Ally Financial (ALLY) 10-K 27 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 22, 2017	Jun. 30, 2016
Document And Entity Information [Abstract]
Entity Registrant Name	Ally Financial Inc.
Entity Central Index Key	40,729
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		465,035,069
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 8,257,669,855

Consolidated Statement of Incom

Consolidated Statement of Income Consolidated Statement of Income - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net Income (Loss) Attributable to Parent	$ 248	$ 209	$ 360	$ 250	$ 263	$ 268	$ 182	$ 576	$ 1,067	$ 1,289	$ 1,150
Financing Revenue and Other Income [Line Items]
Interest and Fee Income, Loans and Leases									5,162	4,570	4,457
Interest and Fee Income, Loans and Leases Held-for-sale									0	40	1
Interest and Dividend Income, Securities, Operating, Available-for-sale									418	381	367
Interest Income, Deposits with Financial Institutions									14	8	8
Operating Leases, Income Statement, Lease Revenue									2,711	3,398	3,558
Total financing revenue and other interest income									8,305	8,397	8,391
Interest Expense [Abstract]
Interest Expense, Deposits									830	718	664
Interest Expense, Short-term Borrowings									57	49	52
Interest Expense, Long-term Debt									1,742	1,662	2,067
Interest Expense									2,629	2,429	2,783
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease									1,769	2,249	2,233
Net Financing Revenue	976	996	984	951	983	970	916	850	3,907	3,719	3,375
Other revenue [Abstract]
Insurance Services Revenue									945	940	979
Gain (Loss) on Sales of Loans, Net									11	45	7
Gain (Loss) on Extinguishment of Debt									(5)	(357)	(202)
Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments									185	155	181
Noninterest Income, Other Operating Income									394	359	311
Nonoperating Income (Expense)	392	388	374	376	356	332	211	243	1,530	1,142	1,276
Revenues									5,437	4,861	4,651
Provision for Loan Losses Expensed	267	258	172	220	240	211	140	116	917	707	457
Noninterest Expense [Abstract]
Labor and Related Expense									992	963	947
Policyholder Benefits and Claims Incurred, Net									342	293	410
Other Noninterest Expense									1,605	1,505	1,591
Noninterest Expense	721	735	773	710	668	674	724	695	2,939	2,761	2,948
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	380	391	413	397	431	417	263	282	1,581	1,393	1,246
Income Tax Expense (Benefit)	134	130	56	150	155	144	94	103	470	496	321
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	246	261	357	247	276	273	169	179	1,111	897	925
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	$ 2	$ (52)	$ 3	$ 3	$ (13)	$ (5)	$ 13	$ 397	$ (44)	$ 392	$ 225
Earnings Per Share, Basic [Abstract]
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.52	$ 0.54	$ 0.70	$ 0.48	$ (1.94)	$ 0.49	$ (2.24)	$ 0.23	$ 2.25	$ (3.47)	$ 1.36
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	0.53	0.43	0.71	0.49	(1.97)	0.48	(2.22)	1.06	(0.09)	0.81	0.47
Earnings Per Share, Basic									2.15	(2.66)	1.83
Earnings Per Share, Diluted [Abstract]
Income (Loss) from Continuing Operations, Per Diluted Share	0.52	0.54	0.70	0.48	(1.94)	0.49	(2.24)	0.23	2.24	(3.47)	1.36
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	0.52	0.43	0.71	0.49	$ (1.97)	$ 0.47	$ (2.22)	$ 1.06	(0.09)	0.81	0.47
Earnings Per Share, Diluted									2.15	(2.66)	1.83
Common Stock, Dividends, Per Share, Declared	$ 0.08	$ 0.08	$ 0	$ 0					$ 0.16	$ 0	$ 0
Retained Earnings [Member]
Net Income (Loss) Attributable to Parent									$ 1,067	$ 1,289	$ 1,150

Consolidated Balance Sheet & Mi

Consolidated Balance Sheet & Mini Balance Sheet - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Assets [Abstract]
Cash and Due from Banks	$ 1,547	$ 2,148
Interest-bearing Deposits in Banks and Other Financial Institutions	4,387	4,232
Cash and Cash Equivalents, at Carrying Value	5,934	6,380
Available-for-sale securities	18,926	17,157
Held-to-maturity securities	839	0
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group	0	105
Finance receivables and loans, net [Abstract]
Loans and Leases Receivable, Gross	118,944	111,600
Loans and Leases Receivable, Allowance	(1,144)	(1,054)
Loans and Leases Receivable, Net Amount	117,800	110,546
Property Subject to or Available for Operating Lease, Net	11,470	16,271
Premiums receivable and other insurance assets	1,905	1,801
Other Assets	6,854	6,321
Assets	163,728	158,581
Liabilities and Equity [Abstract]
Noninterest-bearing deposit liabilities	84	89
Interest-bearing Deposit Liabilities	78,938	66,389
Deposits	79,022	66,478
Short-term Debt	12,673	8,101
Long-term Debt	54,128	66,234
Interest payable	351	350
Unearned Premiums	2,500	2,434
Accounts Payable and Accrued Liabilities	1,737	1,545
Liabilities	150,411	145,142
Equity [Abstract]
Common Stocks, Including Additional Paid in Capital, Net of Discount	21,166	21,100
Non U S Dept Of Treasury Held Preferred Stock And APIC	0	696
Retained Earnings (Accumulated Deficit)	(7,151)	(8,110)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(341)	(231)
Treasury stock, Value	(357)	(16)
Stockholders' Equity Attributable to Parent, Total	13,317	13,439
Liabilities and Equity	163,728	158,581
Variable Interest Entity, Primary Beneficiary [Member]
Finance receivables and loans, net [Abstract]
Loans and Leases Receivable, Gross	24,630	27,929
Loans and Leases Receivable, Allowance	(173)	(196)
Loans and Leases Receivable, Net Amount	24,457	27,733
Property Subject to or Available for Operating Lease, Net	1,745	4,791
Other Assets	1,390	1,624
Assets	27,592	34,148
Liabilities and Equity [Abstract]
Long-term Debt	13,259	20,267
Accounts Payable and Accrued Liabilities	12	22
Liabilities	$ 13,271	$ 20,289

Consolidated Balance Sheet and

Consolidated Balance Sheet and Mini Balance Sheet (Paranthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	1,100,000,000	1,100,000,000	1,100,000,000
Common Stock, Shares, Issued	485,707,644	482,790,696	480,136,000	479,767,000
Common Stock, Shares, Outstanding	467,000,306	481,980,111	480,095,000
Treasury Stock, Shares	18,707,338	810,585	41,000	0

Consolidated Statement of Chang

Consolidated Statement of Changes in Equity - USD ($) $ in Millions	Total	Common stock and paid-in capital [Member]	Preferred stock [Member]	Retained Earnings [Member]	Accumulated other comprehensive (loss) income [Member]	Treasury stock [Member]
Stockholders' Equity Attributable to Parent, Total	$ 14,208	$ 20,939	$ 1,255	$ (7,710)		$ 0
Accumulated Other Comprehensive Income (Loss), Net of Tax	(276)				$ (276)
Net Income (Loss) Attributable to Parent	1,150			1,150
Dividends, Preferred Stock, Cash	(268)			(268)
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	99	99
Other Comprehensive Income (Loss), Net of Tax	$ 210				210
Common Stock, Dividends, Per Share, Declared	$ 0
Stockholders' Equity Attributable to Parent, Total	$ 15,399	21,038	1,255	(6,828)		0
Accumulated Other Comprehensive Income (Loss), Net of Tax	(66)				(66)
Net Income (Loss) Attributable to Parent	1,289			1,289
Dividends, Preferred Stock, Cash	(2,571)			(2,571)
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	62	62
Other Comprehensive Income (Loss), Net of Tax	(165)				(165)
Stock Repurchased During Period, Value	(325)		(325)
Preferred stock redemption	(234)		(234)
Treasury Stock, Value, Acquired, Cost Method	(16)					(16)
Stock Repurchase and Redemption Premium	$ 2,364
Common Stock, Dividends, Per Share, Declared	$ 0
Stockholders' Equity Attributable to Parent, Total	$ 13,439	21,100	696	(8,110)		(16)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(231)				(231)
Net Income (Loss) Attributable to Parent	1,067			1,067
Dividends, Preferred Stock, Cash	(30)			(30)
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	66	66
Other Comprehensive Income (Loss), Net of Tax	(110)				(110)
Stock Repurchased During Period, Value	(696)		(696)
Treasury Stock, Value, Acquired, Cost Method	(341)					(341)
Dividends, Common Stock, Cash	$ (78)			(78)
Common Stock, Dividends, Per Share, Declared	$ 0.16
Stockholders' Equity Attributable to Parent, Total	$ 13,317	$ 21,166	$ 0	$ (7,151)		$ (357)
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (341)				$ (341)

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Originations and repayments of loans held-for-investment and other	$ 8,826	$ 9,344	$ 4,147
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net Income (Loss) Attributable to Parent	1,067	1,289	1,150
Depreciation, Amortization and Accretion, Net	2,382	2,801	2,936
Provision for Loan Losses Expensed Including Discontinued Operations	917	707	457
Gain Loss on Sales of Loans Net Including Discontinued Operations	(11)	(45)	(7)
Availableforsale Securities Gross Realized Gain Loss Excluding Otti Including Disc Ops	(185)	(155)	(181)
Gain (Loss) on Extinguishment of Debt	5	357	202
Payments for Origination and Purchases of Loans Held-for-sale	(141)	(1,770)	0
Proceeds from Sale of Loans Held-for-sale	240	1,658	62
Total Charge Recorded Related to ResCap Bankruptcy	0	0	(150)
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	0	(452)	7
Increase (Decrease) in Deferred Income Taxes	458	565	117
Increase (Decrease) in Interest Payable, Net	1	(127)	(411)
Increase (Decrease) in Other Operating Assets	(120)	526	(132)
Increase (Decrease) in Other Operating Liabilities	(206)	(247)	(400)
Increase (Decrease) in Other Operating Assets and Liabilities, Net	160	4	(247)
Net cash provided by (used in) operating activities	4,567	5,111	3,403
Net Cash Provided by Investing Activities [Abstract]
Payments to Acquire Available-for-sale Securities	(16,031)	(12,250)	(5,417)
Proceeds from sales of available-for-sale securities	11,036	6,874	4,260
Proceeds from maturities and repayment of available-for-sale securities	3,379	4,255	2,657
Payments to Acquire Held-to-maturity Securities	(841)	0	0
Payments for (Proceeds from) Loans and Leases	(3,859)	(4,501)	(877)
Proceeds from Sale of Loans Held-for-investment	4,285	3,197	2,592
Originations and repayments of loans held-for-investment and other	8,826	9,344	4,147
Purchases of operating lease assets	(3,274)	(4,685)	(9,884)
Disposals of operating lease assets	6,304	5,546	5,860
Payments to Acquire Interest in Subsidiaries and Affiliates	(309)	0	0
Proceeds from Divestiture of Businesses	0	1,049	47
Increase (Decrease) in Restricted Cash	392	264	1,625
Increase (Decrease) in Non marketable equity securities	(628)	(147)	66
Payments for (Proceeds from) Other Investing Activities	(312)	(5)	6
Net cash provided by investing activities	(8,684)	(9,747)	(3,212)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from (Repayments of) Short-term Debt	4,564	1,028	(1,494)
Increase (Decrease) in Deposits	12,508	8,247	4,851
Proceeds from issuance of long-term debt	14,155	30,665	27,192
Repayments of long-term debt	(26,412)	(31,350)	(30,426)
Payments for Repurchase of Redeemable Preferred Stock	(696)	(559)	0
Payments for Repurchase of Common Stock	(341)	(16)	0
Payments of Dividends	(108)	(2,571)	(268)
Net cash (used in) provided by financing activities	3,670	5,444	(145)
Effect of exchange-rate changes on cash and cash equivalents	1	(4)	(1)
Cash and Cash Equivalents, Period Increase (Decrease)	(446)	804	45
Cash and Cash Equivalents, at Carrying Value	6,380	5,576	5,531
Cash and Cash Equivalents, at Carrying Value	5,934	6,380	5,576
Supplemental Cash Flow Information [Abstract]
Interest Paid	2,647	2,632	3,090
Income Taxes Paid	19	96	8
Transfer of Portfolio Loans and Leases to Held-for-sale	4,282	1,311	4,631
Proceeds from sales and repayments of mortgage loans held-for-investment originally designated as held-for-sale	$ 40	$ 68	$ 38

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income Statement - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net Income (Loss) Attributable to Parent	$ 1,067	$ 1,289	$ 1,150
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax [Abstract]
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	33	(39)	415
Other Comprehensive Income (Loss), Reclassification Adjustment to Net Income for Sale of Securities, Net of Tax	147	99	167
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent	(114)	(138)	248
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	3	(26)	(17)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	(1)	(22)	(20)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent	4	(48)	(37)
Other Comprehensive Income Unrealized Gain (Loss) on Net Investment Hedges Arising During the Period Net of Tax	1	18	8
Other Comprehensive Income (Loss), Reclassification Adjustment for Net Investment Hedges Included in Net Income, Discontinued Operation, Net of Tax	0	(3)	0
Other Comprehensive Income (Loss), Net Investment Hedges Attributable to Parent, Net of Tax	1	21	8
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustments and Net Investment Hedges, Net of Tax	5	(27)	(29)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	0	1	2
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax	(3)	0	(15)
Other Comprehensive Income (Loss), Reclassification Adjustment to Net Income, Pension and Other Postretirement Benefit Plans, for Net (Gain) Loss, Net of Tax	(2)	1	(4)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent	(1)	(1)	(11)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(110)	(165)	210
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	957	1,124	1,360
Retained Earnings [Member]
Net Income (Loss) Attributable to Parent	$ 1,067	$ 1,289	$ 1,150

