreements to repurchase, refer to Note 12 . Gross amounts of recognized assets/liabilities Gross amounts offset on the Condensed Consolidated Balance Sheet Net amounts of assets/liabilities presented on the Condensed Consolidated Balance Sheet Gross amounts not offset on the Condensed Consolidated Balance Sheet December 31, 2018 ($ in millions) Financial instruments Collateral (a) (b) (c) Net amount Assets Derivative assets in net asset positions $ 41 $ — $ 41 $ — $ (4 ) $ 37 Total assets (d) $ 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 Condensed 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 17 . (e) For additional information on securities sold under agreements to repurchase, refer to Note 12 .

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2019
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 low-to-moderate income (LMI) mortgage loans originated by third parties. Our direct-to-consumer mortgage offering, named Ally Home, consists 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. We also offer 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. Three months ended March 31, ($ in millions) Automotive Finance operations Insurance operations Mortgage Finance operations Corporate Finance operations Corporate and Other Consolidated (a) 2019 Net financing revenue and other interest income $ 980 $ 12 $ 50 $ 54 $ 36 $ 1,132 Other revenue 68 360 2 11 25 466 Total net revenue 1,048 372 52 65 61 1,598 Provision for loan losses 262 — 2 23 (5 ) 282 Total noninterest expense 457 227 37 29 80 830 Income (loss) from continuing operations before income tax expense $ 329 $ 145 $ 13 $ 13 $ (14 ) $ 486 Total assets $ 115,789 $ 8,179 $ 16,301 $ 5,006 $ 34,842 $ 180,117 2018 Net financing revenue and other interest income $ 909 $ 12 $ 43 $ 46 $ 39 $ 1,049 Other revenue 66 246 1 8 33 354 Total net revenue 975 258 44 54 72 1,403 Provision for loan losses 259 — 2 — — 261 Total noninterest expense 448 231 34 25 76 814 Income (loss) from continuing operations before income tax expense $ 268 $ 27 $ 8 $ 29 $ (4 ) $ 328 Total assets $ 114,934 $ 7,557 $ 12,780 $ 4,375 $ 30,375 $ 170,021 (a) Net financing revenue and other interest income after the provision for loan losses totaled $850 million and $788 million for the three months ended March 31, 2019 , and March 31, 2018 , respectively.

Parent and Guarantor Condensed

Parent and Guarantor Condensed Consolidating Financial Statements	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Financial Statements	Parent and Guarantor Condensed 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 March 31, 2019 , 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 Three months ended March 31, 2019 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing revenue and other interest income Interest and fees on finance receivables and loans $ (60 ) $ — $ 1,867 $ — $ 1,807 Interest and fees on finance receivables and loans — intercompany 3 — 2 (5 ) — Interest on loans held-for-sale — — 2 — 2 Interest and dividends on investment securities and other earning assets — — 240 — 240 Interest on cash and cash equivalents 2 — 21 — 23 Interest-bearing cash — intercompany 2 — 3 (5 ) — Operating leases 2 — 359 — 361 Total financing (loss) revenue and other interest income (51 ) — 2,494 (10 ) 2,433 Interest expense Interest on deposits — — 592 — 592 Interest on short-term borrowings 13 — 31 — 44 Interest on long-term debt 211 — 208 — 419 Interest on intercompany debt 5 — 5 (10 ) — Total interest expense 229 — 836 (10 ) 1,055 Net depreciation expense on operating lease assets 1 — 245 — 246 Net financing (loss) revenue (281 ) — 1,413 — 1,132 Cash dividends from subsidiaries Bank subsidiary 400 400 — (800 ) — Nonbank subsidiaries 42 — — (42 ) — Other revenue Insurance premiums and service revenue earned — — 261 — 261 Gain on mortgage and automotive loans, net 4 — 6 — 10 Other gain on investments, net — — 108 — 108 Other income, net of losses 103 — 144 (160 ) 87 Total other revenue 107 — 519 (160 ) 466 Total net revenue 268 400 1,932 (1,002 ) 1,598 Provision for loan losses 27 — 272 (17 ) 282 Noninterest expense Compensation and benefits expense 12 — 306 — 318 Insurance losses and loss adjustment expenses — — 59 — 59 Other operating expenses 155 — 458 (160 ) 453 Total noninterest expense 167 — 823 (160 ) 830 Income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries 74 400 837 (825 ) 486 Income tax (benefit) expense from continuing operations (61 ) — 172 — 111 Net income from continuing operations 135 400 665 (825 ) 375 Loss from discontinued operations, net of tax (1 ) — — — (1 ) Undistributed income of subsidiaries Bank subsidiary 57 57 — (114 ) — Nonbank subsidiaries 183 — — (183 ) — Net income 374 457 665 (1,122 ) 374 Other comprehensive income, net of tax 306 229 320 (549 ) 306 Comprehensive income $ 680 $ 686 $ 985 $ (1,671 ) $ 680 Three months ended March 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 $ 11 $ — $ 1,532 $ — $ 1,543 Interest and fees on finance receivables and loans — intercompany 2 — 1 (3 ) — Interest and dividends on investment securities and other earning assets — — 176 — 176 Interest on cash and cash equivalents 2 — 14 (1 ) 15 Interest-bearing cash — intercompany 2 — 2 (4 ) — Operating leases 2 — 380 — 382 Total financing revenue and other interest income 19 — 2,105 (8 ) 2,116 Interest expense Interest on deposits — — 354 (3 ) 351 Interest on short-term borrowings 10 — 22 — 32 Interest on long-term debt 258 — 153 — 411 Interest on intercompany debt 3 — 2 (5 ) — Total interest expense 271 — 531 (8 ) 794 Net depreciation expense on operating lease assets 4 — 269 — 273 Net financing (loss) revenue (256 ) — 1,305 — 1,049 Cash dividends from subsidiaries Bank subsidiary 1,000 1,000 — (2,000 ) — Nonbank subsidiaries 169 — — (169 ) — Other revenue Insurance premiums and service revenue earned — — 256 — 256 Gain on mortgage and automotive loans, net 28 — 1 (28 ) 1 Other loss on investments, net — — (12 ) — (12 ) Other income, net of losses 96 — 221 (208 ) 109 Total other revenue 124 — 466 (236 ) 354 Total net revenue 1,037 1,000 1,771 (2,405 ) 1,403 Provision for loan losses 81 — 208 (28 ) 261 Noninterest expense Compensation and benefits expense 23 — 283 — 306 Insurance losses and loss adjustment expenses — — 63 — 63 Other operating expenses 182 — 471 (208 ) 445 Total noninterest expense 205 — 817 (208 ) 814 Income from continuing operations before income tax (benefit) expense and undistributed (loss) income of subsidiaries 751 1,000 746 (2,169 ) 328 Income tax (benefit) expense from continuing operations (56 ) — 132 — 76 Net income from continuing operations 807 1,000 614 (2,169 ) 252 Loss from discontinued operations, net of tax (1 ) — (1 ) — (2 ) Undistributed (loss) income of subsidiaries Bank subsidiary (597 ) (597 ) — 1,194 — Nonbank subsidiaries 41 — — (41 ) — Net income 250 403 613 (1,016 ) 250 Other comprehensive loss, net of tax (328 ) (276 ) (339 ) 615 (328 ) Comprehensive (loss) income $ (78 ) $ 127 $ 274 $ (401 ) $ (78 ) Condensed Consolidating Balance Sheet March 31, 2019 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Assets Cash and cash equivalents Noninterest-bearing $ 45 $ — $ 901 $ — $ 946 Interest-bearing 14 — 2,997 — 3,011 Interest-bearing — intercompany 1,345 — 697 (2,042 ) — Total cash and cash equivalents 1,404 — 4,595 (2,042 ) 3,957 Equity securities — — 536 — 536 Available-for-sale securities — — 27,630 — 27,630 Held-to-maturity securities — — 2,404 (17 ) 2,387 Loans held-for-sale, net — — 107 — 107 Finance receivables and loans, net Finance receivables and loans, net 2,109 — 127,928 18 130,055 Intercompany loans to Nonbank subsidiaries 372 — 104 (476 ) — Allowance for loan losses (36 ) — (1,252 ) — (1,288 ) Total finance receivables and loans, net 2,445 — 126,780 (458 ) 128,767 Investment in operating leases, net 3 — 8,336 — 8,339 Intercompany receivables from Bank subsidiary 104 — — (104 ) — Nonbank subsidiaries 46 — 110 (156 ) — Investment in subsidiaries Bank subsidiary 16,499 16,499 — (32,998 ) — Nonbank subsidiaries 6,687 — — (6,687 ) — Premiums receivable and other insurance assets — — 2,401 — 2,401 Other assets 2,292 — 5,440 (1,739 ) 5,993 Total assets $ 29,480 $ 16,499 $ 178,339 $ (44,201 ) $ 180,117 Liabilities and equity Deposit liabilities Noninterest-bearing $ — $ — $ 141 $ — $ 141 Interest-bearing — — 113,158 — 113,158 Interest-bearing — intercompany — — 1,345 (1,345 ) — Total deposit liabilities — — 114,644 (1,345 ) 113,299 Short-term borrowings 2,486 — 3,629 — 6,115 Long-term debt 11,887 — 29,603 — 41,490 Intercompany debt to Bank subsidiary 17 — — (17 ) — Nonbank subsidiaries 801 — 372 (1,173 ) — Intercompany payables to Bank subsidiary 46 — — (46 ) — Nonbank subsidiaries 108 — 113 (221 ) — Interest payable 218 — 478 — 696 Unearned insurance premiums and service revenue — — 3,096 — 3,096 Accrued expenses and other liabilities 218 — 3,236 (1,732 ) 1,722 Total liabilities 15,781 — 155,171 (4,534 ) 166,418 Total equity 13,699 16,499 23,168 (39,667 ) 13,699 Total liabilities and equity $ 29,480 $ 16,499 $ 178,339 $ (44,201 ) $ 180,117 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 Condensed Consolidating Statement of Cash Flows Three months ended March 31, 2019 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 155 $ 400 $ 1,369 $ (843 ) $ 1,081 Investing activities Purchases of equity securities — — (48 ) — (48 ) Proceeds from sales of equity securities — — 383 — 383 Purchases of available-for-sale securities — — (3,401 ) — (3,401 ) Proceeds from sales of available-for-sale securities — — 656 — 656 Proceeds from repayments of available-for-sale securities — — 694 — 694 Purchases of held-to-maturity securities — — (131 ) — (131 ) Proceeds from repayments of held-to-maturity securities — — 44 — 44 Net change in investment securities — intercompany — — 3 (3 ) — Purchases of finance receivables and loans held-for-investment — — (1,843 ) 391 (1,452 ) Proceeds from sales of finance receivables and loans initially held-for-investment 402 — 146 (391 ) 157 Originations and repayments of finance receivables and loans held-for-investment and other, net 301 — 848 — 1,149 Net change in loans — intercompany 507 — 290 (797 ) — Purchases of operating lease assets — — (792 ) — (792 ) Disposals of operating lease assets 1 — 623 — 624 Capital contributions to subsidiaries (1 ) — — 1 — Returns of contributed capital 15 — — (15 ) — Net change in nonmarketable equity investments (1 ) — 172 — 171 Other, net — — (94 ) (1 ) (95 ) Net cash provided by (used in) investing activities 1,224 — (2,450 ) (815 ) (2,041 ) Financing activities Net change in short-term borrowings — third party 9 — (3,881 ) — (3,872 ) Net (decrease) increase in deposits (1 ) — 7,211 (96 ) 7,114 Proceeds from issuance of long-term debt — third party 7 — 1,759 — 1,766 Repayments of long-term debt — third party (900 ) — (3,590 ) — (4,490 ) Net change in debt — intercompany (118 ) — (507 ) 625 — Repurchase of common stock (211 ) — — — (211 ) Dividends paid — third party (70 ) — — — (70 ) Dividends paid and returns of contributed capital — intercompany — (400 ) (458 ) 858 — Capital contributions from parent — — 1 (1 ) — Net cash (used in) provided by financing activities (1,284 ) (400 ) 535 1,386 237 Effect of exchange-rate changes on cash and cash equivalents and restricted cash — — 1 — 1 Net increase (decrease) in cash and cash equivalents and restricted cash 95 — (545 ) (272 ) (722 ) Cash and cash equivalents and restricted cash at beginning of year 1,398 — 5,998 (1,770 ) 5,626 Cash and cash equivalents and restricted cash at March 31, $ 1,493 $ — $ 5,453 $ (2,042 ) $ 4,904 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. March 31, 2019 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Cash and cash equivalents on the Condensed Consolidated Balance Sheet $ 1,404 $ — $ 4,595 $ (2,042 ) $ 3,957 Restricted cash included in other assets on the Condensed Consolidated Balance Sheet (a) 89 — 858 — 947 Total cash and cash equivalents and restricted cash in the Condensed Consolidated Statement of Cash Flows $ 1,493 $ — $ 5,453 $ (2,042 ) $ 4,904 (a) Restricted cash balances relate primarily to Ally securitization arrangements. Refer to Note 10 for additional details describing the nature of restricted cash balances. Three months ended March 31, 2018 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 456 $ 1,000 $ 1,812 $ (2,171 ) $ 1,097 Investing activities Purchases of equity securities — — (374 ) — (374 ) Proceeds from sales of equity securities — — 220 — 220 Purchases of available-for-sale securities — — (2,360 ) — (2,360 ) Proceeds from sales of available-for-sale securities — — 328 — 328 Proceeds from repayments of available-for-sale securities — — 795 — 795 Purchases of held-to-maturity securities — — (155 ) — (155 ) Proceeds from repayments of held-to-maturity securities — — 35 — 35 Net change in investment securities — intercompany — — 9 (9 ) — Purchases of finance receivables and loans held-for-investment — — (2,317 ) 820 (1,497 ) Proceeds from sales of finance receivables and loans initially held-for-investment 820 — — (820 ) — Originations and repayments of finance receivables and loans held-for-investment and other, net 432 — (1,732 ) — (1,300 ) Net change in loans — intercompany (423 ) — 1 422 — Purchases of operating lease assets — — (969 ) — (969 ) Disposals of operating lease assets 4 — 972 — 976 Capital contributions to subsidiaries (49 ) (6 ) — 55 — Returns of contributed capital 38 — — (38 ) — Net change in nonmarketable equity investments — — (19 ) — (19 ) Other, net (3 ) — (80 ) 1 (82 ) Net cash provided by (used in) investing activities 819 (6 ) (5,646 ) 431 (4,402 ) Financing activities Net change in short-term borrowings — third party (214 ) — (1,634 ) — (1,848 ) Net (decrease) increase in deposits (6 ) — 3,776 403 4,173 Proceeds from issuance of long-term debt — third party 15 — 6,650 — 6,665 Repayments of long-term debt — third party (1,152 ) — (4,619 ) — (5,771 ) Net change in debt — intercompany (127 ) — 422 (295 ) — Repurchase of common stock (185 ) — — — (185 ) Dividends paid — third party (58 ) — — — (58 ) Dividends paid and returns of contributed capital — intercompany — (1,000 ) (1,208 ) 2,208 — Capital contributions from parent — 6 49 (55 ) — Net cash (used in) provided by financing activities (1,727 ) (994 ) 3,436 2,261 2,976 Effect of exchange-rate changes on cash and cash equivalents — — (2 ) — (2 ) Net decrease in cash and cash equivalents and restricted cash (452 ) — (400 ) 521 (331 ) 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 March 31, $ 943 $ — $ 5,307 $ (1,312 ) $ 4,938 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. March 31, 2018 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Cash and cash equivalents on the Condensed Consolidated Balance Sheet $ 796 $ — $ 4,237 $ (1,312 ) $ 3,721 Restricted cash included in other assets on the Condensed Consolidated Balance Sheet (a) 147 — 1,070 — 1,217 Total cash and cash equivalents and restricted cash in the Condensed Consolidated Statement of Cash Flows $ 943 $ — $ 5,307 $ (1,312 ) $ 4,938 (a) Restricted cash balances relate primarily to Ally securitization arrangements. Refer to Note 10 for additional details describing the nature of restricted cash balances.

Contingencies and Other Risks

Contingencies and Other Risks	3 Months Ended
	Mar. 31, 2019
Loss Contingency [Abstract]
Contingencies Disclosure	Contingencies and Other Risks 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. Ally and its subsidiaries, including Ally Bank, also are or may be subject to potential liability under other contingent exposures, including indemnification, tax, self-insurance, and other miscellaneous contingencies. We accrue for a legal matter or other 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 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 or other contingent exposure 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 . Refer to Note 1 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K for additional information related to our policy for establishing accruals. 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. Other contingent exposures and their ultimate resolution are similarly unpredictable for reasons that can vary based on the circumstances. As a result, we often are unable to determine how or when threatened or pending legal matters and other contingent exposures will be resolved and what losses may be incrementally and ultimately incurred. Actual losses may be higher or lower than any amounts accrued or estimated for those matters and other exposures, possibly to a significant degree. Subject to the foregoing, based on our current knowledge and after consultation with counsel, we do not believe that the ultimate outcomes of currently threatened or pending legal matters and other contingent exposures are likely to be material to our consolidated financial condition after taking into account existing accruals. In light of the uncertainties inherent in these matters and other exposures, however, one or more of them could be material to our results of operations or cash flows during a particular reporting period, depending on factors such as the amount of the loss or liability and the level of our income for that period.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Declaration of Quarterly Dividend On April 14, 2019 , the Board declared a quarterly cash dividend of $0.17 per share on all common stock. The dividend is payable on May 15, 2019 , to stockholders of record at the close of business on May 1, 2019 .

Description of Business, Basi_2

Description of Business, Basis of Presentation, and Changes in Significant Accounting Policies Description of Business, Basis of Presentation, and Changes in Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
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. 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 lease assets and residuals, fair value of financial instruments, and the determination of the provision for income taxes.
Lessee, Leases, Policy	At contract inception, we determine whether the contract is or contains a lease based on the terms and conditions of the contract. Lease contracts are recognized on our Condensed Consolidated Balance Sheet as right-of-use (ROU) assets and lease liabilities; however, we have elected not to recognize ROU assets and lease liabilities on real estate leases with terms of one year or less. Lease liabilities and their corresponding ROU assets are recorded based on the present value of the future lease payments over the expected lease term. As the interest rate implicit in the lease contract is typically not readily determinable, we utilize our incremental borrowing rate, which is the rate we would incur to borrow on a collateralized basis over a similar term on an amount equal to the lease payments in a similar economic environment. The ROU asset also includes initial direct costs paid less lease incentives received from the lessor. Our lease contracts are generally classified as operating and, as a result, we recognize a single lease cost within other operating expenses on the income statement on a straight-line basis over the lease term. This update to our accounting policy resulted from our adoption of Accounting Standards Update (ASU) 2016-02 on January 1, 2019, as further described within the section below titled Recently Adopted Accounting Standards
Investment, Policy	Premiums on debt securities that have noncontingent call features that are callable at fixed prices on preset dates are amortized to the earliest call date as an adjustment to investment yield. All other premiums and discounts on debt securities are amortized over the stated maturity of the security as an adjustment to investment yield. This method of amortization differs from that described in Note 1 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K , which describes our full accounting policy for Investments. This update to our amortization methodology resulted from the adoption of ASU 2017-08 on January 1, 2019, as further described within the section below titled Recently Adopted Accounting Standards .
Income Tax, Policy	In calculating the provision for interim income taxes, in accordance with Accounting Standards Codification (ASC) 740, Income Taxes , we apply an estimated annual effective tax rate to year-to-date ordinary income. At the end of each interim period, we estimate the effective tax rate expected to be applicable for the full fiscal year. This method differs from that described in Note 1 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K, which describes our annual significant income tax accounting policy and related methodology.
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy	In February 2016, the Financial Accounting Standards Board (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 (previously referred to as capital leases) and lessor accounting requirements for operating leases and sales type and direct financing 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 ROU asset and lease liability equal to the present value of the lease payments. The ROU 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 issued additional ASUs to clarify the guidance and provide certain practical expedients and an additional transition option. We adopted ASU 2016-02 and the subsequent ASUs that modified ASU 2016-02 (collectively, the amendments) on January 1, 2019. This includes the early adoption of ASU 2019-01, which was issued in March 2019 to amend certain provisions included in ASU 2016-02. We adopted this guidance using the modified retrospective approach on January 1, 2019, and have not adjusted prior period comparative information and will continue to disclose prior period financial information in accordance with the previous lease accounting guidance. We have elected certain practical expedients permitted within the amendments 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. We made an accounting policy election to calculate the impact of adoption using the remaining minimum lease payments and remaining lease term for each contract that was identified as a lease, discounted at our incremental borrowing rate as of the adoption date. The adoption of the amendments resulted in a ROU asset of approximately $161 million from operating leases 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 . The adoption did not change our previously reported Condensed Consolidated Statements of Comprehensive Income and did not result in a cumulative catch-up adjustment to opening retained earnings.
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. We adopted the amendments on January 1, 2019, on a modified retrospective basis, which resulted in an increase to our accumulated deficit of $10 million , net of income taxes, partially offset by an $8 million decrease to accumulated other comprehensive loss, net of income taxes.
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, Financial Instruments - Credit Losses (CECL). 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. We plan to adopt these amendments on January 1, 2020, and expect to utilize the modified retrospective approach as required. The new accounting model for credit losses represents a significant departure from existing GAAP, and will materially increase the allowance for credit losses on our finance receivables and loans, with a resulting negative adjustment to retained earnings. We expect that our consumer automotive loan portfolio will generate the majority of this increase. 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. We performed a limited parallel run during the first quarter of 2019, and will continue to refine and enhance our estimation process with additional parallel testing throughout 2019. Additionally, we do not expect a material allowance for credit losses on our debt securities as a result of the standard based upon the current composition of our portfolio.

Fair Value Fair Value (Policies

Fair Value Fair Value (Policies)	3 Months Ended
	Mar. 31, 2019
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)	3 Months Ended
	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
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 revenue recognition principles of ASC 606, Revenue from Contracts with Customers . For further information regarding our revenue recognition policies and details about the nature of our respective revenue streams, refer to Note 1 and Note 3 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K . Three months ended March 31, ($ in millions) Automotive Finance operations Insurance operations Mortgage Finance operations Corporate Finance operations Corporate and Other Consolidated 2019 Revenue from contracts with customers Noninsurance contracts (a) (b) (c) $ — $ 131 $ — $ — $ — $ 131 Remarketing fee income 18 — — — — 18 Brokerage commissions and other revenue — — — — 17 17 Deposit account and other banking fees — — — — 5 5 Brokered/agent commissions — 3 — — — 3 Other 5 — — — — 5 Total revenue from contracts with customers 23 134 — — 22 179 All other revenue 45 226 2 11 3 287 Total other revenue (d) $ 68 $ 360 $ 2 $ 11 $ 25 $ 466 2018 Revenue from contracts with customers Noninsurance contracts (a) (b) (c) $ — $ 123 $ — $ — $ — $ 123 Remarketing fee income 23 — — — — 23 Brokerage commissions and other revenue — — — — 16 16 Deposit account and other banking fees — — — — 3 3 Brokered/agent commissions — 4 — — — 4 Other 2 1 — — — 3 Total revenue from contracts with customers 25 128 — — 19 172 All other revenue 41 118 1 8 14 182 Total other revenue (d) $ 66 $ 246 $ 1 $ 8 $ 33 $ 354 (a) We had $2.6 billion and $2.5 billion in unearned revenue associated with outstanding contracts at January 1, 2019, and January 1, 2018, respectively, and $199 million and $194 million of these balances were recognized as insurance premiums and service revenue earned in our Condensed Consolidated Statement of Comprehensive Income during the three months ended March 31, 2019 , and March 31, 2018 , respectively. (b) At March 31, 2019 , we had unearned revenue of $2.7 billion associated with outstanding contracts, and with respect to this balance we expect to recognize revenue of $554 million during the remainder of 2019 , $672 million in 2020 , $562 million in 2021 , $424 million in 2022 , and $477 million thereafter. At March 31, 2018, we had unearned revenue of $2.5 billion associated with outstanding contracts. (c) We had opening and closing balances of deferred insurance assets of $1.5 billion and $1.6 billion at January 1, 2019, and March 31, 2019 , respectively, and recognized $111 million of expense during the three months ended March 31, 2019 . We had opening and closing balances of deferred insurance assets of $1.4 billion at both January 1, 2018, and March 31, 2018, and recognized $103 million of expense during the three months ended March 31, 2018 . (d) Represents a component of total net revenue. Refer to Note 21 for further information on our reportable operating segments.