Description of Business, Basis

Description of Business, Basis of Presentation, and Changes in Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
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 requires otherwise, Ally, the Company, or we, us, or our) is a leading digital financial services company offering diversified financial products for consumers, businesses, automotive dealers and corporate clients . Our legacy dates back to 1919, and Ally was redesigned in 2009 with a distinctive brand and relentless focus on our customers. We reconverted to a Delaware corporation in 2009 and are registered as a bank holding company (BHC) under the Bank Holding Company Act of 1956 as amended (the BHC Act) and a financial holding company (FHC) under the Gramm-Leach-Bliley Act of 1999 as amended (the GLB Act). Our banking subsidiary, Ally Bank, is an award-winning online bank, and an indirect, wholly-owned subsidiary of Ally Financial Inc. , offering a variety of deposit and other banking products. Consolidation and Basis of Presentation The Consolidated Financial Statements include the accounts of the parent and its consolidated subsidiaries, to which it is deemed to possess control, after eliminating intercompany balances and transactions, and include all variable interest entities (VIEs) in which we are the primary beneficiary. Other entities in which we have invested and have the ability to exercise significant influence over operating and financial policies of the investee, but upon which we do not possess control, are accounted for by the equity method of accounting within the financial statements and they are therefore not consolidated. Refer to Note 11 to the Consolidated Financial Statements for further details on our VIEs. Our accounting and reporting policies conform to accounting principles generally accepted in the United States of America (GAAP). Additionally, where applicable, the policies conform to the accounting and reporting guidelines prescribed by bank regulatory authorities. Certain reclassifications may have been made to the prior periods’ financial statements and notes to conform to the current period’s presentation, which did not have a material impact on our Consolidated Financial Statements. In the past, we have operated our international subsidiaries in a similar manner as we operate in the United States of America (U.S. or United States), subject to local laws or other circumstances that may cause us to modify our procedures accordingly. The financial statements of subsidiaries that operate outside of the United States generally are measured using the local currency as the functional currency. All assets and liabilities of foreign subsidiaries are translated into U.S. dollars at year-end exchange rates. The resulting translation adjustments are recorded in accumulated other comprehensive income until the foreign subsidiaries are sold or substantially liquidated at which point the accumulated translation adjustments are recognized directly in earnings as part of the gain or loss on sale or liquidation. Income and expense items are translated at average exchange rates prevailing during the reporting period. The majority of our international operations have ceased and are included in discontinued operations. Use of Estimates and Assumptions The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and that affect income and expenses during the reporting period and related disclosures. In developing the estimates and assumptions, management uses all available evidence; however, actual results could differ because of uncertainties associated with estimating the amounts, timing, and likelihood of possible outcomes. Our most significant estimates pertain to the allowance for loan losses, valuations of automotive lease assets and residuals, fair value of financial instruments, legal and regulatory reserves, and the determination of the provision for income taxes.
Significant Accounting Policies [Text Block]	Significant Accounting Policies Cash and Cash Equivalents Cash and cash equivalents include cash on hand, cash on deposit at other financial institutions, cash items in process of collection, and certain highly liquid investments with maturities of three months or less from the date of purchase. Cash and cash equivalents that have restrictions on our ability to withdraw the funds are included in other assets on our Consolidated Balance Sheet. The book value of cash equivalents approximates fair value because of the short maturities of these instruments and the insignificant risk they present to changes in value with respect to changes in interest rates. Certain securities with original maturities of three months or less from the date of purchase that are held as a portion of longer-term investment portfolios, primarily held by our Insurance operations, are classified as investment securities. Investments Our portfolio of investments includes various debt and marketable equity securities and nonmarketable equity investments. Debt and marketable equity securities are classified based on management’s intent to sell or hold the security. We classify debt securities as held-to-maturity only when we have both the intent and ability to hold the securities to maturity. We classify debt and marketable equity securities as trading when the securities are acquired for the purpose of selling or holding them for a short period of time. Securities not classified as either held-to-maturity or trading are classified as available-for-sale. Our debt and marketable equity securities include government securities, corporate bonds, asset-backed securities (ABS), mortgage-backed securities (MBS), equity securities and other investments. Our portfolio includes securities classified as available-for-sale and held-to-maturity. Our available-for-sale securities are carried at fair value with unrealized gains and losses included in accumulated other comprehensive income or loss and are subject to impairment. Our held-to-maturity securities are carried at amortized cost and are subject to impairment. We amortize premiums and discounts on debt securities as an adjustment to investment yield generally over the stated maturity of the security. For ABS and MBS where prepayments can be reasonably estimated, amortization is adjusted for expected prepayments. Additionally, we assess our debt and marketable equity securities for potential other-than-temporary impairment. We employ a methodology that considers available evidence in evaluating potential other-than-temporary impairment of our debt and marketable equity securities classified as available-for-sale and held-to-maturity. If the cost of an investment exceeds its fair value, we evaluate, among other factors, the magnitude and duration of the decline in fair value. We also evaluate the financial health of and business outlook for the issuer, the performance of the underlying assets for interests in securitized assets, and, for securities classified as available-for-sale, our intent and ability to hold the investment through recovery of its amortized cost basis. Once a decline in fair value of a debt security is determined to be other-than-temporary, an impairment charge for the credit component is recorded to other gain (loss) on investments, net, in our Consolidated Statement of Income, and a new cost basis in the investment is established. The noncredit loss component of a debt security is recorded in other comprehensive income (loss) when we do not intend to sell the security and it is not more likely than not that we will have to sell the security prior to the security's anticipated recovery. The credit and noncredit loss components are recorded in earnings when we intend to sell the security or it is more likely than not that we will have to sell the security prior to the security’s anticipated recovery. Unrealized losses that we have determined to be other-than-temporary on equity securities are recorded to other gain (loss) on investments, net in our Consolidated Statement of Income. Subsequent increases and decreases to the fair value of available-for-sale debt and equity securities are included in other comprehensive income (loss), so long as they are not attributable to another other-than-temporary impairment. Realized gains and losses on investment securities are reported in other gain (loss) on investments, net, and are determined using the specific identification method. For information on our debt and marketable equity securities, refer to Note 8 to the Consolidated Financial Statements . In addition to our investments in debt and marketable equity securities, we hold equity positions in other entities. These positions include Federal Home Loan Bank (FHLB) and Federal Reserve Bank (FRB) stock held to meet regulatory requirements, other equity investments that are not publicly traded and do not have a readily determinable fair value, equity investments in low income housing tax credits, and Community Reinvestment Act (CRA) equity investments, which are also not publicly traded and do not have a readily determinable fair value. Our investments in FHLB and FRB stock and other equity investments are accounted for using the cost method of accounting. Our low income housing tax credit investments are accounted for using the proportional amortization method of accounting for qualified affordable housing investments. Our obligations related to unfunded commitments for our low income housing tax credit investments are reported in other liabilities. Our CRA investments are accounted for using the equity method of accounting. Our FHLB and FRB stock and other equity investments carried at cost are included in nonmarketable equity investments in other assets. Our investments in low income housing tax credits and CRA are also included in other assets. As conditions warrant, we review our investments for impairment and will adjust the carrying value of the investment if it is deemed to be impaired. No impairment was recognized in 2016 or 2015. For more information on our nonmarketable equity investments, refer to Note 25 to the Consolidated Financial Statements . Finance Receivables and Loans Finance receivables and loans are reported at their gross carrying value, which includes the principal amount outstanding, net of unamortized deferred fees and costs on originated loans, unamortized premiums and discounts on purchased loans, unamortized basis adjustments arising from the designation of finance receivables and loans as the hedged item in qualifying fair value hedge relationships, and cumulative principal charge-offs. We refer to the gross carrying value less the allowance for loan loss as the net carrying value in finance receivables and loans. Unearned rate support received from an automotive manufacturer on certain automotive loans, deferred origination fees and costs, and premiums and discounts on purchased loans, are amortized over the contractual life of the related finance receivable or loan using the effective interest method. We make various incentive payments for consumer automotive loan originations to automotive dealers and account for these payments as direct loan origination costs. Additionally, we make incentive payments to certain commercial automobile wholesale borrowers and account for these payments as a reduction to interest income in the period they are earned. Loan commitment fees are generally deferred and amortized over the commitment period. For information on finance receivables and loans, refer to Note 9 to the Consolidated Financial Statements . We initially classify finance receivables and loans as either loans held-for-sale or loans held-for-investment based on management's assessment of our intent and ability to hold loans for the foreseeable future or until maturity. Management's view of the foreseeable future is based on the longest reasonably reliable net income, liquidity, and capital forecast period. Management's intent and ability with respect to certain loans may change from time to time depending on a number of factors, for example economic, liquidity, and capital conditions. In order to reclassify loans to held-for-sale, management must have the intent to sell the loans and reasonably identify the specific loans to be sold. Loans classified as held-for-sale are carried at the lower of their net carrying value or fair value, unless the fair value option was elected, in which case those loans are carried at fair value. Interest income is recognized based upon the contractual rate of interest on the loan and the unpaid principal balance. We report accrued interest receivable on finance receivables and loans in other assets on the Consolidated Balance Sheet. Our portfolio segments are based on the level at which we develop and document our methodology for determining the allowance for loan losses. Additionally, the classes of finance receivables are based on several factors including the method for monitoring and assessing credit risk, the method of measuring carrying value, and the risk characteristics of the finance receivable. Based on an evaluation of our process for developing the allowance for loan losses including the nature and extent of exposure to credit risk arising from finance receivables, we have determined our portfolio segments to be consumer automotive, consumer mortgage, and commercial. • Consumer automotive — Consists of retail automotive financing for new and used vehicles. • Consumer mortgage — Consists of the following classes of finance receivables. • Mortgage Finance — Consists of consumer first mortgages from our ongoing mortgage operations including bulk acquisitions, originations, and refinancing of high-quality jumbo mortgages and low-to-moderate income (LMI) mortgages. In late 2016, we also introduced limited direct mortgage originations consisting of jumbo and conforming mortgages. Conforming mortgages will be originated as held-for-sale, while jumbo mortgages will be originated as held-for-investment. • Mortgage — Legacy — Consists of consumer mortgage assets originated prior to January 1, 2009, including first mortgages, subordinate-lien mortgages, and home equity mortgages. • Commercial — Consists of the following classes of finance receivables . • Commercial and Industrial • Automotive — Consists of financing operations to fund dealer purchases of new and used vehicles through wholesale floorplan financing. Additional commercial offerings include automotive dealer term loans, revolving lines of credit, and dealer fleet financing. • Other — Consists of senior secured leveraged cash flow and asset based loans. • Commercial Real Estate — Automotive — Consists of term loans to finance dealership land and buildings. Nonaccrual Loans Generally, we recognize loans of all classes as past due when they are 30 days delinquent on making a contractually required payment, and loans are placed on nonaccrual status when principal or interest has been delinquent for 90 days or when full collection is not expected. Interest income recognition is suspended when finance receivables and loans are placed on nonaccrual status. Additionally, amortization of premiums and discounts and deferred fees and costs ceases when finance receivables and loans are placed on nonaccrual. Exceptions include commercial real estate loans that are placed on nonaccrual status when delinquent for 60 days or when full collection is not probable, if sooner. Additionally, our policy is to generally place all loans that have been modified in troubled debt restructurings (TDRs) on nonaccrual status until the loan has been brought fully current, the collection of contractual principal and interest is reasonably assured, and six consecutive months of repayment performance is achieved. In certain cases, if a borrower has been current up to the time of the modification and repayment of the debt subsequent to the modification is reasonably assured, we may choose to continue to accrue interest on the loan. Loans on nonaccrual status are reported as nonperforming loans in Note 9 to the Consolidated Financial Statements . The receivable for interest income that is accrued, but not collected, at the date finance receivables and loans are placed on nonaccrual status is reversed against interest income and subsequently recognized only to the extent it is received in cash or until it qualifies for return to accrual status. However, where there is doubt regarding the ultimate collectability of loan principal, all cash received is applied to reduce the carrying value of such loans. Generally, finance receivables and loans are restored to accrual status only when contractually current and the collection of future payments is reasonably assured. Impaired Loans Loans of all classes are considered impaired when we determine it is probable that we will be unable to collect all amounts due (both principal and interest) according to the terms of the loan agreement. For all classes of consumer loans, impaired loans include all loans that have been modified in TDRs. Commercial loans of all classes are considered impaired on an individual basis and reported as impaired when we determine it is probable that we will be unable to collect all amounts due according to the terms of the loan agreement. With the exception of certain consumer TDRs that have been returned to accruing status, for all classes of impaired loans, income recognition is consistent with that of nonaccrual loans discussed above. Impaired loans may return to accrual status as discussed in the preceding nonaccrual loan section at which time, the normal accrual of interest income resumes. For collateral dependent loans, if the recorded investment in impaired loans exceeds the fair value of the collateral, a charge-off is recorded consistent with the TDR discussion below. Troubled Debt Restructurings When the terms of finance receivables or loans are modified, consideration must be given as to whether or not the modification results in a TDR. A modification is considered to be a TDR when both a) the borrower is experiencing financial difficulty and b) we grant a concession to the borrower. These considerations require significant judgment and vary by portfolio segment. In all cases, the cumulative impacts of all modifications are considered at the time of the most recent modification. For consumer loans of all classes, various qualitative factors are utilized for assessing the financial difficulty of the borrower. These include, but are not limited to, the borrower's default status on any of its debts, bankruptcy and recent changes in financial circumstances (loss of job, etc.). A concession has been granted when as a result of the modification we do not expect to collect all amounts due, including interest accrued at the original contract rate. Types of modifications that may be considered concessions include, but are not limited to, extensions of terms at a rate that does not constitute a market rate, a reduction, deferral or forgiveness of principal or interest owed and loans that have been discharged in a Chapter 7 Bankruptcy and have not been reaffirmed by the borrower. In addition to the modifications noted above, in our consumer automotive portfolio segment of loans we also provide extensions or deferrals of payments to borrowers whom we deem to be experiencing only temporary financial difficulty. In these cases, there are limits within our operational policies to minimize the number of times a loan can be extended, as well as limits to the length of each extension, including a cumulative cap over the life of the loan. Before offering an extension or deferral, we evaluate the capacity of the customer to make the scheduled payments after the deferral period. During the deferral period, we continue to accrue and collect interest on the loan as part of the deferral agreement. We grant these extensions or deferrals when we expect to collect all amounts due including interest accrued at the original contract rate. A restructuring that results in only a delay in payment that is deemed to be insignificant is not a concession and the modification is not considered to be a TDR. In order to assess whether a restructuring that results in a delay in payment is insignificant, we consider the amount of the restructured payments subject to delay in conjunction with the unpaid principal balance or the collateral value of the loan, whether or not the delay is significant with respect to the frequency of payments under the original contract, or the loan's original expected duration. In the cases where payment extensions on our automotive loan portfolio cumulatively extend beyond 90 days and are more than 10% of the original contractual term or where the cumulative payment extension is beyond 180 days, we deem the delay in payment to be more than insignificant, and as such, classify these types of modifications as TDRs. Otherwise, we believe that the modifications do not represent a concessionary modification and accordingly, they are not classified as TDRs. For commercial loans of all classes, similar qualitative factors are considered when assessing the financial difficulty of the borrower. In addition to the factors noted above, consideration is also given to the borrower's forecasted ability to service the debt in accordance with the contractual terms, possible regulatory actions and other potential business disruptions (e.g., the loss of a significant customer or other revenue stream). Consideration of a concession is also similar for commercial loans. In addition to the factors noted above, consideration is also given to whether additional guarantees or collateral have been provided. For all loans, TDR classification typically results from our loss mitigation activities. For loans held-for-investment that are not carried at fair value and are TDRs, impairment is typically measured based on the difference between the gross carrying value of the loan and the present value of the expected future cash flows of the loan. The loan may also be measured for impairment based on the fair value of the underlying collateral less costs to sell for loans that are collateral dependent. We recognize impairment by either establishing a valuation allowance or recording a charge-off. The financial impacts of modifications that meet the definition of a TDR are reported in the period in which they are identified as TDRs. Additionally, if a loan that is classified as a TDR redefaults within twelve months of the modification, we are required to disclose the instances of redefault. For the purpose of this disclosure, we have determined that a loan is considered to have redefaulted when the loan meets the requirements for evaluation under our charge-off policy except for commercial loans where redefault is defined as 90 days past due. Impaired loans may return to accrual status as discussed in the preceding nonaccrual loan section at which time, the normal accrual of interest income resumes. Net Charge-offs We disclose the measurement of net charge-offs as the amount of gross charge-offs recognized less recoveries received. Gross charge-offs reflect the amount of the gross carry value directly written-off. Generally, we recognize recoveries when they are received and record them as an increase to the allowance for loan losses. As a general rule, consumer automotive loans are written down to estimated collateral value, less costs to sell, once a loan becomes 120 days past due. In our consumer mortgage portfolio segment, first-lien mortgages and a subset of our home equity portfolio that are secured by real estate in a first-lien position are written down to the estimated fair value of the collateral, less costs to sell, once a mortgage loan becomes 180 days past due. Consumer mortgage loans that represent second-lien positions are charged off at 180 days past due. Consumer mortgage loans within our second-lien portfolio in bankruptcy that are 60 days past due are fully charged off within 60 days of receipt of notification of filing from the bankruptcy court. Consumer automotive and first-lien consumer mortgage loans in bankruptcy that are 60 days past due are written down to the estimated fair value of the collateral, less costs to sell, within 60 days of receipt of notification of filing from the bankruptcy court. Regardless of other timelines noted within this policy, loans are considered collateral dependent once foreclosure or repossession proceedings begin and are charged-off to the estimated fair value of the underlying collateral, less costs to sell at that time. Commercial loans are individually evaluated and where collectability of the recorded balance is in doubt are written down to the estimated fair value of the collateral less costs to sell. Generally, all commercial loans are charged-off when it becomes unlikely that the borrower is willing or able to repay the remaining balance of the loan and any underlying collateral is not sufficient to recover the outstanding principal. Collateral dependent loans are charged-off to the fair market value of collateral less costs to sell when appropriate. Noncollateral dependent loans are fully written-off. Allowance for Loan Losses The allowance for loan losses (the allowance) is management's estimate of incurred losses in the lending portfolios. We determine the amount of the allowance required for each of our portfolio segments based on its relative risk characteristics. The evaluation of these factors for both consumer and commercial finance receivables and loans involves quantitative analysis combined with sound management judgment. Additions to the allowance are charged to current period earnings through the provision for loan losses; amounts determined to be uncollectible are charged directly against the allowance, net of amounts recovered on previously charged-off accounts. The allowance is comprised of two components: specific reserves established for individual loans evaluated as impaired and portfolio-level reserves established for large groups of typically smaller balance homogeneous loans that are collectively evaluated for impairment. We evaluate the adequacy of the allowance based on the combined total of these two components. Determining the appropriateness of the allowance is complex and requires judgment by management about the effect of matters that are inherently uncertain. It is possible that others, given the same information, may at any point in time reach different reasonable conclusions. Measurement of impairment for specific reserves is generally determined on a loan-by-loan basis. Loans determined to be specifically impaired are measured based on the present value of expected future cash flows discounted at the loan's effective interest rate, an observable market price, or the estimated fair value of the collateral less estimated costs to sell when appropriate, whichever is determined to be the most appropriate. When these measurement values are lower than the net carrying value of that loan, impairment is recognized. Loans that are not identified as individually impaired are pooled with other loans with similar risk characteristics for evaluation of impairment for the portfolio-level allowance. For the purpose of calculating portfolio-level reserves, we have grouped our loans into three portfolio segments: consumer automotive, consumer mortgage, and commercial. The allowance consists of the combination of a quantitative assessment component based on statistical models, a retrospective evaluation of actual loss information to loss forecasts, and includes a qualitative component based on management judgment. Management takes into consideration relevant qualitative factors, including external and internal trends such as the impacts of changes in underwriting standards, collections and account management effectiveness, geographic concentrations, and economic events, among other factors, that have occurred but are not yet reflected in the quantitative assessment component. Qualitative adjustments are documented, reviewed, and approved through our established risk governance processes. During 2016, we did not substantively change any material aspect of our overall approach used to determine the allowance for loan losses for our portfolio segments. There were no material changes in criteria or estimation techniques as compared to prior periods that impacted the determination of the current period allowance for loan losses for our portfolio segments. Refer to Note 9 to the Consolidated Financial Statements for information on the allowance for loan losses. Consumer Loans Our consumer automotive and consumer mortgage portfolio segments are reviewed for impairment based on an analysis of loans that are grouped into common risk categories. We perform periodic and systematic detailed reviews of our lending portfolios to identify inherent risks and to assess the overall collectability of those portfolios. Loss models are utilized for these portfolios, which consider a variety of credit quality indicators including, but not limited to, historical loss experience, current economic conditions, credit scores, and expected loss factors by loan type. Consumer Automotive Portfolio Segment The allowance for loan losses within the consumer automotive portfolio segment is calculated using proprietary statistical models and other risk indicators applied to pools of loans with similar risk characteristics, including credit bureau score and loan-to-value ratios to arrive at an estimate of incurred losses in the portfolio. These statistical loss forecasting models are utilized to estimate incurred losses and consider a variety of factors including, but not limited to, historical loss experience, estimated defaults based on portfolio trends, and general economic and business trends. These statistical models predict forecasted losses inherent in the portfolio. The forecasted losses consider historical factors such as frequency (the number of contracts that we expect to default) and loss severity (the loss amount of contracts we expect to default). The loss severity within the consumer automotive portfolio segment is impacted by the market values of vehicles that are repossessed. Vehicle market values are affected by numerous factors including vehicle supply, the condition of the vehicle upon repossession, the overall price and volatility of gasoline or diesel fuel, consumer preference related to specific vehicle segments, and other factors. The quantitative assessment component of the allowance may be supplemented with qualitative reserves based on management's determination that such adjustments provide a better estimate of credit losses. This qualitative assessment takes into consideration relevant internal and external factors that have occurred but are not yet reflected in the forecasted losses and may affect the performance of the portfolio. Consumer Mortgage Portfolio Segment The allowance for loan losses within the consumer mortgage portfolio segment is calculated by using proprietary statistical models based on pools of loans with similar risk characteristics, including credit score, loan-to-value, loan age, documentation type, product type, and loan purpose, to arrive at an estimate of incurred losses in the portfolio. These statistical loss forecasting models are utilized to estimate incurred losses and consider a variety of factors including, but not limited to, historical loss experience, estimated foreclosures or defaults based on portfolio trends, delinquencies, and general economic and business trends. The forecasted losses are statistically derived based on a suite of behavioral based transition models. This transition framework predicts various stages of delinquency, default, and voluntary prepayment over the course of the life of the loan. The transition probability is a function of the loan and borrower characteristics and economic variables and considers historical factors such as frequency and loss severity. When a default event is predicted, a severity model is applied to estimate future loan losses. Loss severity within the consumer mortgage portfolio segment is impacted by the market values of foreclosed properties, which is affected by numerous factors, including geographic considerations and the condition of the foreclosed property. The quantitative assessment component of the allowance may be supplemented with qualitative reserves based on management's determination that such adjustments provide a better estimate of credit losses. This qualitative assessment takes into consideration relevant internal and external factors that have occurred but are not yet reflected in the forecasted losses and may affect the performance of the portfolio. Commercial Loans The allowance for loan losses within the commercial portfolio is comprised of reserves established for specific loans evaluated as impaired and portfolio-level reserves based on nonimpaired loans grouped into pools based on similar risk characteristics and collectively evaluated. A commercial loan is considered impaired when it is probable that we will be unable to collect all amounts due according to the contractual terms of the loan agreement based on current information and events. These loans are primarily evaluated individually and are risk-rated based on borrower, collateral, and industry-specific information that management believes is relevant in determining the occurrence of a loss event and measuring impairment. Management establishes specific allowances for commercial loans determined to be individually impaired based on the present value of expected future cash flows, discounted at the loan's effective interest rate, observable market price or the fair value of collateral, whichever is determined to be the most appropriate. Estimated costs to sell or realize the value of the collateral on a discounted basis are included in the impairment measurement, when appropriate. Loans not identified as impaired are grouped into pools based on similar risk characteristics and collectively evaluated. Our risk rating models use historical loss experience, concentrations, current economic conditions, and performance trends. The commercial historical loss experience is updated quarterly to incorporate the most recent data reflective of the current economic environment. The determination of the allowance is influenced by numerous assumptions and many factors that may materially affect estimates of loss, including volatility of loss given default, probability of default, and rating migration. In assessing the risk rating of a particular loan, several factors are considered including an evaluation of historical and current information involving subjective assessments and interpretations. In addition, the allowance related to the commercial portfolio segment is influenced by estimated recoveries from automotive manufacturers relative to guarantees or agreements with them to repurchase vehicles used as collateral to secure the loans. The quantitative assessment component of the allowance may be supplemented with qualitative reserves based on management's determination that such adjustments provide a better estimate of credit losses. This qualitative assessment takes into consideration relevant internal and external factors that have occurred but are not yet reflected in the forecasted losses and may affect the performance of the portfolio. Securitizations and Variable Interest Entities We securitize, transfer, and service consumer and commercial automotive loans and operating leases. Securitization transactions typically involve the use of VIEs and are accounted for either as sales or secured borrowings. We may retain economic interests in the securitized and sold assets, which are generally retained in the form of senior or subordinated interests, interest- or principal-only strips, cash reserves, residual interests, and servicing rights. In order to conclude whether or not a variable interest entity is required to be consolidated, careful consideration and judgment must be given to our continuing involvement with the variable interest entity. In circumstances where we have both the power to direct the activities of the entity that most significantly impact the entity's performance and the obligation to absorb losses or the right to receive benefits of the entity that could be significant, we would conclude that we would consolidate the entity, which would also preclude us from recording an accounting sale on the transaction. In the case of a consolidated varia

Acquisitions Acquisitions

Acquisitions Acquisitions	12 Months Ended
	Dec. 31, 2016
Business Acquisition [Line Items]
Business Combination Disclosure [Text Block]	Acquisitions On June 1, 2016 , we acquired 100% of the equity of TradeKing Group, Inc. (TradeKing), a digital wealth management company with an online broker-dealer, digital portfolio management platform, and educational content for $298 million in cash. TradeKing will operate as a wholly-owned subsidiary of Ally. The addition of brokerage and wealth management is a natural extension of our online banking franchise, creating a full suite of financial products for savings and investments. We applied the acquisition method of accounting to this transaction, which generally requires the initial recognition of assets acquired, including identifiable intangible assets, and liabilities assumed at their respective fair value. Goodwill is recognized as the excess of the acquisition price after the recognition of the net assets, including the identifiable intangible assets. Beginning in June 2016, financial information related to TradeKing is included within Corporate and Other. The following table summarizes the allocation of cash consideration paid for TradeKing and the amounts of the identifiable assets acquired and liabilities assumed recognized at the acquisition date. ($ in millions) Purchase price Cash consideration $ 298 Allocation of purchase price to net assets acquired Intangible assets (a) 82 Cash and short-term investments (b) 50 Other assets 14 Deferred tax asset, net 4 Employee compensation and benefits (41 ) Other liabilities (4 ) Goodwill $ 193 (a) We recorded $6 million of amortization on these intangible assets during the year ended December 31, 2016. (b) Includes $40 million in cash proceeds from the acquisition transaction in order to pay employee compensation and benefits that vested upon acquisition as a result of the change in control. The goodwill of $193 million arising from the acquisition consists largely of expected growth of the business as we leverage the Ally brand and our marketing capabilities to scale the acquired technology platform and expand the suite of financial products we offer to our existing growing customer base. None of the goodwill recognized is expected to be deductible for income tax purposes. Refer to Note 14 to the Consolidated Financial Statements for a reconciliation of the carrying amount of goodwill at the beginning and end of the reporting period. On August 1, 2016, we acquired assets that constitute a business from Blue Yield, an online automotive lender exchange, as we continue to expand our automotive finance offerings to include a direct-to-consumer option. We completed the acquisition for $28 million of total consideration. As a result of the purchase, we recognized $20 million of goodwill within Automotive Finance operations.

Discontinued Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	Discontinued Operations Prior to the adoption of ASU 2014-08, which was prospectively applied only to newly identified disposals that qualify as discontinued operations beginning after January 1, 2015, we have classified operations as discontinued when operations and cash flows will be eliminated from our ongoing operations and we do not expect to retain any significant continuing involvement in their operations after the respective sale or disposal transactions. For all periods presented, the operating results for these discontinued operations have been removed from continuing operations and presented separately as discontinued operations, net of tax, in the Consolidated Statement of Income . The Notes to the Consolidated Financial Statements have been adjusted to exclude discontinued operations unless otherwise noted. Select Automotive Finance Operations During the fourth quarter of 2012, we entered into an agreement with General Motors Financial Company Inc. (GMF) to sell our 40% interest in a motor vehicle finance joint venture in China. On January 2, 2015, the sale of our interest in the motor vehicle finance joint venture in China was completed and an after-tax gain of approximately $400 million was recorded. The tax expense included in this gain was reduced by the release of the valuation allowance on our capital loss carryforward deferred tax asset that was utilized to offset capital gains stemming from this sale. The remaining activity relates to previous discontinued operations for which we continue to have minimal residual costs. Other Operations Other operations relate to previous discontinued operations in our Insurance operations, Corporate Finance operations, and Corporate and Other segments for which we continue to have wind-down, legal, and minimal operational costs. Refer to Note 30 to the Consolidated Financial Statements , titled Contingencies and Other Risks , for additional discussion. Select Financial Information Select financial information of discontinued operations is summarized below. The pretax income or loss includes direct costs to transact a sale. Year ended December 31, ($ in millions) 2016 2015 2014 Select Automotive Finance operations Total net revenue $ — $ — $ 123 Pretax (loss) income (a) (2 ) 452 129 Tax expense (b) 2 80 7 Other operations Pretax (loss) income $ (41 ) $ 16 $ 25 Tax benefit (1 ) (4 ) (78 ) (a) Includes certain treasury and other corporate activity recognized by Corporate and Other. (b) Includes certain income tax activity recognized by Corporate and Other.

Insurance Premiums and Service

Insurance Premiums and Service Revenue Earned Insurance Premiums and Service Revenue Earned	12 Months Ended
	Dec. 31, 2016
Insurance Premiums and Service Revenue Earned [Abstract]
Insurance Premiums and Service Revenue Earned [Text Block]	Insurance Premiums and Service Revenue Earned The following table is a summary of insurance premiums and service revenue written and earned. 2016 2015 2014 Year ended December 31, ($ in millions) Written Earned Written Earned Written Earned Insurance premiums Direct $ 317 $ 318 $ 313 $ 296 $ 294 $ 282 Assumed 3 5 2 16 43 54 Gross insurance premiums 320 323 315 312 337 336 Ceded (198 ) (141 ) (184 ) (125 ) (156 ) (117 ) Net insurance premiums 122 182 131 187 181 219 Service revenue 826 763 846 753 842 760 Insurance premiums and service revenue written and earned $ 948 $ 945 $ 977 $ 940 $ 1,023 $ 979

Other Income, Net of Losses

Other Income, Net of Losses	12 Months Ended
	Dec. 31, 2016
Other Nonoperating Income (Expense) [Abstract]
Other Income and Other Expense Disclosure [Text Block]	Other Income, Net of Losses Details of other income, net of losses, were as follows. Year ended December 31, ($ in millions) 2016 2015 2014 Remarketing fees $ 103 $ 101 $ 112 Late charges and other administrative fees 98 90 88 Servicing fees 64 45 31 Income from equity-method investments 18 52 18 Other, net 111 71 62 Total other income, net of losses $ 394 $ 359 $ 311

Reserves for Insurance Losses a

Reserves for Insurance Losses and Loss Adjustment Expenses Reserves for Insurance Losses and Loss Adjustment Expenses (Notes)	12 Months Ended
	Dec. 31, 2016
Insurance Liability for Unpaid Claims and Claims Adjustment Expenses [Abstract]
Short-Duration Insurance and Deposit Contracts [Text Block]	Reserves for Insurance Losses and Loss Adjustment Expenses The following table shows cumulative incurred claims and allocated loss adjustment expenses, net of reinsurance. For the years ended December 31, ($ in millions) December 31, 2016 ($ in millions) Accident year (a) 2012 (b) 2013 (b) 2014 (b) 2015 (b) 2016 Total of incurred-but-not-reported liabilities plus expected development on reported claims (c) Cumulative number of reported claims (c) 2012 $ 435 $ 430 $ 423 $ 423 $ 423 $ 4 772,536 2013 376 365 370 370 2 672,247 2014 390 389 388 — 525,235 2015 274 271 — 342,054 2016 326 $ 24 453,807 Total $ 1,778 (a) Due to the discontinuation of various product lines and sale of certain international operations, information prior to 2012 has been excluded from the table in order to appropriately reflect the number of years for which claims are typically outstanding. In addition, given the short tail of our insurance contracts, the table above reflects the combined presentation of all business lines. (b) Information presented for the years 2012 through 2015 is unaudited supplementary information. (c) Claims are reported on a claimant basis. Claimant is defined as one vehicle for guaranteed asset protection (GAP) products, one repair visit for vehicle service contracts (VSCs) and vehicle maintenance contracts (VMCs), one dealership for dealer inventory products, and per individual/coverage for run-off personal auto products. The following table shows cumulative paid claims and allocated loss adjustment expenses, net of reinsurance. For the years ended December 31, ($ in millions) Accident year (a) 2012 (b) 2013 (b) 2014 (b) 2015 (b) 2016 2012 $ 391 $ 412 $ 416 $ 418 $ 419 2013 347 364 366 368 2014 369 388 388 2015 252 272 2016 302 Total 1,749 All outstanding liabilities for loss and allocated loss adjustment expenses before 2012, net of reinsurance 9 Reserves for insurance losses and allocated loss adjustment expenses, net of reinsurance $ 38 (a) Due to the discontinuation of various product lines and sale of certain international operations, information prior to 2012 has been excluded from the table in order to appropriately reflect the number of years for which claims are typically outstanding. In addition, given the short tail of our insurance contracts, the table above reflects the combined presentation of all business lines. (b) Information presented for the years 2012 through 2015 is unaudited supplementary information. The following table shows the average annual percentage payout of incurred claims by age, net of reinsurance. The information presented is unaudited supplementary information. Year 1 2 3 4 5 Percentage payout of incurred claims 93.4 % 5.5 % 0.4 % 0.5 % 0.1 % The following table shows a reconciliation of the disclosures of incurred and paid claims development to the reserves for insurance losses and loss adjustment expenses . December 31, ($ in millions) 2016 Reserves for insurance losses and loss adjustment expenses, net of reinsurance $ 38 Total reinsurance recoverable on unpaid claims 108 Unallocated loss adjustment expenses 3 Total gross reserves for insurance losses and loss adjustment expenses $ 149 The following table shows a rollforward of our reserves for insurance losses and loss adjustment expenses. ($ in millions) Total gross reserves for insurance losses and loss adjustment expenses at January 1, 2016 $ 169 Less: Reinsurance recoverable 120 Net reserves for insurance losses and loss adjustment expenses at January 1, 2016 49 Net insurance losses and loss adjustment expenses incurred related to: Current year 345 Prior years (a) (3 ) Total net insurance losses and loss adjustment expenses incurred 342 Net insurance losses and loss adjustment expenses paid or payable related to: Current year (320 ) Prior years (30 ) Total net insurance losses and loss adjustment expenses paid or payable (350 ) Net reserves for insurance losses and loss adjustment expenses at December 31, 2016 41 Plus: Reinsurance recoverable 108 Total gross reserves for insurance losses and loss adjustment expenses at December 31, 2016 $ 149 (a) There have been no material adverse changes to the reserve for prior years.

Other Operating Expenses

Other Operating Expenses	12 Months Ended
	Dec. 31, 2016
Operating Expenses [Abstract]
Other Operating Income and Expense [Text Block]	Other Operating Expenses Details of other operating expenses were as follows. Year ended December 31, ($ in millions) 2016 2015 2014 Insurance commissions $ 389 $ 378 $ 374 Technology and communications 274 267 334 Lease and loan administration 136 126 122 Advertising and marketing 112 107 111 Professional services 103 93 100 Vehicle remarketing and repossession 95 78 83 Regulatory and licensing fees 94 79 87 Premises and equipment depreciation 84 82 81 Occupancy 51 50 47 Non-income taxes 25 29 40 Other 242 216 212 Total other operating expenses $ 1,605 $ 1,505 $ 1,591

Investment Securities

Investment Securities	12 Months Ended
	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Investment Securities [Text Block]	Investment Securities Our portfolio of securities includes bonds, equity securities, asset-backed securities, commercial and residential mortgage-backed securities, and other investments. The cost, fair value, and gross unrealized gains and losses on investment securities were as follows. 2016 2015 Amortized cost Gross unrealized Fair value Amortized cost Gross unrealized Fair December 31, ($ in millions) gains losses gains losses Available-for-sale securities Debt securities U.S. Treasury and federal agencies $ 1,680 $ — $ (60 ) $ 1,620 $ 1,760 $ — $ (19 ) $ 1,741 U.S. States and political subdivisions 794 7 (19 ) 782 693 24 (1 ) 716 Foreign government 157 5 — 162 169 8 — 177 Agency mortgage-backed residential 10,473 29 (212 ) 10,290 7,553 46 (55 ) 7,544 Mortgage-backed residential 2,162 5 (70 ) 2,097 2,906 6 (90 ) 2,822 Mortgage-backed commercial 537 2 (2 ) 537 486 — (5 ) 481 Asset-backed 1,396 6 (2 ) 1,400 1,762 1 (8 ) 1,755 Corporate debt 1,452 7 (16 ) 1,443 1,213 8 (17 ) 1,204 Total debt securities (a) (b) 18,651 61 (381 ) 18,331 16,542 93 (195 ) 16,440 Equity securities 642 7 (54 ) 595 808 3 (94 ) 717 Total available-for-sale securities $ 19,293 $ 68 $ (435 ) $ 18,926 $ 17,350 $ 96 $ (289 ) $ 17,157 Total held-to-maturity securities (c) (d) $ 839 $ — $ (50 ) $ 789 $ — $ — $ — $ — (a) Certain entities related to our Insurance operations are required to deposit securities with state regulatory authorities. These deposited securities totaled $14 million at both December 31, 2016 , and December 31, 2015 . (b) Investment securities with a fair value of $4,881 million and $2,506 million at December 31, 2016 , and December 31, 2015 , were pledged to secure advances from the FHLB, short-term borrowings or repurchase agreements and for other purposes as required by contractual obligation or law. Under these agreements, Ally has granted the counterparty the right to sell or pledge $737 million and $745 million of the underlying investment securities at December 31, 2016 , and December 31, 2015 , respectively. (c) Held-to-maturity securities are recorded at amortized cost and consist of agency-backed residential mortgage-backed debt securities for liquidity purposes. (d) Held-to-maturity securities with a fair value of $87 million at December 31, 2016 , were pledged to secure advances from the FHLB. The maturity distribution of investment securities outstanding is summarized in the following tables. Call or prepayment options may cause actual maturities to differ from contractual maturities. Total Due in one year or less Due after one year through five years Due after five years through ten years Due after ten years ($ in millions) Amount Yield Amount Yield Amount Yield Amount Yield Amount Yield December 31, 2016 Fair value of available-for-sale debt securities (a) U.S. Treasury and federal agencies $ 1,620 1.7 % $ 2 4.6 % $ 60 1.6 % $ 1,558 1.7 % $ — — % U.S. States and political subdivisions 782 3.1 64 1.7 29 2.3 172 2.8 517 3.4 Foreign government 162 2.6 — — 58 2.8 104 2.4 — — Agency mortgage-backed residential 10,290 2.9 — — — — 29 2.6 10,261 2.9 Mortgage-backed residential 2,097 2.9 — — — — — — 2,097 2.9 Mortgage-backed commercial 537 2.6 — — — — 3 2.8 534 2.6 Asset-backed 1,400 2.8 — — 1,059 2.8 143 3.2 198 2.6 Corporate debt 1,443 2.8 72 2.2 840 2.6 489 3.2 42 4.7 Total available-for-sale debt securities $ 18,331 2.8 $ 138 2.0 $ 2,046 2.7 $ 2,498 2.2 $ 13,649 2.9 Amortized cost of available-for-sale debt securities $ 18,651 $ 138 $ 2,040 $ 2,563 $ 13,910 Amortized cost of held-to-maturity securities $ 839 2.9 % $ — — % $ — — % $ — — % $ 839 2.9 % December 31, 2015 Fair value of available-for-sale debt securities (a) U.S. Treasury and federal agencies $ 1,741 1.8 % $ 6 5.1 % $ 510 1.2 % $ 1,225 2.1 % $ — — % U.S. States and political subdivisions 716 3.2 86 1.3 37 2.2 141 2.8 452 3.7 Foreign government 177 2.6 9 1.9 77 2.8 91 2.6 — — Agency mortgage-backed residential 7,544 2.9 — — 32 2.0 36 2.5 7,476 2.9 Mortgage-backed residential 2,822 2.9 — — 1 4.5 — — 2,821 2.9 Mortgage-backed commercial 481 2.0 — — — — 3 2.7 478 2.0 Asset-backed 1,755 2.3 6 1.4 1,027 2.1 518 2.6 204 2.2 Corporate debt 1,204 2.9 50 3.0 713 2.5 410 3.4 31 5.4 Total available-for-sale debt securities $ 16,440 2.7 $ 157 2.0 $ 2,397 2.1 $ 2,424 2.5 $ 11,462 2.9 Amortized cost of available-for-sale debt securities $ 16,542 $ 156 $ 2,404 $ 2,436 $ 11,546 (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 $291 million and $1.0 billion at December 31, 2016 , and December 31, 2015 , respectively, and were composed primarily of money market accounts and short-term securities, including U.S. Treasury bills. The following table presents interest and dividends on investment securities. Year ended December 31, ($ in millions) 2016 2015 2014 Taxable interest $ 375 $ 340 $ 336 Taxable dividends 17 23 20 Interest and dividends exempt from U.S. federal income tax 19 18 11 Interest and dividends on investment securities $ 411 $ 381 $ 367 The following table presents gross gains and losses realized upon the sales of available-for-sale securities and other-than-temporary impairment. Year ended December 31, ($ in millions) 2016 2015 2014 Gross realized gains $ 187 $ 184 $ 209 Gross realized losses (a) (2 ) (15 ) (14 ) Other-than-temporary impairment — (14 ) (14 ) Other gain on investments, net $ 185 $ 155 $ 181 (a) In accordance with our risk management policies and practice, certain available-for-sale securities were sold at a loss in 2016, 2015, and 2014 as a result of changing conditions within these respective periods (e.g., a downgrade in the rating of a debt security) or events outside of our control (such as issuer calls). The table below summarizes available-for-sale securities in an unrealized loss position in accumulated other comprehensive income. Based on the assessment of whether such losses were deemed to be other-than-temporary, we believe that the unrealized losses are not indicative of an other-than-temporary impairment of these securities. As of December 31, 2016 , we did not have the intent to sell the debt securities with an unrealized loss position in accumulated other comprehensive income, it is not more likely than not that we will be required to sell these securities before recovery of their amortized cost basis, and we expect to recover the entire amortized cost basis of the securities. As of December 31, 2016 , we had the ability and intent to hold equity securities with an unrealized loss position in accumulated other comprehensive income, and it is not more likely than not that we will be required to sell these securities before recovery of their amortized cost basis. As a result, we believe that the securities with an unrealized loss position in accumulated other comprehensive income are not considered to be other-than-temporarily impaired at December 31, 2016 . Refer to Note 1 to the Consolidated Financial Statements for additional information related to investment securities and our methodology for evaluating potential other-than-temporary impairments. 2016 2015 Less than 12 months 12 months or longer Less than 12 months 12 months or longer December 31, ($ in millions) Fair value Unrealized loss Fair value Unrealized loss Fair value Unrealized loss Fair value Unrealized loss Available-for-sale securities Debt securities U.S. Treasury and federal agencies $ 1,612 $ (60 ) $ — $ — $ 1,553 $ (17 ) $ 173 $ (2 ) U.S. States and political subdivisions 524 (19 ) — — 179 (1 ) — — Foreign government 38 — — — 2 — — — Agency mortgage-backed residential 8,052 (196 ) 587 (16 ) 2,524 (21 ) 1,132 (34 ) Mortgage-backed residential 813 (17 ) 860 (53 ) 1,231 (19 ) 1,180 (71 ) Mortgage-backed commercial 47 (1 ) 149 (1 ) 341 (3 ) 141 (2 ) Asset-backed 375 (2 ) 127 — 1,402 (8 ) 64 — Corporate debt 744 (14 ) 46 (2 ) 745 (16 ) 12 (1 ) Total temporarily impaired debt securities 12,205 (309 ) 1,769 (72 ) 7,977 (85 ) 2,702 (110 ) Temporarily impaired equity securities 151 (8 ) 269 (46 ) 534 (54 ) 96 (40 ) Total temporarily impaired available-for-sale securities $ 12,356 $ (317 ) $ 2,038 $ (118 ) $ 8,511 $ (139 ) $ 2,798 $ (150 )