Other Income, Net of Losses (Ta

Other Income, Net of Losses (Tables)	3 Months Ended
	Mar. 31, 2019
Other Nonoperating Income (Expense) [Abstract]
Schedule of Other Nonoperating Income, by Component	Details of other income, net of losses, were as follows. Three months ended March 31, ($ in millions) 2019 2018 Late charges and other administrative fees $ 29 $ 29 Remarketing fees 18 23 Servicing fees 6 8 Income from equity-method investments 4 6 Other, net 30 43 Total other income, net of losses $ 87 $ 109

Reserves for Insurance Losses_2

Reserves for Insurance Losses and Loss Adjustment Expenses Reserves for Insurance Losses and Loss Adjustment Expenses (Tables)	3 Months Ended
	Mar. 31, 2019
Reserves for Insurance Losses and Loss Adjustment Expenses [Abstract]
Short-Duration Insurance and Deposit Contracts [Text Block]	The following table shows a rollforward of our reserves for insurance losses and loss adjustment expenses. ($ in millions) 2019 2018 Total gross reserves for insurance losses and loss adjustment expenses at January 1, $ 134 $ 140 Less: Reinsurance recoverable 96 108 Net reserves for insurance losses and loss adjustment expenses at January 1, 38 32 Net insurance losses and loss adjustment expenses incurred related to: Current year 59 60 Prior years (a) — 3 Total net insurance losses and loss adjustment expenses incurred 59 63 Net insurance losses and loss adjustment expenses paid or payable related to: Current year (33 ) (31 ) Prior years (23 ) (19 ) Total net insurance losses and loss adjustment expenses paid or payable (56 ) (50 ) Net reserves for insurance losses and loss adjustment expenses at March 31, 41 45 Plus: Reinsurance recoverable 94 112 Total gross reserves for insurance losses and loss adjustment expenses at March 31, $ 135 $ 157 (a) There have been no material adverse changes to the reserve for prior years.

Other Operating Expenses (Table

Other Operating Expenses (Tables)	3 Months Ended
	Mar. 31, 2019
Operating Expenses [Abstract]
Schedule of Other Operating Cost and Expense, by Component	Details of other operating expenses were as follows. Three months ended March 31, ($ in millions) 2019 2018 Insurance commissions $ 114 $ 110 Technology and communications 77 71 Advertising and marketing 48 39 Lease and loan administration 39 42 Professional services 29 32 Regulatory and licensing fees 28 30 Vehicle remarketing and repossession 27 32 Premises and equipment depreciation 22 20 Occupancy 13 11 Non-income taxes 9 8 Amortization of intangible assets 3 3 Other 44 47 Total other operating expenses $ 453 $ 445

Investment Securities (Tables)

Investment Securities (Tables)	3 Months Ended
	Mar. 31, 2019
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. March 31, 2019 December 31, 2018 Amortized cost Gross unrealized Fair value Amortized cost Gross unrealized Fair value ($ in millions) gains losses gains losses Available-for-sale securities Debt securities U.S. Treasury and federal agencies $ 1,990 $ 1 $ (49 ) $ 1,942 $ 1,911 $ — $ (60 ) $ 1,851 U.S. States and political subdivisions 771 13 (3 ) 781 816 3 (17 ) 802 Foreign government 170 2 — 172 145 1 (1 ) 145 Agency mortgage-backed residential 18,939 98 (193 ) 18,844 17,486 47 (395 ) 17,138 Agency mortgage-backed commercial 316 4 — 320 3 — — 3 Mortgage-backed residential 2,912 7 (33 ) 2,886 2,796 1 (111 ) 2,686 Mortgage-backed commercial 725 — (2 ) 723 715 1 (2 ) 714 Asset-backed 665 4 (1 ) 668 723 2 (2 ) 723 Corporate debt 1,301 7 (14 ) 1,294 1,286 1 (46 ) 1,241 Total available-for-sale securities (a) (b) (c) $ 27,789 $ 136 $ (295 ) $ 27,630 $ 25,881 $ 56 $ (634 ) $ 25,303 Held-to-maturity securities Debt securities Agency mortgage-backed residential (d) $ 2,351 $ 15 $ (28 ) $ 2,338 $ 2,319 $ 6 $ (61 ) $ 2,264 Asset-backed retained notes 36 — — 36 43 — — 43 Total held-to-maturity securities $ 2,387 $ 15 $ (28 ) $ 2,374 $ 2,362 $ 6 $ (61 ) $ 2,307 (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 March 31, 2019 , and December 31, 2018 . (b) Certain available-for-sale securities are included in fair value hedging relationships. Refer to Note 17 for additional information. (c) Available-for-sale securities with a fair value of $4.1 billion and $9.2 billion at March 31, 2019 , and December 31, 2018 , respectively, were pledged to secure advances from the Federal Home Loan Bank (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 $985 million and $821 million of the underlying investment securities at March 31, 2019 , and December 31, 2018 , respectively. (d) Held-to-maturity securities with a fair value of $1.3 billion and $1.2 billion at March 31, 2019 , and December 31, 2018, respectively, were pledged to secure advances from the FHLB.
Investments Classified by Contractual Maturity Date	The maturity distribution of debt securities outstanding is summarized in the following tables. Call or prepayment options may cause actual maturities to differ from contractual maturities. Total Due in one year or less Due after one year through five years Due after five years through ten years Due after ten years ($ in millions) Amount Yield Amount Yield Amount Yield Amount Yield Amount Yield March 31, 2019 Fair value of available-for-sale securities (a) U.S. Treasury and federal agencies $ 1,942 1.7 % $ 28 1.7 % $ 1,341 1.6 % $ 573 1.9 % $ — — % U.S. States and political subdivisions 781 3.2 52 2.7 43 2.5 212 2.7 474 3.5 Foreign government 172 2.3 41 2.1 55 2.3 73 2.4 3 2.7 Agency mortgage-backed residential 18,844 3.4 — — — — 52 1.9 18,792 3.4 Agency mortgage-backed commercial 320 3.2 — — 3 3.1 83 3.3 234 3.2 Mortgage-backed residential 2,886 3.3 — — — — — — 2,886 3.3 Mortgage-backed commercial 723 3.8 — — — — 36 4.0 687 3.8 Asset-backed 668 3.5 — — 390 3.4 165 4.0 113 3.3 Corporate debt 1,294 3.2 152 3.1 512 2.9 606 3.4 24 5.9 Total available-for-sale securities $ 27,630 3.3 $ 273 2.7 $ 2,344 2.2 $ 1,800 2.8 $ 23,213 3.4 Amortized cost of available-for-sale securities $ 27,789 $ 273 $ 2,376 $ 1,814 $ 23,326 Amortized cost of held-to-maturity securities Agency mortgage-backed residential $ 2,351 3.2 % $ — — % $ — — % $ — — % $ 2,351 3.2 % Asset-backed retained notes 36 2.1 — — 36 2.1 — — — — Total held-to-maturity securities $ 2,387 3.2 $ — — $ 36 2.1 $ — — $ 2,351 3.2 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 Agency mortgage-backed commercial 3 3.1 — — 3 3.1 — — — — Mortgage-backed residential 2,686 3.3 — — — — — — 2,686 3.3 Mortgage-backed commercial 714 3.8 — — — — 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 (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. Three months ended March 31, ($ in millions) 2019 2018 Taxable interest $ 214 $ 154 Taxable dividends 3 3 Interest and dividends exempt from U.S. federal income tax 5 6 Interest and dividends on investment securities $ 222 $ 163
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. Three months ended March 31, ($ in millions) 2019 2018 Available-for-sale securities Gross realized gains $ 10 $ 6 Gross realized losses (a) (1 ) — Net realized gains on available-for-sale securities 9 6 Net realized gain on equity securities 29 22 Net unrealized gain (loss) on equity securities 70 (40 ) Other gain (loss) on investments, net $ 108 $ (12 ) (a) Certain available-for-sale securities were sold at a loss during the three months ended March 31, 2019 , as a result of market conditions within these 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.
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. For additional information on our methodology, refer to Note 1 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K. As of March 31, 2019 , 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 March 31, 2019 . March 31, 2019 December 31, 2018 Less than 12 months 12 months or longer Less than 12 months 12 months or longer ($ 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 $ 42 $ — $ 1,749 $ (49 ) $ 31 $ — $ 1,758 $ (60 ) U.S. States and political subdivisions 23 — 189 (3 ) 259 (3 ) 317 (14 ) Foreign government 4 — 22 — 6 — 74 (1 ) Agency mortgage-backed residential 510 (1 ) 11,145 (192 ) 5,537 (94 ) 7,808 (301 ) Agency mortgage-backed commercial 30 — — — — — — — Mortgage-backed residential 131 — 1,676 (33 ) 1,024 (20 ) 1,360 (91 ) Mortgage-backed commercial 517 (2 ) 41 — 347 (1 ) 36 (1 ) Asset-backed 6 — 214 (1 ) 294 (1 ) 124 (1 ) Corporate debt 105 — 764 (14 ) 576 (19 ) 569 (27 ) Total temporarily impaired available-for-sale securities $ 1,368 $ (3 ) $ 15,800 $ (292 ) $ 8,074 $ (138 ) $ 12,046 $ (496 ) Held-to-maturity securities Debt securities Agency mortgage-backed residential $ 86 $ — $ 1,376 $ (28 ) $ 457 $ (6 ) $ 1,376 $ (55 ) Asset-backed retained notes — — 16 — 16 — 19 — Total held-to-maturity debt securities $ 86 $ — $ 1,392 $ (28 ) $ 473 $ (6 ) $ 1,395 $ (55 )

Finance Receivables and Loans_2

Finance Receivables and Loans, Net (Tables)	3 Months Ended
	Mar. 31, 2019
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. ($ in millions) March 31, 2019 December 31, 2018 Consumer automotive (a) $ 71,553 $ 70,539 Consumer mortgage Mortgage Finance (b) 16,225 15,155 Mortgage — Legacy (c) 1,433 1,546 Total consumer mortgage 17,658 16,701 Total consumer 89,211 87,240 Commercial Commercial and industrial Automotive 31,559 33,672 Other 4,516 4,205 Commercial real estate 4,769 4,809 Total commercial 40,844 42,686 Total finance receivables and loans (d) $ 130,055 $ 129,926 (a) Certain finance receivables and loans are included in fair value hedging relationships. Refer to Note 17 for additional information. (b) Includes loans originated as interest-only mortgage loans of $17 million and $18 million at March 31, 2019 , and December 31, 2018 , respectively, 33% of which are expected to start principal amortization in 2019, and 40% in 2020 . The remainder of these loans have exited the interest-only period. (c) Includes loans originated as interest-only mortgage loans of $305 million and $341 million at March 31, 2019 , and December 31, 2018 , 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 $584 million and $587 million at March 31, 2019 , and December 31, 2018 , respectively.
Allowance for Credit Losses on Financing Receivables	The following tables present an analysis of the activity in the allowance for loan losses on finance receivables and loans. Three months ended March 31, 2019 ($ in millions) Consumer automotive Consumer mortgage Commercial Total Allowance at January 1, 2019 $ 1,048 $ 53 $ 141 $ 1,242 Charge-offs (a) (352 ) (3 ) (5 ) (360 ) Recoveries 118 5 — 123 Net charge-offs (234 ) 2 (5 ) (237 ) Provision for loan losses 257 (3 ) 28 282 Other (b) (1 ) — 2 1 Allowance at March 31, 2019 $ 1,070 $ 52 $ 166 $ 1,288 Allowance for loan losses at March 31, 2019 Individually evaluated for impairment $ 46 $ 22 $ 58 $ 126 Collectively evaluated for impairment 1,024 30 108 1,162 Finance receivables and loans at gross carrying value Ending balance $ 71,553 $ 17,658 $ 40,844 $ 130,055 Individually evaluated for impairment 501 227 269 997 Collectively evaluated for impairment 71,052 17,431 40,575 129,058 (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 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K for more information regarding our charge-off policies. (b) Primarily related to the transfer of finance receivables and loans from held-for-sale to held-for-investment. Three months ended March 31, 2018 ($ in millions) Consumer automotive Consumer mortgage Commercial Total Allowance at January 1, 2018 $ 1,066 $ 79 $ 131 $ 1,276 Charge-offs (a) (365 ) (12 ) — (377 ) Recoveries 112 6 — 118 Net charge-offs (253 ) (6 ) — (259 ) Provision for loan losses 253 1 7 261 Allowance at March 31, 2018 $ 1,066 $ 74 $ 138 $ 1,278 Allowance for loan losses at March 31, 2018 Individually evaluated for impairment $ 40 $ 27 $ 21 $ 88 Collectively evaluated for impairment 1,026 47 117 1,190 Finance receivables and loans at gross carrying value Ending balance $ 69,318 $ 14,683 $ 41,326 $ 125,327 Individually evaluated for impairment 463 230 147 840 Collectively evaluated for impairment 68,855 14,453 41,179 124,487 (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 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K for more information regarding our charge-off policies.
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. Three months ended March 31, ($ in millions) 2019 2018 Consumer automotive $ 20 $ — Consumer mortgage — 1 Total sales and transfers (a) $ 20 $ 1 (a) During the three months ended March 31, 2019 , we also sold $128 million of finance receivables that were classified as held-for-sale and transferred $63 million of finance receivables from held-for-sale to held-for-investment as of March 31, 2019 , both relating to equipment finance receivables from our commercial automotive business.
Schedule of Purchases of Financing Receivables and Loans	The following table presents information about significant purchases of finance receivables and loans based on unpaid principal balance at the time of purchase. Three months ended March 31, ($ in millions) 2019 2018 Consumer automotive $ 99 $ 168 Consumer mortgage 1,235 1,295 Total purchases of finance receivables and loans $ 1,334 $ 1,463
Past Due Financing Receivables	The following table presents an analysis of our past-due finance receivables and loans recorded at gross carrying value. ($ 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 March 31, 2019 Consumer automotive $ 1,575 $ 379 $ 260 $ 2,214 $ 69,339 $ 71,553 Consumer mortgage Mortgage Finance 52 8 9 69 16,156 16,225 Mortgage — Legacy 31 11 36 78 1,355 1,433 Total consumer mortgage 83 19 45 147 17,511 17,658 Total consumer 1,658 398 305 2,361 86,850 89,211 Commercial Commercial and industrial Automotive 1 8 78 87 31,472 31,559 Other — — 2 2 4,514 4,516 Commercial real estate — — 2 2 4,767 4,769 Total commercial 1 8 82 91 40,753 40,844 Total consumer and commercial $ 1,659 $ 406 $ 387 $ 2,452 $ 127,603 $ 130,055 December 31, 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
Schedule of Financing Receivables, Non Accrual Status	The following table presents the gross carrying value of our finance receivables and loans on nonaccrual status. ($ in millions) March 31, 2019 December 31, 2018 Consumer automotive $ 643 $ 664 Consumer mortgage Mortgage Finance 13 9 Mortgage — Legacy 62 70 Total consumer mortgage 75 79 Total consumer 718 743 Commercial Commercial and industrial Automotive 138 203 Other 125 142 Commercial real estate 6 4 Total commercial 269 349 Total consumer and commercial finance receivables and loans $ 987 $ 1,092
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 90 days or more, or when full collection is not expected. Refer to Note 1 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K for additional information. March 31, 2019 December 31, 2018 ($ in millions) Performing Nonperforming Total Performing Nonperforming Total Consumer automotive $ 70,910 $ 643 $ 71,553 $ 69,875 $ 664 $ 70,539 Consumer mortgage Mortgage Finance 16,212 13 16,225 15,146 9 15,155 Mortgage — Legacy 1,371 62 1,433 1,476 70 1,546 Total consumer mortgage 17,583 75 17,658 16,622 79 16,701 Total consumer $ 88,493 $ 718 $ 89,211 $ 86,497 $ 743 $ 87,240
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. March 31, 2019 December 31, 2018 ($ in millions) Pass Criticized (a) Total Pass Criticized (a) Total Commercial and industrial Automotive $ 28,774 $ 2,785 $ 31,559 $ 30,799 $ 2,873 $ 33,672 Other 3,711 805 4,516 3,373 832 4,205 Commercial real estate 4,526 243 4,769 4,538 271 4,809 Total commercial $ 37,011 $ 3,833 $ 40,844 $ 38,710 $ 3,976 $ 42,686 (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. ($ in millions) Unpaid principal balance (a) Gross carrying value Impaired with no allowance Impaired with an allowance Allowance for impaired loans March 31, 2019 Consumer automotive $ 509 $ 501 $ 99 $ 402 $ 46 Consumer mortgage Mortgage Finance 15 15 6 9 1 Mortgage — Legacy 216 212 65 147 21 Total consumer mortgage 231 227 71 156 22 Total consumer 740 728 170 558 68 Commercial Commercial and industrial Automotive 138 138 41 97 18 Other 144 125 56 69 40 Commercial real estate 6 6 3 3 — Total commercial 288 269 100 169 58 Total consumer and commercial finance receivables and loans $ 1,028 $ 997 $ 270 $ 727 $ 126 December 31, 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 (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. 2019 2018 Three months ended March 31, ($ in millions) Average balance Interest income Average balance Interest income Consumer automotive $ 499 $ 8 $ 444 $ 7 Consumer mortgage Mortgage Finance 15 — 9 — Mortgage — Legacy 214 3 221 2 Total consumer mortgage 229 3 230 2 Total consumer 728 11 674 9 Commercial Commercial and industrial Automotive 170 1 47 1 Other 130 — 52 — Commercial real estate 5 — 3 — Total commercial 305 1 102 1 Total consumer and commercial finance receivables and loans $ 1,033 $ 12 $ 776 $ 10
Troubled Debt Restructurings on Financing Receivables	The following table presents information related to finance receivables and loans recorded at gross carrying value modified in connection with a TDR during the period. 2019 2018 Three months ended March 31, ($ in millions) Number of loans Pre-modification gross carrying value Post-modification gross carrying value Number of loans Pre-modification gross carrying value Post-modification gross carrying value Consumer automotive 7,427 $ 129 $ 111 7,042 $ 128 $ 110 Consumer mortgage Mortgage Finance 1 — — 1 1 1 Mortgage — Legacy 20 3 3 62 10 9 Total consumer mortgage 21 3 3 63 11 10 Total consumer finance receivables and loans 7,448 132 114 7,105 139 120 Commercial Commercial and Industrial Automotive 6 41 41 — — — Total commercial 6 41 41 — — — Total consumer and commercial finance receivables and loans 7,454 $ 173 $ 155 7,105 $ 139 $ 120
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 to the Consolidated Financial Statements in our 2018 Annual Report on Form 10-K for additional information) except for commercial finance receivables and loans, where redefault is defined as 90 days past due. 2019 2018 Three months ended March 31, ($ in millions) Number of loans Gross carrying value Charge-off amount Number of loans Gross carrying value Charge-off amount Consumer automotive 2,209 $ 26 $ 16 2,326 $ 28 $ 18 Total consumer finance receivables and loans 2,209 $ 26 $ 16 2,326 $ 28 $ 18

Leasing (Tables)

Leasing (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Investment in Operating Leases	The following table details our total investment in operating leases. ($ in millions) March 31, 2019 January 1, 2019 (a) Assets Operating lease right-of-use assets (b) $ 177 $ 161 Liabilities Operating lease liabilities (c) $ 206 $ 190 (a) Date of adoption. (b) Included in other assets on our Condensed Consolidated Balance Sheet . (c) Included in accrued expenses and other liabilities on our Condensed Consolidated Balance Sheet .
Lessee, Operating Lease, Liability, Maturity	The following table presents future minimum rental payments we are required to make under operating leases that have commenced as of March 31, 2019 , and that have noncancellable lease terms expiring after March 31, 2019 . ($ in millions) 2019 $ 36 2020 46 2021 36 2022 24 2023 16 2024 and thereafter 71 Total undiscounted cash flows 229 Difference between undiscounted cash flows and discounted cash flows (23 ) Total lease liability $ 206
Schedule of Future Minimum Rental Payments for Operating Leases	Future minimum rental payments required under operating leases as of December 31, 2018, prior to the date of adoption and as defined by the previous lease accounting guidance, with noncancellable lease terms expiring after December 31, 2018, were as follows. Year ended December 31, ($ in millions) 2019 $ 48 2020 47 2021 46 2022 37 2023 31 2024 and thereafter 294 Total minimum payments required $ 503
Lease, Cost	The following table details the components of total net operating lease expense. Three months ended March 31, ($ in millions) 2019 2018 Operating lease expense $ 11 $ 10 Variable lease expense 2 2 Total lease expense, net (a) $ 13 $ 12 (a) Included in other operating expenses in our Condensed Consolidated Statement of Comprehensive Income .
Schedule of Property Subject to or Available for Operating Lease	The following table details our investment in operating leases. ($ in millions) March 31, 2019 December 31, 2018 Vehicles $ 9,903 $ 9,995 Accumulated depreciation (1,564 ) (1,578 ) Investment in operating leases, net $ 8,339 $ 8,417
Lessor, Operating Lease, Payments to be Received, Maturity	The following table presents future minimum rental payments we have the right to receive under operating leases with noncancellable lease terms expiring after March 31, 2019 . ($ in millions) 2019 $ 1,024 2020 933 2021 402 2022 57 2023 5 2024 and thereafter — Total lease payments from operating leases $ 2,421
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 table summarizes the components of depreciation expense on operating lease assets. Three months ended March 31, ($ in millions) 2019 2018 Depreciation expense on operating lease assets (excluding remarketing gains) $ 261 $ 291 Remarketing gains, net (15 ) (18 ) Net depreciation expense on operating lease assets $ 246 $ 273
Finance Lease, Liability, Maturity	The following table presents future minimum rental payments we have the right to receive under finance leases with noncancellable lease terms expiring after March 31, 2019 . ($ in millions) 2019 $ 110 2020 139 2021 134 2022 67 2023 38 2024 and thereafter 29 Total undiscounted cash flows 517 Difference between undiscounted cash flows and discounted cash flows (52 ) Present value of lease payments recorded as lease receivable $ 465

Securitizations and Variable _2

Securitizations and Variable Interest Entities (Tables)	3 Months Ended
	Mar. 31, 2019
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 Condensed Consolidated Balance Sheet . ($ 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 March 31, 2019 On-balance sheet variable interest entities Consumer automotive $ 16,226 (b) $ 6,480 (c) Commercial automotive 9,620 3,297 Off-balance sheet variable interest entities Consumer automotive 38 (d) — $ 957 $ 995 (e) Commercial other 867 (f) 343 (g) — 1,115 (h) Total $ 26,751 $ 10,120 $ 957 $ 2,110 December 31, 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 45 (d) — $ 1,235 $ 1,280 (e) Commercial other 806 (f) 326 (g) — 1,054 (h) Total $ 28,195 $ 10,845 $ 1,235 $ 2,334 (a) Asset values represent the current unpaid principal balance of outstanding consumer finance receivables and loans within the VIEs. (b) Includes $8.4 billion of assets that were not encumbered by VIE beneficial interests held by third parties at both March 31, 2019 , and December 31, 2018 . Ally or consolidated affiliates hold the interests in these assets. (c) Includes $24 million and $25 million of liabilities that were not obligations to third-party beneficial interest holders at March 31, 2019 , and December 31, 2018 , respectively. (d) Represents retained notes and certificated residual interests, of which $36 million and $43 million were classified as held-to-maturity securities at March 31, 2019 , and December 31, 2018 , respectively, and $2 million were classified as other assets at both March 31, 2019 , and December 31, 2018 . These assets represent our five percent interest in the credit risk of the assets underlying asset-backed securitizations. (e) 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. (f) Amounts are classified as other assets. (g) Amounts are classified as accrued expenses and other liabilities. (h) 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.
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 three months ended March 31, 2019 , and 2018 . Additionally, this table contains information regarding cash flows received from and paid to nonconsolidated SPEs that existed during each period. Three months ended March 31, ($ in millions) Consumer automotive 2019 Cash flows received on retained interests in securitization entities $ 7 Servicing fees 3 Cash disbursements for repurchases during the period (1 ) 2018 Cash flows received on retained interests in securitization entities $ 5 Servicing fees 5 Cash disbursements for repurchases during the period (1 )
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 ($ in millions) March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018 Off-balance sheet securitization entities Consumer automotive $ 957 $ 1,235 $ 8 $ 13 Whole-loan sales (a) Consumer automotive 503 634 2 3 Total $ 1,460 $ 1,869 $ 10 $ 16 (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 Three months ended March 31, ($ in millions) 2019 2018 Off-balance sheet securitization entities Consumer automotive $ 2 $ 3 Whole-loan sales (a) Consumer automotive — 1 Total $ 2 $ 4 (a) Whole-loan sales are not part of a securitization transaction, but represent consumer automotive pools of loans sold to third-party investors.

Other Assets (Tables)

Other Assets (Tables)	3 Months Ended
	Mar. 31, 2019
Other Assets [Abstract]
Schedule of Other Assets	The components of other assets were as follows. ($ in millions) March 31, 2019 December 31, 2018 Property and equipment at cost $ 1,286 $ 1,250 Accumulated depreciation (708 ) (686 ) Net property and equipment 578 564 Nonmarketable equity investments (a) 1,240 1,410 Restricted cash held for securitization trusts (b) 838 965 Investment in qualified affordable housing projects (c) 687 649 Accrued interest, fees, and rent receivables 624 599 Equity-method investments (d) 289 262 Other accounts receivable 269 203 Goodwill (e) 240 240 Net deferred tax assets 137 317 Restricted cash and cash equivalents (f) 109 124 Fair value of derivative contracts in receivable position (g) 22 41 Cash collateral placed with counterparties 20 26 Other assets 940 753 Total other assets $ 5,993 $ 6,153 (a) Includes investments in FHLB stock of $732 million and $903 million at March 31, 2019 , and December 31, 2018 , respectively; Federal Reserve Bank (FRB) stock of $448 million at both March 31, 2019 , and December 31, 2018 ; and equity securities without a readily determinable fair value of $60 million and $59 million at March 31, 2019 , and December 31, 2018 , respectively, measured at cost with adjustments for impairment and observable changes in price. Through March 31, 2019 , we recorded $3 million of cumulative impairments and downward adjustments 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 $336 million and $319 million of unfunded commitments to provide additional capital contributions to investees at March 31, 2019 , and December 31, 2018 , respectively. Substantially all of the unfunded commitments at March 31, 2019 , are expected to be paid out over the next five years. (d) Primarily relates to investments made in connection with our Community Reinvestment Act (CRA) program. (e) Includes goodwill of $27 million within our Insurance operations at both March 31, 2019 , and December 31, 2018 ; $193 million within Corporate and Other at both March 31, 2019 , and December 31, 2018 ; and $20 million within Automotive Finance operations at both March 31, 2019 , and December 31, 2018 . No changes to the carrying amount of goodwill were recorded during the three months ended March 31, 2019 . (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 17 .

Deposit Liabilities (Tables)

Deposit Liabilities (Tables)	3 Months Ended
	Mar. 31, 2019
Deposits [Abstract]
Deposit Liabilities, Type	Deposit liabilities consisted of the following. ($ in millions) March 31, 2019 December 31, 2018 Noninterest-bearing deposits $ 141 $ 142 Interest-bearing deposits Savings and money-market checking accounts 60,258 56,050 Certificates of deposit 52,899 49,985 Other deposits 1 1 Total deposit liabilities $ 113,299 $ 106,178

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Schedule of Short-term Debt	The following table presents the composition of our short-term borrowings portfolio. March 31, 2019 December 31, 2018 ($ in millions) Unsecured Secured (a) Total Unsecured Secured (a) Total Demand notes $ 2,486 $ — $ 2,486 $ 2,477 $ — $ 2,477 Federal Home Loan Bank — 2,775 2,775 — 6,825 6,825 Securities sold under agreements to repurchase — 854 854 — 685 685 Total short-term borrowings $ 2,486 $ 3,629 $ 6,115 $ 2,477 $ 7,510 $ 9,987 (a) Refer to the section below titled Long-term Debt for further details on assets restricted as collateral for payment of the related debt.
Long-term Debt	The following table presents the composition of our long-term debt portfolio. March 31, 2019 December 31, 2018 ($ in millions) Unsecured Secured Total Unsecured Secured Total Long-term debt (a) Due within one year $ 2,630 $ 6,948 $ 9,578 $ 1,663 $ 7,313 $ 8,976 Due after one year 8,708 23,204 31,912 10,444 24,773 35,217 Total long-term debt (b) (c) $ 11,338 $ 30,152 $ 41,490 $ 12,107 $ 32,086 $ 44,193 (a) Includes basis adjustments related to the application of hedge accounting. Refer to Note 17 for additional information. (b) Includes $2.6 billion of trust preferred securities at both March 31, 2019 , and December 31, 2018 . (c) Includes advances net of hedge basis adjustment from the FHLB of Pittsburgh of $14.7 billion and $14.9 billion at March 31, 2019 , and December 31, 2018 , respectively.
Scheduled of Maturities of Long-term Debt	The following table presents the scheduled remaining maturity of long-term debt at March 31, 2019 , assuming no early redemptions will occur. The amounts below include adjustments to the carrying value resulting from the application of hedge accounting. The actual payment of secured debt may vary based on the payment activity of the related pledged assets. ($ in millions) 2019 2020 2021 2022 2023 2024 and thereafter Total Unsecured Long-term debt $ 917 $ 2,258 $ 697 $ 1,075 $ 12 $ 7,504 $ 12,463 Original issue discount (31 ) (41 ) (45 ) (49 ) (56 ) (903 ) (1,125 ) Total unsecured 886 2,217 652 1,026 (44 ) 6,601 11,338 Secured Long-term debt 4,998 6,909 10,185 6,008 1,236 816 30,152 Total long-term debt $ 5,884 $ 9,126 $ 10,837 $ 7,034 $ 1,192 $ 7,417 $ 41,490
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. March 31, 2019 December 31, 2018 ($ in millions) Total (a) Ally Bank Total (a) Ally Bank Investment securities (b) $ 5,243 $ 4,357 $ 10,280 $ 9,564 Mortgage assets held-for-investment and lending receivables 17,447 17,447 16,498 16,498 Consumer automotive finance receivables 15,882 9,777 17,015 9,715 Commercial automotive finance receivables 14,269 14,269 15,563 15,563 Operating leases 132 — 170 — Total assets restricted as collateral (c) (d) $ 52,973 $ 45,850 $ 59,526 $ 51,340 Secured debt $ 33,781 (e) $ 27,233 $ 39,596 (e) $ 32,072 (a) Ally Bank is a component of the total column. (b) A portion of the restricted investment securities at March 31, 2019 , and December 31, 2018 , 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 $26.6 billion and $30.8 billion at March 31, 2019 , and December 31, 2018 , 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 at both March 31, 2019 , and December 31, 2018 . 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 Condensed Consolidated Balance Sheet . Refer to Note 10 for additional information. (e) Includes $3.6 billion and $7.5 billion of short-term borrowings at March 31, 2019 , and December 31, 2018 , respectively.
Schedule Of Committed Funding Facilities	Outstanding Unused capacity (a) Total capacity ($ in millions) March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018 Bank funding Secured $ 3,050 $ 3,500 $ 700 $ 1,300 $ 3,750 $ 4,800 Parent funding Secured 2,666 3,165 1,134 635 3,800 3,800 Total committed secured credit facilities $ 5,716 $ 6,665 $ 1,834 $ 1,935 $ 7,550 $ 8,600 (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)	3 Months Ended
	Mar. 31, 2019
Accounts Payable and Accrued Liabilities [Abstract]
Schedule of Accrued Liabilities	The components of accrued expenses and other liabilities were as follows. ($ in millions) March 31, 2019 December 31, 2018 Accounts payable $ 347 $ 516 Unfunded commitments for investment in qualified affordable housing projects 336 319 Employee compensation and benefits 165 255 Reserves for insurance losses and loss adjustment expenses 135 134 Deferred revenue 28 27 Cash collateral received from counterparties 27 41 Fair value of derivative contracts in payable position (a) 21 37 Other liabilities 663 347 Total accrued expenses and other liabilities $ 1,722 $ 1,676 (a) For additional information on derivative instruments and hedging activities, refer to Note 17 .

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	3 Months Ended
	Mar. 31, 2019
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 December 31, 2017 $ (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 (186 ) 20 11 (95 ) (250 ) 2018 net change (338 ) (1 ) 14 (3 ) (328 ) Balance at March 31, 2018 $ (524 ) $ 19 $ 25 $ (98 ) $ (578 ) Balance at December 31, 2018 $ (481 ) $ 18 $ 19 $ (95 ) $ (539 ) Cumulative effect of changes in accounting principles, net of tax (c) Adoption of Accounting Standards Update 2017-08 8 — — — 8 Balance at January 1, 2019 (473 ) 18 19 (95 ) (531 ) 2019 net change 315 — (8 ) (1 ) 306 Balance at March 31, 2019 $ (158 ) $ 18 $ 11 $ (96 ) $ (225 ) (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 17 . (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. Three months ended March 31, 2019 ($ in millions) Before tax Tax effect After tax Investment securities Net unrealized gains arising during the period $ 421 $ (99 ) $ 322 Less: Net realized gains reclassified to income from continuing operations 9 (a) (2 ) (b) 7 Net change 412 (97 ) 315 Translation adjustments Net unrealized gains arising during the period 2 (1 ) 1 Net investment hedges (c) Net unrealized losses arising during the period (2 ) 1 (1 ) Cash flow hedges (c) Net unrealized losses arising during the period (5 ) 1 (4 ) Less: Net realized gains reclassified to income from continuing operations 5 (1 ) 4 Net change (10 ) 2 (8 ) Defined benefit pension plans Net unrealized losses arising during the period (1 ) — (1 ) Other comprehensive loss $ 401 $ (95 ) $ 306 (a) Includes gains reclassified to other gain (loss) on investments, net in our Condensed Consolidated Statement of Comprehensive Income . (b) Includes amounts reclassified to income tax expense from continuing operations in our Condensed Consolidated Statement of Comprehensive Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 17 . Three months ended March 31, 2018 ($ in millions) Before tax Tax effect After tax Investment securities Net unrealized losses arising during the period $ (436 ) $ 103 $ (333 ) Less: Net realized gains reclassified to income from continuing operations 6 (a) (1 ) (b) 5 Net change (442 ) 104 (338 ) Translation adjustments Net unrealized losses arising during the period (5 ) 1 (4 ) Net investment hedges (c) Net unrealized gains arising during the period 4 (1 ) 3 Cash flow hedges (c) Net unrealized gains arising during the period 18 (4 ) 14 Defined benefit pension plans Net unrealized losses arising during the period (3 ) — (3 ) Other comprehensive loss $ (428 ) $ 100 $ (328 ) (a) Includes gains reclassified to other (loss) gain on investments, net in our Condensed Consolidated Statement of Comprehensive Income . (b) Includes amounts reclassified to income tax expense from continuing operations in our Condensed Consolidated Statement of Comprehensive Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 17 .

Earnings per Common Share (Tabl

Earnings per Common Share (Tables)	3 Months Ended
	Mar. 31, 2019
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. Three months ended March 31, ($ in millions, except per share data; shares in thousands) (a) 2019 2018 Net income from continuing operations attributable to common stockholders $ 375 $ 252 Loss from discontinued operations, net of tax (1 ) (2 ) Net income attributable to common stockholders $ 374 $ 250 Basic weighted-average common shares outstanding (b) 404,129 436,213 Diluted weighted-average common shares outstanding (b) 405,959 438,931 Basic earnings per common share Net income from continuing operations $ 0.93 $ 0.58 Loss from discontinued operations, net of tax — (0.01 ) Net income $ 0.93 $ 0.57 Diluted earnings per common share Net income from continuing operations $ 0.92 $ 0.57 Loss from discontinued operations, net of tax — (0.01 ) Net income $ 0.92 $ 0.57 (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)	3 Months Ended
	Mar. 31, 2019
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. March 31, 2019 December 31, 2018 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. $ 13,603 9.33 % $ 13,397 9.14 % 4.50 % (b) Ally Bank 16,609 12.55 16,552 12.61 4.50 6.50 % Tier 1 (to risk-weighted assets) Ally Financial Inc. $ 16,035 10.99 % $ 15,831 10.80 % 6.00 % 6.00 % Ally Bank 16,609 12.55 16,552 12.61 6.00 8.00 Total (to risk-weighted assets) Ally Financial Inc. $ 18,292 12.54 % $ 18,046 12.31 % 8.00 % 10.00 % Ally Bank 17,802 13.46 17,620 13.42 8.00 10.00 Tier 1 leverage (to adjusted quarterly average assets) (c) Ally Financial Inc. $ 16,035 9.02 % $ 15,831 9.00 % 4.00 % (b) Ally Bank 16,609 10.45 16,552 10.69 4.00 5.00 % (a) In addition to the minimum risk-based capital requirements for the 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 2.5% and 1.875% at March 31, 2019 , and December 31, 2018 , respectively. (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 and distributions to our common stockholders over the last five quarters. 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 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 2019 First quarter $ 211 8,113 404,900 399,761 $ 0.17 (a) Includes shares of common stock withheld to cover income taxes owed by participants in our share-based incentive plans. (b) On April 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 May 15, 2019 . Refer to Note 24 for further information regarding this common stock dividend.

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2019
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 Condensed 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 Condensed 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. March 31, 2019 December 31, 2018 Derivative contracts in a Notional amount Derivative contracts in a Notional amount ($ in millions) receivable position payable position receivable position payable position Derivatives designated as accounting hedges Interest rate contracts Swaps $ — $ — $ 12,085 $ — $ — $ 24,203 Purchased options 1 — 100 — — — Foreign exchange contracts Forwards — 1 134 1 — 136 Total derivatives designated as accounting hedges 1 1 12,319 1 — 24,339 Derivatives not designated as accounting hedges Interest rate contracts Futures and forwards — — 11 — — 11 Written options 2 19 6,180 — 37 6,793 Purchased options 19 — 6,081 37 — 6,742 Total interest rate risk 21 19 12,272 37 37 13,546 Foreign exchange contracts Futures and forwards — — 124 3 — 181 Total foreign exchange risk — — 124 3 — 181 Equity contracts Written options — 1 1 — — — Total equity risk — 1 1 — — — Total derivatives not designated as accounting hedges 21 20 12,397 40 37 13,727 Total derivatives $ 22 $ 21 $ 24,716 $ 41 $ 37 $ 38,066
Schedule of Fair Value Hedging Instruments, Statements of Financial Performance and Financial Position, Location	The following table presents amounts recorded on our Condensed Consolidated Balance Sheet related to cumulative basis adjustments for fair value hedges. ($ 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) March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018 Assets Available-for-sale securities (b) (c) $ 1,495 $ 1,485 $ 10 $ — $ 8 $ (5 ) Finance receivables and loans, net (d) 36,433 40,850 63 24 68 5 Liabilities Long-term debt $ 12,263 $ 13,001 $ 66 $ 67 $ 66 $ 67 (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 6 for a reconciliation of the amortized cost and fair value of available-for-sale securities. (c) The amount identified as the last of layer in the hedge relationship was $28 million at both March 31, 2019 , and December 31, 2018 , but the hedge relationship was discontinued during the three months ended March 31, 2019 . The carrying amount associated with the last-of-layer relationship was $46 million and $47 million , respectively. There was no basis adjustment associated with the last-of-layer relationships for either period. (d) The hedged item represents the carrying value of the hedged portfolio of assets. The amount identified as the last of layer in the open hedge relationship was $9.6 billion as of March 31, 2019 , and $21.4 billion as of December 31, 2018 . The basis adjustment associated with the open last-of-layer relationship was a $5 million liability as of March 31, 2019 , and 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. The amount that is identified as the last of layer in the discontinued hedge relationship was $11.2 billion for the three months ended March 31, 2019 . The basis adjustment associated with the discontinued last-of-layer relationship was a $65 million asset for the three months ended March 31, 2019 , which was allocated across the entire remaining pool upon termination of the hedge relationship.
Derivative Instruments, Gain (Loss)	The following table summarizes the location and amounts of gains and losses on derivative instruments not designated as accounting hedges reported in our Condensed Consolidated Statement of Comprehensive Income . Three months ended March 31, ($ in millions) 2019 2018 Gain (loss) recognized in earnings Interest rate contracts Gain on mortgage and automotive loans, net $ 1 $ — Other income, net of losses (5 ) 2 Total interest rate contracts (4 ) 2 Foreign exchange contracts Other income, net of losses (1 ) — Total foreign exchange contracts (1 ) — (Loss) gain recognized in earnings $ (5 ) $ 2
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 hedges reported in our Condensed Consolidated Statement of Comprehensive 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 Three months ended March 31, ($ in millions) 2019 2018 2019 2018 2019 2018 2019 2018 Gain (loss) on fair value hedging relationships Interest rate contracts Hedged fixed-rate unsecured debt $ — $ — $ — $ — $ — $ — $ — $ 36 Derivatives designated as hedging instruments on fixed-rate unsecured debt — — — — — — — (35 ) Hedged fixed-rate FHLB advances — — — — — — — 33 Derivatives designated as hedging instruments on fixed-rate FHLB advances — — — — — — — (33 ) Hedged available-for-sale securities — — 10 (3 ) — — — — Derivatives designated as hedging instruments on available-for-sale securities — — (10 ) 3 — — — — Hedged fixed-rate consumer automotive loans 43 (45 ) — — — — — — Derivatives designated as hedging instruments on fixed-rate consumer automotive loans (43 ) 45 — — — — — — Total gain on fair value hedging relationships — — — — — — — 1 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 — — — — — — 4 — Total gain on cash flow hedging relationships $ — $ — $ — $ — $ 1 $ — $ 4 $ — Total amounts presented in the Condensed Consolidated Statement of Comprehensive Income $ 1,807 $ 1,543 $ 240 $ 176 $ 592 $ 351 $ 419 $ 411
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 Condensed Consolidated Statement of Comprehensive Income . Interest and fees on finance receivables and loans Interest and dividends on investment securities and other earning assets Interest on long-term debt Three months ended March 31, ($ in millions) 2019 2018 2019 2018 2019 2018 Gain (loss) on fair value hedging relationships Interest rate contracts Amortization of deferred unsecured debt basis adjustments $ — $ — $ — $ — $ 6 $ 15 Interest for qualifying accounting hedges of unsecured debt — — — — — 3 Amortization of deferred secured debt basis adjustments (FHLB advances) — — — — (6 ) (1 ) Interest for qualifying accounting hedges of secured debt (FHLB advances) — — — — — 2 Interest for qualifying accounting hedges of available-for-sale securities — — — (1 ) — — Amortization of deferred loan basis adjustments (4 ) (4 ) — — — — Interest for qualifying accounting hedges of consumer automotive loans held-for-investment 6 (7 ) — — — — Total gain (loss) on fair value hedging relationships 2 (11 ) — (1 ) — 19 Gain on cash flow hedging relationships Interest rate contracts Interest for qualifying accounting hedges of variable-rate borrowings — — — — — 1 Total gain on cash flow hedging relationships $ — $ — $ — $ — $ — $ 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. Three months ended March 31, ($ in millions) 2019 2018 Interest rate contracts (Loss) gain recognized in other comprehensive loss $ (10 ) $ 18
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 Condensed Consolidated Statement of Comprehensive Income . Three months ended March 31, ($ in millions) 2019 2018 Foreign exchange contracts (a) (b) (Loss) gain recognized in other comprehensive loss $ (2 ) $ 4 (a) There were no amounts excluded from effectiveness testing for the three months ended March 31, 2019 , or 2018 . (b) Gains and losses reclassified from accumulated other comprehensive loss are reported as other income, net of losses, in the Condensed Consolidated Statement of Comprehensive Income. There were no amounts reclassified for the three months ended March 31, 2019 , or 2018

Fair Value (Tables)

Fair Value (Tables)	3 Months Ended
	Mar. 31, 2019
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 March 31, 2019 ($ in millions) Level 1 Level 2 Level 3 Total Assets Investment securities Equity securities (a) $ 525 $ — $ 11 $ 536 Available-for-sale securities Debt securities U.S. Treasury and federal agencies 1,941 1 — 1,942 U.S. States and political subdivisions — 781 — 781 Foreign government 7 165 — 172 Agency mortgage-backed residential — 18,844 — 18,844 Agency mortgage-backed commercial — 320 — 320 Mortgage-backed residential — 2,886 — 2,886 Mortgage-backed commercial — 723 — 723 Asset-backed — 668 — 668 Corporate debt — 1,294 — 1,294 Total available-for-sale securities 1,948 25,682 — 27,630 Mortgage loans held-for-sale (b) — — 15 15 Interests retained in financial asset sales — — 4 4 Derivative contracts in a receivable position Interest rate — 20 2 22 Total derivative contracts in a receivable position — 20 2 22 Total assets $ 2,473 $ 25,702 $ 32 $ 28,207 Liabilities Accrued expenses and other liabilities Derivative contracts in a payable position Interest rate $ — $ 19 $ — $ 19 Foreign currency — 1 — 1 Other 1 — — 1 Total derivative contracts in a payable position 1 20 — 21 Total liabilities $ 1 $ 20 $ — $ 21 (a) Our investment in any one industry did not exceed 15% . (b) Carried at fair value due to fair value option elections. 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 Agency mortgage-backed commercial — 3 — 3 Mortgage-backed residential — 2,686 — 2,686 Mortgage-backed commercial — 714 — 714 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.
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 gains Fair value at March 31, 2019 Net unrealized gains still held at March 31, 2019 ($ in millions) Fair value at Jan. 1, 2019 included in earnings included in OCI Purchases Sales Issuances Settlements included in earnings included in OCI Assets Equity securities $ 7 $ 4 (a) $ — $ — $ — $ — $ — $ 11 $ 4 $ — Mortgage loans held-for-sale (b) 8 1 (c) — 90 (84 ) — — 15 — — Other assets Interests retained in financial asset sales 4 — — — — — — 4 — — Derivative assets — 2 (c) — — — — — 2 2 — Total assets $ 19 $ 7 $ — $ 90 $ (84 ) $ — $ — $ 32 $ 6 $ — (a) Reported as other gain on investments, net, in the Condensed Consolidated Statement of Comprehensive Income . (b) Carried at fair value due to fair value option elections. (c) Reported as gain on mortgage and automotive loans, net, in the Condensed Consolidated Statement of Comprehensive Income . Level 3 recurring fair value measurements Fair value at Jan. 1, 2018 Net realized/unrealized (losses) gains Purchases Sales Issuances Settlements Fair value at March 31, 2018 Net unrealized losses included in earnings still held at March 31, 2018 ($ in millions) included in earnings included in OCI Assets Equity securities $ 19 $ (4 ) (a) $ — $ — $ — $ — $ (3 ) $ 12 $ (5 ) Mortgage loans held-for-sale (b) 13 1 (c) — 59 (66 ) — — 7 — Other assets Interests retained in financial asset sales 5 — — — — — — 5 — Derivative assets 1 — — — — — — 1 — Total assets $ 38 $ (3 ) $ — $ 59 $ (66 ) $ — $ (3 ) $ 25 $ (5 ) (a) Reported as other loss on investments, net, in the Condensed Consolidated Statement of Comprehensive Income . (b) Carried at fair value due to fair value option elections. (c) Reported as gain on mortgage and automotive loans, net, in the Condensed Consolidated Statement of Comprehensive 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 March 31, 2019 , and December 31, 2018 , 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 reserve, valuation reserve, or cumulative impairment Total gain (loss) included in earnings March 31, 2019 ($ in millions) Level 1 Level 2 Level 3 Total Assets Loans held-for-sale, net Automotive $ — $ — $ 18 $ 18 $ — n/m (a) Other — — 74 74 — n/m (a) Total loans held-for-sale, net — — 92 92 — n/m (a) Commercial finance receivables and loans, net (b) Automotive — — 83 83 (18 ) n/m (a) Other — — 30 30 (40 ) n/m (a) Total commercial finance receivables and loans, net — — 113 113 (58 ) n/m (a) Other assets Repossessed and foreclosed assets (c) — — 12 12 (1 ) n/m (a) Nonmarketable equity investments — — 2 2 — n/m (a) Equity-method investments — — 1 1 (3 ) n/m (a) Total assets $ — $ — $ 220 $ 220 $ (62 ) n/m n/m = not meaningful (a) We consider the applicable valuation allowance, loan loss allowance, or cumulative impairment 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 allowance, loan loss allowance, or cumulative impairment. (b) Represents the portion of the portfolio specifically impaired during 2019 . 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. Nonrecurring fair value measurements Lower-of-cost or fair value reserve, valuation reserve, or cumulative impairment 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 $106 million was valued using a discounted cash flow analysis, with a spread over forward interest rates as a significant unobservable input utilizing a range of 0.08 – 1.09% and weighted average of 0.72% . (b) We consider the applicable valuation allowance, loan loss allowance, or cumulative impairment to be the most relevant indicator of the impact on earnings caused by the fair value measurement. Accordingly, the table above excludes total gains and losses included in earnings for these items. The carrying values are inclusive of the respective valuation allowance, loan loss allowance, or cumulative impairment. (c) Represents the portion of the portfolio specifically impaired during 2018 . The related valuation allowance represents the cumulative adjustment to fair value of those specific receivables. (d) The allowance provided for repossessed and foreclosed assets represents any cumulative valuation adjustment recognized to adjust the assets to fair value.
Financial Instruments Disclosure	The following table presents the carrying and estimated fair value of financial instruments, except for those recorded at fair value on a recurring basis presented in the previous section of this note titled Recurring Fair Value. When possible, we use quoted market prices to determine fair value. Where quoted market prices are not available, the fair value is internally derived based on appropriate valuation methodologies with respect to the amount and timing of future cash flows and estimated discount rates. However, considerable judgment is required in interpreting current market data to develop the market assumptions and inputs necessary to estimate fair value. As such, the actual amount received to sell an asset or the amount paid to settle a liability could differ from our estimates. Fair value information presented herein was based on information available at March 31, 2019 , and December 31, 2018 . Estimated fair value ($ in millions) Carrying value Level 1 Level 2 Level 3 Total March 31, 2019 Financial assets Held-to-maturity securities $ 2,387 $ — $ 2,374 $ — $ 2,374 Loans held-for-sale, net 92 — — 92 92 Finance receivables and loans, net 128,767 — — 131,541 131,541 FHLB/FRB stock (a) 1,180 — 1,180 — 1,180 Financial liabilities Deposit liabilities $ 54,899 $ — $ — $ 55,106 $ 55,106 Short-term borrowings 6,115 — — 6,119 6,119 Long-term debt 41,490 — 23,038 20,661 43,699 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 $ 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 (a) Included in other assets on our Condensed Consolidated Balance Sheet .