Finance Receivables and Loans,

Finance Receivables and Loans, Net	12 Months Ended
	Dec. 31, 2016
Loans and Leases Receivable, Net Amount [Abstract]
Loans, Notes, Trade and Other Receivables Disclosure [Text Block]	Finance Receivables and Loans, Net The composition of finance receivables and loans reported at gross carrying value was as follows. December 31, ($ in millions) 2016 2015 Consumer automotive (a) $ 65,793 $ 64,292 Consumer mortgage Mortgage Finance (b) 8,294 6,413 Mortgage — Legacy (c) 2,756 3,360 Total consumer mortgage 11,050 9,773 Total consumer 76,843 74,065 Commercial Commercial and industrial Automotive 35,041 31,469 Other 3,248 2,640 Commercial real estate — Automotive 3,812 3,426 Total commercial 42,101 37,535 Total finance receivables and loans (d) $ 118,944 $ 111,600 (a) Includes $43 million and $66 million of fair value adjustment for loans in hedge accounting relationships at December 31, 2016 , and December 31, 2015 , respectively. Refer to Note 22 to the Consolidated Financial Statements for additional information. (b) Includes loans originated as interest-only mortgage loans of $30 million and $44 million at December 31, 2016 , and December 31, 2015 , respectively, 3% of which are expected to start principal amortization in 2017 , none in 2018 , 38% in 2019 , 39% in 2020 , and none thereafter. (c) Includes loans originated as interest-only mortgage loans of $714 million and $941 million at December 31, 2016 , and December 31, 2015 , respectively, 23% of which are expected to start principal amortization in 2017 , 2% in 2018 , none in 2019 , none in 2020 , and 1% thereafter. (d) Totals include net increases of $359 million and $110 million at December 31, 2016 , and December 31, 2015 , respectively, for unearned income, unamortized premiums and discounts, and deferred fees and costs. The following tables present an analysis of the activity in the allowance for loan losses on finance receivables and loans. ($ in millions) Consumer automotive Consumer mortgage Commercial Total Allowance at January 1, 2016 $ 834 $ 114 $ 106 $ 1,054 Charge-offs (a) (1,102 ) (39 ) (1 ) (1,142 ) Recoveries 307 32 2 341 Net charge-offs (795 ) (7 ) 1 (801 ) Provision for loan losses 919 (16 ) 14 917 Other (b) (26 ) — — (26 ) Allowance at December 31, 2016 $ 932 $ 91 $ 121 $ 1,144 Allowance for loan losses at December 31, 2016 Individually evaluated for impairment $ 28 $ 34 $ 23 $ 85 Collectively evaluated for impairment 904 57 98 1,059 Loans acquired with deteriorated credit quality — — — — Finance receivables and loans at gross carrying value Ending balance $ 65,793 $ 11,050 $ 42,101 $ 118,944 Individually evaluated for impairment 370 247 122 739 Collectively evaluated for impairment 65,423 10,803 41,979 118,205 Loans acquired with deteriorated credit quality — — — — (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 for more information regarding our charge-off policies. (b) Primarily related to the transfer of finance receivables and loans from held-for-investment to held-for-sale. ($ in millions) Consumer automotive Consumer mortgage Commercial Total Allowance at January 1, 2015 $ 685 $ 152 $ 140 $ 977 Charge-offs (a) (840 ) (48 ) (4 ) (892 ) Recoveries 262 17 4 283 Net charge-offs (578 ) (31 ) — (609 ) Provision for loan losses 739 1 (33 ) 707 Other (b) (12 ) (8 ) (1 ) (21 ) Allowance at December 31, 2015 $ 834 $ 114 $ 106 $ 1,054 Allowance for loan losses at December 31, 2015 Individually evaluated for impairment $ 22 $ 44 $ 20 $ 86 Collectively evaluated for impairment 812 70 86 968 Loans acquired with deteriorated credit quality — — — — Finance receivables and loans at gross carrying value Ending balance $ 64,292 $ 9,773 $ 37,535 $ 111,600 Individually evaluated for impairment 315 266 77 658 Collectively evaluated for impairment 63,977 9,507 37,458 110,942 Loans acquired with deteriorated credit quality — — — — (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 for more information regarding our charge-off policies. (b) Primarily related to the transfer of finance receivables and loans from held-for-investment to held-for-sale. The following table presents information about significant sales of finance receivables and loans and transfers of finance receivables and loans from held-for-investment to held-for-sale. December 31, ($ in millions) 2016 2015 Consumer automotive $ 4,267 $ 1,237 Consumer mortgage 15 78 Commercial 29 2 Total sales and transfers $ 4,311 $ 1,317 The following table presents information about significant purchases of finance receivables and loans. December 31, ($ in millions) 2016 2015 Consumer automotive $ 21 $ 272 Consumer mortgage 3,747 4,125 Total purchases of finance receivables and loans $ 3,768 $ 4,397 The following table presents an analysis of our past due finance receivables and loans recorded at gross carrying value. December 31, ($ in millions) 30–59 days past due 60–89 days past due 90 days or more past due Total past due Current Total finance receivables and loans 2016 Consumer automotive $ 1,850 $ 428 $ 302 $ 2,580 $ 63,213 $ 65,793 Consumer mortgage Mortgage Finance 39 6 4 49 8,245 8,294 Mortgage — Legacy 45 18 57 120 2,636 2,756 Total consumer mortgage 84 24 61 169 10,881 11,050 Total consumer 1,934 452 363 2,749 74,094 76,843 Commercial Commercial and industrial Automotive 3 — 7 10 35,031 35,041 Other — — — — 3,248 3,248 Commercial real estate — Automotive — — — — 3,812 3,812 Total commercial 3 — 7 10 42,091 42,101 Total consumer and commercial $ 1,937 $ 452 $ 370 $ 2,759 $ 116,185 $ 118,944 2015 Consumer automotive $ 1,618 $ 369 $ 222 $ 2,209 $ 62,083 $ 64,292 Consumer mortgage Mortgage Finance 44 5 10 59 6,354 6,413 Mortgage — Legacy 53 20 73 146 3,214 3,360 Total consumer mortgage 97 25 83 205 9,568 9,773 Total consumer 1,715 394 305 2,414 71,651 74,065 Commercial Commercial and industrial Automotive — — — — 31,469 31,469 Other — — — — 2,640 2,640 Commercial real estate — Automotive — — — — 3,426 3,426 Total commercial — — — — 37,535 37,535 Total consumer and commercial $ 1,715 $ 394 $ 305 $ 2,414 $ 109,186 $ 111,600 The following table presents the gross carrying value of our finance receivables and loans on nonaccrual status. December 31, ($ in millions) 2016 2015 Consumer automotive $ 598 $ 475 Consumer mortgage Mortgage Finance 10 15 Mortgage — Legacy 89 113 Total consumer mortgage 99 128 Total consumer 697 603 Commercial Commercial and industrial Automotive 33 25 Other 84 44 Commercial real estate — Automotive 5 8 Total commercial 122 77 Total consumer and commercial finance receivables and loans $ 819 $ 680 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 when full collection is not expected. Refer to Note 1 to the Consolidated Financial Statements for additional information. 2016 2015 December 31, ( $ in millions ) Performing Nonperforming Total Performing Nonperforming Total Consumer automotive $ 65,195 $ 598 $ 65,793 $ 63,817 $ 475 $ 64,292 Consumer mortgage Mortgage Finance 8,284 10 8,294 6,398 15 6,413 Mortgage — Legacy 2,667 89 2,756 3,247 113 3,360 Total consumer mortgage 10,951 99 11,050 9,645 128 9,773 Total consumer $ 76,146 $ 697 $ 76,843 $ 73,462 $ 603 $ 74,065 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. 2016 2015 December 31, ( $ in millions ) Pass Criticized (a) Total Pass Criticized (a) Total Commercial and industrial Automotive $ 33,160 $ 1,881 $ 35,041 $ 29,613 $ 1,856 $ 31,469 Other 2,597 651 3,248 2,122 518 2,640 Commercial real estate — Automotive 3,653 159 3,812 3,265 161 3,426 Total commercial $ 39,410 $ 2,691 $ 42,101 $ 35,000 $ 2,535 $ 37,535 (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 . The following table presents information about our impaired finance receivables and loans. December 31, ( $ in millions ) Unpaid principal balance (a) Gross carrying value Impaired with no allowance Impaired with an allowance Allowance for impaired loans 2016 Consumer automotive $ 407 $ 370 $ 131 $ 239 $ 28 Consumer mortgage Mortgage Finance 8 8 3 5 — Mortgage — Legacy 243 239 56 183 34 Total consumer mortgage 251 247 59 188 34 Total consumer 658 617 190 427 62 Commercial Commercial and industrial Automotive 33 33 7 26 3 Other 99 84 — 84 19 Commercial real estate — Automotive 5 5 2 3 1 Total commercial 137 122 9 113 23 Total consumer and commercial finance receivables and loans $ 795 $ 739 $ 199 $ 540 $ 85 2015 Consumer automotive $ 315 $ 315 $ — $ 315 $ 22 Consumer mortgage Mortgage Finance 9 9 5 4 1 Mortgage — Legacy 260 257 59 198 43 Total consumer mortgage 269 266 64 202 44 Total consumer 584 581 64 517 66 Commercial Commercial and industrial Automotive 25 25 4 21 3 Other 44 44 — 44 15 Commercial real estate — Automotive 8 8 1 7 2 Total commercial 77 77 5 72 20 Total consumer and commercial finance receivables and loans $ 661 $ 658 $ 69 $ 589 $ 86 (a) Adjusted for charge-offs. The following table presents average balance and interest income for our impaired finance receivables and loans. 2016 2015 2014 Year ended December 31, ($ in millions) Average balance Interest income Average balance Interest income Average balance Interest income Consumer automotive $ 344 $ 17 $ 295 $ 16 $ 317 $ 20 Consumer mortgage Mortgage Finance 8 — 8 — 12 — Mortgage — Legacy 248 9 272 9 861 12 Total consumer mortgage 256 9 280 9 873 12 Total consumer 600 26 575 25 1,190 32 Commercial Commercial and industrial Automotive 35 1 33 1 61 2 Other 60 1 41 3 59 3 Commercial real estate — Automotive 6 — 5 — 6 — Total commercial 101 2 79 4 126 5 Total consumer and commercial finance receivables and loans $ 701 $ 28 $ 654 $ 29 $ 1,316 $ 37 Troubled Debt Restructurings TDRs are loan modifications where concessions were granted to borrowers experiencing financial difficulties. For automotive loans, we may offer several types of assistance to aid our customers, including extension of the loan maturity date and rewriting the loan terms. Additionally, for mortgage loans, as part of certain programs, we offer mortgage loan modifications to qualified borrowers. Numerous initiatives 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 $663 million and $625 million at December 31, 2016 , and December 31, 2015 , respectively. Commercial commitments to lend additional funds to borrowers whose terms had been modified in a TDR were $2 million at both December 31, 2016 , and December 31, 2015 . Refer to Note 1 to the Consolidated Financial Statements for additional information. The following table presents information related to finance receivables and loans recorded at gross carrying value modified in connection with a TDR during the period. 2016 2015 Year ended December 31, ($ 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 20,227 $ 347 $ 293 17,222 $ 278 $ 237 Consumer mortgage Mortgage Finance 7 3 3 7 4 4 Mortgage — Legacy 120 18 18 197 42 40 Total consumer mortgage 127 21 21 204 46 44 Total consumer 20,354 368 314 17,426 324 281 Commercial Commercial and industrial Automotive 1 7 7 — — — Other — — — 1 21 21 Commercial real estate — Automotive — — — 1 3 3 Total commercial 1 7 7 2 24 24 Total consumer and commercial finance receivables and loans 20,355 $ 375 $ 321 17,428 $ 348 $ 305 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 12 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 for additional information) except for commercial finance receivables and loans, where redefault is defined as 90 days past due. 2016 2015 Year ended December 31, ($ in millions) Number of loans Gross carrying value Charge-off amount Number of loans Gross carrying value Charge-off amount Consumer automotive 7,800 $ 94 $ 56 6,836 $ 82 $ 47 Consumer mortgage Mortgage Finance — — — — — — Mortgage — Legacy 4 — — 10 1 — Total consumer finance receivables and loans 7,804 $ 94 $ 56 6,846 $ 83 $ 47 Concentration Risk Consumer We monitor our consumer loan portfolio for concentration risk across the states in which we lend. The highest concentrations of loans are in Texas and California, which represent an aggregate of 24.2% and 23.5% of our total outstanding consumer finance receivables and loans at December 31, 2016 , and December 31, 2015 , respectively. The following table shows the percentage of total consumer finance receivables and loans recorded at gross carrying value by state concentration. 2016 (a) 2015 December 31, Consumer automotive Consumer mortgage Consumer automotive Consumer mortgage Texas 13.6 % 6.6 % 13.7 % 6.2 % California 7.8 34.2 7.3 33.6 Florida 8.2 4.4 7.7 4.1 Pennsylvania 4.7 1.5 5.0 1.5 Illinois 4.3 3.4 4.4 4.1 Georgia 4.3 2.2 4.4 2.2 North Carolina 3.6 1.6 3.6 1.8 Ohio 3.5 0.5 3.7 0.6 New York 3.2 1.9 3.5 1.9 Michigan 2.7 1.9 3.1 2.4 Other United States 44.1 41.8 43.6 41.6 Total consumer loans 100.0 % 100.0 % 100.0 % 100.0 % (a) Presentation is in descending order as a percentage of total consumer finance receivables and loans at December 31, 2016. Commercial Real Estate The commercial real estate portfolio consists of loans issued primarily to automotive dealers. The following table shows the percentage of total commercial real estate finance receivables and loans reported at gross carrying value by state concentration. December 31, 2016 2015 Texas 16.1 % 17.7 % Florida 10.2 10.0 California 7.9 8.7 Michigan 7.6 8.9 New Jersey 4.2 2.1 Georgia 3.6 3.6 North Carolina 3.6 3.8 Pennsylvania 3.1 3.4 South Carolina 2.7 2.2 New York 2.6 3.1 Other United States 38.4 36.5 Total commercial real estate finance receivables and loans 100.0 % 100.0 % Commercial Criticized Exposure Finance receivables and loans classified as special mention, substandard, or doubtful are reported as criticized. These classifications are based on regulatory definitions and generally represent finance receivables and loans within our portfolio that have a higher default risk or have already defaulted. These finance receivables and loans require additional monitoring and review including specific actions to mitigate our potential loss. The following table presents the percentage of total commercial criticized finance receivables and loans reported at gross carrying value by industry concentrations. December 31, 2016 2015 Automotive 81.2 % 80.5 % Services 6.3 5.3 Electronics 4.2 3.3 Other 8.3 10.9 Total commercial criticized finance receivables and loans 100.0 % 100.0 %

Investment in Operating Leases,

Investment in Operating Leases, Net	12 Months Ended
	Dec. 31, 2016
Leases, Operating [Abstract]
Operating Leases of Lessor Disclosure [Text Block]	Investment in Operating Leases, Net Investments in operating leases were as follows. December 31, ( $ in millions ) 2016 2015 Vehicles $ 14,584 $ 20,211 Accumulated depreciation (3,114 ) (3,940 ) Investment in operating leases, net $ 11,470 $ 16,271 Depreciation expense on operating lease assets includes remarketing gains and losses recognized on the sale of operating lease assets. The following summarizes the components of depreciation expense on operating lease assets. Year ended December 31, ( $ in millions ) 2016 2015 2014 Depreciation expense on operating lease assets (excluding remarketing gains) $ 1,982 $ 2,600 $ 2,666 Remarketing gains (213 ) (351 ) (433 ) Net depreciation expense on operating lease assets $ 1,769 $ 2,249 $ 2,233 The following table presents the future lease nonresidual rental payments due from customers for vehicles on operating leases. Year ended December 31, ( $ in millions ) 2017 $ 1,759 2018 821 2019 307 2020 44 2021 and thereafter 2 Total $ 2,933

Securitizations and Variable In

Securitizations and Variable Interest Entities	12 Months Ended
	Dec. 31, 2016
Securitizations And Variable Interest Entities [Abstract]
Variable Interest Entity Disclosure [Text Block]	Securitizations and Variable Interest Entities Overview We are involved in several types of securitization and financing transactions that utilize special-purpose entities (SPEs). A SPE is an 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 and operating lease assets. The transaction-specific SPEs involved in our securitization and other financing transactions are often considered VIEs. VIEs are entities that have either a total equity investment at risk that is insufficient to permit the entity to finance its activities without additional subordinated financial support or whose equity investors at risk lack the ability to control the entity's activities. We no longer securitize consumer mortgage loans through transactions involving the Federal National Mortgage Association (Fannie Mae), the Federal Home Loan Mortgage Corporation (Freddie Mac), and the Government National Mortgage Association (Ginnie Mae) (collectively, the Government-sponsored Enterprises, or GSEs), or through private-label mortgage securitizations. Accordingly, the discussion below represents our current involvement with VIEs as of December 31, 2016 , except where otherwise stated or where comparative information is presented. Securitizations We provide a wide range of consumer and commercial automotive loans, operating leases, and commercial loans to a diverse customer base. We securitize consumer and commercial automotive loans, and operating leases through private-label securitizations. We often securitize these loans and notes securitized by operating leases (collectively referred to as financial assets) through the use of securitization entities, which may or may not be consolidated on our Consolidated Balance Sheet. In executing a securitization transaction, we typically sell pools of financial assets to a wholly-owned, bankruptcy-remote SPE, which then transfers the financial assets to a separate, transaction-specific SPE for cash, and typically, other retained interests. The securitization entity is funded through the issuance of beneficial interests in the securitized financial assets. The beneficial interests take the form of either notes or trust certificates, which are sold to investors and/or retained by us. These beneficial interests are collateralized by the transferred financial assets and entitle the investors to specified cash flows generated from the underlying securitized assets. In addition to providing a source of liquidity and cost-efficient funding, securitizing these financial assets also reduces our credit exposure to the borrowers beyond any economic interest we may retain. Each securitization is governed by various legal documents that limit and specify the activities of the securitization entity. The securitization entity is generally allowed to acquire the financial assets, to issue beneficial interests to investors to fund the acquisition of the financial assets, and to enter into derivatives or other yield maintenance contracts to hedge or mitigate certain risks related to the financial assets or beneficial interests of the entity. A servicer, who is generally us, is appointed pursuant to the underlying legal documents to service the assets the securitization entity holds and the beneficial interests it issues. Servicing functions include, but are not limited to, general collection activity on current and noncurrent accounts, loss mitigation efforts including repossession and sale of collateral, as well as preparing and furnishing statements summarizing the asset and beneficial interest performance. These servicing responsibilities constitute continued involvement in the transferred financial assets. Cash flows from the assets initially transferred into the securitization entity represent the sole source for payment of distributions on the beneficial interests issued by the securitization entity and for payments to the parties that perform services for the securitization entity, such as the servicer or the trustee. We typically hold retained beneficial interests in our securitizations including, but not limited to, senior or subordinated ABS and residuals; and other residual interests. These retained interests may represent a form of significant continuing economic interests. Certain of these retained interests provide credit enhancement to the trust as they may absorb credit losses or other cash shortfalls. We generally hold certain conditional repurchase options specific to securitizations that allow us to repurchase assets from the securitization entity. The majority of the securitizations provide us, as servicer, with a call option that allows us to repurchase the remaining transferred financial assets or redeem outstanding beneficial interests at our discretion once the asset pool reaches a predefined level, which represents the point where servicing becomes burdensome (a clean-up call option). The repurchase price is typically the discounted securitization balance of the assets plus accrued interest when applicable. We generally have discretion regarding when or if we will exercise these options, but we would do so only when it is in our best interest. Other than our customary representation and warranty provisions, these securitizations are nonrecourse to us, thereby transferring the risk of future credit losses to the extent the beneficial interests in the securitization entities are held by third parties. Representation and warranty provisions generally require us to repurchase assets or indemnify the investor or other party for incurred losses to the extent it is determined that the assets were ineligible or were otherwise defective at the time of sale. We did not provide any noncontractual financial support to any of these entities during 2016 or 2015. Consolidation of Variable Interest Entities The determination of whether the assets and liabilities of the VIEs are consolidated on our balance sheet (also referred to as on-balance sheet) or not consolidated on our balance sheet (also referred to as off-balance sheet) depends on the terms of the related transaction and our continuing involvement (if any) with the VIE. We are deemed the primary beneficiary and therefore consolidate VIEs for which we have both (a) the power, through voting rights or similar rights, to direct the activities that most significantly impact the VIE's economic performance, and (b) a variable interest (or variable interests) that (i) obligates us to absorb losses that could potentially be significant to the VIE; and/or (ii) provides us the right to receive residual returns of the VIE that could potentially be significant to the VIE. We determine whether we hold a significant variable interest in a VIE based on a consideration of both qualitative and quantitative factors regarding the nature, size, and form of our involvement with the VIE. We assess whether we are the primary beneficiary of a VIE on an ongoing basis. We are generally determined to be the primary beneficiary in VIEs established for our securitization activities when we have a controlling financial interest in the VIE, primarily due to our servicing activities, and we hold a beneficial interest in the VIE that could be potentially significant. The consolidated VIEs included in the Consolidated Balance Sheet represent separate entities with which we are involved. The third-party investors in the obligations of consolidated VIEs have legal recourse only to the assets of the VIEs and do not have such recourse to us, except for the customary representation and warranty provisions. In addition, the cash flows from the assets are restricted only to pay such liabilities. Thus, our economic exposure to loss from outstanding third-party financing related to consolidated VIEs is limited to the carrying value of the consolidated VIE assets. Generally, all assets of consolidated VIEs, presented below based upon the legal transfer of the underlying assets in order to reflect legal ownership, are restricted for the benefit of the beneficial interest holders. The nature, purpose, and activities of nonconsolidated securitization entities are similar to those of our consolidated securitization entities with the primary difference being the nature and extent of our continuing involvement. We are generally not determined to be the primary beneficiary in VIEs established for our securitization activities when we either do not hold potentially significant variable interests or do not provide servicing or asset management functions for the financial assets held by the securitization entity. Additionally, to qualify for off-balance sheet treatment, transfers of financial assets must meet appropriate sale accounting conditions. For nonconsolidated securitization entities, 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 securitization transactions, such as representation and warranty provisions, are recorded at fair value at the time of sale and are reported as accrued expenses and other liabilities on our Consolidated Balance Sheet. Upon the sale of the loans, we recognize a gain or loss on sale for the difference between the assets recognized, the assets derecognized, and the liabilities recognized as part of the transaction. There was no pretax gain or loss on sales of financial assets into nonconsolidated consumer automotive securitization trusts for the year ended December 31, 2016 . The pretax loss recognized was $3 million for the year ended December 31, 2015 , while there was a pretax gain of $1 million for the year ended December 31, 2014 . We provide long-term guarantee contracts to investors in certain nonconsolidated affordable housing entities and have extended a line of credit to provide liquidity. Since we do not have control over the entities or the power to make decisions, we do not consolidate the entities and our involvement is limited to the guarantee and the line of credit. We have involvement with various other nonconsolidated equity investments, including affordable housing entities and venture capital funds and loan funds. We do not consolidate these entities and our involvement is limited to our outstanding investment, additional capital committed to these funds plus any previously recognized low income housing tax credits that are subject to recapture. The following table presents our involvement in consolidated and nonconsolidated VIEs in which we hold variable interests. For additional detail related to the assets and liabilities of consolidated variable interest entities refer to the Consolidated Balance Sheet. December 31, ($ in millions) Net carrying value of total assets Carrying value of total liabilities Assets sold to Maximum exposure to 2016 On-balance sheet variable interest entities Consumer automotive $ 20,869 (b) $ 8,557 (c) Commercial automotive 16,278 4,764 Off-balance sheet variable interest entities Consumer automotive 24 — $ 2,899 $ 2,923 (d) Commercial other 460 (e) 169 (f) — 651 (g) Total $ 37,631 $ 13,490 $ 2,899 $ 3,574 2015 On-balance sheet variable interest entities Consumer automotive $ 27,967 (b) $ 12,406 (c) Commercial automotive 16,763 7,982 Off-balance sheet variable interest entities Consumer automotive — — $ 3,034 $ 3,034 (d) Commercial other 210 (e) — — 493 (g) Total $ 44,940 $ 20,388 $ 3,034 $ 3,527 (a) Asset values represent the current unpaid principal balance of outstanding consumer finance receivables and loans within the VIEs. (b) Includes $9.6 billion and $10.6 billion of assets that are not encumbered by VIE beneficial interests held by third parties at December 31, 2016 , and December 31, 2015 , respectively. Ally or consolidated affiliates hold the interests in these assets, which eliminate in consolidation. (c) Includes $50 million and $99 million of liabilities due to consolidated affiliates at December 31, 2016 , and December 31, 2015 , respectively. These liabilities are not obligations to third-party beneficial interest holders. These liabilities are secured by a portion of the unencumbered assets and eliminate in consolidation. (d) Maximum exposure to loss represents the current unpaid principal balance of outstanding loans based on our customary representation and warranty provisions and certain noncertificated interests retained from the sale of automotive finance receivables. This measure is based on the unlikely event that all of the loans have underwriting defects or other defects that trigger a representation and warranty provision and the collateral supporting the loans are worthless. This required disclosure is not an indication of our expected loss. (e) Amounts are classified as other assets. (f) Amounts are classified as accrued expenses and other liabilities. (g) For certain nonconsolidated affordable housing entities, maximum exposure to loss represents the yield we guaranteed investors through long term guarantee contracts. The amount disclosed is based on the unlikely event that the underlying properties cease generating yield to investors and the yield delivered to investors in the form of low income tax housing credits is recaptured. For nonconsolidated equity investments, maximum exposure to loss represents our outstanding investment, additional committed capital, and low income housing tax credits subject to recapture. The amount disclosed is based on the unlikely event that our committed capital is funded, our investments become worthless, and the tax credits previously delivered to us are recaptured. This required disclosure is not an indication of our expected loss. On-balance Sheet Variable Interest Entities The consolidated VIEs included in the Consolidated Balance Sheet represent separate entities with which we are involved. The third-party investors in the obligations of consolidated VIEs have legal recourse only to the assets of the VIEs and do not have such recourse to us, except for the customary representation and warranty provisions. In addition, the cash flows from the assets are restricted only to pay such liabilities. Thus, our economic exposure to loss from outstanding third-party financing related to consolidated VIEs is significantly less than the carrying value of the consolidated VIE assets. All assets of consolidated VIEs, presented below based upon the legal transfer of the underlying assets in order to reflect legal ownership, are restricted for the benefit of the beneficial interest holders. December 31, ( $ in millions ) 2016 2015 Assets Finance receivables and loans, net Consumer $ 8,929 $ 11,682 Commercial 15,701 16,247 Allowance for loan losses (173 ) (196 ) Total finance receivables and loans, net 24,457 27,733 Investment in operating leases, net 1,745 4,791 Other assets 1,390 1,624 Total assets $ 27,592 $ 34,148 Liabilities Long-term debt 13,259 20,267 Accrued expenses and other liabilities 12 22 Total liabilities $ 13,271 $ 20,289 Cash Flows with Off-balance Sheet Securitization Entities The following table summarizes cash flows received and paid related to securitization entities and asset-backed financings where the transfer is accounted for as a sale and we have a continuing involvement with the transferred assets (e.g., servicing) that were outstanding during the years ended December 31, 2016 , 2015 , and 2014 . Additionally, this table contains information regarding cash flows received from and paid to nonconsolidated securitization entities that existed during each period. Year ended December 31, ($ in millions) Consumer automotive Consumer mortgage 2016 Cash proceeds from transfers completed during the period $ 1,715 $ — Servicing fees 35 — Other cash flows 8 — 2015 Cash proceeds from transfers completed during the period $ 1,551 $ — Servicing fees 28 — 2014 Cash proceeds from transfers completed during the period $ 2,594 $ — Servicing fees 11 — Representations and warranties obligations — (31 ) Delinquencies and Net Credit Losses The following table represents on-balance sheet loans held-for-sale and finance receivable and loans, off-balance sheet securitizations, and whole-loan sales where we have continuing involvement. The table presents quantitative information about delinquencies and net credit losses. Total Amount Amount 60 days or more Net credit losses December 31, ($ in millions) 2016 2015 2016 2015 2016 2015 On-balance sheet loans Consumer automotive $ 65,793 $ 64,292 $ 730 $ 591 $ 795 $ 578 Consumer mortgage 11,050 9,773 85 108 7 31 Commercial automotive 38,853 34,895 7 — 1 3 Commercial other 3,248 2,745 — — (2 ) (3 ) Total on-balance sheet loans 118,944 111,705 822 699 801 609 Off-balance sheet securitization entities Consumer automotive 2,392 2,529 13 9 8 5 Total off-balance sheet securitization entities 2,392 2,529 13 9 8 5 Whole-loan sales (a) 3,164 2,252 6 13 3 — Total $ 124,500 $ 116,486 $ 841 $ 721 $ 812 $ 614 (a) Whole-loan sales are not part of a securitization transaction, but represent consumer automotive pools of loans sold to third-party investors.