Offsetting Assets and Liabili_2

Offsetting Assets and Liabilities (Tables)	3 Months Ended
	Mar. 31, 2019
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 Condensed Consolidated Balance Sheet Net amounts of assets/liabilities presented on the Condensed Consolidated Balance Sheet Gross amounts not offset on the Condensed Consolidated Balance Sheet March 31, 2019 ($ in millions) Financial instruments Collateral (a) (b) (c) Net amount Assets Derivative assets in net asset positions (d) $ 20 $ — $ 20 $ (1 ) $ (1 ) $ 18 Derivative assets with no offsetting arrangements 2 — 2 — — 2 Total assets $ 22 $ — $ 22 $ (1 ) $ (1 ) $ 20 Liabilities Derivative liabilities in net liability positions (d) $ 20 $ — $ 20 $ — $ (1 ) $ 19 Derivative liabilities in net asset positions 1 — 1 (1 ) — — Total derivative liabilities (d) 21 — 21 (1 ) (1 ) 19 Securities sold under agreements to repurchase (e) 854 — 854 — (854 ) — Total liabilities $ 875 $ — $ 875 $ (1 ) $ (855 ) $ 19 (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 collateral associated with our repurchase agreements pledged to us that was excluded at March 31, 2019 . We do not record such collateral received on our Condensed 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 $3 million at March 31, 2019 . We have not sold or pledged any of the noncash collateral received under these agreements as of March 31, 2019 . (d) For additional information on derivative instruments and hedging activities, refer to Note 17 . (e) For additional information on securities sold under agreements to repurchase, refer to Note 12 . Gross amounts of recognized assets/liabilities Gross amounts offset on the Condensed Consolidated Balance Sheet Net amounts of assets/liabilities presented on the Condensed Consolidated Balance Sheet Gross amounts not offset on the Condensed Consolidated Balance Sheet December 31, 2018 ($ in millions) Financial instruments Collateral (a) (b) (c) Net amount Assets Derivative assets in net asset positions $ 41 $ — $ 41 $ — $ (4 ) $ 37 Total assets (d) $ 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 Condensed 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 17 . (e) For additional information on securities sold under agreements to repurchase, refer to Note 12 .

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Financial information for our reportable operating segments is summarized as follows. Three months ended March 31, ($ in millions) Automotive Finance operations Insurance operations Mortgage Finance operations Corporate Finance operations Corporate and Other Consolidated (a) 2019 Net financing revenue and other interest income $ 980 $ 12 $ 50 $ 54 $ 36 $ 1,132 Other revenue 68 360 2 11 25 466 Total net revenue 1,048 372 52 65 61 1,598 Provision for loan losses 262 — 2 23 (5 ) 282 Total noninterest expense 457 227 37 29 80 830 Income (loss) from continuing operations before income tax expense $ 329 $ 145 $ 13 $ 13 $ (14 ) $ 486 Total assets $ 115,789 $ 8,179 $ 16,301 $ 5,006 $ 34,842 $ 180,117 2018 Net financing revenue and other interest income $ 909 $ 12 $ 43 $ 46 $ 39 $ 1,049 Other revenue 66 246 1 8 33 354 Total net revenue 975 258 44 54 72 1,403 Provision for loan losses 259 — 2 — — 261 Total noninterest expense 448 231 34 25 76 814 Income (loss) from continuing operations before income tax expense $ 268 $ 27 $ 8 $ 29 $ (4 ) $ 328 Total assets $ 114,934 $ 7,557 $ 12,780 $ 4,375 $ 30,375 $ 170,021 (a) Net financing revenue and other interest income after the provision for loan losses totaled $850 million and $788 million for the three months ended March 31, 2019 , and March 31, 2018 , respectively.

Parent and Guarantor Condense_2

Parent and Guarantor Condensed Consolidating Financial Statements (Tables)	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Income Statement	Condensed Consolidating Statements of Comprehensive Income Three months ended March 31, 2019 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing revenue and other interest income Interest and fees on finance receivables and loans $ (60 ) $ — $ 1,867 $ — $ 1,807 Interest and fees on finance receivables and loans — intercompany 3 — 2 (5 ) — Interest on loans held-for-sale — — 2 — 2 Interest and dividends on investment securities and other earning assets — — 240 — 240 Interest on cash and cash equivalents 2 — 21 — 23 Interest-bearing cash — intercompany 2 — 3 (5 ) — Operating leases 2 — 359 — 361 Total financing (loss) revenue and other interest income (51 ) — 2,494 (10 ) 2,433 Interest expense Interest on deposits — — 592 — 592 Interest on short-term borrowings 13 — 31 — 44 Interest on long-term debt 211 — 208 — 419 Interest on intercompany debt 5 — 5 (10 ) — Total interest expense 229 — 836 (10 ) 1,055 Net depreciation expense on operating lease assets 1 — 245 — 246 Net financing (loss) revenue (281 ) — 1,413 — 1,132 Cash dividends from subsidiaries Bank subsidiary 400 400 — (800 ) — Nonbank subsidiaries 42 — — (42 ) — Other revenue Insurance premiums and service revenue earned — — 261 — 261 Gain on mortgage and automotive loans, net 4 — 6 — 10 Other gain on investments, net — — 108 — 108 Other income, net of losses 103 — 144 (160 ) 87 Total other revenue 107 — 519 (160 ) 466 Total net revenue 268 400 1,932 (1,002 ) 1,598 Provision for loan losses 27 — 272 (17 ) 282 Noninterest expense Compensation and benefits expense 12 — 306 — 318 Insurance losses and loss adjustment expenses — — 59 — 59 Other operating expenses 155 — 458 (160 ) 453 Total noninterest expense 167 — 823 (160 ) 830 Income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries 74 400 837 (825 ) 486 Income tax (benefit) expense from continuing operations (61 ) — 172 — 111 Net income from continuing operations 135 400 665 (825 ) 375 Loss from discontinued operations, net of tax (1 ) — — — (1 ) Undistributed income of subsidiaries Bank subsidiary 57 57 — (114 ) — Nonbank subsidiaries 183 — — (183 ) — Net income 374 457 665 (1,122 ) 374 Other comprehensive income, net of tax 306 229 320 (549 ) 306 Comprehensive income $ 680 $ 686 $ 985 $ (1,671 ) $ 680 Three months ended March 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 $ 11 $ — $ 1,532 $ — $ 1,543 Interest and fees on finance receivables and loans — intercompany 2 — 1 (3 ) — Interest and dividends on investment securities and other earning assets — — 176 — 176 Interest on cash and cash equivalents 2 — 14 (1 ) 15 Interest-bearing cash — intercompany 2 — 2 (4 ) — Operating leases 2 — 380 — 382 Total financing revenue and other interest income 19 — 2,105 (8 ) 2,116 Interest expense Interest on deposits — — 354 (3 ) 351 Interest on short-term borrowings 10 — 22 — 32 Interest on long-term debt 258 — 153 — 411 Interest on intercompany debt 3 — 2 (5 ) — Total interest expense 271 — 531 (8 ) 794 Net depreciation expense on operating lease assets 4 — 269 — 273 Net financing (loss) revenue (256 ) — 1,305 — 1,049 Cash dividends from subsidiaries Bank subsidiary 1,000 1,000 — (2,000 ) — Nonbank subsidiaries 169 — — (169 ) — Other revenue Insurance premiums and service revenue earned — — 256 — 256 Gain on mortgage and automotive loans, net 28 — 1 (28 ) 1 Other loss on investments, net — — (12 ) — (12 ) Other income, net of losses 96 — 221 (208 ) 109 Total other revenue 124 — 466 (236 ) 354 Total net revenue 1,037 1,000 1,771 (2,405 ) 1,403 Provision for loan losses 81 — 208 (28 ) 261 Noninterest expense Compensation and benefits expense 23 — 283 — 306 Insurance losses and loss adjustment expenses — — 63 — 63 Other operating expenses 182 — 471 (208 ) 445 Total noninterest expense 205 — 817 (208 ) 814 Income from continuing operations before income tax (benefit) expense and undistributed (loss) income of subsidiaries 751 1,000 746 (2,169 ) 328 Income tax (benefit) expense from continuing operations (56 ) — 132 — 76 Net income from continuing operations 807 1,000 614 (2,169 ) 252 Loss from discontinued operations, net of tax (1 ) — (1 ) — (2 ) Undistributed (loss) income of subsidiaries Bank subsidiary (597 ) (597 ) — 1,194 — Nonbank subsidiaries 41 — — (41 ) — Net income 250 403 613 (1,016 ) 250 Other comprehensive loss, net of tax (328 ) (276 ) (339 ) 615 (328 ) Comprehensive (loss) income $ (78 ) $ 127 $ 274 $ (401 ) $ (78 )
Condensed Balance Sheet	Condensed Consolidating Balance Sheet March 31, 2019 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Assets Cash and cash equivalents Noninterest-bearing $ 45 $ — $ 901 $ — $ 946 Interest-bearing 14 — 2,997 — 3,011 Interest-bearing — intercompany 1,345 — 697 (2,042 ) — Total cash and cash equivalents 1,404 — 4,595 (2,042 ) 3,957 Equity securities — — 536 — 536 Available-for-sale securities — — 27,630 — 27,630 Held-to-maturity securities — — 2,404 (17 ) 2,387 Loans held-for-sale, net — — 107 — 107 Finance receivables and loans, net Finance receivables and loans, net 2,109 — 127,928 18 130,055 Intercompany loans to Nonbank subsidiaries 372 — 104 (476 ) — Allowance for loan losses (36 ) — (1,252 ) — (1,288 ) Total finance receivables and loans, net 2,445 — 126,780 (458 ) 128,767 Investment in operating leases, net 3 — 8,336 — 8,339 Intercompany receivables from Bank subsidiary 104 — — (104 ) — Nonbank subsidiaries 46 — 110 (156 ) — Investment in subsidiaries Bank subsidiary 16,499 16,499 — (32,998 ) — Nonbank subsidiaries 6,687 — — (6,687 ) — Premiums receivable and other insurance assets — — 2,401 — 2,401 Other assets 2,292 — 5,440 (1,739 ) 5,993 Total assets $ 29,480 $ 16,499 $ 178,339 $ (44,201 ) $ 180,117 Liabilities and equity Deposit liabilities Noninterest-bearing $ — $ — $ 141 $ — $ 141 Interest-bearing — — 113,158 — 113,158 Interest-bearing — intercompany — — 1,345 (1,345 ) — Total deposit liabilities — — 114,644 (1,345 ) 113,299 Short-term borrowings 2,486 — 3,629 — 6,115 Long-term debt 11,887 — 29,603 — 41,490 Intercompany debt to Bank subsidiary 17 — — (17 ) — Nonbank subsidiaries 801 — 372 (1,173 ) — Intercompany payables to Bank subsidiary 46 — — (46 ) — Nonbank subsidiaries 108 — 113 (221 ) — Interest payable 218 — 478 — 696 Unearned insurance premiums and service revenue — — 3,096 — 3,096 Accrued expenses and other liabilities 218 — 3,236 (1,732 ) 1,722 Total liabilities 15,781 — 155,171 (4,534 ) 166,418 Total equity 13,699 16,499 23,168 (39,667 ) 13,699 Total liabilities and equity $ 29,480 $ 16,499 $ 178,339 $ (44,201 ) $ 180,117 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
Condensed Cash Flow Statement	Condensed Consolidating Statement of Cash Flows Three months ended March 31, 2019 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 155 $ 400 $ 1,369 $ (843 ) $ 1,081 Investing activities Purchases of equity securities — — (48 ) — (48 ) Proceeds from sales of equity securities — — 383 — 383 Purchases of available-for-sale securities — — (3,401 ) — (3,401 ) Proceeds from sales of available-for-sale securities — — 656 — 656 Proceeds from repayments of available-for-sale securities — — 694 — 694 Purchases of held-to-maturity securities — — (131 ) — (131 ) Proceeds from repayments of held-to-maturity securities — — 44 — 44 Net change in investment securities — intercompany — — 3 (3 ) — Purchases of finance receivables and loans held-for-investment — — (1,843 ) 391 (1,452 ) Proceeds from sales of finance receivables and loans initially held-for-investment 402 — 146 (391 ) 157 Originations and repayments of finance receivables and loans held-for-investment and other, net 301 — 848 — 1,149 Net change in loans — intercompany 507 — 290 (797 ) — Purchases of operating lease assets — — (792 ) — (792 ) Disposals of operating lease assets 1 — 623 — 624 Capital contributions to subsidiaries (1 ) — — 1 — Returns of contributed capital 15 — — (15 ) — Net change in nonmarketable equity investments (1 ) — 172 — 171 Other, net — — (94 ) (1 ) (95 ) Net cash provided by (used in) investing activities 1,224 — (2,450 ) (815 ) (2,041 ) Financing activities Net change in short-term borrowings — third party 9 — (3,881 ) — (3,872 ) Net (decrease) increase in deposits (1 ) — 7,211 (96 ) 7,114 Proceeds from issuance of long-term debt — third party 7 — 1,759 — 1,766 Repayments of long-term debt — third party (900 ) — (3,590 ) — (4,490 ) Net change in debt — intercompany (118 ) — (507 ) 625 — Repurchase of common stock (211 ) — — — (211 ) Dividends paid — third party (70 ) — — — (70 ) Dividends paid and returns of contributed capital — intercompany — (400 ) (458 ) 858 — Capital contributions from parent — — 1 (1 ) — Net cash (used in) provided by financing activities (1,284 ) (400 ) 535 1,386 237 Effect of exchange-rate changes on cash and cash equivalents and restricted cash — — 1 — 1 Net increase (decrease) in cash and cash equivalents and restricted cash 95 — (545 ) (272 ) (722 ) Cash and cash equivalents and restricted cash at beginning of year 1,398 — 5,998 (1,770 ) 5,626 Cash and cash equivalents and restricted cash at March 31, $ 1,493 $ — $ 5,453 $ (2,042 ) $ 4,904 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. March 31, 2019 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Cash and cash equivalents on the Condensed Consolidated Balance Sheet $ 1,404 $ — $ 4,595 $ (2,042 ) $ 3,957 Restricted cash included in other assets on the Condensed Consolidated Balance Sheet (a) 89 — 858 — 947 Total cash and cash equivalents and restricted cash in the Condensed Consolidated Statement of Cash Flows $ 1,493 $ — $ 5,453 $ (2,042 ) $ 4,904 (a) Restricted cash balances relate primarily to Ally securitization arrangements. Refer to Note 10 for additional details describing the nature of restricted cash balances. Three months ended March 31, 2018 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 456 $ 1,000 $ 1,812 $ (2,171 ) $ 1,097 Investing activities Purchases of equity securities — — (374 ) — (374 ) Proceeds from sales of equity securities — — 220 — 220 Purchases of available-for-sale securities — — (2,360 ) — (2,360 ) Proceeds from sales of available-for-sale securities — — 328 — 328 Proceeds from repayments of available-for-sale securities — — 795 — 795 Purchases of held-to-maturity securities — — (155 ) — (155 ) Proceeds from repayments of held-to-maturity securities — — 35 — 35 Net change in investment securities — intercompany — — 9 (9 ) — Purchases of finance receivables and loans held-for-investment — — (2,317 ) 820 (1,497 ) Proceeds from sales of finance receivables and loans initially held-for-investment 820 — — (820 ) — Originations and repayments of finance receivables and loans held-for-investment and other, net 432 — (1,732 ) — (1,300 ) Net change in loans — intercompany (423 ) — 1 422 — Purchases of operating lease assets — — (969 ) — (969 ) Disposals of operating lease assets 4 — 972 — 976 Capital contributions to subsidiaries (49 ) (6 ) — 55 — Returns of contributed capital 38 — — (38 ) — Net change in nonmarketable equity investments — — (19 ) — (19 ) Other, net (3 ) — (80 ) 1 (82 ) Net cash provided by (used in) investing activities 819 (6 ) (5,646 ) 431 (4,402 ) Financing activities Net change in short-term borrowings — third party (214 ) — (1,634 ) — (1,848 ) Net (decrease) increase in deposits (6 ) — 3,776 403 4,173 Proceeds from issuance of long-term debt — third party 15 — 6,650 — 6,665 Repayments of long-term debt — third party (1,152 ) — (4,619 ) — (5,771 ) Net change in debt — intercompany (127 ) — 422 (295 ) — Repurchase of common stock (185 ) — — — (185 ) Dividends paid — third party (58 ) — — — (58 ) Dividends paid and returns of contributed capital — intercompany — (1,000 ) (1,208 ) 2,208 — Capital contributions from parent — 6 49 (55 ) — Net cash (used in) provided by financing activities (1,727 ) (994 ) 3,436 2,261 2,976 Effect of exchange-rate changes on cash and cash equivalents — — (2 ) — (2 ) Net decrease in cash and cash equivalents and restricted cash (452 ) — (400 ) 521 (331 ) 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 March 31, $ 943 $ — $ 5,307 $ (1,312 ) $ 4,938 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. March 31, 2018 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Cash and cash equivalents on the Condensed Consolidated Balance Sheet $ 796 $ — $ 4,237 $ (1,312 ) $ 3,721 Restricted cash included in other assets on the Condensed Consolidated Balance Sheet (a) 147 — 1,070 — 1,217 Total cash and cash equivalents and restricted cash in the Condensed Consolidated Statement of Cash Flows $ 943 $ — $ 5,307 $ (1,312 ) $ 4,938 (a) Restricted cash balances relate primarily to Ally securitization arrangements. Refer to Note 10 for additional details describing the nature of restricted cash balances.

Description of Business, Basi_3

Description of Business, Basis of Presentation, and Changes in Significant Accounting Policies Description of Business, Basis of Presentation, and Changes in Significant Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Lease, Right-of-Use Asset	$ 177
Operating Lease, Liability	206
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Lease, Right-of-Use Asset		$ 161
Operating Lease, Liability		$ 190
Accounting Standards Update 2016-02 | Accrued expenses and other liabilities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	29
Accounting Standards Update 2016-02 | Accumulated other comprehensive loss
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	8
Accounting Standards Update 2017-08 | Retained earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ (10)

Revenue from Contracts with C_3

Revenue from Contracts with Customers (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019	Jan. 01, 2018
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 179	$ 172
Other revenue	466	354
Insurance commissions	114	110
Out of scope of Topic 606
Disaggregation of Revenue [Line Items]
Other revenue	287	182
Corporate and Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	22	19
Other revenue	25	33
Corporate and Other | Out of scope of Topic 606
Disaggregation of Revenue [Line Items]
Other revenue	3	14
Noninsurance contracts
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	131	123
Unearned revenue, remaining performance obligation, amount	2,700	2,500	$ 2,600	$ 2,500
Unearned revenue, revenue recognized	199	194
Deferred commissions	1,600	1,400	$ 1,500
Insurance commissions	111	103
Noninsurance contracts | 2019
Disaggregation of Revenue [Line Items]
Unearned revenue, remaining performance obligation, amount	554
Noninsurance contracts | 2020
Disaggregation of Revenue [Line Items]
Unearned revenue, remaining performance obligation, amount	672
Noninsurance contracts | 2021
Disaggregation of Revenue [Line Items]
Unearned revenue, remaining performance obligation, amount	562
Noninsurance contracts | 2022
Disaggregation of Revenue [Line Items]
Unearned revenue, remaining performance obligation, amount	424
Noninsurance contracts | 2023 and thereafter
Disaggregation of Revenue [Line Items]
Unearned revenue, remaining performance obligation, amount	477
Noninsurance contracts | Corporate and Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Remarketing fee income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	18	23
Remarketing fee income | Corporate and Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Brokerage commissions and other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	17	16
Brokerage commissions and other revenue | Corporate and Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	17	16
Deposit account and other banking fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5	3
Deposit account and other banking fees | Corporate and Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5	3
Brokered/agent commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3	4
Brokered/agent commissions | Corporate and Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5	3
Other | Corporate and Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Automotive Finance operations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	23	25
Other revenue	68	66
Automotive Finance operations | Out of scope of Topic 606
Disaggregation of Revenue [Line Items]
Other revenue	45	41
Automotive Finance operations | Noninsurance contracts
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Automotive Finance operations | Remarketing fee income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	18	23
Automotive Finance operations | Brokerage commissions and other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Automotive Finance operations | Deposit account and other banking fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Automotive Finance operations | Brokered/agent commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Automotive Finance operations | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5	2
Automotive Finance operations | Sale of off-lease vehicles
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	15	18
Insurance operations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	134	128
Other revenue	360	246
Insurance operations | Out of scope of Topic 606
Disaggregation of Revenue [Line Items]
Other revenue	226	118
Insurance operations | Noninsurance contracts
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	131	123
Insurance operations | Remarketing fee income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Insurance operations | Brokerage commissions and other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Insurance operations | Deposit account and other banking fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Insurance operations | Brokered/agent commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3	4
Insurance operations | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	1
Mortgage Finance operations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Other revenue	2	1
Mortgage Finance operations | Out of scope of Topic 606
Disaggregation of Revenue [Line Items]
Other revenue	2	1
Mortgage Finance operations | Noninsurance contracts
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Mortgage Finance operations | Remarketing fee income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Mortgage Finance operations | Brokerage commissions and other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Mortgage Finance operations | Deposit account and other banking fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Mortgage Finance operations | Brokered/agent commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Mortgage Finance operations | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Corporate Finance operations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Other revenue	11	8
Corporate Finance operations | Out of scope of Topic 606
Disaggregation of Revenue [Line Items]
Other revenue	11	8
Corporate Finance operations | Noninsurance contracts
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Corporate Finance operations | Remarketing fee income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Corporate Finance operations | Brokerage commissions and other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Corporate Finance operations | Deposit account and other banking fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Corporate Finance operations | Brokered/agent commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Corporate Finance operations | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 0	$ 0

Other Income, Net of Losses (Sc

Other Income, Net of Losses (Schedule of Other Income, Net of Losses) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Other Nonoperating Income (Expense) [Abstract]
Late charges and other administrative fees	$ 29	$ 29
Remarketing fees	18	23
Servicing fees	6	8
Income from equity-method investments	4	6
Other income, net	30	43
Total other income, net of losses	$ 87	$ 109

Reserves for Insurance Losses_3

Reserves for Insurance Losses and Loss Adjustment Expenses Reserves for Insurance Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Gross reserves for insurance losses and loss adjustment expenses	$ 134	$ 140
Reinsurance recoverable	96	108
Net reserves for insurance losses and loss adjustment expenses	38	32
Net insurance losses and loss adjustment expenses, current year	59	60
Net insurance losses and loss adjustment expenses, prior years	0	3
Net insurance losses and loss adjustment expenses incurred	59	63
Net insurance losses and loss adjustment expenses paid or payable, current year	33	31
Net insurance losses and loss adjustment expenses paid or payable, prior years	23	19
Total net insurance losses and loss adjustment expenses paid or payable	56	50
Net reserves for insurance losses and loss adjustment expenses	41	45
Reinsurance recoverable	94	112
Gross reserves for insurance losses and loss adjustment expenses	$ 135	$ 157

Other Operating Expenses (Sched

Other Operating Expenses (Schedule Of Other Operating Expenses) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Expenses [Abstract]
Insurance commissions	$ 114	$ 110
Technology and communications	77	71
Advertising and marketing	48	39
Lease and loan administration	39	42
Professional services	29	32
Regulatory and licensing fees	28	30
Vehicle remarketing and repossession	27	32
Premises and equipment depreciation	22	20
Occupancy	13	11
Non-income taxes	9	8
Amortization of intangible assets	3	3
Other operating expenses	44	47
Total other operating expenses	$ 453	$ 445

Investment Securities (Investme

Investment Securities (Investment Table) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	$ 2,387	$ 2,362
Held-to-maturity securities, fair value	2,374	2,307
Securities, amount eligible to be repledged or sold by counterparty	985	821
Available-for-sale securities
Schedule of Investments [Line Items]
Securities pledged for Federal Home Loan Bank, at fair value	4,100	9,200
US Treasury | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	1,990	1,911
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	49	60
Debt securities, available-for-sale, fair value	1,942	1,851
US States and political subdivisions | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	771	816
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	13	3
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	3	17
Debt securities, available-for-sale, fair value	781	802
Foreign government | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	170	145
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	2	1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	1
Debt securities, available-for-sale, fair value	172	145
Agency mortgage-backed residential | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	18,939	17,486
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	98	47
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	193	395
Debt securities, available-for-sale, fair value	18,844	17,138
Agency mortgage-backed residential | Held-to-maturity securities
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	2,351	2,319
Debt securities, held-to-maturity, unrecognized gain	15	6
Debt securities, held-to-maturity, unrecognized loss	28	61
Held-to-maturity securities, fair value	2,338	2,264
Agency mortgage-backed commercial | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	316	3
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	4	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0
Debt securities, available-for-sale, fair value	320	3
Mortgage-backed residential | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	2,912	2,796
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	7	1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	33	111
Debt securities, available-for-sale, fair value	2,886	2,686
Mortgage-backed commercial | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	725	715
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	2	2
Debt securities, available-for-sale, fair value	723	714
Asset-backed | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	665	723
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	4	2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	1	2
Debt securities, available-for-sale, fair value	668	723
Asset-backed | Held-to-maturity securities
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	36	43
Debt securities, held-to-maturity, unrecognized gain	0	0
Debt securities, held-to-maturity, unrecognized loss	0	0
Held-to-maturity securities, fair value	36	43
Corporate debt | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	1,301	1,286
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	7	1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	14	46
Debt securities, available-for-sale, fair value	1,294	1,241
Available-for-sale debt securities | Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	27,789	25,881
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	136	56
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	295	634
Debt securities, available-for-sale, fair value	27,630	25,303
Held-to-maturity securities
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	2,387	2,362
Debt securities, held-to-maturity, unrecognized gain	15	6
Debt securities, held-to-maturity, unrecognized loss	28	61
Held-to-maturity securities, fair value	2,374	2,307
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	1,300	1,200
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	Mar. 31, 2019	Dec. 31, 2018
Schedule of Investments [Line Items]
Cash equivalents	$ 56	$ 35
Held-to-maturity securities
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost, before other-than-temporary impairment	$ 2,387	$ 2,362
Debt securities, held-to-maturity, yield	3.20%	3.20%
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	$ 36	$ 42
Debt securities, held-to-maturity, due after one year through five years, yield	2.10%	2.00%
Debt securities, held-to-maturity, maturity, after five through ten years, amortized cost	$ 0	$ 1
Debt securities, held-to-maturity, due after five years through ten years, yield	0.00%	3.30%
Debt securities, held-to-maturity, maturity, after 10 Years, amortized cost	$ 2,351	$ 2,319
Debt securities, held-to-maturity, due after ten years, yield	3.20%	3.20%
Available-for-sale securities | US Treasury
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 1,942	$ 1,851
Debt securities, available-for-sale, yield	1.70%	1.90%
Debt securities, available-for-sale, due in one year or less	$ 28	$ 12
Debt securities, available-for-sale, due in one year or less, yield	1.70%	1.00%
Debt securities, available-for-sale, due after one year through five years	$ 1,341	$ 1,277
Debt securities, available-for-sale, due after one year through five years, yield	1.60%	1.80%
Debt securities, available-for-sale, due after five years through ten years	$ 573	$ 562
Debt securities, available-for-sale, due after five years through ten years, yield	1.90%	2.00%
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	$ 1,990	$ 1,911
Available-for-sale securities | US States and political subdivisions
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 781	$ 802
Debt securities, available-for-sale, yield	3.20%	3.00%
Debt securities, available-for-sale, due in one year or less	$ 52	$ 49
Debt securities, available-for-sale, due in one year or less, yield	2.70%	1.90%
Debt securities, available-for-sale, due after one year through five years	$ 43	$ 43
Debt securities, available-for-sale, due after one year through five years, yield	2.50%	2.30%
Debt securities, available-for-sale, due after five years through ten years	$ 212	$ 252
Debt securities, available-for-sale, due after five years through ten years, yield	2.70%	2.60%
Debt securities, available-for-sale, due after ten years	$ 474	$ 458
Debt securities, available-for-sale, due after ten years, yield	3.50%	3.40%
Debt securities, available-for-sale, amortized cost	$ 771	$ 816
Available-for-sale securities | Foreign government
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 172	$ 145
Debt securities, available-for-sale, yield	2.30%	2.40%
Debt securities, available-for-sale, due in one year or less	$ 41	$ 18
Debt securities, available-for-sale, due in one year or less, yield	2.10%	3.10%
Debt securities, available-for-sale, due after one year through five years	$ 55	$ 60
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	$ 73	$ 67
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	$ 3	$ 0
Debt securities, available-for-sale, due after ten years, yield	2.70%	0.00%
Debt securities, available-for-sale, amortized cost	$ 170	$ 145
Available-for-sale securities | Agency mortgage-backed residential
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 18,844	$ 17,138
Debt securities, available-for-sale, yield	3.40%	3.30%
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	$ 52	$ 54
Debt securities, available-for-sale, due after five years through ten years, yield	1.90%	1.90%
Debt securities, available-for-sale, due after ten years	$ 18,792	$ 17,084
Debt securities, available-for-sale, due after ten years, yield	3.40%	3.30%
Debt securities, available-for-sale, amortized cost	$ 18,939	$ 17,486
Available-for-sale securities | Agency mortgage-backed commercial [Member]
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 320	$ 3
Debt securities, available-for-sale, yield	3.20%	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	$ 3	$ 3
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	$ 83	$ 0
Debt securities, available-for-sale, due after five years through ten years, yield	3.30%	0.00%
Debt securities, available-for-sale, due after ten years	$ 234	$ 0
Debt securities, available-for-sale, due after ten years, yield	3.20%	0.00%
Debt securities, available-for-sale, amortized cost	$ 316	$ 3
Available-for-sale securities | Mortgage-backed residential
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 2,886	$ 2,686
Debt securities, available-for-sale, yield	3.30%	3.30%
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	$ 2,886	$ 2,686
Debt securities, available-for-sale, due after ten years, yield	3.30%	3.30%
Debt securities, available-for-sale, amortized cost	$ 2,912	$ 2,796
Available-for-sale securities | Mortgage-backed commercial
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 723	$ 714
Debt securities, available-for-sale, yield	3.80%	3.80%
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	$ 36	$ 46
Debt securities, available-for-sale, due after five years through ten years, yield	4.00%	3.90%
Debt securities, available-for-sale, due after ten years	$ 687	$ 668
Debt securities, available-for-sale, due after ten years, yield	3.80%	3.80%
Debt securities, available-for-sale, amortized cost	$ 725	$ 715
Available-for-sale securities | Asset-backed
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 668	$ 723
Debt securities, available-for-sale, yield	3.50%	3.50%
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	$ 390	$ 478
Debt securities, available-for-sale, due after one year through five years, yield	3.40%	3.40%
Debt securities, available-for-sale, due after five years through ten years	$ 165	$ 121
Debt securities, available-for-sale, due after five years through ten years, yield	4.00%	4.00%
Debt securities, available-for-sale, due after ten years	$ 113	$ 124
Debt securities, available-for-sale, due after ten years, yield	3.30%	3.30%
Debt securities, available-for-sale, amortized cost	$ 665	$ 723
Available-for-sale securities | Corporate debt
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 1,294	$ 1,241
Debt securities, available-for-sale, yield	3.20%	3.10%
Debt securities, available-for-sale, due in one year or less	$ 152	$ 144
Debt securities, available-for-sale, due in one year or less, yield	3.10%	2.80%
Debt securities, available-for-sale, due after one year through five years	$ 512	$ 496
Debt securities, available-for-sale, due after one year through five years, yield	2.90%	2.90%
Debt securities, available-for-sale, due after five years through ten years	$ 606	$ 581
Debt securities, available-for-sale, due after five years through ten years, yield	3.40%	3.30%
Debt securities, available-for-sale, due after ten years	$ 24	$ 20
Debt securities, available-for-sale, due after ten years, yield	5.90%	5.50%
Debt securities, available-for-sale, amortized cost	$ 1,301	$ 1,286
Available-for-sale securities | Available-for-sale debt securities
Schedule of Investments [Line Items]
Total available-for-sale debt securities	$ 27,630	$ 25,303
Debt securities, available-for-sale, yield	3.30%	3.20%
Debt securities, available-for-sale, due in one year or less	$ 273	$ 223
Debt securities, available-for-sale, due in one year or less, yield	2.70%	2.60%
Debt securities, available-for-sale, due after one year through five years	$ 2,344	$ 2,357
Debt securities, available-for-sale, due after one year through five years, yield	2.20%	2.40%
Debt securities, available-for-sale, due after five years through ten years	$ 1,800	$ 1,683
Debt securities, available-for-sale, due after five years through ten years, yield	2.80%	2.80%
Debt securities, available-for-sale, due after ten years	$ 23,213	$ 21,040
Debt securities, available-for-sale, due after ten years, yield	3.40%	3.30%
Debt securities, available-for-sale, amortized cost	$ 27,789	$ 25,881
Debt securities, available-for-sale, maturity, within one year, amortized cost	273	224
Debt securities, available-for-sale, maturity, after one through five years, amortized cost	2,376	2,405
Debt securities, available-for-sale, maturity, after five through ten years, amortized cost	1,814	1,743
Debt securities, available-for-sale, maturity, after 10 Years, amortized cost	23,326	21,509
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	$ 2,351	$ 2,319
Debt securities, held-to-maturity, yield	3.20%	3.20%
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	$ 2,351	$ 2,319
Debt securities, held-to-maturity, due after ten years, yield	3.20%	3.20%
Held-to-maturity securities | Asset-backed
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost, before other-than-temporary impairment	$ 36	$ 43
Debt securities, held-to-maturity, yield	2.10%	2.00%
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	$ 36	$ 42
Debt securities, held-to-maturity, due after one year through five years, yield	2.10%	2.00%
Debt securities, held-to-maturity, maturity, after five through ten years, amortized cost	$ 0	$ 1
Debt securities, held-to-maturity, due after five years through ten years, yield	0.00%	3.30%
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	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Taxable interest	$ 214	$ 154
Taxable dividends	3	3
Interest and dividends exempt from U.S. federal income tax	5	6
Interest and dividends on investment securities	240	176
Excludes other earning assets
Interest and dividends on investment securities	$ 222	$ 163

Investment Securities (Schedule

Investment Securities (Schedule Of Realized Gain (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Debt Securities, Available-for-sale [Abstract]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities	$ 0	$ 0
Available-for-sale securities, gross realized gains	10	6
Available-for-sale securities, gross realized losses	(1)	0
Net realized gains (losses) on available-for-sale securities	9	6
Net realized gain (loss) on equity securities	29	22
Net unrealized gain (loss) on equity securities	70	(40)
Other (loss) gain on investments, net	$ 108	$ (12)

Investment Securities (Schedu_2

Investment Securities (Schedule of Unrealized Loss on Investments) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	$ 1,368	$ 8,074
Debt securities, available-for-sale, unrealized loss, less than 12 months	(3)	(138)
Debt securities, available-for-sale, fair value, 12 months or longer	15,800	12,046
Debt securities, available-for-sale, unrealized loss, 12 months or longer	(292)	(496)
Debt Securities, held-to-maturity, less than 12 Months, fair value	86	473
Debt securities, held-to-maturity, unrealized loss, less than 12 Months	0	6
Debt Securities, held-to-maturity, 12 Months or Longer, fair value	1,392	1,395
Debt securities, held-to-maturity, unrealized loss, 12 months or longer	28	55
US Treasury
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	42	31
Debt securities, available-for-sale, unrealized loss, less than 12 months	0	0
Debt securities, available-for-sale, fair value, 12 months or longer	1,749	1,758
Debt securities, available-for-sale, unrealized loss, 12 months or longer	(49)	(60)
US States and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	23	259
Debt securities, available-for-sale, unrealized loss, less than 12 months	0	(3)
Debt securities, available-for-sale, fair value, 12 months or longer	189	317
Debt securities, available-for-sale, unrealized loss, 12 months or longer	(3)	(14)
Foreign government
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	4	6
Debt securities, available-for-sale, unrealized loss, less than 12 months	0	0
Debt securities, available-for-sale, fair value, 12 months or longer	22	74
Debt securities, available-for-sale, unrealized loss, 12 months or longer	0	(1)
Agency mortgage-backed residential
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	510	5,537
Debt securities, available-for-sale, unrealized loss, less than 12 months	(1)	(94)
Debt securities, available-for-sale, fair value, 12 months or longer	11,145	7,808
Debt securities, available-for-sale, unrealized loss, 12 months or longer	(192)	(301)
Debt Securities, held-to-maturity, less than 12 Months, fair value	86	457
Debt securities, held-to-maturity, unrealized loss, less than 12 Months	0	6
Debt Securities, held-to-maturity, 12 Months or Longer, fair value	1,376	1,376
Debt securities, held-to-maturity, unrealized loss, 12 months or longer	28	55
Agency mortgage-backed commercial [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	30	0
Debt securities, available-for-sale, unrealized loss, less than 12 months	0	0
Debt securities, available-for-sale, fair value, 12 months or longer	0	0
Debt securities, available-for-sale, unrealized loss, 12 months or longer	0	0
Mortgage-backed residential
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	131	1,024
Debt securities, available-for-sale, unrealized loss, less than 12 months	0	(20)
Debt securities, available-for-sale, fair value, 12 months or longer	1,676	1,360
Debt securities, available-for-sale, unrealized loss, 12 months or longer	(33)	(91)
Mortgage-backed commercial
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	517	347
Debt securities, available-for-sale, unrealized loss, less than 12 months	(2)	(1)
Debt securities, available-for-sale, fair value, 12 months or longer	41	36
Debt securities, available-for-sale, unrealized loss, 12 months or longer	0	(1)
Asset-backed
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, fair value, less than 12 months	6	294
Debt securities, available-for-sale, unrealized loss, less than 12 months	0	(1)
Debt securities, available-for-sale, fair value, 12 months or longer	214	124
Debt securities, available-for-sale, unrealized loss, 12 months or longer	(1)	(1)
Debt Securities, held-to-maturity, less than 12 Months, fair value	0	16
Debt securities, held-to-maturity, unrealized loss, less than 12 Months	0	0
Debt Securities, held-to-maturity, 12 Months or Longer, fair value	16	19
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	105	576
Debt securities, available-for-sale, unrealized loss, less than 12 months	0	(19)
Debt securities, available-for-sale, fair value, 12 months or longer	764	569
Debt securities, available-for-sale, unrealized loss, 12 months or longer	$ (14)	$ (27)

Finance Receivables and Loans_3

Finance Receivables and Loans, Net (Schedule of Accounts, Notes, Loans and Financing Receivables) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 130,055	$ 129,926	$ 125,327
Loans and finance receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unamortized premiums and discounts and deferred fees and costs	584	587
Consumer portfolio segment | Consumer loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	89,211	87,240
Consumer portfolio segment | Automobile loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	71,553	70,539	69,318
Consumer portfolio segment | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	17,658	16,701	14,683
Consumer portfolio segment | Mortgage Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	16,225	15,155
Interest-only mortgage loans	$ 17	18
Consumer portfolio segment | Mortgage Finance | 2019, or sooner
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	33.00%
Consumer portfolio segment | Mortgage Finance | 2020, or sooner
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	40.00%
Consumer portfolio segment | Mortgage - Legacy
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 1,433	1,546
Interest-only mortgage loans	$ 305	341
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	$ 40,844	42,686	$ 41,326
Commercial portfolio segment | Commercial and industrial automotive
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	31,559	33,672
Commercial portfolio segment | Commercial and industrial other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	4,516	4,205
Commercial portfolio segment | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 4,769	$ 4,809

Finance Receivables and Loans_4

Finance Receivables and Loans, Net (Allowance for Credit Losses on Financing Receivables) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan losses	$ 1,242	$ 1,276
Allowance for loan and lease losses, charge-offs	(360)	(377)
Allowance for loan and lease losses, recoveries	123	118
Allowance for loan and lease losses, net charge-offs	(237)	(259)
Provision for loan losses	282	261
Allowance for loan losses	1,288	1,278
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses, individually evaluated for impairment	126	88
Allowance for loan losses, collectively evaluated for impairment	1,162	1,190
Finance receivables and loans, net	130,055	125,327	$ 129,926
Finance receivables and loans, individually evaluated for impairment	997	840
Finance receivables and loans, collectively evaluated for impairment	129,058	124,487
Allowance for Loan and Lease Losses, Adjustments, Other	1
Consumer portfolio segment | Automobile loan
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan losses	1,048	1,066
Allowance for loan and lease losses, charge-offs	(352)	(365)
Allowance for loan and lease losses, recoveries	118	112
Allowance for loan and lease losses, net charge-offs	(234)	(253)
Provision for loan losses	257	253
Allowance for loan losses	1,070	1,066
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses, individually evaluated for impairment	46	40
Allowance for loan losses, collectively evaluated for impairment	1,024	1,026
Finance receivables and loans, net	71,553	69,318	70,539
Finance receivables and loans, individually evaluated for impairment	501	463
Finance receivables and loans, collectively evaluated for impairment	71,052	68,855
Allowance for Loan and Lease Losses, Adjustments, Other	(1)
Consumer portfolio segment | Residential mortgage
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan losses	53	79
Allowance for loan and lease losses, charge-offs	(3)	(12)
Allowance for loan and lease losses, recoveries	5	6
Allowance for loan and lease losses, net charge-offs	2	(6)
Provision for loan losses	(3)	1
Allowance for loan losses	52	74
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses, individually evaluated for impairment	22	27
Allowance for loan losses, collectively evaluated for impairment	30	47
Finance receivables and loans, net	17,658	14,683	16,701
Finance receivables and loans, individually evaluated for impairment	227	230
Finance receivables and loans, collectively evaluated for impairment	17,431	14,453
Allowance for Loan and Lease Losses, Adjustments, Other	0
Commercial portfolio segment | Commercial loan
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan losses	141	131
Allowance for loan and lease losses, charge-offs	(5)	0
Allowance for loan and lease losses, recoveries	0	0
Allowance for loan and lease losses, net charge-offs	(5)	0
Provision for loan losses	28	7
Allowance for loan losses	166	138
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses, individually evaluated for impairment	58	21
Allowance for loan losses, collectively evaluated for impairment	108	117
Finance receivables and loans, net	40,844	41,326	$ 42,686
Finance receivables and loans, individually evaluated for impairment	269	147
Finance receivables and loans, collectively evaluated for impairment	40,575	$ 41,179
Allowance for Loan and Lease Losses, Adjustments, Other	$ 2

Finance Receivables and Loans_5

Finance Receivables and Loans, Net (Schedule of Sales of Financing Receivables and Loans) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, significant sales and transfers	$ 20	$ 1
Financing Receivable, Significant Sales	128
Loans held-for-sale transferred to finance receivables and loans held-for-investment	63	0
Consumer portfolio segment | Automobile loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, significant sales and transfers	20	0
Consumer portfolio segment | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, significant sales and transfers	$ 0	$ 1

Finance Receivables and Loans_6

Finance Receivables and Loans, Net (Schedule of Purchases of Financing Receivables and Loans) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables and loans, significant purchases	$ 1,334	$ 1,463
Consumer portfolio segment | Automobile loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables and loans, significant purchases	99	168
Consumer portfolio segment | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables and loans, significant purchases	$ 1,235	$ 1,295

Finance Receivables and Loans_7

Finance Receivables and Loans, Net (Past Due Financing Receivables and Loans) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	$ 2,452	$ 3,151
Financing receivable, recorded investment, current	127,603	126,775
Total finance receivables and loans	130,055	129,926	$ 125,327
Consumer portfolio segment | Consumer loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	2,361	3,098
Financing receivable, recorded investment, current	86,850	84,142
Total finance receivables and loans	89,211	87,240
Consumer portfolio segment | Automobile loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	2,214	2,940
Financing receivable, recorded investment, current	69,339	67,599
Total finance receivables and loans	71,553	70,539	69,318
Consumer portfolio segment | Residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	147	158
Financing receivable, recorded investment, current	17,511	16,543
Total finance receivables and loans	17,658	16,701	14,683
Consumer portfolio segment | Mortgage Finance
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	69	76
Financing receivable, recorded investment, current	16,156	15,079
Total finance receivables and loans	16,225	15,155
Consumer portfolio segment | Mortgage - Legacy
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	78	82
Financing receivable, recorded investment, current	1,355	1,464
Total finance receivables and loans	1,433	1,546
Commercial portfolio segment | Commercial loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	91	53
Financing receivable, recorded investment, current	40,753	42,633
Total finance receivables and loans	40,844	42,686	$ 41,326
Commercial portfolio segment | Commercial and industrial automotive
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	87	32
Financing receivable, recorded investment, current	31,472	33,640
Total finance receivables and loans	31,559	33,672
Commercial portfolio segment | Commercial and industrial other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	2	20
Financing receivable, recorded investment, current	4,514	4,185
Total finance receivables and loans	4,516	4,205
Commercial portfolio segment | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	2	1
Financing receivable, recorded investment, current	4,767	4,808
Total finance receivables and loans	4,769	4,809
Financing receivables, 30 to 59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	1,659	2,204
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	1,658	2,204
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	1,575	2,107
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	83	97
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	52	67
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	31	30
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	1	0
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	1	0
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	406	557
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	398	552
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	379	537
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	19	15
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	8	5
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	11	10
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	8	5
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	8	1
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	0	4
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	387	390
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	305	342
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	260	296
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	45	46
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	9	4
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	36	42
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	82	48
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	78	31
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	2	16
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	$ 2	$ 1

Finance Receivables and Loans_8

Finance Receivables and Loans, Net (Schedule of Financing Receivables, Non Accrual Status) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	$ 987	$ 1,092
Consumer portfolio segment | Consumer loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	718	743
Consumer portfolio segment | Automobile loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	643	664
Consumer portfolio segment | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	75	79
Consumer portfolio segment | Mortgage Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	13	9
Consumer portfolio segment | Mortgage - Legacy
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	62	70
Commercial portfolio segment | Commercial loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	269	349
Commercial portfolio segment | Commercial and industrial automotive
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	138	203
Commercial portfolio segment | Commercial and industrial other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	125	142
Commercial portfolio segment | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	$ 6	$ 4

Finance Receivables and Loans_9

Finance Receivables and Loans, Net (Financing Receivable Credit Quality Indicators) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 130,055	$ 129,926	$ 125,327
Consumer portfolio segment | Consumer loan
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	89,211	87,240
Consumer portfolio segment | Consumer loan | Performing financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	88,493	86,497
Consumer portfolio segment | Consumer loan | Nonperforming financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	718	743
Consumer portfolio segment | Automobile loan
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	71,553	70,539	69,318
Consumer portfolio segment | Automobile loan | Performing financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	70,910	69,875
Consumer portfolio segment | Automobile loan | Nonperforming financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	643	664
Consumer portfolio segment | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	17,658	16,701	$ 14,683
Consumer portfolio segment | Residential mortgage | Performing financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	17,583	16,622
Consumer portfolio segment | Residential mortgage | Nonperforming financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	75	79
Consumer portfolio segment | Mortgage Finance
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	16,225	15,155
Consumer portfolio segment | Mortgage Finance | Performing financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	16,212	15,146
Consumer portfolio segment | Mortgage Finance | Nonperforming financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	13	9
Consumer portfolio segment | Mortgage - Legacy
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	1,433	1,546
Consumer portfolio segment | Mortgage - Legacy | Performing financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	1,371	1,476
Consumer portfolio segment | Mortgage - Legacy | Nonperforming financial instruments
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 62	$ 70

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	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 130,055	$ 129,926	$ 125,327
Commercial portfolio segment | Commercial loan
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	40,844	42,686	$ 41,326
Commercial portfolio segment | Commercial loan | Pass
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	37,011	38,710
Commercial portfolio segment | Commercial loan | Criticized
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	3,833	3,976
Commercial portfolio segment | Commercial and industrial automotive
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	31,559	33,672
Commercial portfolio segment | Commercial and industrial automotive | Pass
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	28,774	30,799
Commercial portfolio segment | Commercial and industrial automotive | Criticized
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	2,785	2,873
Commercial portfolio segment | Commercial and industrial other
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	4,516	4,205
Commercial portfolio segment | Commercial and industrial other | Pass
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	3,711	3,373
Commercial portfolio segment | Commercial and industrial other | Criticized
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	805	832
Commercial portfolio segment | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	4,769	4,809
Commercial portfolio segment | Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	4,526	4,538
Commercial portfolio segment | Commercial real estate | Criticized
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 243	$ 271

Finance Receivables and Loan_11

Finance Receivables and Loans, Net (Impaired Financing Receivables) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	$ 1,028	$ 1,105
Financing receivable, impaired, gross carrying value	997	1,075
Financing receivable, impaired, with no allowance	270	332
Financing receivable, impaired, with related allowance	727	743
Financing receivable, impaired, allowance for impaired loans	126	123
Consumer portfolio segment | Consumer loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	740	739
Financing receivable, impaired, gross carrying value	728	726
Financing receivable, impaired, with no allowance	170	176
Financing receivable, impaired, with related allowance	558	550
Financing receivable, impaired, allowance for impaired loans	68	67
Consumer portfolio segment | Automobile loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	509	503
Financing receivable, impaired, gross carrying value	501	495
Financing receivable, impaired, with no allowance	99	105
Financing receivable, impaired, with related allowance	402	390
Financing receivable, impaired, allowance for impaired loans	46	44
Consumer portfolio segment | Residential mortgage
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	231	236
Financing receivable, impaired, gross carrying value	227	231
Financing receivable, impaired, with no allowance	71	71
Financing receivable, impaired, with related allowance	156	160
Financing receivable, impaired, allowance for impaired loans	22	23
Consumer portfolio segment | Mortgage Finance
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	15	15
Financing receivable, impaired, gross carrying value	15	15
Financing receivable, impaired, with no allowance	6	6
Financing receivable, impaired, with related allowance	9	9
Financing receivable, impaired, allowance for impaired loans	1	1
Consumer portfolio segment | Mortgage - Legacy
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	216	221
Financing receivable, impaired, gross carrying value	212	216
Financing receivable, impaired, with no allowance	65	65
Financing receivable, impaired, with related allowance	147	151
Financing receivable, impaired, allowance for impaired loans	21	22
Commercial portfolio segment | Commercial loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	288	366
Financing receivable, impaired, gross carrying value	269	349
Financing receivable, impaired, with no allowance	100	156
Financing receivable, impaired, with related allowance	169	193
Financing receivable, impaired, allowance for impaired loans	58	56
Commercial portfolio segment | Commercial and industrial automotive
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	138	203
Financing receivable, impaired, gross carrying value	138	203
Financing receivable, impaired, with no allowance	41	112
Financing receivable, impaired, with related allowance	97	91
Financing receivable, impaired, allowance for impaired loans	18	10
Commercial portfolio segment | Commercial and industrial other
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	144	159
Financing receivable, impaired, gross carrying value	125	142
Financing receivable, impaired, with no allowance	56	40
Financing receivable, impaired, with related allowance	69	102
Financing receivable, impaired, allowance for impaired loans	40	46
Commercial portfolio segment | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, unpaid principal balance	6	4
Financing receivable, impaired, gross carrying value	6	4
Financing receivable, impaired, with no allowance	3	4
Financing receivable, impaired, with related allowance	3	0
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	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	$ 1,033	$ 776
Financing receivable, impaired, interest income	12	10
Consumer portfolio segment | Consumer loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	728	674
Financing receivable, impaired, interest income	11	9
Consumer portfolio segment | Automobile loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	499	444
Financing receivable, impaired, interest income	8	7
Consumer portfolio segment | Residential mortgage
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	229	230
Financing receivable, impaired, interest income	3	2
Consumer portfolio segment | Mortgage Finance
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	15	9
Financing receivable, impaired, interest income	0	0
Consumer portfolio segment | Mortgage - Legacy
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	214	221
Financing receivable, impaired, interest income	3	2
Commercial portfolio segment | Commercial loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	305	102
Financing receivable, impaired, interest income	1	1
Commercial portfolio segment | Commercial and industrial automotive
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	170	47
Financing receivable, impaired, interest income	1	1
Commercial portfolio segment | Commercial and industrial other
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	130	52
Financing receivable, impaired, interest income	0	0
Commercial portfolio segment | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	5	3
Financing receivable, impaired, interest income	$ 0	$ 0