Servicing Activities

Servicing Activities	12 Months Ended
	Dec. 31, 2016
Servicing Asset [Abstract]
Servicing Activities [Text Block]	Servicing Activities Automotive Finance Servicing Activities We service consumer automotive contracts. Historically, we have sold a portion of our consumer automotive contracts. With respect to contracts we sell, we retain the right to service and earn a servicing fee for our servicing function. We have concluded that the fee we are paid for servicing consumer automotive finance receivables represents adequate compensation, and consequently, we do not recognize a servicing asset or liability. We recognized automotive servicing fee income of $64 million , $45 million , and $31 million during the years ended December 31, 2016 , 2015 , and 2014 , respectively. Automotive Finance Serviced Assets The current unpaid principal balance and any related unamortized deferred fees and costs of total serviced automotive finance loans and leases outstanding were as follows. December 31, ($ in millions) 2016 2015 On-balance sheet automotive finance loans and leases Consumer automotive $ 65,646 $ 64,067 Commercial automotive 38,853 34,895 Operating leases 11,311 15,965 Other 67 72 Off-balance sheet automotive finance loans Securitizations 2,412 2,550 Whole-loan 3,191 2,259 Total serviced automotive finance loans and leases $ 121,480 $ 119,808

Premiums Receivable and Other I

Premiums Receivable and Other Insurance Assets Premiums Receivable and Other Insurance Assets	12 Months Ended
	Dec. 31, 2016
Premiums Receivable and Other Insurance Assets [Abstract]
Premiums Receivable Note [Text Block]	Premiums Receivable and Other Insurance Assets Premiums receivable and other insurance assets consisted of the following. December 31, ( $ in millions ) 2016 2015 Prepaid reinsurance premiums $ 439 $ 382 Reinsurance recoverable on unpaid losses 108 120 Reinsurance recoverable on paid losses 20 18 Premiums receivable 80 82 Deferred policy acquisition costs 1,258 1,199 Total premiums receivable and other insurance assets $ 1,905 $ 1,801

Other Assets

Other Assets	12 Months Ended
	Dec. 31, 2016
Other Assets [Abstract]
Other Assets Disclosure [Text Block]	Other Assets The components of other assets were as follows. December 31, ($ in millions) 2016 2015 Property and equipment at cost $ 901 $ 691 Accumulated depreciation (525 ) (456 ) Net property and equipment 376 235 Restricted cash collections for securitization trusts (a) 1,694 2,010 Nonmarketable equity investments (b) 1,046 418 Net deferred tax assets 994 1,369 Accrued interest and rent receivables 476 402 Goodwill (c) 240 27 Cash reserve deposits held-for-securitization trusts (d) 184 252 Cash collateral placed with counterparties 167 125 Restricted cash and cash equivalents 111 120 Other accounts receivable 100 158 Fair value of derivative contracts in receivable position (e) 95 233 Other assets 1,371 972 Total other assets $ 6,854 $ 6,321 (a) Represents cash collections from customer payments on securitized receivables. These funds are distributed to investors as payments on the related secured debt. (b) Includes investments in FHLB stock of $577 million and $391 million and FRB stock of $435 million and $0 million at December 31, 2016 , and December 31, 2015 , respectively. (c) Includes goodwill of $27 million at our Insurance operations at both December 31, 2016 , and December 31, 2015 , $193 million and $0 million within Corporate and Other at December 31, 2016 , and December 31, 2015 , respectively, and $20 million and $0 million within Automotive Finance operations at December 31, 2016 , and December 31, 2015 , respectively. As a result of our acquisition of TradeKing, we recognized $193 million of goodwill within Corporate and Other on June 1, 2016 . On August 1, 2016, we purchased assets from Blue Yield. As a result of this purchase, we recognized $20 million of goodwill within Automotive Finance operations. No other changes in the carrying amount of goodwill were recorded during the year ended December 31, 2016 . (d) Represents credit enhancement in the form of cash reserves for various securitization transactions. (e) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements .

Deposit Liabilities

Deposit Liabilities	12 Months Ended
	Dec. 31, 2016
Deposits [Abstract]
Deposit Liabilities Disclosures [Text Block]	Deposit Liabilities Deposit liabilities consisted of the following. December 31, ( $ in millions ) 2016 2015 Noninterest-bearing deposits $ 84 $ 89 Interest-bearing deposits Savings and money market checking accounts 46,976 36,386 Certificates of deposit 31,795 29,774 Dealer deposits 167 229 Total deposit liabilities $ 79,022 $ 66,478 At December 31, 2016 , and December 31, 2015 , certificates of deposit included $12.1 billion and $11.5 billion , respectively, of certificates of deposit in denominations of $100 thousand or more. At December 31, 2016 , and December 31, 2015 , certificates of deposit included $3.5 billion and $3.2 billion , respectively, in denominations in excess of $250 thousand federal insurance limits. The following table presents the scheduled maturity of total certificates of deposit. ( $ in millions ) Due in 2017 $ 16,206 Due in 2018 9,984 Due in 2019 3,041 Due in 2020 1,348 Due in 2021 1,216 Total certificates of deposit $ 31,795

Debt

Debt	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	Debt Short-term Borrowings The following table presents the composition of our short-term borrowings portfolio. 2016 2015 December 31, ($ in millions) Unsecured Secured (a) Total Unsecured Secured (a) Total Demand notes $ 3,622 $ — $ 3,622 $ 3,369 $ — $ 3,369 Federal Home Loan Bank — 7,875 7,875 — 4,000 4,000 Financial instruments sold under agreements to repurchase — 1,176 1,176 — 648 648 Other — — — 84 — 84 Total short-term borrowings $ 3,622 $ 9,051 $ 12,673 $ 3,453 $ 4,648 $ 8,101 Weighted average interest rate (b) 1.0 % 0.8 % (a) Refer to the section below titled Long-term Debt for further details on assets restricted as collateral for payment of the related debt. (b) Based on the debt outstanding and the interest rate at December 31 of each year. We periodically enter into term repurchase agreements, short-term borrowing agreements in which we sell financial instruments to one or more investors while simultaneously committing to repurchase them at a specified future date, at the stated price plus accrued interest. As of December 31, 2016 , the financial instruments sold under agreement to repurchase consisted of $676 million of mortgage-backed residential securities maturing within 31 to 60 days . For further details refer to Note 8 and Note 26 to the Consolidated Financial Statements . Additionally, the company sold asset-backed automotive financial instruments, which are our retained interests from certain on-balance sheet securitizations, subject to a repurchase agreement set to mature by July 2017 in exchange for $500 million which was recorded as a short-term secured borrowing. The asset-backed automotive financial instruments that we sold subject to the repurchase agreement are secured by finance receivables that we have securitized. Refer to Note 11 to the Consolidated Financial Statements for additional information on our securitization activities. 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. As of December 31, 2016 , we placed cash collateral totaling $45 million with counterparties under these collateral arrangements associated with our repurchase agreements. Long-term Debt The following tables present the composition of our long-term debt portfolio. December 31, ($ in millions) Amount Interest rate Weighted-average interest rate (a) Due date range 2016 Unsecured debt Fixed rate (b) $ 17,155 Variable rate 1 Trust preferred securities 2,568 Fair value adjustment (c) 326 Total unsecured debt 20,050 0.68–8.00% 5.36 % 2017–2049 Secured debt Fixed rate 17,935 Variable rate 16,154 Fair value adjustment (11 ) Total secured debt (d) (e) (f) 34,078 0.63–4.55% 1.53 % 2017–2035 Total long-term debt $ 54,128 2015 Unsecured debt Fixed rate (b) $ 17,657 Variable rate 375 Trust preferred securities 2,600 Fair value adjustment (c) 334 Total unsecured debt 20,966 0.37–8.13% 5.40 % 2016–2049 Secured debt Fixed rate 20,511 Variable rate 24,760 Fair value adjustment (c) (3 ) Total secured debt (d) (e) (f) 45,268 0.48–4.06% 1.18 % 2016–2035 Total long-term debt $ 66,234 (a) Based on the debt outstanding and the interest rate at December 31 of each year excluding any impacts of interest rate hedges. (b) Includes subordinated debt of $1.4 billion and $1.1 billion at December 31, 2016 , and 2015 , respectively. (c) Represents the fair value adjustment associated with the application of hedge accounting on certain of our long-term debt positions. Refer to Note 22 to the Consolidated Financial Statements for additional information. (d) Includes $13.3 billion and $20.3 billion of VIE secured debt at December 31, 2016 , and 2015 , respectively. (e) Includes $14.8 billion and $19.9 billion of debt outstanding from the Automotive secured revolving credit facilities at December 31, 2016 , and 2015 , respectively. (f) Includes advances from the Federal Home Loan Bank of Pittsburgh of $6.1 billion and $ 5.4 billion at December 31, 2016 , and December 31, 2015 , respectively. 2016 2015 December 31, ($ in millions) Unsecured Secured Total Unsecured Secured Total Long-term debt Due within one year $ 4,274 $ 10,279 $ 14,553 $ 1,829 $ 9,427 $ 11,256 Due after one year 15,450 23,810 39,260 18,803 35,844 54,647 Fair value adjustment 326 (11 ) 315 334 (3 ) 331 Total long-term debt $ 20,050 $ 34,078 $ 54,128 $ 20,966 $ 45,268 $ 66,234 The following table presents the scheduled remaining maturity of long-term debt at December 31, 2016 , assuming no early redemptions will occur. The actual payment of secured debt may vary based on the payment activity of the related pledged assets. ($ in millions) 2017 2018 2019 2020 2021 2022 and thereafter Fair value adjustment Total Unsecured Long-term debt $ 4,365 $ 3,700 $ 1,681 $ 2,212 $ 638 $ 8,454 $ 326 $ 21,376 Original issue discount (91 ) (101 ) (39 ) (39 ) (43 ) (1,013 ) — (1,326 ) Total unsecured 4,274 3,599 1,642 2,173 595 7,441 326 20,050 Secured Long-term debt 10,279 8,156 7,334 4,248 2,481 1,591 (11 ) 34,078 Total long-term debt $ 14,553 $ 11,755 $ 8,976 $ 6,421 $ 3,076 $ 9,032 $ 315 $ 54,128 To achieve the desired balance between fixed- and variable-rate debt, we utilize interest rate swap agreements. The use of these derivative financial instruments had the effect of synthetically converting $2.1 billion of our fixed-rate debt into variable-rate obligations and $132 million of our variable-rate debt into fixed-rate obligations at December 31, 2016 . The following summarizes assets restricted as collateral for the payment of the related debt obligation primarily arising from securitization transactions accounted for as secured borrowings and repurchase agreements. 2016 2015 December 31, ($ in millions) Total Ally Bank (a) Total Ally Bank (a) Investment securities (b) $ 4,895 $ 4,231 $ 2,420 $ 1,761 Mortgage assets held-for-investment and lending receivables 10,954 10,954 9,743 9,743 Consumer automotive finance receivables (b) 27,846 5,751 34,324 9,167 Commercial automotive finance receivables 19,487 19,280 19,623 19,177 Investment in operating leases, net 2,040 913 5,539 3,205 Total assets restricted as collateral (c) (d) $ 65,222 $ 41,129 $ 71,649 $ 43,053 Secured debt $ 43,129 (e) $ 22,149 $ 49,916 (e) $ 24,787 (a) Ally Bank is a component of the total column. (b) A portion of the restricted investment securities and consumer automotive finance receivables are 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 $19.0 billion and $14.9 billion at December 31, 2016 , and December 31, 2015 , respectively. These assets were composed primarily of consumer mortgage finance receivables and loans, net, and investment securities. Ally Bank has access to the Federal Reserve Bank Discount Window. Ally Bank had assets pledged and restricted as collateral to the Federal Reserve Bank totaling $2.4 billion and $2.9 billion at December 31, 2016 , and December 31, 2015 , respectively. These assets were composed of consumer automotive finance receivables and loans, net, and investment in operating leases, net. Availability under these programs is only for the operations of Ally Bank and cannot be used to fund the operations or liabilities of Ally or its subsidiaries. (d) Excludes restricted cash and cash reserves for securitization trusts recorded within other assets on the Consolidated Balance Sheet . Refer to Note 14 to the Consolidated Financial Statements for additional information. (e) Includes $9.1 billion and $4.6 billion of short-term borrowings at December 31, 2016 , and December 31, 2015 , respectively. Trust Preferred Securities At December 31, 2016 , we have issued and outstanding approximately $2.6 billion in aggregate liquidation preference of 8.125% Fixed Rate / Floating Rate Trust Preferred Securities, Series 2 (Series 2 TRUPS). Each Series 2 TRUPS security has a liquidation amount of $25. Distributions are cumulative and are payable until redemption at the applicable coupon rate. Distributions were payable at an annual rate of 8.125% payable quarterly in arrears, through but excluding February 15, 2016. From and including February 15, 2016, to but excluding February 15, 2040, distributions will be payable at an annual rate equal to three-month London interbank offer rate plus 5.785% payable quarterly in arrears, beginning May 15, 2016. 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 on or after February 15, 2016, may redeem the Series 2 TRUPS at a redemption price equal to 100% of the principal amount being redeemed, plus accrued and unpaid interest through the date of redemption. The Series 2 TRUPS are generally nonvoting, other than with respect to certain limited matters. During any period in which any Series 2 TRUPS remain outstanding but in which distributions on the Series 2 TRUPS have not been fully paid, none of Ally or its subsidiaries will be permitted to (i) declare or pay dividends on, make any distributions with respect to, or redeem, purchase, acquire or otherwise make a liquidation payment with respect to, any of Ally’s capital stock or make any guarantee payment with respect thereto; or (ii) make any payments of principal, interest, or premium on, or repay, repurchase or redeem, any debt securities or guarantees that rank on a parity with or junior in interest to the Debentures with certain specified exceptions in each case. Covenants and Other Requirements In secured funding transactions, there are trigger events that could cause the debt to be prepaid at an accelerated rate or could cause our usage of the credit facility to be discontinued. The triggers are generally based on the financial health and performance of the servicer as well as performance criteria for the pool of receivables, such as delinquency ratios, loss ratios, and commercial payment rates. During 2016 , there were no trigger events that resulted in the repayment of debt at an accelerated rate or impacted the usage of our credit facilities. In December 2016, we closed a private unsecured committed funding facility that contains covenants requiring us to maintain minimum levels of liquidity and capital. At December 31, 2016, there was no debt outstanding under this facility and we were in compliance with all applicable covenants. This facility was fully drawn in January 2017. Refer to Note 32 for further information. Funding Facilities We utilize both committed credit facilities and other collateralized funding vehicles. The debt outstanding under our various funding facilities is included on our Consolidated Balance Sheet . As of December 31, 2016 , Ally Bank had exclusive access to $3.6 billion of funding capacity from committed credit facilities. Funding programs supported by the Federal Reserve and the FHLB, together with repurchase agreements, complement Ally Bank’s private collateralized funding vehicles. The total capacity in our committed funding facilities is provided by banks through private transactions. The committed secured funding facilities can be revolving in nature and allow for additional funding during the commitment period, or they can be amortizing and not allow for any further funding after the closing date. At December 31, 2016 , $17.5 billion of our $18.4 billion of committed capacity was revolving. Our revolving facilities generally have an original tenor ranging from 364 days to two years. As of December 31, 2016 , we had $14.1 billion of committed funding capacity from revolving facilities with a remaining tenor greater than 364 days. Committed Funding Facilities Outstanding Unused capacity (a) Total capacity December 31, ($ in millions) 2016 2015 2016 2015 2016 2015 Bank funding Secured (b) $ 3,250 $ 3,250 $ 350 $ — $ 3,600 $ 3,250 Parent funding Secured 11,550 16,914 1,975 251 13,525 17,165 Unsecured (c) — — 1,250 — 1,250 — Total committed facilities $ 14,800 $ 20,164 $ 3,575 $ 251 $ 18,375 $ 20,415 (a) Funding from committed secured facilities is available on request in the event excess collateral resides in certain facilities or is available to the extent incremental collateral is available and contributed to the facilities. (b) Excludes off-balance sheet credit facility amounts. (c) This facility was fully drawn in January 2017. Refer to Note 32 for further information.