Finance Receivables and Loan_13

Finance Receivables and Loans, Net (Troubled Debt Restructurings) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, gross carrying value	$ 837		$ 812
Loans and leases receivable, impaired, commitment to lend	$ 13		$ 4
Financing receivable, modifications, number of loans	7,454	7,105
Financing receivable, modifications, pre-modification gross carrying value	$ 173	$ 139
Financing receivable, modifications, post-modification gross carrying value	$ 155	$ 120
Consumer portfolio segment | Consumer loan
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, number of loans	7,448	7,105
Financing receivable, modifications, pre-modification gross carrying value	$ 132	$ 139
Financing receivable, modifications, post-modification gross carrying value	$ 114	$ 120
Consumer portfolio segment | Automobile loan
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, number of loans	7,427	7,042
Financing receivable, modifications, pre-modification gross carrying value	$ 129	$ 128
Financing receivable, modifications, post-modification gross carrying value	$ 111	$ 110
Consumer portfolio segment | Residential mortgage
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, number of loans	21	63
Financing receivable, modifications, pre-modification gross carrying value	$ 3	$ 11
Financing receivable, modifications, post-modification gross carrying value	$ 3	$ 10
Consumer portfolio segment | Mortgage Finance
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, number of loans	1	1
Financing receivable, modifications, pre-modification gross carrying value	$ 0	$ 1
Financing receivable, modifications, post-modification gross carrying value	$ 0	$ 1
Consumer portfolio segment | Mortgage - Legacy
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, number of loans	20	62
Financing receivable, modifications, pre-modification gross carrying value	$ 3	$ 10
Financing receivable, modifications, post-modification gross carrying value	$ 3	$ 9
Commercial portfolio segment | Commercial and industrial automotive
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, number of loans	6	0
Financing receivable, modifications, pre-modification gross carrying value	$ 41	$ 0
Financing receivable, modifications, post-modification gross carrying value	$ 41	$ 0
Commercial portfolio segment | Commercial loan
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, number of loans	6	0
Financing receivable, modifications, pre-modification gross carrying value	$ 41	$ 0
Financing receivable, modifications, post-modification gross carrying value	$ 41	$ 0

Finance Receivables and Loan_14

Finance Receivables and Loans, Net (Finance receivables and loans redefaulted during the period) (Details) - Consumer portfolio segment $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)
Consumer loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, modifications, subsequent default, number of loans	2,209	2,326
Financing receivable, modifications, subsequent default, gross carrying value	$ 26	$ 28
Financing receivables, impaired, troubled debt restructuring, charge-off amount	$ 16	$ 18
Automobile loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, modifications, subsequent default, number of loans	2,209	2,326
Financing receivable, modifications, subsequent default, gross carrying value	$ 26	$ 28
Financing receivables, impaired, troubled debt restructuring, charge-off amount	$ 16	$ 18

Leasing (Investments In Operati

Leasing (Investments In Operating Leases) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Jan. 01, 2019
Operating Leased Assets [Line Items]
Lessee, operating lease, remaining lease term, minimum	6 months
Lessee, operating lease, remaining lease term, maximum	13 years
Lessee, operating lease, option to extend, minimum	1 year
Lessee, operating lease, option to extend, maximum	15 years
Lessee, operating lease, option to terminate, minimum	2 years
Lessee, operating lease, option to terminate, maximum	5 years
Lessee, operating lease, noncancellable lease term	367 days
Lessee, operating lease, lease extension, maximum	48 months
Operating Lease, Right-of-Use Asset	$ 177
Operating Lease, Liability	206
Cash paid for amounts included in the measurement of lease liabilities	$ 12
Operating lease, weighted-average remaining lease term	7 years
Operating lease, weighted average discount rate	2.98%
Leasing Arrangement [Member]
Operating Leased Assets [Line Items]
Operating Lease, Right-of-Use Asset	$ 27
Accounting Standards Update 2016-02
Operating Leased Assets [Line Items]
Operating Lease, Right-of-Use Asset		$ 161
Operating Lease, Liability		$ 190

Leasing Leasing (Lessee, Operat

Leasing Leasing (Lessee, Operating Lease, Liability, Maturity) (Details) $ in Millions	Mar. 31, 2019USD ($)
Operating Lease Liabilities, Payments Due [Abstract]
Lessee, operating lease, payments due next twelve months	$ 36
Lessee, operating lease, payments due year two	46
Lessee, operating lease, payments due year three	36
Lessee, operating lease, payments due year four	24
Lessee, operating lease, payments due year five	16
Lessee, operating lease, payments due after year five	71
Lessee, Operating Lease, Liability, Payments, Due	229
Difference between undiscounted cash flows and discounted cash flows	(23)
Operating Lease, Liability	206
Lessee, Operating Lease, Lease Not yet Commenced, Undiscounted Future Lease Payments	$ 290
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract	15 years

Leasing Leasing (Schedule of Fu

Leasing Leasing (Schedule of Future Minimum Rental Payments for Operating Leases) (Details) $ in Millions	Dec. 31, 2018USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [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 minimum payments required	$ 503

Leasing Leasing (Lease, Cost) (

Leasing Leasing (Lease, Cost) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Lease, Cost [Abstract]
Operating lease expense	$ 11	$ 10
Variable lease expense	2	2
Total lease expense, net	$ 13	$ 12

Leasing Leasing (Schedule of Pr

Leasing Leasing (Schedule of Property Subject to or Available for Operating Lease) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Property Subject to or Available for Operating Lease, Net [Abstract]
Operating leases with a residual value guarantee	$ 394
Lessor, operating lease, lessee option to purchase underlying asset, minimum lease term	24 months
Residual value guarantee	15.00%
Vehicles available for operating lease, gross	$ 9,903	$ 9,995
Vehicles available for operating lease, accumulated depreciation	(1,564)	(1,578)
Investment in operating leases, net	$ 8,339	$ 8,417
Lessor, operating lease, lessee option to purchase underlying asset, maximum lease term	60 months

Leasing Leasing (Lessor, Operat

Leasing Leasing (Lessor, Operating Lease, Payments to be Received, Maturity) (Details) $ in Millions	Mar. 31, 2019USD ($)
Operating Leases, Future Minimum Payments Receivable [Abstract]
Operating lease, future minimum payments receivable, current	$ 1,024
Operating leases, future minimum payments receivable, in two years	933
Operating leases, future minimum payments receivable, in three years	402
Operating leases, future minimum payments receivable, in four years	57
Operating leases, future minimum payments receivable, in five years	5
Operating leases, future minimum payments receivable, thereafter	0
Total lease payments from operating leases	$ 2,421

Leasing Leasing (Depreciation E

Leasing Leasing (Depreciation Expense on Operating Lease Assets) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Leases, Operating [Abstract]
Operating lease revenue	$ 361	$ 382
Depreciation expense on operating lease assets	261	291
Remarketing (gains) and losses, net	(15)	(18)
Net depreciation expense on operating lease assets	$ 246	$ 273

Leasing Leasing (Sales-type and

Leasing Leasing (Sales-type and Direct Financing Leases, Lease Receivable, Maturity) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]
Direct financing lease, net investment in lease	$ 481		$ 439
Direct financing lease, present value of lease payments recorded as lease receivable	465		425
Direct financing lease, unguaranteed residual asset	16		$ 14
Direct financing lease, interest income	6	$ 6
Direct financing leases, payments to be received, remainder of fiscal year	110
Direct financing leases, payments to be received, two years	139
Direct financing leases, payments to be received, three years	134
Direct financing leases, payments to be received, four years	67
Direct financing leases, payments to be received, five years	38
Direct financing leases, payments to be received, thereafter	29
Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received	517
Direct financing leases, lease receivable, difference between undiscounted cash flows and discounted cash flows	$ (52)

Securitizations and Variable _3

Securitizations and Variable Interest Entities (Schedule of Variable Interest Entities) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Variable Interest Entity [Line Items]
Securitization or asset-backed financing arrangement, financial asset for which transfer is accounted as sale, gain on sale	$ 0	$ 0
Variable interest entity, assets deconsolidated	(957)		$ (1,235)
Variable interest entity, carrying value of assets for which we have continuing involvement	26,751		28,195
Variable interest entity, carrying value of liabilities for which we have continuing involvement	10,120		10,845
Variable interest entity, maximum loss exposure	2,110		2,334
Commercial portfolio segment
Variable Interest Entity [Line Items]
Variable interest entity, nonconsolidated, carrying amount, assets	867		806
Variable interest entity, nonconsolidated, carrying amount, liabilities	343		326
Variable interest entity, assets deconsolidated	0		0
Variable interest entity, maximum loss exposure	1,115		1,054
Automobile loan | Consumer portfolio segment
Variable Interest Entity [Line Items]
Variable interest entity, consolidated, carrying amount, assets	16,226		16,255
Variable interest entity, consolidated, carrying amount, liabilities	6,480		6,573
Variable interest entity, nonconsolidated, carrying amount, assets	38		45
Variable interest entity, nonconsolidated, carrying amount, liabilities	0		0
Variable interest entity, assets deconsolidated	(957)		(1,235)
Variable interest entity, maximum loss exposure	995		1,280
Automobile loan | Consumer portfolio segment | Held-to-maturity securities
Variable Interest Entity [Line Items]
Variable interest entity, consolidated, carrying amount, assets	36		43
Automobile loan | Consumer portfolio segment | Other assets
Variable Interest Entity [Line Items]
Variable interest entity, consolidated, carrying amount, assets	2		2
Automobile loan | Commercial portfolio segment
Variable Interest Entity [Line Items]
Variable interest entity, consolidated, carrying amount, assets	9,620		11,089
Variable interest entity, consolidated, carrying amount, liabilities	3,297		3,946
Unencumbered | Automobile loan | Consumer portfolio segment
Variable Interest Entity [Line Items]
Variable interest entity, consolidated, carrying amount, assets	8,400		8,400
Variable interest entity, consolidated, carrying amount, liabilities	$ 24		$ 25

Securitizations and Variable _4

Securitizations and Variable Interest Entities (Schedule of Cash Flow Received from and Paid to Nonconsolidated Securitization Entities) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash Flow Received and Paid to Nonconsolidated Securitization Entities [Line Items]
Cash flows between transferor and transferee, disbursement for repurchases during the period	$ (1)
Consumer portfolio segment | Automobile loan
Cash Flow Received and Paid to Nonconsolidated Securitization Entities [Line Items]
Cash flows between transferor and transferee, cash flows received on retained interests in securitization entities	7	$ 5
Cash flows between transferor and transferee, servicing fees	$ 3	5
Cash flows between transferor and transferee, disbursement for repurchases during the period		$ (1)

Securitizations and Variable _5

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	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Loans managed and securitized, principal amount outstanding	$ 1,460		$ 1,869
Loans managed and securitized, delinquent amount at end of period	10		16
Loans managed and securitized, net credit losses	2	$ 4
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	957		1,235
Loans managed and securitized, delinquent amount at end of period	8		13
Loans managed and securitized, net credit losses	2	3
Whole-loan sales
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Loans managed and securitized, principal amount outstanding	503		634
Loans managed and securitized, delinquent amount at end of period	2		$ 3
Loans managed and securitized, net credit losses	$ 0	$ 1

Other Assets (Schedule of Other

Other Assets (Schedule of Other Assets) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Other Assets [Abstract]
Property and equipment at cost	$ 1,286	$ 1,250
Accumulated depreciation, property and equipment	(708)	(686)
Property and equipment, net	578	564
Nonmarketable equity securities	1,240	1,410
Restricted cash collections for securitization trusts	838	965
Investments in qualified affordable housing projects	687	649
Accrued interest, late fees, and rent receivables	624	599
Equity method investments	289	262
Other accounts receivable	269	203
Goodwill	240	240
Deferred tax assets, net	137	317
Restricted cash and cash equivalents	109	124
Derivative contracts in a receivable position, fair value	22	41
Cash collateral placed with counterparties	20	26
Other assets, other	940	753
Total other assets	5,993	6,153
Federal Home Loan Bank stock	732	903
Federal Reserve Bank stock	448	448
Equity securities without a readily determinable fair value	60	59
Impairment related to equity securities without a readily determinable fair value	3
Investments in qualified affordable housing projects, unfunded commitment	336	319
Goodwill [Line Items]
Goodwill	240	240
Corporate and Other
Other Assets [Abstract]
Goodwill	193	193
Goodwill [Line Items]
Goodwill	193	193
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

Deposit Liabilities (Schedule o

Deposit Liabilities (Schedule of Deposit Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Deposits [Abstract]
Noninterest-bearing deposits	$ 141	$ 142
Interest-bearing Deposit Liabilities, by Component [Abstract]
Interest-bearing deposits, savings and money-market checking accounts	60,258	56,050
Interest-bearing deposits, certificates of deposits	52,899	49,985
Interest-bearing deposits, other	1	1
Total deposit liabilities	113,299	106,178
Certificates of deposit, $100,000 or more	22,100	21,000
Certificates of deposit, in excess of $250,000 federal insurance limit	$ 6,600	$ 6,100

Debt (Schedule of Short-term De

Debt (Schedule of Short-term Debt) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Short-term Debt [Line Items]
Demand notes	$ 2,486	$ 2,477
Federal Home Loan Bank, advances	2,775	6,825
Securities sold under agreements to repurchase	854	685
Total short-term borrowings	6,115	9,987
Non-derivative cash collateral placed with counterparties associated with repurchase agreements		0
Non-derivative cash collateral received from counterparties associated with repurchase agreements	8	8
Non-derivative noncash collateral received from counterparties associated with repurchase agreements	3	4
Unsecured debt
Short-term Debt [Line Items]
Demand notes	2,486	2,477
Federal Home Loan Bank, advances	0	0
Securities sold under agreements to repurchase	0	0
Total short-term borrowings	2,486	2,477
Secured debt
Short-term Debt [Line Items]
Demand notes	0	0
Federal Home Loan Bank, advances	2,775	6,825
Securities sold under agreements to repurchase	854	685
Total short-term borrowings	3,629	$ 7,510
Maturity within 30 days | Secured debt
Short-term Debt [Line Items]
Financial instruments sold under agreements to repurchase	513
Maturity within 31 to 60 days | Secured debt
Short-term Debt [Line Items]
Financial instruments sold under agreements to repurchase	268
Maturity within 61 to 90 days | Secured debt
Short-term Debt [Line Items]
Financial instruments sold under agreements to repurchase	73
US Treasury | Secured debt
Short-term Debt [Line Items]
Financial instruments sold under agreements to repurchase	448
Agency mortgage-backed residential | Secured debt
Short-term Debt [Line Items]
Financial instruments sold under agreements to repurchase	$ 406

Debt (Long-term Debt) (Details)

Debt (Long-term Debt) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Long-term debt, due within one year	$ 9,578	$ 8,976
Long-term debt, due after one year	31,912	35,217
Total long-term debt	41,490	44,193
Trust preferred securities	2,600	2,600
Secured debt	33,781	39,596
Unsecured debt
Debt Instrument [Line Items]
Long-term debt, due within one year	2,630	1,663
Long-term debt, due after one year	8,708	10,444
Total long-term debt	11,338	12,107
Secured debt
Debt Instrument [Line Items]
Long-term debt, due within one year	6,948	7,313
Long-term debt, due after one year	23,204	24,773
Total long-term debt	30,152	32,086
Federal Home Loan Bank advances
Debt Instrument [Line Items]
Secured debt	$ 14,700	$ 14,900

Debt (Scheduled Remaining Matur

Debt (Scheduled Remaining Maturity of Long-term Debt) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Long-term debt, maturities, repayments of principal in next 12 months	$ 5,884
Long-term debt, maturities, repayments of principal in year two	9,126
Long-term debt, maturities, repayments of principal in year three	10,837
Long-term debt, maturities, repayments of principal in year four	7,034
Long-term debt, maturities, repayments of principal in year five	1,192
Long-term debt, maturities, repayments of principal after year five	7,417
Total long-term debt	41,490	$ 44,193
Unsecured debt
Debt Instrument [Line Items]
Long-term debt, maturities, repayments of principal in next 12 months	886
Long-term debt, maturities, repayments of principal in year two	2,217
Long-term debt, maturities, repayments of principal in year three	652
Long-term debt, maturities, repayments of principal in year four	1,026
Long-term debt, maturities, repayments of principal in year five	(44)
Long-term debt, maturities, repayments of principal after year five	6,601
Total long-term debt	11,338	12,107
Secured debt
Debt Instrument [Line Items]
Total long-term debt	30,152	$ 32,086
Long-term debt | Unsecured debt
Debt Instrument [Line Items]
Long-term debt, maturities, repayments of principal in next 12 months	917
Long-term debt, maturities, repayments of principal in year two	2,258
Long-term debt, maturities, repayments of principal in year three	697
Long-term debt, maturities, repayments of principal in year four	1,075
Long-term debt, maturities, repayments of principal in year five	12
Long-term debt, maturities, repayments of principal after year five	7,504
Total long-term debt	12,463
Long-term debt | Secured debt
Debt Instrument [Line Items]
Long-term debt, maturities, repayments of principal in next 12 months	4,998
Long-term debt, maturities, repayments of principal in year two	6,909
Long-term debt, maturities, repayments of principal in year three	10,185
Long-term debt, maturities, repayments of principal in year four	6,008
Long-term debt, maturities, repayments of principal in year five	1,236
Long-term debt, maturities, repayments of principal after year five	816
Total long-term debt	30,152
Original issue discount | Unsecured debt
Debt Instrument [Line Items]
Debt instrument, unamortized discount, current	(31)
Debt instrument, unamortized discount	(1,125)
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	Mar. 31, 2019	Dec. 31, 2018
Pledged Assets related to secured borrowings [Line Items]
Pledged financial instruments, investment securities	$ 5,243	$ 10,280
Pledged assets, mortgage assets held-for-investment and lending receivables	17,447	16,498
Pledged assets,operating leases	132	170
Pledged assets, restricted as collateral	52,973	59,526
Secured debt	33,781	39,596
Ally Bank
Pledged Assets related to secured borrowings [Line Items]
Pledged financial instruments, investment securities	4,357	9,564
Pledged assets, mortgage assets held-for-investment and lending receivables	17,447	16,498
Pledged assets,operating leases	0	0
Pledged assets, restricted as collateral	45,850	51,340
Secured debt	27,233	32,072
Pledged assets for Federal Home Loan Bank | Ally Bank
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	26,600	30,800
Pledged assets for Federal Reserve Bank | Ally Bank
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	2,400	2,400
Short-term borrowings
Pledged Assets related to secured borrowings [Line Items]
Secured debt	3,600	7,500
Consumer portfolio segment | Automobile loan
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, finance receivables	15,882	17,015
Consumer portfolio segment | Automobile loan | Ally Bank
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, finance receivables	9,777	9,715
Commercial portfolio segment | Automobile loan
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, finance receivables	14,269	15,563
Commercial portfolio segment | Automobile loan | Ally Bank
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, finance receivables	$ 14,269	$ 15,563

Debt (Narrative - Trust Preferr

Debt (Narrative - Trust Preferred Securities) (Details) $ / shares in Units, $ in Billions	Mar. 31, 2019USD ($)$ / shares	Dec. 31, 2018USD ($)
Narrative - Trust Preferred Securities [Line Items]
Trust preferred securities	$ 2.6	$ 2.6
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	$ 2.6

Debt (Committed Funding Facilit

Debt (Committed Funding Facilities) (Details) - Committed funding facilities - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Long-term line of credit	$ 5,716	$ 6,665
Line of credit facility, remaining borrowing capacity	1,834	1,935
Line of credit facility, maximum borrowing capacity	7,550	8,600
Ally Bank | Secured debt
Debt Instrument [Line Items]
Long-term line of credit	3,050	3,500
Line of credit facility, remaining borrowing capacity	700	1,300
Line of credit facility, maximum borrowing capacity	3,750	4,800
Secured funding facilities, revolving, one year or greater
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	6,000
Nonbank funding | Secured debt
Debt Instrument [Line Items]
Long-term line of credit	2,666	3,165
Line of credit facility, remaining borrowing capacity	1,134	635
Line of credit facility, maximum borrowing capacity	$ 3,800	$ 3,800

Accrued Expenses and Other Li_3

Accrued Expenses and Other Liabilities (Schedule of Accrued Expenses and Other Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Accounts Payable and Accrued Liabilities [Abstract]
Accounts payable	$ 347	$ 516
Unfunded commitments for investment in qualified affordable housing projects	336	319
Employee compensation and benefits	165	255
Reserves for insurance losses and loss adjustment expenses	135	134	$ 157	$ 140
Deferred revenue	28	27
Cash collateral received from counterparties	27	41
Fair value of derivative contracts in a payable position	21	37
Other liabilities	663	347
Total accrued expenses and other liabilities	$ 1,722	$ 1,676

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss (Rollforward) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax [Abstract]
Accumulated other comprehensive income (loss), investment securities, adjustment, after tax	$ (158)	$ (524)	$ (473)	$ (481)	$ (186)	$ (173)
Other comprehensive income (loss), investment securities, net change, after tax	315	(338)
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	19	18	18	20	16
Other comprehensive income (loss), foreign currency translation adjustment, net of tax	0	(1)
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	11	25	19	19	11	11
Other comprehensive income (loss), cash flow hedges, net change, after tax	(8)	14
Other Comprehensive Income (Loss), Defined Benefit Plan, Net of Tax [Abstract]
Accumulated other comprehensive income (loss), defined benefit pension plans, after tax	(96)	(98)	(95)	(95)	(95)	(89)
Other comprehensive (income) loss, defined benefit plan, after reclassification adjustment, after tax	(1)	(3)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Total accumulated other comprehensive loss, net of tax	225	578	531	$ 539	250	$ 235
Other comprehensive income (loss), net of tax	$ 306	$ (328)
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
Accounting Standards Update 2017-08
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax [Abstract]
Accumulated other comprehensive income (loss), investment securities, adjustment, after tax			8
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			$ (8)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Loss (Before and After Tax) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
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	$ 421	$ (436)
Other compehrensive income (loss), investement securities, net realized gains reclassified to income from continuing operations, before tax	9	6
Other comprehensive income, investment securities, net change, before tax	412	(442)
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	(99)	103
Other comprehensive income (loss), investment securities, net realized gains reclassified to income from continuing operations, tax effect	(2)	(1)
Other comprehensive income (loss), investment securities, net change, tax effect	(97)	104
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	322	(333)
Other comprehensive income (loss), investment securities, net realized gains reclassified to income from continuing operations, after tax	7	5
Other comprehensive income (loss), investment securities, net change, after tax	315	(338)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax [Abstract]
Other comprehensive income (loss), translation adjustments, net change, before tax	2	(5)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax [Abstract]
Other comprehensive income (loss), translation adjustments, net unrealized gains (losses) arising during the period, tax effect	1	(1)
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, after tax	1	(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	(2)	4
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	1	(1)
Other Comprehensive Income (Loss), Net investment hedges, Net of Tax [Abstract]
Net investment hedges, unrealized gains (losses) arising during the period, after tax	(1)	3
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	(5)	18
Other comprehensive income (loss), cash flow hedge, gain (loss), reclassification, before tax	5
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	1	(4)
Other comprehensive income (loss), cash flow hedge, gain (loss), reclassification, tax	(1)
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	(4)	14
Other comprehensive income (loss), cash flow hedge, gain (loss), reclassification, after tax	4
Other comprehensive income (loss), cash flow hedge, gain (loss), after reclassification and tax	(8)
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)	(3)
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	0	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Net of Tax [Abstract]
Other comprehensive (income), defined benefit pension plans, net unrealized gains (losses) arising during period, after tax	(1)	(3)
Other Comprehensive Income (Loss), before Tax [Abstract]
Other comprehensive income (loss), before tax	401	(428)
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income (loss), tax effect	(95)	100
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other comprehensive income (loss), net of tax	$ 306	$ (328)

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
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Net income from continuing operations attributable to common shareholders	$ 375	$ 252
Income (loss) from discontinued operations, net of tax	(1)	(2)
Net income attributable to common stockholders	$ 374	$ 250
Basic weighted-average common shares outstanding	404,129	436,213
Diluted weighted-average common shares outstanding	405,959	438,931
Earnings Per Share, Basic [Abstract]
Net income from continuing operations, basic earnings per common share	$ 0.93	$ 0.58
Income (loss) from discontinued operations, net of tax, basic earnings per common share	0	(0.01)
Net income, basic earnings per common share	0.93	0.57
Earnings Per Share, Diluted [Abstract]
Net income from continuing operations, diluted earnings per common share	0.92	0.57
Income (loss) from discontinued operations, net of tax, diluted earnings per common share	0	(0.01)
Net income, diluted earnings per common share	$ 0.92	$ 0.57