Accrued Expenses and Other Liab

Accrued Expenses and Other Liabilities	12 Months Ended
	Dec. 31, 2016
Accounts Payable and Accrued Liabilities [Abstract]
Accounts Payable and Accrued Liabilities Disclosure [Text Block]	Accrued Expenses and Other Liabilities The components of accrued expenses and other liabilities were as follows. December 31, ( $ in millions ) 2016 2015 Accounts payable $ 649 $ 391 Employee compensation and benefits 232 242 Reserves for insurance losses and loss adjustment expenses 149 169 Fair value of derivative contracts in payable position (a) 95 145 Deferred revenue 56 108 Cash collateral received from counterparties 10 82 Other liabilities 546 408 Total accrued expenses and other liabilities $ 1,737 $ 1,545 (a) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements .

Equity

Equity	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Stockholders' Equity Note Disclosure [Text Block]	18 . Equity Common Stock In April 2014, we completed an initial public offering (IPO) of our common stock. All proceeds from the offering were obtained by the U.S. Department of the Treasury (Treasury) as the single selling stockholder. In connection with the IPO, we effected a 310 -for-one stock split on shares of our common stock, $0.01 par value per share. Accordingly, all references in the Consolidated Financial Statements to share and per share amounts relating to common stock have been adjusted, on a retroactive basis, to recognize the 310 -for-one stock split. In addition, on April 9, 2014, we increased the number of shares authorized for issuance of common stock to 1.1 billion . The following table presents changes in the number of shares issued and outstanding. Year ended December 31, ( shares in thousands ) (a) 2016 2015 2014 Common stock Total issued, January 1, 482,791 480,136 479,767 New issuances Employee benefits and compensation plans 2,917 2,655 369 Total issued, December 31, 485,708 482,791 480,136 Treasury balance, January 1, (811 ) (41 ) — Repurchase of common stock (b) (c) (17,897 ) (769 ) (41 ) Total treasury stock, December 31, (18,707 ) (811 ) (41 ) Total outstanding, December 31, 467,000 481,980 480,095 (a) Figures in the table may not recalculate exactly due to rounding. Number of shares issued, in treasury, and outstanding are calculated based on unrounded numbers. (b) Includes shares of common stock withheld to cover income taxes owed by participants in our share-based incentive plans. (c) On July 19, 2016, we announced a common stock repurchase program of up to $700 million . The program commenced in the third quarter of 2016 and will expire on June 30, 2017. Preferred Stock Series A Preferred Stock At December 31, 2015 , the carrying value of our Series A Preferred Stock was $696 million and there were 27,870,560 shares outstanding. On April 14, 2016, we issued a Notice of Redemption to the holders of the outstanding Series A Preferred Stock to redeem the remaining 27,870,560 shares at a redemption price of $25 per share, plus approximately $0.53 per share of accrued and unpaid dividends through the redemption date. On May 16, 2016, we redeemed the 27,870,560 outstanding shares of Series A Preferred Stock, with an aggregate liquidation preference of $697 million for $712 million in cash, which included $15 million in accrued and unpaid dividends through the redemption date. Upon redemption of the shares of Series A Preferred Stock, we derecognized the carrying value of $696 million . Effective May 16, 2016, the Series A Preferred Stock was retired.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	12 Months Ended
	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Abstract]
Comprehensive Income (Loss) Note [Text Block]	Accumulated Other Comprehensive Loss The following table presents changes, net of tax, in each component of accumulated other comprehensive loss. ($ in millions) Unrealized (losses) gains on investment securities (a) Translation adjustments and net investment hedges (b) Cash flow hedges (b) Defined benefit pension plans Accumulated other comprehensive loss Balance at January 1, 2014 $ (269 ) $ 65 $ 5 $ (77 ) $ (276 ) 2014 net change 248 (29 ) 2 (11 ) 210 Balance at December 31, 2014 $ (21 ) $ 36 $ 7 $ (88 ) $ (66 ) 2015 net change (138 ) (27 ) 1 (1 ) (165 ) Balance at December 31, 2015 $ (159 ) $ 9 $ 8 $ (89 ) $ (231 ) 2016 net change (114 ) 5 — (1 ) (110 ) Balance at December 31, 2016 $ (273 ) $ 14 $ 8 $ (90 ) $ (341 ) (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 22 to the Consolidated Financial Statements . The following tables present the before- and after-tax changes in each component of accumulated other comprehensive loss. Year ended December 31, 2016 ($ in millions) Before tax Tax effect After tax Investment securities Net unrealized gains arising during the period $ 13 $ 20 $ 33 Less: Net realized gains reclassified to income from continuing operations 185 (a) (38 ) (b) 147 Net change (172 ) 58 (114 ) Translation adjustments Net unrealized gains arising during the period 5 (2 ) 3 Less: Net realized losses reclassified to income from discontinued operations, net of tax (1 ) — (1 ) Net change 6 (2 ) 4 Net investment hedges (c) Net unrealized gains arising during the period 1 — 1 Defined benefit pension plans Net unrealized losses arising during the period (5 ) 2 (3 ) Less: Net realized losses reclassified to income from continuing operations (4 ) (d) 2 (b) (2 ) Net change (1 ) — (1 ) Other comprehensive loss $ (166 ) $ 56 $ (110 ) (a) Includes gains reclassified to other gain on investments, net in our Consolidated Statement of Income . (b) Includes amounts reclassified to income tax expense from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements . (d) Includes gains reclassified to compensation and benefits expense in our Consolidated Statement of Income . Year ended December 31, 2015 ($ in millions) Before tax Tax effect After tax Investment securities Net unrealized losses arising during the period $ (65 ) $ 26 $ (39 ) Less: Net realized gains reclassified to income from continuing operations 155 (a) (56 ) (b) 99 Net change (220 ) 82 (138 ) Translation adjustments Net unrealized losses arising during the period (39 ) 13 (26 ) Less: Net realized gains reclassified to income from discontinued operations, net of tax 42 (20 ) 22 Net change (81 ) 33 (48 ) Net investment hedges (c) Net unrealized gains arising during the period 29 (11 ) 18 Less: Net realized losses reclassified to income from discontinued operations, net of tax (4 ) 1 (3 ) Net change 33 (12 ) 21 Cash flow hedges (c) Net unrealized gains arising during the period 2 (1 ) 1 Defined benefit pension plans Net unrealized gains (losses) arising during the period — — — Less: Net realized gains reclassified to income from continuing operations 1 (d) — (b) 1 Net change (1 ) — (1 ) Other comprehensive loss $ (267 ) $ 102 $ (165 ) (a) Includes gains reclassified to other gain on investments, net in our Consolidated Statement of Income . (b) Includes amounts reclassified to income tax expense from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements . (d) Includes gains reclassified to compensation and benefits expense in our Consolidated Statement of Income . Year ended December 31, 2014 ($ in millions) Before tax Tax effect After tax Investment securities Net unrealized gains arising during the period $ 557 $ (142 ) $ 415 Less: Net realized gains reclassified to income from continuing operations 181 (a) (14 ) (b) 167 Net change 376 (128 ) 248 Translation adjustments Net unrealized losses arising during the period (27 ) 10 (17 ) Less: Net realized gains reclassified to income from discontinued operations, net of tax 23 (3 ) 20 Net change (50 ) 13 (37 ) Net investment hedges (c) Net unrealized gains arising during the period 13 (5 ) 8 Cash flow hedges (c) Net unrealized gains arising during the period 2 — 2 Defined benefit pension plans Net unrealized losses arising during the period (24 ) 9 (15 ) Less: Net realized losses reclassified to income from continuing operations (7 ) (d) 3 (b) (4 ) Net change (17 ) 6 (11 ) Other comprehensive income $ 324 $ (114 ) $ 210 (a) Includes gains reclassified to other gain on investments, net in our Consolidated Statement of Income . (b) Includes amounts reclassified to income tax expense from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements . (d) Includes losses reclassified to compensation and benefits expense in our Consolidated Statement of Income .

Earnings per Common Share

Earnings per Common Share	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	Earnings per Common Share The following table presents the calculation of basic and diluted earnings per common share. Year ended December 31, ( $ in millions, except per share data; shares in thousands ) (a) 2016 2015 2014 Net income from continuing operations $ 1,111 $ 897 $ 925 Preferred stock dividends (b) (30 ) (2,571 ) (268 ) Net income (loss) from continuing operations attributable to common shareholders 1,081 (1,674 ) 657 (Loss) income from discontinued operations, net of tax (44 ) 392 225 Net income (loss) attributable to common shareholders $ 1,037 $ (1,282 ) $ 882 Basic weighted-average common shares outstanding (c) 481,105 482,873 481,155 Diluted weighted-average common shares outstanding (c) (d) 482,182 482,873 481,934 Basic earnings per common share Net income (loss) from continuing operations $ 2.25 $ (3.47 ) $ 1.36 (Loss) income from discontinued operations, net of tax (0.09 ) 0.81 0.47 Net income (loss) $ 2.15 $ (2.66 ) $ 1.83 Diluted earnings per common share Net income (loss) from continuing operations $ 2.24 $ (3.47 ) $ 1.36 (Loss) income from discontinued operations, net of tax (0.09 ) 0.81 0.47 Net income (loss) $ 2.15 $ (2.66 ) $ 1.83 (a) Figures in the table may not recalculate exactly due to rounding. Earnings per share is calculated based on unrounded numbers. (b) Preferred stock dividends for the year ended December 31, 2015 , include $2,364 million recognized in connection with the partial redemption of the Series G Preferred Stock and the repurchase of the Series A Preferred Stock. These dividends represent an additional return to preferred shareholders calculated as the excess consideration paid over the carrying amount derecognized. (c) Includes shares related to share-based compensation that vested but were not yet issued for the years ended December 31, 2016 , 2015 , and 2014 , respectively. (d) Due to the antidilutive effect of the net loss from continuing operations attributable to common shareholders for the year ended December 31, 2015 , basic weighted-average common shares outstanding was used to calculate basic and diluted earnings per share.

Regulatory Capital and Other Re

Regulatory Capital and Other Regulatory Matters	12 Months Ended
	Dec. 31, 2016
Regulatory Capital Requirements [Abstract]
Regulatory Capital Requirements under Banking Regulations [Text Block]	Regulatory Capital and Other Regulatory Matters As a BHC, we and our wholly-owned state-chartered banking subsidiary, 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. A risk-based capital ratio is a ratio of a banking organization’s regulatory capital to its risk-weighted assets. A leverage capital ratio is a ratio of a banking organization’s regulatory capital to a measure of assets or exposures that is not risk-weighted. 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 and certain regulatory capital deductions, will be phased in over several years. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary action by regulators that, if undertaken, could have a direct material effect on the Consolidated Financial Statements or the results of operations and financial condition of Ally and Ally Bank. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, we and Ally Bank must meet specific capital guidelines that involve quantitative measures of capital, assets and certain off-balance sheet items. These measures and related classifications, which are used in the calculation of our risk-based and leverage capital ratios and those of Ally Bank, are also subject to qualitative judgments by the regulators about the components of capital, the risk-weightings of assets and other exposures, and other factors. The U.S. banking regulators also use 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 a FHC, Ally and its bank subsidiary, Ally Bank, must remain “well-capitalized” and “well-managed,” as defined under applicable law. Effective January 1, 2015, the “well-capitalized” standard for insured depository institutions, such as Ally Bank, was revised to reflect the capital requirements under U.S. Basel III. Under U.S. Basel III, Ally 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 requirements, Ally is also subject to a Common Equity Tier 1 capital conservation buffer of more than 2.5% , subject to a phase-in from January 1, 2016 through December 31, 2018. Failure to maintain the full amount of the buffer will result in restrictions on Ally’s ability to make capital distributions, including dividend payment and stock repurchases and redemptions, and to pay discretionary bonuses to executive officers. In addition to these new risk-based capital standards, U.S. Basel III subjects all U.S. banking organizations, including Ally, to a minimum Tier 1 leverage ratio of 4% , the denominator of which takes into account only on-balance sheet assets. 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. Subject to certain exceptions (e.g., for certain debt or equity issued to the U.S. government under the Emergency Economic Stabilization Act), trust preferred and other “hybrid” securities are no longer included in 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 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 shares of unconsolidated financial institutions, mortgage servicing rights, 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 risk-weighted assets by, among other things, modifying certain risk weights and the methods for calculating risk-weighted assets for certain types of assets and exposures. Ally is subject to the U.S. Basel III standardized approach for credit risk. It is not subject to the U.S. Basel III advanced approaches for credit risk. Ally is currently not subject to the U.S. market risk capital rule, which applies only to banking organizations with significant trading assets and liabilities. On March 7, 2016, Ally Bank received approval from the Federal Reserve to become a state member bank. Ally Bank is now regulated by the FRB through the Federal Reserve Bank of Chicago, as well as the Utah Department of Financial Institutions (UDFI). In addition, in connection with the application for membership in the Federal Reserve System, Ally Bank made commitments to the FRB relating to capital, liquidity, and business plan requirements. These commitments are consistent with the prior requirements under the now-terminated Capital and Liquidity Maintenance Agreement with the Federal Deposit Insurance Corporation (FDIC), including the requirement to maintain capital at a level such that Ally Bank’s Tier 1 leverage ratio is at least 15% . For this purpose, the leverage ratio is determined in accordance with the FRB's regulations related to capital maintenance. As a requirement of Federal Reserve membership, we held $435 million of FRB stock at December 31, 2016 . Compliance with capital requirements is a strategic priority for Ally. We expect to be in compliance with all applicable requirements within the established timeframes. The following table summarizes our capital ratios under the U.S. Basel III capital framework. December 31, 2016 December 31, 2015 Required Well-capitalized ( $ in millions ) Amount Ratio Amount Ratio Capital ratios Common Equity Tier 1 (to risk-weighted assets) Ally Financial Inc. $ 12,978 9.37 % $ 12,507 9.21 % 4.50 % (a) Ally Bank 17,888 16.70 16,594 17.05 4.50 6.50 % Tier 1 (to risk-weighted assets) Ally Financial Inc. $ 15,147 10.93 % $ 15,077 11.10 % 6.00 % 6.00 % Ally Bank 17,888 16.70 16,594 17.05 6.00 8.00 Total (to risk-weighted assets) Ally Financial Inc. $ 17,419 12.57 % $ 17,005 12.52 % 8.00 % 10.00 % Ally Bank 18,458 17.24 17,043 17.51 8.00 10.00 Tier 1 leverage (to adjusted quarterly average assets) (b) Ally Financial Inc. $ 15,147 9.54 % $ 15,077 9.73 % 4.00 % (a) Ally Bank 17,888 15.21 16,594 15.38 15.00 (c) 5.00 % (a) Currently, there is no ratio component for determining whether a BHC is "well-capitalized." (b) Federal regulatory reporting guidelines require the calculation of adjusted quarterly average assets using a daily average methodology. (c) Ally Bank has committed to the FRB to maintain a Tier 1 leverage ratio of at least 15% . At December 31, 2016 , Ally and Ally Bank were “well-capitalized” and met all capital requirements to which each was subject. Capital Planning and Stress Tests As a BHC with $50 billion or more of consolidated assets, 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 an annual capital plan to the FRB. Ally’s capital plan must include a description of all planned capital actions over a nine-quarter planning horizon. The capital plan must also include a discussion of how Ally will maintain capital above the minimum regulatory capital ratios under baseline, adverse, and severely adverse economic scenarios, and serve as a source of strength to Ally Bank. The FRB must approve Ally's capital plan before Ally may take any capital action. Even with an approved capital plan, Ally must seek the approval of the FRB before making a capital distribution if, among other factors, Ally would not meet its regulatory capital requirements after making the proposed capital distribution. On April 5, 2016, we submitted the results of our semi-annual stress test and our 2016 annual capital plan to the FRB. On June 23, 2016, we publicly disclosed summary results of the stress test under the most severe scenario in accordance with regulatory requirements. On June 29, 2016, we received a non-objection to our capital plan from the FRB, including the proposed capital actions contained in our submission. The proposed capital actions include a quarterly cash dividend of $0.08 per share of our common stock, subject to quarterly approval by the Board of Directors, and the ability to repurchase up to $700 million of our common stock from time to time through the second quarter of 2017. In addition, we submitted to the FRB the results of our company-run mid-year stress test conducted under multiple macroeconomic scenarios and disclosed the results of this stress test under the most severe scenario on October 5, 2016, in accordance with regulatory requirements. Ally expects to submit its 2017 capital plan by April 5, 2017, with a response expected from the FRB by June 30, 2017. On July 18, 2016, and October 18, 2016, the Ally Board of Directors declared quarterly cash dividend payments of $0.08 per share on all common stock. The dividends were paid on August 15, 2016, and November 15, 2016, respectively, to shareholders of record at the close of business on August 1, 2016, and November 1, 2016, respectively. On January 11, 2017 , the Ally Board of Directors declared another quarterly cash dividend payment of $0.08 per share on all common stock. Refer to Note 32 to the Consolidated Financial Statements for further information regarding this common share dividend. Additionally, the Ally Board of Directors authorized a common stock repurchase program of up to $700 million beginning in the third quarter of 2016 and continuing through the second quarter of 2017. During the second half of 2016, we repurchased $326 million , or 17,043,021 shares of common stock, which reduced total shares outstanding by approximately 3.5% . We had 467,000,306 shares of common stock outstanding at December 31, 2016. In January 2017, the FRB finalized a rule amending the capital planning and stress testing rules, effective for the 2017 cycle. The final rule, among other things, revises the capital plan rule to no longer subject large and noncomplex firms, including Ally, to the provisions of the existing rule whereby the FRB may object to a capital plan on the basis of qualitative deficiencies in the firm’s capital planning process. Under the final rule, the qualitative assessment of Ally’s capital plan will be conducted outside of the Comprehensive Capital Analysis and Review (CCAR) process, through the supervisory review process, and Ally’s reporting requirements will be modified to reduce certain reporting burdens related to capital planning and stress testing. The final rule will also decrease the de minimis threshold for the amount of capital that Ally could distribute to shareholders outside of an approved capital plan without seeking prior approval of the FRB. Depository Institutions Ally Bank is a state member bank, chartered by the State of Utah, and subject to the supervision of the FRB and the UDFI. Ally Bank's deposits are insured by the FDIC, and Ally Bank is required to file periodic reports with the FDIC concerning its financial condition. Total assets of Ally Bank were $123.5 billion and $111.3 billion at December 31, 2016, and 2015, respectively. Ally Bank is subject to Utah law (and, in certain instances, federal law) that places restrictions and limitations on the amount of dividends or other distributions. Dividends or other distributions made by Ally Bank to Ally were $525 million in 2015. No dividends were paid in 2016. The FRB requires banks to maintain minimum average reserve balances. The amount of the required reserve balance for Ally Bank was $149 million and $216 million at December 31, 2016, and 2015, respectively. Ally Bank is required to satisfy regulatory net worth requirements. Failure to meet minimum capital requirements can initiate certain mandatory actions by federal, state, and foreign agencies that could have a material effect on our results of operations and financial condition. Ally Bank was in compliance with these requirements at December 31, 2016. Mortgage Operations Our mortgage business is subject to extensive federal, state, and local laws, rules, and regulations, in addition to judicial and administrative decisions that impose requirements and restrictions on this business. The mortgage business is also subject to examination by the Federal Housing Commissioner to assure compliance with Federal Housing Administration regulations, policies, and procedures. The federal, state, and local laws, rules, and regulations to which our mortgage business is subject, among other things, impose licensing obligations and financial requirements; limit the interest rates, finance charges, and other fees that can be charged; regulate the use of credit reports and the reporting of credit information; impose underwriting requirements; regulate marketing techniques and practices; require the safeguarding of nonpublic information about customers; and regulate servicing practices, including the assessment, collection, foreclosure, claims handling, and investment of interest payments on escrow accounts. Insurance Companies Some of our Insurance companies are subject to certain minimum aggregate capital requirements, net asset and dividend restrictions under applicable state and foreign insurance law, and the rules and regulations promulgated by various U.S. and foreign regulatory agencies. Under various state and foreign insurance regulations, dividend distributions may be made only from statutory unassigned surplus, with approvals required from the regulatory authorities for dividends in excess of certain statutory limitations. At December 31, 2016, the maximum dividend that could be paid by the U.S. insurance subsidiaries over the next twelve months without prior statutory approval was $75 million .