Regulatory Capital and Other _3

Regulatory Capital and Other Regulatory Matters (Schedule of Regulatory Capital Amount and Ratios) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier one capital ratio	4.50%
Tier one capital to risk-weighted assets, required minimum	6.00%
Capital to risk-weighted assets, required minimum	8.00%
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	2.50%	1.875%
Parent company
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier one capital	$ 13,603	$ 13,397
Common equity tier one capital ratio	9.33%	9.14%
Tier one capital to risk-weighted assets, amount	$ 16,035	$ 15,831
Tier one capital to risk-weighted assets, ratio	10.99%	10.80%
Capital to risk-weighted assets, amount	$ 18,292	$ 18,046
Capital to risk-weighted assets, ratio	12.54%	12.31%
Tier one leverage to adjusted quarterly average assets, amount	$ 16,035	$ 15,831
Tier one leverage to adjusted quarterly average assets, ratio	9.02%	9.00%
Subsidiaries
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier one capital	$ 16,609	$ 16,552
Common equity tier one capital ratio	12.55%	12.61%
Tier one capital to risk-weighted assets, amount	$ 16,609	$ 16,552
Tier one capital to risk-weighted assets, ratio	12.55%	12.61%
Capital to risk-weighted assets, amount	$ 17,802	$ 17,620
Capital to risk-weighted assets, ratio	13.46%	13.42%
Tier one leverage to adjusted quarterly average assets, amount	$ 16,609	$ 16,552
Tier one leverage to adjusted quarterly average assets, ratio	10.45%	10.69%
Required minimum | Parent company
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier one capital ratio	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%
Required minimum | Subsidiaries
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier one capital ratio	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%
Well-capitalized minimum | Parent company
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier one capital to risk-weighted assets, well-capitalized minimum	6.00%
Capital to risk weighted assets, well-capitalzed minimum	10.00%
Well-capitalized minimum | Subsidiaries
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier one capital ratio	6.50%
Tier one capital to risk-weighted assets, well-capitalized minimum	8.00%
Capital to risk weighted assets, well-capitalzed minimum	10.00%
Tier one leverage to adjusted quarterly average assets, well-capitalized minimum	5.00%

Regulatory Capital and Other _4

Regulatory Capital and Other Regulatory Matters (Common Share Repurchases) (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 14, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Accelerated Share Repurchases [Line Items]
Treasury stock, common, amount		$ 211	$ 309	$ 250	$ 195	$ 185
Treasury stock, common, shares		8,113,000	12,121,000	9,194,000	7,280,000	6,473,000
Common stock, shares outstanding		399,760,804	404,899,599
Dividends declared, amount per common share		$ 0.17	$ 0.15	$ 0.15	$ 0.13	$ 0.13
Beginning of period
Accelerated Share Repurchases [Line Items]
Common stock, shares outstanding			404,900,000	416,591,000	425,752,000	432,691,000	437,054,000
End of period
Accelerated Share Repurchases [Line Items]
Common stock, shares outstanding		399,761,000	404,900,000	416,591,000	425,752,000	432,691,000
Subsequent event
Accelerated Share Repurchases [Line Items]
Dividends declared, amount per common share	$ 0.17
Current period
Accelerated Share Repurchases [Line Items]
Stock repurchase program, authorized amount		$ 1,000
Future period
Accelerated Share Repurchases [Line Items]
Stock repurchase program, authorized amount		$ 1,250
Increase (decrease) in share repurchase program		25.00%

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Cash collateral placed with counterparties	$ 19	$ 26
Noncash collateral placed with counterparties	99	105
Cash collateral received from counterparties	$ 12	30
Noncash collateral received from counterparties		$ 3

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	Mar. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	$ 22	$ 41
Fair value of derivative contracts in a payable position	21	37
Derivative, notional amount	24,716	38,066
Designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	1	1
Fair value of derivative contracts in a payable position	1	0
Derivative, notional amount	12,319	24,339
Not designated as hedging instrument | Other trading
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	21	40
Fair value of derivative contracts in a payable position	20	37
Derivative, notional amount	12,397	13,727
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	12,085	24,203
Foreign exchange forwards | Designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	0	1
Fair value of derivative contracts in a payable position	1	0
Derivative, notional amount	134	136
Interest rate contracts | Designated as hedging instrument | Purchased options
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	0
Derivative, notional amount	100	0
Interest rate contracts | Not designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	21	37
Fair value of derivative contracts in a payable position	19	37
Derivative, notional amount	12,272	13,546
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	11
Interest rate contracts | Not designated as hedging instrument | Written options
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	2	0
Fair value of derivative contracts in a payable position	19	37
Derivative, notional amount	6,180	6,793
Interest rate contracts | Not designated as hedging instrument | Purchased options
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	19	37
Fair value of derivative contracts in a payable position	0	0
Derivative, notional amount	6,081	6,742
Foreign exchange contracts | Not designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	0	3
Fair value of derivative contracts in a payable position	0	0
Derivative, notional amount	124	181
Foreign exchange contracts | Not designated as hedging instrument | Futures and forwards
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	0	3
Fair value of derivative contracts in a payable position	0	0
Derivative, notional amount	124	181
Equity contract | Not 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	1	0
Derivative, notional amount	1	0
Equity contract | Not designated as hedging instrument | Written options
Derivatives, Fair Value [Line Items]
Derivative contracts in a receivable position, fair value	0	0
Fair value of derivative contracts in a payable position	1	0
Derivative, notional amount	$ 1	$ 0

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	Mar. 31, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Long-term debt	$ 41,490	$ 44,193
Amortized cost basis of the closed portfolios used in hedging relationships	46	47
Hedged asset, last-of-layer, amount	9,600	21,400
Hedged liability, fair value hedge, cumulative increase (decrease)	5
Hedge basis adjustment, last-of-layer		19
Hedged asset, discontinued fair value hedge, last-of-layer amount	11,200
Carrying amount
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Available-for-sale debt securities	1,495	1,485
Finance receivables and loans, net	36,433	40,850
Long-term debt	12,263	13,001
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	(10)	0
Hedged asset, last-of-layer, amount	28	28
Hedged asset, discontinued fair value hedge, cumulative increase (decrease)	0	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	(8)	5
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	(63)	(24)
Hedged asset, discontinued fair value hedge, cumulative increase (decrease)	65
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	(68)	(5)
Long-term debt
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged liability, fair value hedge, cumulative increase (decrease)	66	67
Long-term debt | Discontinued hedge
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged liability, fair value hedge, cumulative increase (decrease)	$ 66	$ 67

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	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments, net, pretax	$ (5)	$ 2
Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest rate derivative instruments	(4)	2
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on foreign currency derivative instruments	(1)	0
Gains on mortgage and automotive loans | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest rate derivative instruments	1	0
Other income | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest rate derivative instruments	(5)	2
Other income | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on foreign currency derivative instruments	$ (1)	$ 0

Derivative Instruments and He_7

Derivative Instruments and Hedging Activities (Derivative Instruments Designated as Fair Value Hedges, Gain (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Interest and fees on finance receivables and loans	$ 1,807	$ 1,543
Interest and dividends on investment securities and other earning assets	240	176
Interest on deposits	592	351
Interest on long-term debt	419	411
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	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
Designated as hedging instrument | interest on deposits [Member] | Fair value hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on fair value hedges	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	0	1
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
Change in unrealized gain (loss) on fair value hedging instruments	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
Change in unrealized gain (loss) on fair value hedging instruments	0	0
Designated as hedging instrument | Unsecured debt | interest on deposits [Member] | 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
Change in unrealized gain (loss) on fair value hedging instruments	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	0	36
Change in unrealized gain (loss) on fair value hedging instruments	0	(35)
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
Change in unrealized gain (loss) on fair value hedging instruments	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
Change in unrealized gain (loss) on fair value hedging instruments	0	0
Designated as hedging instrument | Federal Home Loan Bank certificates and obligations | interest on deposits [Member] | 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
Change in unrealized gain (loss) on fair value hedging instruments	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	0	33
Change in unrealized gain (loss) on fair value hedging instruments	0	(33)
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
Change in unrealized gain (loss) on fair value hedging instruments	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	10	(3)
Change in unrealized gain (loss) on fair value hedging instruments	(10)	3
Designated as hedging instrument | Available-for-sale securities | interest on deposits [Member] | 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
Change in unrealized gain (loss) on fair value hedging instruments	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
Change in unrealized gain (loss) on fair value hedging instruments	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	43	(45)
Change in unrealized gain (loss) on fair value hedging instruments	(43)	45
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
Change in unrealized gain (loss) on fair value hedging instruments	0	0
Designated as hedging instrument | Fixed-rate automotive loans | interest on deposits [Member] | 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
Change in unrealized gain (loss) on fair value hedging instruments	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
Change in unrealized gain (loss) on fair value hedging instruments	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]
Interest rate cash flow hedge gain (loss) reclassified to earnings	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]
Interest rate cash flow hedge gain (loss) reclassified to earnings	0	0
Deposit liabilities | Designated as hedging instrument | interest on deposits [Member] | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate cash flow hedge gain (loss) reclassified to earnings	1	0
Deposit liabilities | Designated as hedging instrument | Interest on long-term debt | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate cash flow hedge gain (loss) reclassified to earnings	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
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]
Interest rate cash flow hedge gain (loss) reclassified to earnings	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
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]
Interest rate cash flow hedge gain (loss) reclassified to earnings	0	0
Variable-rate borrowings | Designated as hedging instrument | interest on deposits [Member] | Cash flow hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedging relationships	1	0
Variable-rate borrowings | Designated as hedging instrument | interest on deposits [Member] | Cash flow hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate cash flow hedge gain (loss) reclassified to earnings	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	4	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]
Interest rate cash flow hedge gain (loss) reclassified to earnings	$ 4	$ 0

Derivative Instruments and He_8

Derivative Instruments and Hedging Activities (Interest and Amortization on Derivative Instruments) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Interest and dividends on investment securities and other earning assets	$ 240	$ 176
Interest on long-term debt	419	411
Earnings on cash flow hedges to be recognized within twelve months	7
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	0
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	(11)
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
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
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	0	(1)
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
Designated as hedging instrument | Interest on long-term debt | Fair value hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on fair value hedges	0	1
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	0	19
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	0	1
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
Gain (loss) on interest for qualifying hedge	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
Gain (loss) on interest for qualifying hedge	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	6	15
Gain (loss) on interest for qualifying hedge	0	3
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
Gain (loss) on interest for qualifying hedge	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
Gain (loss) on interest for qualifying hedge	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	(6)	(1)
Gain (loss) on interest for qualifying hedge	0	2
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
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	0	(1)
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
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	(4)	(4)
Gain (loss) on interest for qualifying hedge	6	(7)
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
Gain (loss) on interest for qualifying hedge	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
Gain (loss) on interest for qualifying hedge	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
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
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
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
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	4	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	$ 0	$ 1

Derivative Instruments and He_9

Derivative Instruments and Hedging Activities (Derivative Instruments Used in Net Investment Hedge Accounting Relationships) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, amounts excluded from effectiveness testing, net	$ 0	$ 0
Derivatives used in net Investment hedge, gain (loss), reclassified to earnings, net of tax	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)	18
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	$ (2)	$ 4

Income Taxes Income Taxes (Deta

Income Taxes Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income tax expense from continuing operations	$ 111	$ 76

Fair Value (Fair Value Measurem

Fair Value (Fair Value Measurements - Recurring Basis) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	$ 536	$ 773
Available-for-sale securities	$ 27,630	$ 25,303
Investment in any one industry did not exceed percentage	15.00%	9.00%
Fair value, measurements, recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 27,630	$ 25,303
Derivative assets	22	41
Assets, fair value	28,207	26,129
Derivative liabilities	(21)	(37)
Liabilities, fair value	21	37
Fair value, measurements, recurring | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	(19)	(37)
Fair value, measurements, recurring | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	(1)
Fair value, measurements, recurring | Other contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	(1)
Fair value, measurements, recurring | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	536	773
Fair value, measurements, recurring | US Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,942	1,851
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	781	802
Fair value, measurements, recurring | Foreign government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	172	145
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	18,844	17,138
Fair value, measurements, recurring | Agency mortgage-backed commercial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	320	3
Fair value, measurements, recurring | Mortgage-backed residential
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,886	2,686
Fair value, measurements, recurring | Mortgage-backed commercial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	723	714
Fair value, measurements, recurring | Asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	668	723
Fair value, measurements, recurring | Corporate debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,294	1,241
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	15	8
Fair value, measurements, recurring | Retained interest
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Retained interest, fair value	4	4
Fair value, measurements, recurring | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	22	37
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	1,948	1,857
Derivative assets	0	0
Assets, fair value	2,473	2,623
Derivative liabilities	(1)	0
Liabilities, fair value	1	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 | Other contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	(1)
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	525	766
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	1,941	1,850
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	7
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 | Agency 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 | 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	25,682	23,446
Derivative assets	20	41
Assets, fair value	25,702	23,487
Derivative liabilities	(20)	(37)
Liabilities, fair value	20	37
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	(19)	(37)
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	(1)
Fair value, measurements, recurring | Fair value, inputs, level 2 | Other 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 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	1
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	781	802
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	165	138
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	18,844	17,138
Fair value, measurements, recurring | Fair value, inputs, level 2 | Agency mortgage-backed commercial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	320	3
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	2,886	2,686
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	723	714
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	668	723
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	1,294	1,241
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	20	37
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	2	0
Assets, fair value	32	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 | Other 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	11	7
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 | Agency 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 | 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	15	8
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	4
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	$ 2	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 assets		$ 0

Fair Value (Fair Value Measur_2

Fair Value (Fair Value Measurements - Reconciliation of Level 3 Assets And Liabilities) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, measurement, recurring, asset value, beginning balance	$ 19	$ 38
Fair value, measurement, recurring, asset, gain (loss) included in earnings	7	(3)
Fair value, measurement, recurring, asset, gain (loss) included in other comprehensive income (loss)	0	0
Fair value, measurement, recurring, asset, purchases	90	59
Fair value, measurement, recurring, asset, sales	(84)	(66)
Fair value, measurement , recurring, asset, issuances	0	0
Fair value, measurement, recurring, asset, settlements	0	(3)
Fair value, measurement, recurring, asset value, ending balance	32	25
Fair value, assets, recurring, net unrealized gains (losses)	6	(5)
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	7	19
Fair value, measurement, recurring, asset, gain (loss) included in earnings	4	(4)
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	(3)
Fair value, measurement, recurring, asset value, ending balance	11	12
Fair value, assets, recurring, net unrealized gains (losses)	4	(5)
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	8	13
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	90	59
Fair value, measurement, recurring, asset, sales	(84)	(66)
Fair value, measurement , recurring, asset, issuances	0	0
Fair value, measurement, recurring, asset, settlements	0	0
Fair value, measurement, recurring, asset value, ending balance	15	7
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	4	5
Fair value, measurement, recurring, asset, gain (loss) included in earnings	0	0
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	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	0	1
Fair value, measurement, recurring, asset, gain (loss) included in earnings	2	0
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	2	1
Fair value, assets, recurring, net unrealized gains (losses)	2	$ 0
Fair value, assets measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	$ 0

Fair Value (Fair Value Measur_3

Fair Value (Fair Value Measurements - Nonrecurring Basis) (Details) $ in Millions	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	$ 107	$ 314
Fair Value, measurements, nonrecurring | Automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	18	210
Lower of cost or fair value or valuation reserve allowance	0	(2)
Fair Value, measurements, nonrecurring | Loans held-for-sale, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	74	96
Lower of cost or fair value or valuation reserve allowance	0	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	92	306
Lower of cost or fair value or valuation reserve allowance	0	(2)
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	83	84
Lower of cost or fair value or valuation reserve allowance	(18)	(10)
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	30	55
Lower of cost or fair value or valuation reserve allowance	(40)	(46)
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	113	139
Lower of cost or fair value or valuation reserve allowance	(58)	(56)
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	12	13
Lower of cost or fair value or valuation reserve allowance	(1)	(1)
Fair Value, measurements, nonrecurring | Nonmarketable equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value	2	1
Lower of cost or fair value or valuation reserve allowance	0	(1)
Fair Value, measurements, nonrecurring | Equity method investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets, fair value	1	3
Lower of cost or fair value or valuation reserve allowance	(3)	0
Fair Value, measurements, nonrecurring | Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	220	462
Lower of cost or fair value or valuation reserve allowance	(62)	(60)
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	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 1 | Loans held-for-sale, other
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 | 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 | 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 | Nonmarketable equity investments
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 | Equity method investments
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 | 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	0
Fair Value, measurements, nonrecurring | Fair value, inputs, level 2 | Loans held-for-sale, other
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 | 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 | 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 | Nonmarketable equity investments
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 | Equity method investments
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 | 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	18	210
Fair Value, measurements, nonrecurring | Fair value, inputs, level 3 | Loans held-for-sale, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net	74	96
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	92	306
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	83	84
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	30	55
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	113	139
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	12	13
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	2	1
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	1	3
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	$ 220	462
Valuation technique, market approach | Fair Value, measurements, nonrecurring | Automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net		104
Valuation technique, discounted cash flow | Fair Value, measurements, nonrecurring | Automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, net		$ 106
Minimum | Valuation technique, discounted cash flow | Fair Value, measurements, nonrecurring | Automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input		0.0008
Maximum | Valuation technique, discounted cash flow | Fair Value, measurements, nonrecurring | Automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input		0.0109
Weighted average | Valuation technique, discounted cash flow | Fair Value, measurements, nonrecurring | Automotive
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input		0.0072

Fair Value (Fair Value of Finan

Fair Value (Fair Value of Financial Instruments) (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	$ 2,387,000,000	$ 2,362,000,000
Loans held-for-sale, net	107,000,000	314,000,000
Finance receivables and loans, net	128,767,000,000	128,684,000,000
Deposit liabilities	113,299,000,000	106,178,000,000
Short-term borrowings	6,115,000,000	9,987,000,000
Long-term debt	41,490,000,000	44,193,000,000
Reported value measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	2,387,000,000	2,362,000,000
Loans held-for-sale, net	92,000,000	306,000,000
Finance receivables and loans, net	128,767,000,000	128,684,000,000
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	1,180,000,000	1,351,000,000
Deposit liabilities	54,899,000,000	51,985,000,000
Short-term borrowings	6,115,000,000	9,987,000,000
Long-term debt	41,490,000,000	44,193,000,000
Estimate of fair value measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	2,374,000,000	2,307,000,000
Loans held-for-sale, net	92,000,000	306,000,000
Finance receivables and loans, net	131,541,000,000	130,878,000,000
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	1,180,000,000	1,351,000,000
Deposit liabilities	55,106,000,000	51,997,000,000
Short-term borrowings	6,119,000,000	9,992,000,000
Long-term debt	43,699,000,000	45,646,000,000
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
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	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	2,374,000,000	2,307,000,000
Loans held-for-sale, net	0	0
Finance receivables and loans, net	0	0
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	1,180,000,000	1,351,000,000
Deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	23,038,000,000	23,846,000,000
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	92,000,000	306,000,000
Finance receivables and loans, net	131,541,000,000	130,878,000,000
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	0	0
Deposit liabilities	55,106,000,000	51,997,000,000
Short-term borrowings	6,119,000,000	9,992,000,000
Long-term debt	$ 20,661,000,000	$ 21,800,000,000

Offsetting Assets and Liabili_3

Offsetting Assets and Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Offsetting Assets and Liabilities [Line Items]
Derivative asset, gross amount of recognized assets	$ 22	$ 41
Derivative liability, gross amounts of recognized liabilities	21	37
Noncash Derivative Collateral Pledged to Ally	3	3
Noncash Repurchase Collateral pledged to Ally		4
Customer securities, entity has right to sell or repledge, fair value	3	7
Derivative assets in net asset positions
Offsetting Assets and Liabilities [Line Items]
Derivative asset, gross amount of recognized assets	20	41
Derivative assets and liabilities, gross amounts offset	0	0
Derivative asset, fair value, net amounts offset against collateral	20	41
Derivative asset, gross amounts not offset	1	0
Derivative, Collateral, Obligation to Return Cash	(1)	(4)
Derivative assets, net	18	37
Derivative assets with no offsetting arrangements [Member] [Domain]
Offsetting Assets and Liabilities [Line Items]
Derivative asset, gross amount of recognized assets	2
Derivative assets and liabilities, gross amounts offset	0
Derivative asset, fair value, net amounts offset against collateral	2
Derivative asset, gross amounts not offset	0
Derivative, Collateral, Obligation to Return Cash	0
Derivative assets, net	2
Derivative assets
Offsetting Assets and Liabilities [Line Items]
Derivative asset, gross amount of recognized assets	22	41
Derivative assets and liabilities, gross amounts offset	0	0
Derivative asset, fair value, net amounts offset against collateral	22	41
Derivative asset, gross amounts not offset	1	0
Derivative, Collateral, Obligation to Return Cash	(1)	(4)
Derivative assets, net	20	37
Derivative liabilities in net liability positions
Offsetting Assets and Liabilities [Line Items]
Derivative assets and liabilities, gross amounts offset	0	0
Derivative liabilities, collateral	(1)	0
Derivative liability, gross amounts of recognized liabilities	20	37
Derivative liability, fair value, net amounts offset against collateral	20	37
Derivative liability, gross amounts not offset	0	0
Derivative liabilities, net	19	37
Derivative liabilities in net asset positions [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative assets and liabilities, gross amounts offset	0
Derivative liabilities, collateral	0
Derivative liability, gross amounts of recognized liabilities	1
Derivative liability, fair value, net amounts offset against collateral	1
Derivative liability, gross amounts not offset	(1)
Derivative liabilities, net	0
Total derivative liabilities excluding repurchase agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative assets and liabilities, gross amounts offset	0
Derivative liabilities, collateral	(1)
Derivative liability, gross amounts of recognized liabilities	21
Derivative liability, fair value, net amounts offset against collateral	21
Derivative liability, gross amounts not offset	(1)
Derivative liabilities, net	19
Securities sold under agreements to repurchase
Offsetting Assets and Liabilities [Line Items]
Derivative assets and liabilities, gross amounts offset	0	0
Derivative liabilities, collateral	(854)	(685)
Derivative liability, gross amounts of recognized liabilities	854	685
Derivative liability, fair value, net amounts offset against collateral	854	685
Derivative liability, gross amounts not offset	0	0
Derivative liabilities, net	0	0
Derivative liabilities
Offsetting Assets and Liabilities [Line Items]
Derivative assets and liabilities, gross amounts offset	0	0
Derivative liabilities, collateral	(855)	(685)
Derivative liability, gross amounts of recognized liabilities	875	722
Derivative liability, fair value, net amounts offset against collateral	875	722
Derivative liability, gross amounts not offset	(1)	0
Derivative liabilities, net	$ 19	$ 37

Segment Information (Details)

Segment Information (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)
Segment Reporting Information [Line Items]
Number of operating segments	4
Net financing revenue and other interest income	$ 1,132	$ 1,049
Other revenue	466	354
Net revenue	1,598	1,403
Provision for loan losses	282	261
Noninterest expense	830	814
Income from continuing operations before income tax expense	486	328
Assets	180,117	170,021	$ 178,869
Net financing revenue and other interest income after provision for loan losses	850	788
Corporate and Other
Segment Reporting Information [Line Items]
Net financing revenue and other interest income	36	39
Other revenue	25	33
Net revenue	61	72
Provision for loan losses	(5)	0
Noninterest expense	80	76
Income from continuing operations before income tax expense	(14)	(4)
Assets	34,842	30,375
Automotive Finance operations
Segment Reporting Information [Line Items]
Net financing revenue and other interest income	980	909
Other revenue	68	66
Net revenue	1,048	975
Provision for loan losses	262	259
Noninterest expense	457	448
Income from continuing operations before income tax expense	329	268
Assets	115,789	114,934
Insurance operations
Segment Reporting Information [Line Items]
Net financing revenue and other interest income	12	12
Other revenue	360	246
Net revenue	372	258
Provision for loan losses	0	0
Noninterest expense	227	231
Income from continuing operations before income tax expense	145	27
Assets	8,179	7,557
Mortgage Finance operations
Segment Reporting Information [Line Items]
Net financing revenue and other interest income	50	43
Other revenue	2	1
Net revenue	52	44
Provision for loan losses	2	2
Noninterest expense	37	34
Income from continuing operations before income tax expense	13	8
Assets	16,301	12,780
Corporate Finance operations
Segment Reporting Information [Line Items]
Net financing revenue and other interest income	54	46
Other revenue	11	8
Net revenue	65	54
Provision for loan losses	23	0
Noninterest expense	29	25
Income from continuing operations before income tax expense	13	29
Assets	$ 5,006	$ 4,375