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities Disclosure [Text Block]	Derivative Instruments and Hedging Activities We enter into interest rate, foreign-currency, and equity swaps, futures, forwards, options, and swaptions in connection with our market risk management activities. Derivative instruments are used to manage interest rate risk relating to specific groups of assets and liabilities, including automotive loan assets and debt. We use foreign exchange contracts to mitigate foreign-currency risk associated with foreign-currency-denominated debt, foreign exchange transactions, and our net investment in foreign subsidiaries. In addition, we also enter into equity option contracts to manage our exposure to the equity markets. 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 market risks related to our investment portfolio and certain of our executive share-based compensation plans. Interest Rate Risk We monitor our mix of fixed- and variable-rate assets and liabilities. When it is cost-effective to do so, we 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 interest rate swaps, forwards, futures, options, and swaptions 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 consist of 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 and pay-fixed swaps designated as fair value hedges of specific portfolios of fixed-rate held-for-investment retail automotive loan assets. We also execute economic hedges, which consist of interest rate swaps and interest rate caps held to mitigate interest rate risk associated with our debt portfolio. We also use interest rate swaps to economically hedge our net fixed-versus-variable interest rate exposure. We enter into economic hedges in the form of short-dated, exchange-traded Eurodollar futures to hedge the interest rate exposure of our fixed-rate automotive loans, as well as forwards, options, and swaptions to economically hedge our net fixed-versus-variable interest rate exposure. 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 investments 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 enter into foreign-currency forwards to economically hedge our foreign-denominated debt, our centralized lending program, and foreign-denominated third-party loans. These forward 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. We utilized a cross-currency swap to economically hedge foreign exchange exposure on foreign-currency-denominated debt by converting the funding currency to our functional currency. This swap matured during the second quarter of 2015. Market Risk We enter into equity options to economically hedge our exposure to the equity markets. We purchase options to assume a long position on certain equities and write options to assume a short position. We also enter into prepaid equity forward contracts to economically hedge the price risk associated with certain of our executive share-based compensation plans. The prepaid equity forward contracts are hybrid instruments containing an embedded forward contract, which is considered a derivative instrument. The embedded derivative instrument is bifurcated from the host contract and is recorded at fair value with changes in fair value recorded in compensation and benefits expense. The balance of the prepaid component of these equity forward contracts was $0 million and $32 million as of December 31, 2016 , and 2015, respectively, and was recorded within other assets on the Consolidated Balance Sheet . During the fourth quarter of 2016, the hedging program of the executive share-based compensation plans was fully terminated. 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. To mitigate the risk of counterparty default, we maintain collateral agreements with certain counterparties. The agreements require both parties to post collateral in the event the fair values of the derivative financial instruments meet posting thresholds established under the agreements. In the event that either party defaults on the obligation, the secured party may seize the collateral. Generally, our collateral arrangements are bilateral such that we and the counterparty post collateral for the value of our total obligation to each other. Contractual terms provide for standard and customary exchange of collateral based on changes in the market value of the outstanding derivatives. The securing party posts additional collateral when their obligation rises or removes collateral when it falls. Certain derivative instruments contain provisions that require us to either post additional collateral or immediately settle any outstanding liability balances upon the occurrence of a specified credit risk-related event. No such specified credit risk related events occurred during the years ended December 31, 2016, and 2015. We placed cash collateral totaling $122 million and securities collateral totaling $72 million at December 31, 2016 , and $103 million and $86 million at December 31, 2015 , respectively, in accounts maintained by counterparties. This amount primarily relates to collateral posted to support our derivative positions. This amount also excludes cash and securities pledged as collateral under repurchase agreements. At December 31, 2016 , and December 31, 2015 , we placed cash collateral totaling $45 million and $21 million , respectively, with counterparties under collateral arrangements associated with repurchase agreements. Refer to Note 16 to the Consolidated Financial Statements for details on the repurchase agreements. The receivables for cash collateral placed are included in our Consolidated Balance Sheet in other assets. We received cash collateral from counterparties totaling $10 million and $82 million at December 31, 2016, and 2015, respectively, primarily to support these derivative positions. This amount also excludes cash and securities pledged as collateral under repurchase agreements. Refer to Note 16 to the Consolidated Financial Statements for details on the repurchase agreements. The payables for cash collateral received are included on our Consolidated Balance Sheet in accrued expenses and other liabilities. In certain circumstances, we receive or post securities as collateral with counterparties. We do not record collateral received on our Consolidated Balance Sheet unless certain conditions are met. At December 31, 2016 , and December 31, 2015 , we received noncash collateral of $6 million and $7 million , respectively. Included in these amounts is noncash collateral where we have been granted the right to sell or pledge the underlying assets. We have not sold or pledged any of the noncash collateral received under these agreements. Balance Sheet Presentation The following table summarizes the fair value amounts of derivative instruments reported on our Consolidated Balance Sheet . The fair value amounts are presented on a gross basis, are segregated by derivatives that are designated and qualifying as hedging instruments or those that are not, and are further segregated by type of contract within those two categories. Notional amounts are reference amounts from which contractual obligations are derived and are not recorded on the balance sheet. In our view, derivative notional is not an accurate measure of our derivative exposure when viewed in isolation from other factors, such as market rate fluctuations and counterparty credit risk. 2016 2015 Derivative contracts in a Notional Derivative contracts in a Notional December 31, ($ in millions) receivable payable receivable payable Derivatives designated as accounting hedges Interest rate contracts Swaps (c) (d) (e) $ 19 $ 21 $ 4,731 $ 126 $ 9 $ 14,151 Foreign exchange contracts Forwards 1 — 171 — 1 189 Total derivatives designated as accounting hedges 20 21 4,902 126 10 14,340 Derivatives not designated as accounting hedges Interest rate contracts Swaps — — 137 30 51 6,101 Futures and forwards — — — 2 2 1,905 Written options — 73 14,518 — 72 18,220 Purchased options 73 — 14,517 73 — 18,240 Total interest rate risk 73 73 29,172 105 125 44,466 Foreign exchange contracts Futures and forwards 1 — 92 — — 278 Total foreign exchange risk 1 — 92 — — 278 Equity contracts Forwards — — — — 9 32 Written options — 1 — — 1 — Purchased options 1 — — 2 — — Total equity risk 1 1 — 2 10 32 Total derivatives not designated as accounting hedges 75 74 29,264 107 135 44,776 Total derivatives $ 95 $ 95 $ 34,166 $ 233 $ 145 $ 59,116 (a) Derivative contracts in a receivable position are classified as other assets on the Consolidated Balance Sheet , and include accrued interest of $7 million and $46 million at December 31, 2016 , and December 31, 2015 , respectively. (b) Derivative contracts in a liability position are classified as accrued expenses and other liabilities on the Consolidated Balance Sheet , and include accrued interest of $1 million and $12 million at December 31, 2016 , and December 31, 2015 , respectively. (c) Includes fair value hedges consisting of receive-fixed swaps on fixed-rate unsecured debt obligations with $8 million and $112 million in a receivable position, $14 million and $3 million in a payable position, and a $1.7 billion and $6.8 billion notional amount at December 31, 2016 , and December 31, 2015 , respectively. The hedge notional amount of $1.7 billion at December 31, 2016 , is associated with debt maturing in five or more years. (d) Includes fair value hedges consisting of receive-fixed swaps on fixed-rate secured debt obligations (FHLB Advances) with $0 million and $1 million in a receivable position, $7 million and $2 million in a payable position, and a $240 million and $500 million notional amount at December 31, 2016 , and December 31, 2015 , respectively. (e) Other fair value hedges include pay-fixed swaps on portfolios of held-for-investment automotive loan assets with $10 million and $13 million in a receivable position, $1 million and $3 million in a payable position, and a $2.8 billion and $6.8 billion notional amount at December 31, 2016 , and December 31, 2015 , respectively. Statement of Comprehensive Income Presentation The following table summarizes the location and amounts of gains and losses on derivative instruments reported in our Consolidated Statement of Income . Year ended December 31, ( $ in millions ) 2016 2015 2014 Derivatives qualifying for hedge accounting (Loss) gain recognized in earnings on derivatives Interest rate contracts Interest and fees on finance receivables and loans (a) $ (2 ) $ (9 ) $ 15 Interest on long-term debt (b) (c) 65 35 199 Gain (loss) recognized in earnings on hedged items Interest rate contracts Interest and fees on finance receivables and loans (d) — 39 34 Interest on long-term debt (e) (70 ) (30 ) (185 ) Total derivatives qualifying for hedge accounting (7 ) 35 63 Derivatives not designated as accounting hedges (Loss) gain recognized in earnings on derivatives Interest rate contracts Loss on mortgage and automotive loans, net — (2 ) — Other income, net of losses — (17 ) (37 ) Total interest rate contracts — (19 ) (37 ) Foreign exchange contracts (f) Interest on long-term debt (2 ) (139 ) (172 ) Other income, net of losses 1 12 12 Total foreign exchange contracts (1 ) (127 ) (160 ) Equity contracts Compensation and benefits expense — (10 ) (5 ) Total equity contracts — (10 ) (5 ) Loss recognized in earnings on derivatives $ (8 ) $ (121 ) $ (139 ) (a) Amounts exclude losses related to interest for qualifying accounting hedges of retail automotive loans held-for-investment, which are primarily offset by the fixed coupon payments of the loans. The losses were $18 million , $64 million , and $61 million for the years ended December 31, 2016 , 2015 , and 2014 respectively. (b) Amounts exclude gains related to interest for qualifying accounting hedges of unsecured debt, which are primarily offset by the fixed coupon payment on the long-term debt. The gains were $40 million , $97 million , and $112 million and for the years ended December 31, 2016 , 2015 , and 2014, respectively. (c) Amounts exclude gains related to interest for qualifying accounting hedges of secured debt (FHLB Advances), which are primarily offset by the fixed coupon payment on the long-term debt. The gains were $5 million and $1 million for the years ended December 31, 2016 , and 2015 , respectively. (d) Amounts exclude losses related to amortization of deferred loan basis adjustments on the de-designated hedged item of $20 million and $8 million for the year ended December 31, 2016 , and 2015 , respectively. (e) Amounts exclude gains related to amortization of deferred debt basis adjustments on the de-designated hedged item of $84 million , $73 million , and $155 million for the years ended December 31, 2016 , 2015 , and 2014 respectively. (f) Amounts exclude gains and losses related to the revaluation of the related foreign-denominated debt or receivable. Gains of $0 million , $132 million , and $165 million were recognized for the years ended December 31, 2016 , 2015 , and 2014, respectively. The following table summarizes derivative instruments used in cash flow and net investment hedge accounting relationships. Year ended December 31, ( $ in millions ) 2016 2015 2014 Cash flow hedges Interest rate contracts Loss reclassified from accumulated other comprehensive loss to interest on long-term debt $ — $ — $ (2 ) Total interest on long-term debt $ — $ — $ (2 ) Gain recognized in other comprehensive loss $ — $ 2 $ 2 Net investment hedges Foreign exchange contracts Loss reclassified from accumulated other comprehensive loss to income from discontinued operations, net $ — $ (4 ) $ — Total loss from discontinued operations, net $ — $ (4 ) $ — Gain recognized in other comprehensive loss (a) $ 1 $ 33 $ 13 (a) The amounts represent the effective portion of net investment hedges. There are offsetting amounts recognized in accumulated other comprehensive loss related to the revaluation of the related net investment in foreign operations, including the tax impacts of the hedge and related net investment, as disclosed separately in Note 19 to the Consolidated Financial Statements . There were gains of $4 million for the year ended December 31, 2016 , and losses of $59 million , and $41 million for the years ended December 31, 2015 , and 2014, respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	Income Taxes The significant components of income tax expense from continuing operations were as follows. Year ended December 31, ( $ in millions ) 2016 2015 2014 Current income tax expense U.S. federal $ — $ — $ (3 ) Foreign 8 6 8 State and local 9 3 5 Total current expense 17 9 10 Deferred income tax expense U.S. federal 423 454 270 Foreign — 1 2 State and local 30 32 39 Total deferred expense 453 487 311 Total income tax expense from continuing operations $ 470 $ 496 $ 321 A reconciliation of income tax expense from continuing operations with the amounts at the statutory U.S. federal income tax rate is shown in the following table. Year ended December 31, ( $ in millions ) 2016 2015 2014 Statutory U.S. federal tax expense $ 553 $ 488 $ 436 Change in tax resulting from Changes in unrecognized tax benefits (a) (161 ) (5 ) (63 ) Valuation allowance change, excluding expirations 51 (25 ) (47 ) State and local income taxes, net of federal income tax benefit 35 38 48 Tax credits, excluding expirations (15 ) (13 ) (27 ) Nondeductible expenses 7 14 31 Tax law enactment — — (39 ) Other, net — (1 ) (18 ) Total income tax expense from continuing operations $ 470 $ 496 $ 321 (a) Primarily the result of a Q2 2016 U.S. tax reserve release related to a prior year federal return. For the tax year ended December 31, 2016, consolidated income tax expense from continuing operations is largely driven by tax attributable to pretax earnings for the year and the establishment of a valuation allowance on capital loss carryforwards, offset by a reduction in the liability for unrecognized tax benefits that resulted from the completion of a U.S. federal audit related to a prior tax year. For the year ended December 31, 2015, consolidated income tax expense from continuing operations is largely driven by tax attributable to pretax earnings for the year, offset by tax benefits recognized from the release of our valuation allowance on capital loss carryforwards utilized against current year capital gains. For the year ended December 31, 2014, consolidated income tax expense from continuing operations was largely driven by tax attributable to pretax earnings for the year, offset by tax benefits recognized from the release of a portion of our valuation allowance on capital loss carryforwards utilized against 2014 capital gains, a reduction in the liability for unrecognized tax benefits that resulted from the completion of the U.S. federal audit related to our 2009 tax year, and the reinstatement of the active financing exception included in the Tax Increase Prevention Act of 2014. 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 credits, state net operating loss carryforwards, and state capital 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. Finally, as a result of the U.S. tax reserve release, we recorded additional capital loss carryforward deferred tax assets. After assessing the positive and negative evidence surrounding our ability to realize these carryforwards before expiration, we established a full valuation allowance against these deferred tax assets. The significant components of deferred tax assets and liabilities are reflected in the following table. December 31, ( $ in millions ) 2016 2015 Deferred tax assets Tax credit carryforwards $ 1,987 $ 1,941 Tax loss carryforwards 936 950 Adjustments to loan value 546 311 State and local taxes 162 194 Unearned insurance premiums 141 141 Hedging transactions 123 99 Other 208 212 Gross deferred tax assets 4,103 3,848 Valuation allowance (646 ) (582 ) Deferred tax assets, net of valuation allowance 3,457 3,266 Deferred tax liabilities Lease transactions 1,789 1,273 Deferred acquisition costs 424 403 Debt transactions 161 162 Other 107 69 Gross deferred tax liabilities 2,481 1,907 Net deferred tax assets (a) $ 976 $ 1,359 (a) Total net deferred tax assets include $994 million and $1,369 million of net deferred tax assets included in other assets on our Consolidated Balance Sheet for tax jurisdictions in a total net deferred tax asset position and $18 million and $10 million included in accrued expenses and other liabilities on our Consolidated Balance Sheet for tax jurisdictions in a total net deferred tax liability position at December 31, 2016, and 2015, respectively. The following table summarizes net deferred tax assets including related valuation allowances at December 31, 2016. ( $ in millions ) Deferred tax asset/(liability) Valuation allowance Net deferred tax asset/(liability) Years of expiration Tax credit carryforwards Foreign tax credits $ 1,771 $ (485 ) $ 1,286 2017–2026 General business credits 191 — 191 2023–2036 Alternative minimum tax (AMT) credits 25 — 25 n/a Total tax credit carryforwards 1,987 (485 ) 1,502 Tax loss carryforwards Net operating losses — federal 900 — 900 2027–2036 Net operating losses — state 193 (a) (83 ) 110 2017–2036 Capital losses — federal 36 (36 ) — 2017 Capital losses — state 9 (a) (9 ) — 2017–2027 Total tax loss carryforwards 1,138 (128 ) 1,010 Other deferred tax assets 978 (33 ) 945 n/a Deferred tax assets 4,103 (646 ) 3,457 Deferred tax liabilities (2,481 ) — (2,481 ) n/a Net deferred tax assets $ 1,622 $ (646 ) $ 976 (a) State net operating loss and capital loss carryforwards are included in the state and local taxes total disclosed in our deferred inventory table above. As of December 31, 2016, we do not assert that foreign earnings are indefinitely reinvested outside of the United States. As a result, deferred tax liabilities for incremental U.S. tax that stem from temporary differences related to investments in foreign subsidiaries or foreign corporate joint ventures have been recognized as of December 31, 2016. The following table provides a reconciliation of the beginning and ending amount of unrecognized tax benefits. ( $ in millions ) 2016 2015 2014 Balance at January 1, $ 185 $ 191 $ 262 Additions based on tax positions related to the current year — — — Additions for tax positions of prior years 12 7 9 Settlements (182 ) (10 ) (79 ) Expiration of statute of limitations (1 ) (3 ) (1 ) Balance at December 31, $ 14 $ 185 $ 191 Included in the unrecognized tax benefits balances are some items, the recognition of which would not affect the effective tax rate, such as the tax effect of certain temporary differences and the portion of gross state unrecognized tax benefits that would be offset by the tax benefit of the associated federal deduction. At December 31, 2016, 2015, and 2014, the balance of unrecognized tax benefits that, if recognized, would affect our effective tax rate is $9 million , $177 million , and $182 million , respectively. We recognize accrued interest and penalties related to uncertain income tax positions in interest expense and other operating expenses, respectively. The cumulative accrued balance for interest and penalties is $1 million at December 31, 2016, $2 million at December 31, 2015, and $5 million at December 31, 2014. For each of the years ended December 31, 2016, 2015, and 2014, interest and penalties of $1 million or less were accrued. It is reasonably possible that the unrecognized tax benefits will decrease by up to $3 million over the next twelve months if certain tax matters ultimately settle with the applicable taxing jurisdiction. We file tax returns in the U.S. federal jurisdiction and various states and foreign jurisdictions. Our most significant operations remaining following our divestitures of various international operations are the U.S. and Canada. The oldest tax years that remain subject to examination for those jurisdictions are 2012 and 2011, respectively.