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
	Mar. 31, 2019	Mar. 31, 2018
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans	$ 1,807	$ 1,543
Interest on loans held-for-sale	2	0
Interest and dividends on investment securities and other earning assets	240	176
Interest on cash and cash equivalents	23	15
Operating leases	361	382
Financing revenue and other interest income	2,433	2,116
Interest on deposits	592	351
Interest on short-term borrowings	44	32
Interest on long-term debt	419	411
Interest on intercompany debt	0	0
Interest expense	1,055	794
Net depreciation expense on operating lease assets	246	273
Net financing (loss) revenue	1,132	1,049
Cash dividends from bank subsidiaries	0	0
Cash dividends from nonbank subsidiaries	0	0
Insurance premiums and service revenue earned	261	256
Gain on mortgage and automotive loans, net	10	1
Other (loss) gain on investments, net	108	(12)
Other income, net of losses	87	109
Other revenue	466	354
Net revenue	1,598	1,403
Provision for loan losses	282	261
Compensation and benefits expense	318	306
Insurance losses and loss adjustment expenses	59	63
Other operating expenses	453	445
Noninterest expense	830	814
Income from continuing operations before income tax (benefit) expense and undistributed (loss) income of subsidiaries	486	328
Income tax (benefit) expense from continuing operations	111	76
Net (loss) income from continuing operations	375	252
Income (loss) from discontinued operations, net of tax	(1)	(2)
Undistributed income of bank subsidiary	0	0
Undistributed income of nonbank subsidiaries	0	0
Net income	374	250
Other comprehensive income (loss), net of tax	306	(328)
Comprehensive income	680	(78)
Parent
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans	(60)	11
Interest on loans held-for-sale	0
Interest and dividends on investment securities and other earning assets	0	0
Interest on cash and cash equivalents	2	2
Operating leases	2	2
Financing revenue and other interest income	(51)	19
Interest on deposits	0	0
Interest on short-term borrowings	13	10
Interest on long-term debt	211	258
Interest on intercompany debt	5	3
Interest expense	229	271
Net depreciation expense on operating lease assets	1	4
Net financing (loss) revenue	(281)	(256)
Cash dividends from bank subsidiaries	400	1,000
Cash dividends from nonbank subsidiaries	42	169
Insurance premiums and service revenue earned	0	0
Gain on mortgage and automotive loans, net	4	28
Other (loss) gain on investments, net	0	0
Other income, net of losses	103	96
Other revenue	107	124
Net revenue	268	1,037
Provision for loan losses	27	81
Compensation and benefits expense	12	23
Insurance losses and loss adjustment expenses	0	0
Other operating expenses	155	182
Noninterest expense	167	205
Income from continuing operations before income tax (benefit) expense and undistributed (loss) income of subsidiaries	74	751
Income tax (benefit) expense from continuing operations	(61)	(56)
Net (loss) income from continuing operations	135	807
Income (loss) from discontinued operations, net of tax	(1)	(1)
Undistributed income of bank subsidiary	57	(597)
Undistributed income of nonbank subsidiaries	183	41
Net income	374	250
Other comprehensive income (loss), net of tax	306	(328)
Comprehensive income	680	(78)
Guarantors
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans	0	0
Interest on loans held-for-sale	0
Interest and dividends on investment securities and other earning assets	0	0
Interest on cash and cash equivalents	0	0
Operating leases	0	0
Financing revenue and other interest income	0	0
Interest on deposits	0	0
Interest on short-term borrowings	0	0
Interest on long-term debt	0	0
Interest on intercompany debt	0	0
Interest expense	0	0
Net depreciation expense on operating lease assets	0	0
Net financing (loss) revenue	0	0
Cash dividends from bank subsidiaries	400	1,000
Cash dividends from nonbank subsidiaries	0	0
Insurance premiums and service revenue earned	0	0
Gain on mortgage and automotive loans, net	0	0
Other (loss) gain on investments, net	0	0
Other income, net of losses	0	0
Other revenue	0	0
Net revenue	400	1,000
Provision for loan losses	0	0
Compensation and benefits expense	0	0
Insurance losses and loss adjustment expenses	0	0
Other operating expenses	0	0
Noninterest expense	0	0
Income from continuing operations before income tax (benefit) expense and undistributed (loss) income of subsidiaries	400	1,000
Income tax (benefit) expense from continuing operations	0	0
Net (loss) income from continuing operations	400	1,000
Income (loss) from discontinued operations, net of tax	0	0
Undistributed income of bank subsidiary	57	(597)
Undistributed income of nonbank subsidiaries	0	0
Net income	457	403
Other comprehensive income (loss), net of tax	229	(276)
Comprehensive income	686	127
Nonguarantors
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans	1,867	1,532
Interest on loans held-for-sale	2
Interest and dividends on investment securities and other earning assets	240	176
Interest on cash and cash equivalents	21	14
Operating leases	359	380
Financing revenue and other interest income	2,494	2,105
Interest on deposits	592	354
Interest on short-term borrowings	31	22
Interest on long-term debt	208	153
Interest on intercompany debt	5	2
Interest expense	836	531
Net depreciation expense on operating lease assets	245	269
Net financing (loss) revenue	1,413	1,305
Cash dividends from bank subsidiaries	0	0
Cash dividends from nonbank subsidiaries	0	0
Insurance premiums and service revenue earned	261	256
Gain on mortgage and automotive loans, net	6	1
Other (loss) gain on investments, net	108	(12)
Other income, net of losses	144	221
Other revenue	519	466
Net revenue	1,932	1,771
Provision for loan losses	272	208
Compensation and benefits expense	306	283
Insurance losses and loss adjustment expenses	59	63
Other operating expenses	458	471
Noninterest expense	823	817
Income from continuing operations before income tax (benefit) expense and undistributed (loss) income of subsidiaries	837	746
Income tax (benefit) expense from continuing operations	172	132
Net (loss) income from continuing operations	665	614
Income (loss) from discontinued operations, net of tax	0	(1)
Undistributed income of bank subsidiary	0	0
Undistributed income of nonbank subsidiaries	0	0
Net income	665	613
Other comprehensive income (loss), net of tax	320	(339)
Comprehensive income	985	274
Affiliated entity
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans	0	0
Interest on cash and cash equivalents	0	0
Gain on mortgage and automotive loans, net	0	0
Affiliated entity | Parent
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans	3	2
Interest on cash and cash equivalents	2	2
Gain on mortgage and automotive loans, net	507	(423)
Affiliated entity | Guarantors
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans	0	0
Interest on cash and cash equivalents	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	2	1
Interest on cash and cash equivalents	3	2
Gain on mortgage and automotive loans, net	290	1
Consolidating adjustments
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans	0	0
Interest on loans held-for-sale	0
Interest and dividends on investment securities and other earning assets	0	0
Interest on cash and cash equivalents	0	(1)
Operating leases	0	0
Financing revenue and other interest income	(10)	(8)
Interest on deposits	0	(3)
Interest on short-term borrowings	0	0
Interest on long-term debt	0	0
Interest on intercompany debt	(10)	(5)
Interest expense	(10)	(8)
Net depreciation expense on operating lease assets	0	0
Net financing (loss) revenue	0	0
Cash dividends from bank subsidiaries	(800)	(2,000)
Cash dividends from nonbank subsidiaries	(42)	(169)
Insurance premiums and service revenue earned	0	0
Gain on mortgage and automotive loans, net	0	(28)
Other (loss) gain on investments, net	0	0
Other income, net of losses	(160)	(208)
Other revenue	(160)	(236)
Net revenue	(1,002)	(2,405)
Provision for loan losses	(17)	(28)
Compensation and benefits expense	0	0
Insurance losses and loss adjustment expenses	0	0
Other operating expenses	(160)	(208)
Noninterest expense	(160)	(208)
Income from continuing operations before income tax (benefit) expense and undistributed (loss) income of subsidiaries	(825)	(2,169)
Income tax (benefit) expense from continuing operations	0	0
Net (loss) income from continuing operations	(825)	(2,169)
Income (loss) from discontinued operations, net of tax	0	0
Undistributed income of bank subsidiary	(114)	1,194
Undistributed income of nonbank subsidiaries	(183)	(41)
Net income	(1,122)	(1,016)
Other comprehensive income (loss), net of tax	(549)	615
Comprehensive income	(1,671)	(401)
Consolidating adjustments | Affiliated entity
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans	(5)	(3)
Interest on cash and cash equivalents	(5)	(4)
Gain on mortgage and automotive loans, net	$ (797)	$ 422

Parent and Guarantor Condense_4

Parent and Guarantor Condensed Consolidating Financial Statements (Schedule of Condensed Consolidating Balance Sheet) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents, noninterest-bearing	$ 946		$ 810
Cash and cash equivalents, interest-bearing	3,011		3,727
Cash and cash equivalents	3,957		4,537	$ 3,721
Equity securities	536		773
Available-for-sale securities	27,630		25,303
Held-to-maturity securities	2,387		2,362
Loans held-for-sale, net	107		314
Finance receivables and loans, net	130,055		129,926	125,327
Intercompany loans to nonbank subsidiary	0		0
Allowance for loan losses	1,288		1,242	1,278		$ 1,276
Total finance receivables and loans, net	128,767		128,684
Investment in operating leases, net	8,339		8,417
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	2,401		2,326
Other assets	5,993		6,153
Assets	180,117		178,869	170,021
Deposit liabilities, noninterest-bearing	141		142
Deposit liabilities, interest-bearing	113,158		106,036
Deposit liabilities	113,299		106,178
Short-term borrowings	6,115		9,987
Long-term debt	41,490		44,193
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	696		523
Unearned insurance premiums and service revenue	3,096		3,044
Accrued expenses and other liabilities	1,722		1,676
Total liabilities	166,418		165,601
Equity	13,699	$ 13,266	13,268	13,082	$ 13,375	$ 13,494
Total liabilities and equity	180,117		178,869
Parent
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents, noninterest-bearing	45		55
Cash and cash equivalents, interest-bearing	14		5
Cash and cash equivalents	1,404		1,309	796
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	2,109		2,349
Intercompany loans to nonbank subsidiary	372		882
Allowance for loan losses	36		55
Total finance receivables and loans, net	2,445		3,176
Investment in operating leases, net	3		5
Intercompany receivables from bank subsidiary	104		158
Intercompany receivables from nonbank subsidiary	46		45
Investment in bank subsidiaries	16,499		16,213
Investment in nonbank subsidiaries	6,687		6,928
Premiums receivable and other insurance assets	0		0
Other assets	2,292		2,226
Assets	29,480		30,060
Deposit liabilities, noninterest-bearing	0		0
Deposit liabilities, interest-bearing	0		1
Deposit liabilities	0		1
Short-term borrowings	2,486		2,477
Long-term debt	11,887		12,774
Intercompany debt payable to bank subsidiaries	17		20
Intercompany debt payable to nonbank subsidiaries	801		918
Intercompany payables to bank subsidiary	46		45
Intercompany payables to nonbank subsidiaries	108		124
Interest payable	218		159
Unearned insurance premiums and service revenue	0		0
Accrued expenses and other liabilities	218		274
Total liabilities	15,781		16,792
Equity	13,699		13,268
Total liabilities and equity	29,480		30,060
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	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	16,499		16,213
Investment in nonbank subsidiaries	0		0
Premiums receivable and other insurance assets	0		0
Other assets	0		0
Assets	16,499		16,213
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	16,499		16,213
Total liabilities and equity	16,499		16,213
Nonguarantors
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents, noninterest-bearing	901		755
Cash and cash equivalents, interest-bearing	2,997		3,722
Cash and cash equivalents	4,595		4,998	4,237
Equity securities	536		773
Available-for-sale securities	27,630		25,303
Held-to-maturity securities	2,404		2,382
Loans held-for-sale, net	107		314
Finance receivables and loans, net	127,928		127,577
Intercompany loans to nonbank subsidiary	104		397
Allowance for loan losses	1,252		1,187
Total finance receivables and loans, net	126,780		126,787
Investment in operating leases, net	8,336		8,412
Intercompany receivables from bank subsidiary	0		0
Intercompany receivables from nonbank subsidiary	110		129
Investment in bank subsidiaries	0		0
Investment in nonbank subsidiaries	0		0
Premiums receivable and other insurance assets	2,401		2,326
Other assets	5,440		5,453
Assets	178,339		176,877
Deposit liabilities, noninterest-bearing	141		142
Deposit liabilities, interest-bearing	113,158		106,035
Deposit liabilities	114,644		107,426
Short-term borrowings	3,629		7,510
Long-term debt	29,603		31,419
Intercompany debt payable to bank subsidiaries	0		0
Intercompany debt payable to nonbank subsidiaries	372		882
Intercompany payables to bank subsidiary	0		0
Intercompany payables to nonbank subsidiaries	113		129
Interest payable	478		364
Unearned insurance premiums and service revenue	3,096		3,044
Accrued expenses and other liabilities	3,236		2,962
Total liabilities	155,171		153,736
Equity	23,168		23,141
Total liabilities and equity	178,339		176,877
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	1,345		1,249
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	697		521
Deposit liabilities, interest-bearing	1,345		1,249
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	(2,042)		(1,770)	$ (1,312)
Equity securities	0		0
Available-for-sale securities	0		0
Held-to-maturity securities	(17)		(20)
Loans held-for-sale, net	0		0
Finance receivables and loans, net	18		0
Intercompany loans to nonbank subsidiary	(476)		(1,279)
Allowance for loan losses	0		0
Total finance receivables and loans, net	(458)		(1,279)
Investment in operating leases, net	0		0
Intercompany receivables from bank subsidiary	(104)		(158)
Intercompany receivables from nonbank subsidiary	(156)		(174)
Investment in bank subsidiaries	(32,998)		(32,426)
Investment in nonbank subsidiaries	(6,687)		(6,928)
Premiums receivable and other insurance assets	0		0
Other assets	(1,739)		(1,526)
Assets	(44,201)		(44,281)
Deposit liabilities, noninterest-bearing	0		0
Deposit liabilities, interest-bearing	0		0
Deposit liabilities	(1,345)		(1,249)
Short-term borrowings	0		0
Long-term debt	0		0
Intercompany debt payable to bank subsidiaries	(17)		(20)
Intercompany debt payable to nonbank subsidiaries	(1,173)		(1,800)
Intercompany payables to bank subsidiary	(46)		(45)
Intercompany payables to nonbank subsidiaries	(221)		(253)
Interest payable	0		0
Unearned insurance premiums and service revenue	0		0
Accrued expenses and other liabilities	(1,732)		(1,560)
Total liabilities	(4,534)		(4,927)
Equity	(39,667)		(39,354)
Total liabilities and equity	(44,201)		(44,281)
Consolidating adjustments | Affiliated entity
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents, interest-bearing	(2,042)		(1,770)
Deposit liabilities, interest-bearing	$ (1,345)		$ (1,249)

Parent and Guarantor Condense_5

Parent and Guarantor Condensed Consolidating Financial Statements (Statement of Cash Flows) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net cash provided by (used in) operating activities	$ 1,081	$ 1,097
Purchases of equity securities	(48)	(374)
Proceeds from sales of equity securities	383	220
Purchases of available-for-sale securities	(3,401)	(2,360)
Proceeds from sale of available-for-sale securities	656	328
Proceeds from repayments of available-for-sale securities	694	795
Purchases of held-to-maturity securities	(131)	(155)
Proceeds from repayments of held-to-maturity securities	44	35
Purchases of finance receivables and loans held-for-investment	(1,452)	(1,497)
Proceeds from sales of finance receivables and loans initially held-for-investment	157	0
Originations and repayments of finance receivables and loans held-for-investment and other, net	1,149	(1,300)
Net change in intercompany loans	10	1
Purchases of operating lease assets	(792)	(969)
Disposals of operating lease assets	624	976
Capital contributions to subsidiaries	0	0
Returns of contributed capital	0	0
Net change in nonmarketable equity investments	171	(19)
Payments for (proceeds from) other, net	(95)	(82)
Net cash provided by investing activities	(2,041)	(4,402)
Net change in short-term borrowings	(3,872)	(1,848)
Net (decrease) increase in deposits	7,114	4,173
Proceeds from issuance of long-term debt	1,766	6,665
Repayments of long-term debt	(4,490)	(5,771)
Repurchase of common stock	(211)	(185)
Dividends paid	(70)	(58)
Capital contributions from parent	0	0
Net cash provided by (used in) financing activities	237	2,976
Effect of exchange-rate changes on cash and cash equivalents and restricted cash	1	(2)
Net increase (decrease) in cash and cash equivalents and restricted cash	(722)	(331)
Cash and cash equivalents and restricted cash	4,904	4,938	$ 5,626	$ 5,269
Cash and cash equivalents	3,957	3,721	4,537
Restricted cash included in other assets on the Condensed Consolidated Balance Sheet	947	1,217
Parent
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net cash provided by (used in) operating activities	155	456
Purchases of equity securities	0	0
Proceeds from sales of equity securities	0	0
Purchases of available-for-sale securities	0	0
Proceeds from sale of available-for-sale securities	0	0
Proceeds from repayments of available-for-sale securities	0	0
Purchases of held-to-maturity securities	0	0
Proceeds from repayments of held-to-maturity securities	0	0
Purchases of finance receivables and loans held-for-investment	0	0
Proceeds from sales of finance receivables and loans initially held-for-investment	402	820
Originations and repayments of finance receivables and loans held-for-investment and other, net	301	432
Net change in intercompany loans	4	28
Purchases of operating lease assets	0	0
Disposals of operating lease assets	1	4
Capital contributions to subsidiaries	(1)	(49)
Returns of contributed capital	15	38
Net change in nonmarketable equity investments	(1)	0
Payments for (proceeds from) other, net	0	(3)
Net cash provided by investing activities	1,224	819
Net change in short-term borrowings	9	(214)
Net (decrease) increase in deposits	(1)	(6)
Proceeds from issuance of long-term debt	7	15
Repayments of long-term debt	(900)	(1,152)
Repurchase of common stock	(211)	(185)
Dividends paid	(70)	(58)
Capital contributions from parent	0	0
Net cash provided by (used in) financing activities	(1,284)	(1,727)
Effect of exchange-rate changes on cash and cash equivalents and restricted cash	0	0
Net increase (decrease) in cash and cash equivalents and restricted cash	95	(452)
Cash and cash equivalents and restricted cash	1,493	943	1,398	1,395
Cash and cash equivalents	1,404	796	1,309
Restricted cash included in other assets on the Condensed Consolidated Balance Sheet	89	147
Guarantors
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net cash provided by (used in) operating activities	400	1,000
Purchases of equity securities	0	0
Proceeds from sales of equity securities	0	0
Purchases of available-for-sale securities	0	0
Proceeds from sale of available-for-sale securities	0	0
Proceeds from repayments of available-for-sale securities	0	0
Purchases of held-to-maturity securities	0	0
Proceeds from repayments of held-to-maturity securities	0	0
Purchases of finance receivables and loans held-for-investment	0	0
Proceeds from sales of finance receivables and loans initially held-for-investment	0	0
Originations and repayments of finance receivables and loans held-for-investment and other, net	0	0
Net change in intercompany loans	0	0
Purchases of operating lease assets	0	0
Disposals of operating lease assets	0	0
Capital contributions to subsidiaries	0	(6)
Returns of contributed capital	0	0
Net change in nonmarketable equity investments	0	0
Payments for (proceeds from) other, net	0	0
Net cash provided by investing activities	0	(6)
Net change in short-term borrowings	0	0
Net (decrease) increase in deposits	0	0
Proceeds from issuance of long-term debt	0	0
Repayments of long-term debt	0	0
Repurchase of common stock	0	0
Dividends paid	0	0
Capital contributions from parent	0	6
Net cash provided by (used in) financing activities	(400)	(994)
Effect of exchange-rate changes on cash and cash equivalents and restricted cash	0	0
Net increase (decrease) in cash and cash equivalents and restricted cash	0	0
Cash and cash equivalents and restricted cash	0	0	0	0
Cash and cash equivalents	0	0	0
Restricted cash included in other assets on the Condensed Consolidated Balance Sheet	0	0
Nonguarantors
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net cash provided by (used in) operating activities	1,369	1,812
Purchases of equity securities	(48)	(374)
Proceeds from sales of equity securities	383	220
Purchases of available-for-sale securities	(3,401)	(2,360)
Proceeds from sale of available-for-sale securities	656	328
Proceeds from repayments of available-for-sale securities	694	795
Purchases of held-to-maturity securities	(131)	(155)
Proceeds from repayments of held-to-maturity securities	44	35
Purchases of finance receivables and loans held-for-investment	(1,843)	(2,317)
Proceeds from sales of finance receivables and loans initially held-for-investment	146	0
Originations and repayments of finance receivables and loans held-for-investment and other, net	848	(1,732)
Net change in intercompany loans	6	1
Purchases of operating lease assets	(792)	(969)
Disposals of operating lease assets	623	972
Capital contributions to subsidiaries	0	0
Returns of contributed capital	0	0
Net change in nonmarketable equity investments	172	(19)
Payments for (proceeds from) other, net	(94)	(80)
Net cash provided by investing activities	(2,450)	(5,646)
Net change in short-term borrowings	(3,881)	(1,634)
Net (decrease) increase in deposits	7,211	3,776
Proceeds from issuance of long-term debt	1,759	6,650
Repayments of long-term debt	(3,590)	(4,619)
Repurchase of common stock	0	0
Dividends paid	0	0
Capital contributions from parent	1	49
Net cash provided by (used in) financing activities	535	3,436
Effect of exchange-rate changes on cash and cash equivalents and restricted cash	1	(2)
Net increase (decrease) in cash and cash equivalents and restricted cash	(545)	(400)
Cash and cash equivalents and restricted cash	5,453	5,307	5,998	5,707
Cash and cash equivalents	4,595	4,237	4,998
Restricted cash included in other assets on the Condensed Consolidated Balance Sheet	858	1,070
Consolidating adjustments
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net cash provided by (used in) operating activities	(843)	(2,171)
Purchases of equity securities	0	0
Proceeds from sales of equity securities	0	0
Purchases of available-for-sale securities	0	0
Proceeds from sale of available-for-sale securities	0	0
Proceeds from repayments of available-for-sale securities	0	0
Purchases of held-to-maturity securities	0	0
Proceeds from repayments of held-to-maturity securities	0	0
Purchases of finance receivables and loans held-for-investment	391	820
Proceeds from sales of finance receivables and loans initially held-for-investment	(391)	(820)
Originations and repayments of finance receivables and loans held-for-investment and other, net	0	0
Net change in intercompany loans	0	(28)
Purchases of operating lease assets	0	0
Disposals of operating lease assets	0	0
Capital contributions to subsidiaries	1	55
Returns of contributed capital	(15)	(38)
Net change in nonmarketable equity investments	0	0
Payments for (proceeds from) other, net	(1)	1
Net cash provided by investing activities	(815)	431
Net change in short-term borrowings	0	0
Net (decrease) increase in deposits	(96)	403
Proceeds from issuance of long-term debt	0	0
Repayments of long-term debt	0	0
Repurchase of common stock	0	0
Dividends paid	0	0
Capital contributions from parent	(1)	(55)
Net cash provided by (used in) financing activities	1,386	2,261
Effect of exchange-rate changes on cash and cash equivalents and restricted cash	0	0
Net increase (decrease) in cash and cash equivalents and restricted cash	(272)	521
Cash and cash equivalents and restricted cash	(2,042)	(1,312)	(1,770)	$ (1,833)
Cash and cash equivalents	(2,042)	(1,312)	$ (1,770)
Restricted cash included in other assets on the Condensed 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
Net change in intercompany debt	0	0
Dividends paid and returns of contributed capital, intercompany	0	0
Affiliated entity | Parent
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net change in intercompany investment securities	0	0
Net change in intercompany loans	507	(423)
Net change in intercompany debt	(118)	(127)
Dividends paid and returns of contributed capital, intercompany	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
Dividends paid and returns of contributed capital, intercompany	(400)	(1,000)
Affiliated entity | Nonguarantors
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net change in intercompany investment securities	3	9
Net change in intercompany loans	290	1
Net change in intercompany debt	(507)	422
Dividends paid and returns of contributed capital, intercompany	(458)	(1,208)
Affiliated entity | Consolidating adjustments
Parent and Guarantor Consolidating Statement of Cash Flows [Line Items]
Net change in intercompany investment securities	(3)	(9)
Net change in intercompany loans	(797)	422
Net change in intercompany debt	625	(295)
Dividends paid and returns of contributed capital, intercompany	$ 858	$ 2,208

Subsequent Events (Details)

Subsequent Events (Details) - $ / shares	Apr. 14, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Subsequent Event [Line Items]
Dividends declared, amount per common share		$ 0.17	$ 0.15	$ 0.15	$ 0.13	$ 0.13
Subsequent event
Subsequent Event [Line Items]
Dividends declared, amount per common share	$ 0.17

Uncategorized Items - ally-2019

Label	Element	Value
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax	$ (250,000,000)
Accumulated Other Comprehensive Income (Loss), Net of Tax	us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax	(531,000,000)
Treasury Stock [Member]
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	(1,110,000,000)
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	(2,049,000,000)
Common Stock Including Additional Paid in Capital [Member]
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	21,245,000,000
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	21,345,000,000
Retained Earnings [Member]
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	(6,510,000,000)
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	(5,499,000,000)
Accounting Standards Update 2017-08 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(2,000,000)
Accounting Standards Update 2017-08 [Member] | AOCI Attributable to Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	8,000,000
Accounting Standards Update 2017-08 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(10,000,000)
Accounting Standards Update 2016-01 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	7,000,000
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]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(126,000,000)
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]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	0
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