Share-based Compensation Plans

Share-based Compensation Plans Share-based Compensation Plans	12 Months Ended
	Dec. 31, 2016
Share-based Compensation Plans [Abstract]
Compensation and Employee Benefit Plans [Text Block]	Share-based Compensation Plans On December 24, 2014, as a result of Treasury completing the sale of all of its remaining shares in Ally's common stock, Ally exited the Troubled Asset Relief Program (TARP), which required us to comply with certain limitations on executive pay as determined by the Special Master of TARP Compensation (Special Master). Under TARP we established stock salary, or Deferred Stock Units (DSUs), and TARP Stock, or Incentive Restricted Stock Units (IRSUs), as forms of compensation to our senior executives, which were approved by the Special Master. During 2015, we discontinued granting DSU and IRSU awards to senior executives. We also grant Restricted Stock Units (RSUs) and Performance Share Awards (PSU) to executives under the Ally Financial 2014 Incentive Compensation Plan, which allows us to grant an array of equity-based and cash incentive awards to our named executive officers and other employees. Each of our approved compensation plans and awards were designed to provide our executives with an opportunity to share in the future growth in the value of Ally, which is necessary to attract and retain key executives. Prior to our IPO in April 2014, all share-based awards were settled in cash and required liability treatment under the accounting guidance. Accounting treatment for liability-classified awards requires compensation expense to be adjusted each period until the awards are settled based on the value of the underlying share price. Prior to IPO, the Ally Board of Directors was required to determine a share price valuation (Share Price Valuation) for share-based compensation awards not less than annually. The Share Price Valuation considered, among other things, the stock price performance, on an indexed basis, of publicly traded common stock issued by certain comparative companies and considered Ally’s common stock as if it were freely tradable in the public markets. After the IPO, the share price valuation is based on the trading price for our stock. Also, after the IPO, certain awards will be settled in Ally common stock. As a result, these awards will be accounted for as equity awards under the accounting guidance. For equity-classified awards, the compensation expense to be recognized over the vesting and service period is determined on the grant date. For valuation purposes, we utilize Ally’s share price as of the grant date and the end of each reporting period for determining the necessary share-based compensation expense, depending on the classification of the awards. The per-share fair value based on market price for purposes of share-based compensation was $19.02 as of December 31, 2016 . We had 32,921,120 shares authorized and available for future grants of incentive-based equity awards at December 31, 2016 . During 2016, 2015, and 2014, we entered into prepaid equity forward contracts to economically hedge a portion of the price risk driven by fluctuations in the fair value of our DSU and IRSU awards. The prepaid equity forward contracts are hybrid instruments containing an embedded forward contract, which is considered a derivative instrument. The embedded derivative instrument is bifurcated from the host contract and is recorded at fair value with changes in fair value recorded as compensation and benefits expense in our Consolidated Statement of Income . During the fourth quarter of 2016, the hedging program of the executive share-based compensation plans was fully terminated. For further information on our derivative instruments, refer to Note 22 to the Consolidated Financial Statements . PSU and RSU Awards PSU awards are payable contingent upon Ally achieving certain predefined performance objectives over the two-year measurement period and a three-year service condition. The PSU awards settle in the form of Ally common stock. The per-share fair value of these awards is determined by Ally's closing stock price on the grant date. RSU awards are incentive awards that have been granted to employees as phantom shares of Ally at no cost to the recipient upon their grant. Prior to our IPO, these awards were paid in cash. As a result, RSU awards required liability treatment and were remeasured quarterly at the Share Price Valuation until they were paid. The compensation costs related to these awards were ratably charged to expense over the applicable service period. Changes in the value related to the portion of the awards that had vested and had not been paid were recognized in earnings in the period in which the changes occurred. After the IPO, the majority of existing RSU awards settle in the form of Ally common stock, which changed the award classification from a liability award to an equity award. As a result of this classification change, a modification to the accounting for the existing awards was required. As part of the modification, the stock closing price on the date of the IPO (April 10, 2014) of $23.98 was used as the modification date value. The remaining RSU cost for these awards, based on the modification date value, was ratably charged to expense over the applicable service periods with an offset to additional paid-in capital. RSU awards granted in 2015, 2014, and 2013 generally vest ratably over a two-year period starting on the date the award was issued and convert into shares of common stock at the end of the two-year period. RSU awards granted in 2016 generally vest one third ratably each year over a three-year period starting on the date the award was issued and are converted into shares of common stock as of the vesting date. At December 31, 2016 , there were a total of 7,307,246 PSU and RSU award shares outstanding, composed of 253,461 shares awarded during 2014 , 3,687,361 shares awarded during 2015 , and 3,366,424 shares awarded during 2016 . At December 31, 2015 , there were a total of 6,476,427 RSU award shares outstanding, composed of 254,150 shares awarded during 2013 , 1,691,509 shares awarded during 2014 , and 4,530,768 shares awarded during 2015 . We recognized expense related to PSU and RSU awards of $54 million , $49 million , and $46 million , for the years ended December 31, 2016 , 2015 , and 2014 , respectively. These costs were recorded as compensation and benefits expense in our Consolidated Statement of Income . DSU Awards We discontinued granting DSU awards in 2015. DSU awards were generally granted to senior executives as phantom shares of Ally and were included as part of their base salary. DSU awards were commonly granted ratably each pay period throughout the year, vested immediately upon grant, and paid in cash. DSUs awarded in 2015 and 2014 will generally be redeemable in three equal installments: the first on the final payroll date of the respective year of grant, the second ratably over the first year following the grant date, and the third ratably over the second year following the grant date. The DSU awards require liability treatment and are remeasured monthly at fair value based on market price until they are paid, with each change in value fully charged to compensation expense in the period in which the change occurs. At December 31, 2016 , and December 31, 2015 , there were a total of 356,979 and 1,395,105 DSU awards outstanding, respectively. We recognized a reduction of expense related to DSU awards, before economic hedge, of $1 million for the year ended December 31, 2016 , and expense, before economic hedge, of $3 million , and $42 million for the years ended December 31, 2015 , and 2014 , respectively, for the outstanding awards. These costs were recorded as compensation and benefits expense in our Consolidated Statement of Income . For further information on our derivative instruments, refer to Note 22 to the Consolidated Financial Statements . IRSU Awards We discontinued granting IRSU awards in 2015. IRSU awards were incentive awards that had been granted to senior executives as phantom shares of Ally and vested based on continued service with Ally. The awards were paid in cash after the vesting requirements were met. Payouts were based on fair value of Ally shares at the time of the payout. The awards required liability treatment and were remeasured monthly at fair value based on market price until they were paid. The compensation costs related to these awards were ratably charged to expense over the requisite service period. Changes in value related to the portion of the awards that were vested and had not been paid were recognized in earnings in the period in which the changes occurred. As of December 31, 2016, all IRSU awards granted had fully vested and been paid. At December 31, 2015 , there were a total of 51,103 IRSU award shares outstanding. We recognized an expense related to IRSU awards, before economic hedge, of $0 million and $1 million for the years ended December 31, 2016 , and 2015 , respectively, and a reduction of expense, before economic hedge, of $2 million for the year ended December 31, 2014 , for the outstanding awards. These costs were recorded as compensation and benefits expense in our Consolidated Statement of Income . For further information on our derivative instruments, refer to Note 22 to the Consolidated Financial Statements .

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Disclosures [Text Block]	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. 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. Transfers Transfers into or out of any hierarchy level are recognized at the end of the reporting period in which the transfer occurred. There were no transfers between any levels for the year ended December 31, 2016 . 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. • 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 over-the-counter (OTC) and centrally-cleared derivative contracts, such as interest rate swaps, a cross-currency swap, swaptions, foreign-currency denominated forward contracts, prepaid equity forward contracts, caps, floors, and agency to-be-announced securities. For OTC contracts, we utilize third-party-developed valuation models that are widely accepted in the market to value these OTC 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 OTC derivative contracts as Level 2 because all significant inputs into these models were market observable. For centrally-cleared contracts, we utilize unadjusted prices obtained from the clearing house as the basis for valuation, and they are also classified as Level 2. We did not have any derivative instruments classified as Level 3 as of December 31, 2016 , or December 31, 2015 . We are required to consider all aspects of nonperformance risk, including our own credit standing, when measuring fair value of a liability. We reduce credit risk on the majority of our derivatives by entering into legally enforceable agreements that enable the posting and receiving of collateral associated with the fair value of our derivative positions on an ongoing basis. In the event that we do not enter into legally enforceable agreements that enable the posting and receiving of collateral, we will consider our credit risk and the credit risk of our counterparties in the valuation of derivative instruments through a credit valuation adjustment (CVA), if warranted. The CVA calculation utilizes the credit default swap spreads of the counterparty. Recurring Fair Value The following tables display the assets and liabilities measured at fair value on a recurring basis including financial instruments elected for the fair value option. We often economically hedge the fair value change of our assets or liabilities with derivatives and other financial instruments. The tables below display the hedges separately from the hedged items; therefore, they do not directly display the impact of our risk management activities. Recurring fair value measurements December 31, 2016 ($ in millions) Level 1 Level 2 Level 3 Total Assets Investment securities Available-for-sale securities Debt securities U.S. Treasury and federal agencies $ 1,620 $ — $ — $ 1,620 U.S. States and political subdivisions — 782 — 782 Foreign government 11 151 — 162 Agency mortgage-backed residential — 10,290 — 10,290 Mortgage-backed residential — 2,097 — 2,097 Mortgage-backed commercial — 537 — 537 Asset-backed — 1,400 — 1,400 Corporate debt — 1,443 — 1,443 Total debt securities 1,631 16,700 — 18,331 Equity securities (a) 595 — — 595 Total available-for-sale securities 2,226 16,700 — 18,926 Other assets Interests retained in financial asset sales — — 29 29 Derivative contracts in a receivable position (b) Interest rate — 92 — 92 Foreign currency — 2 — 2 Other 1 — — 1 Total derivative contracts in a receivable position 1 94 — 95 Total assets $ 2,227 $ 16,794 $ 29 $ 19,050 Liabilities Accrued expenses and other liabilities Derivative contracts in a payable position (b) Interest rate $ — $ (94 ) $ — $ (94 ) Other (1 ) — — (1 ) Total derivative contracts in a payable position (1 ) (94 ) — (95 ) Total liabilities $ (1 ) $ (94 ) $ — $ (95 ) (a) Our investment in any one industry did not exceed 14% . (b) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements . Recurring fair value measurements December 31, 2015 ($ in millions) Level 1 Level 2 Level 3 Total Assets Investment securities Available-for-sale securities Debt securities U.S. Treasury and federal agencies $ 1,469 $ 272 $ — $ 1,741 U.S. States and political subdivisions — 716 — 716 Foreign government 10 167 — 177 Agency mortgage-backed residential — 7,544 — 7,544 Mortgage-backed residential — 2,822 — 2,822 Mortgage-backed commercial — 481 — 481 Asset-backed — 1,755 — 1,755 Corporate debt — 1,204 — 1,204 Total debt securities 1,479 14,961 — 16,440 Equity securities (a) 717 — — 717 Total available-for-sale securities 2,196 14,961 — 17,157 Other assets Interests retained in financial asset sales — — 40 40 Derivative contracts in a receivable position (b) Interest rate 2 229 — 231 Other 2 — — 2 Total derivative contracts in a receivable position 4 229 — 233 Total assets $ 2,200 $ 15,190 $ 40 $ 17,430 Liabilities Accrued expenses and other liabilities Derivative contracts in a payable position (b) Interest rate $ (2 ) $ (133 ) $ — $ (135 ) Foreign currency — (1 ) — (1 ) Other (1 ) (8 ) — (9 ) Total derivative contracts in a payable position (3 ) (142 ) — (145 ) Total liabilities $ (3 ) $ (142 ) $ — $ (145 ) (a) Our investment in any one industry did not exceed 14% . (b) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements . The following tables present the reconciliation for all Level 3 assets and liabilities measured at fair value on a recurring basis. 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 Fair value at Net unrealized gains included in earnings ($ in millions) Fair value at Jan. 1, 2016 included in earnings included in OCI Purchases Sales Issuances Settlements Assets Other assets Interests retained in financial asset sales $ 40 $ 4 (a) $ — $ — $ 9 $ — $ (24 ) $ 29 $ — Total assets $ 40 $ 4 $ — $ — $ 9 $ — $ (24 ) $ 29 $ — (a) Reported as other income, net of losses, in the Consolidated Statement of Income . Level 3 recurring fair value measurements Fair value at Jan. 1, 2015 Net realized/unrealized Purchases Sales Issuances Settlements Fair value at Net unrealized gains included in earnings ($ in millions) included in earnings included in OCI Assets Mortgage loans held-for-sale, net $ 3 $ 1 $ — $ — $ (4 ) $ — $ — $ — $ — Other assets Interests retained in financial asset sales 47 9 (a) — — — 26 (42 ) 40 — Total assets $ 50 $ 10 $ — $ — $ (4 ) $ 26 $ (42 ) $ 40 $ — (a) Reported as other income, net of losses, in the Consolidated Statement of Income . Nonrecurring Fair Value We may be required to measure certain assets and liabilities at fair value from time to time. These periodic fair value measures typically result from the application of lower-of-cost or fair value accounting or certain impairment measures. These items would constitute nonrecurring fair value measures. The following tables display the assets and liabilities measured at fair value on a nonrecurring basis. Nonrecurring Lower-of-cost or Total (loss)gain included in earnings for the year ended December 31, 2016 ($ in millions) Level 1 Level 2 Level 3 Total Assets Commercial finance receivables and loans, net (a) Commercial and industrial Automotive $ — $ — $ 27 $ 27 $ (4 ) n/m (b) Other — — 65 65 (19 ) n/m (b) Total commercial finance receivables and loans, net — — 92 92 (23 ) n/m (b) Other assets Repossessed and foreclosed assets (c) — — 12 12 (4 ) n/m (b) Other — — 4 4 — n/m (b) Total assets $ — $ — $ 108 $ 108 $ (27 ) n/m n/m = not meaningful (a) Represents the portion of the portfolio specifically impaired during 2016 . The related valuation allowance represents the cumulative adjustment to fair value of those specific receivables. (b) We consider the applicable valuation or loan loss allowance to be the most relevant indicator of the impact on earnings caused by the fair value measurement. Accordingly, the table above excludes total gains and losses included in earnings for these items. The carrying values are inclusive of the respective valuation or loan loss allowance. (c) The allowance provided for repossessed and foreclosed assets represents any cumulative valuation adjustment recognized to adjust the assets to fair value. Nonrecurring Lower-of-cost or Total loss included in earnings for the year ended December 31, 2015 ($ in millions) Level 1 Level 2 Level 3 Total Assets Loans held-for-sale, net $ — $ — $ 105 $ 105 $ — n/m (a) Commercial finance receivables and loans, net (b) Commercial and industrial Automotive — — 19 19 (2 ) n/m (a) Other — — 29 29 (15 ) n/m (a) Commercial real estate — Automotive — — 4 4 (3 ) n/m (a) Total commercial finance receivables and loans, net — — 52 52 (20 ) n/m (a) Other assets Repossessed and foreclosed assets (c) — — 9 9 (3 ) n/m (a) Other — — 6 6 (2 ) n/m (a) Total assets $ — $ — $ 172 $ 172 $ (25 ) n/m n/m = not meaningful (a) We consider the applicable valuation or loan loss allowance to be the most relevant indicator of the impact on earnings caused by the fair value measurement. Accordingly, the table above excludes total gains and losses included in earnings for these items. The carrying values are inclusive of the respective valuation or loan loss allowance. (b) Represents the portion of the portfolio specifically impaired during 2015 . The related valuation allowance represents the cumulative adjustment to fair value of those specific receivables. (c) The allowance provided for repossessed and foreclosed assets represents any cumulative valuation adjustment recognized to adjust the assets to fair value. Fair Value Option for Financial Assets We elected the fair value option for an insignificant amount of conforming and non-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 hedges. Our intent in electing fair value measurement was to mitigate a divergence between accounting losses and economic exposure for certain assets and liabilities. Fair Value of Financial Instruments The following table presents the carrying and estimated fair value of financial instruments, except for those recorded at fair value on a recurring basis presented in the previous section of this note titled Recurring Fair Value. When possible, we use quoted market prices to determine fair value. Where quoted market prices are not available, the fair value is internally derived based on appropriate valuation methodologies with respect to the amount and timing of future cash flows and estimated discount rates. However, considerable judgment is required in interpreting current market data to develop the market assumptions and inputs necessary to estimate fair value. As such, the actual amount received to sell an asset or the amount paid to settle a liability could differ from our estimates. Fair value information presented herein was based on information available at December 31, 2016 , and December 31, 2015 . Estimated fair value December 31, ($ in millions) Carrying value Level 1 Level 2 Level 3 Total 2016 Financial assets Held-to-maturity securities $ 839 $ — $ 789 $ — $ 789 Finance receivables and loans, net 117,800 — — 118,750 118,750 Nonmarketable equity investments 1,046 — 1,012 55 1,067 Financial liabilities Deposit liabilities $ 79,022 $ — $ — $ 78,469 $ 78,469 Short-term borrowings 12,673 — — 12,675 12,675 Long-term debt 54,128 — 22,036 34,084 56,120 2015 Financial assets Loans held-for-sale, net $ 105 $ — $ — $ 105 $ 105 Finance receivables and loans, net 110,546 — — 110,737 110,737 Nonmarketable equity investments 418 — 391 42 433 Financial liabilities Deposit liabilities $ 66,478 $ — $ — $ 66,889 $ 66,889 Short-term borrowings 8,101 — — 8,102 8,102 Long-term debt 66,234 — 23,018 45,157 68,175 The following describes the methodologies and assumptions used to determine fair value for the significant classes of financial instruments. In addition to the valuation methods discussed below, we also followed guidelines for determining whether a market was not active and a transaction was not distressed. We assumed the price that would be received in an orderly transaction (including a market-based return) and not in forced liquidation or distressed sale. • Cash and cash equivalents — Included in cash and cash equivalents are highly liquid investments that are readily convertible to known amounts of cash and which are subject to an insignificant risk of change in value due to interest rate, quoted price, or penalty on withdrawal. Classified as Level 1 under the fair value hierarchy, cash and cash equivalents generally expose us to limited credit risk and are so near maturity that they present insignificant risk of changes in value because of changes in interest rates. Accordingly, the carrying value approximates the fair value of these instruments. • Held-to-maturity securities — Held-to-maturity securities, which consist of residential mortgage-backed debt securities issued by government agencies, are carried at amortized cost. For fair value disclosure purposes, held-to-maturity securities are classified as Level 2, with fair value based on observable market prices, when available. • Finance receivables and loans, net — With the exception of mortgage loans held-for-investment, the fair value of finance receivables and loans was based on discounted future cash flows using applicable spreads to approximate current rates applicable to each category of finance receivables and loans (an income approach using Level 3 inputs). The carrying value of commercial receivables in certain markets and certain automotive and other receivables for which interest rates reset on a short-term basis with applicable market indices are assumed to approximate fair value either because of the short-term nature or because of the interest rate adjustment feature. The fair value of commercial receivables in other markets was based on discounted future cash flows using applicable spreads to approximate current rates applicable to similar assets in those markets. The fair value of mortgage loans held-for-investment was based on a discounted cash flow basis utilizing cash flow projections from internally developed models that utilized prepayment, default, and discount rate assumptions. These valuations consider unique attributes of the loans such as geography, delinquency status, product type, and other factors. • Nonmarketable equity investments — Nonmarketable equity investments primarily include investments in FHLB and FRB stock and other equity investments carried at cost. As a member of the FHLB and FRB, Ally Bank is required to hold FHLB and FRB stock. The stock can be sold only to the FHLB and FRB upon termination of membership, or redeemed at the sole discretion of the FHLB and FRB, respectively. The fair value of FHLB and FRB stock is equal to the stock’s par value since the stock is bought, sold, and/or redeemed at par. FHLB and FRB stock is carried at cost, which generally represents the stock’s par value. • Deposit liabilities — Deposit liabilities represent certain consumer and brokered bank deposits, mortgage escrow deposits, and dealer deposits. The fair value of deposits at Level 3 was estimated by discounting projected cash flows based on discount factors derived from the forward interest rate swap curve. • Short-term borrowings and Long-term debt — Level 2 debt was valued using quoted market prices for similar instruments, when available, or other means for substantiation with observable inputs. Debt valued by discounting projected cash flows using internally derived inputs, such as prepayment speeds and discount rates, was classified as Level 3. • Financial instruments for which carrying value approximates fair value — Certain financial instruments that are not carried at fair value on the consolidated balance sheet are carried at amounts that approximate fair value primarily due to their short term nature and limited credit risk. These instruments include restricted cash, cash collateral, accrued interest receivable, accrued interest payable, trade receivables and payables, and other short term receivables and payables.

Offsetting Assets and Liabiliti

Offsetting Assets and Liabilities Offsetting Assets and Liabilities	12 Months Ended
	Dec. 31, 2016
Offsetting Assets and Liabilities [Abstract]
Offsetting Assets and Liabilities [Text Block]	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 (1) 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 (2) 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 value of our total obligation to each other. Contractual terms provide for standard and customary exchange of collateral based on changes in the market value of the outstanding derivatives. The securing party posts additional collateral when their obligation rises or removes collateral when it falls, such that the net replacement cost of the nondefaulting party is covered in the event of counterparty default. In certain instances as it relates to our derivative instruments, we have the option to report derivative assets and liabilities as well as assets and liabilities associated with cash collateral received or delivered that is governed by a master netting agreement on a net basis as long as certain qualifying criteria are met. Similarly, for our repurchase/reverse repurchase transactions, we have the option to report recognized assets and liabilities subject to a master netting agreement on a net basis if certain qualifying criteria are met. At December 31, 2016 , these instruments are reported as gross assets and gross liabilities on the Consolidated Balance Sheet . The composition of offsetting derivative instruments, financial assets, and financial liabilities was as follows. Gross amounts of recognized assets/(liabilities) Gross amounts offset in the Consolidated Balance Sheet Net amounts of assets/(liabilities) Gross amounts not offset in the Consolidated Balance Sheet December 31, 2016 ($ in millions) Financial instruments Collateral Net amount Assets Derivative assets in net asset positions $ 87 $ — $ 87 $ (4 ) $ (9 ) $ 74 Derivative assets in net liability positions 8 — 8 (8 ) — — Total assets (d) $ 95 $ — $ 95 $ (12 ) $ (9 ) $ 74 Liabilities Derivative liabilities in net liability positions $ (91 ) $ — $ (91 ) $ 8 $ 13 $ (70 ) Derivative liabilities in net asset positions (4 ) — (4 ) 4 — — Total derivative liabilities (d) (95 ) — (95 ) 12 13 (70 ) Securities sold under agreements to repurchase (e) (676 ) — (676 ) — 676 — Total liabilities $ (771 ) $ — $ (771 ) $ 12 $ 689 $ (70 ) (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. $6 million of noncash derivative collateral pledged to us was excluded at December 31, 2016 . We do not record such collateral received on our Consolidated Balance Sheet unless certain conditions are met. (c) Certain agreements grant us the right to sell or pledge the noncash assets we receive as collateral. Noncash collateral pledged to us where the agreement grants us the right to sell or pledge the underlying assets had a fair value of $6 million at December 31, 2016 . We have not sold or pledged any of the noncash collateral received under these agreements as of December 31, 2016 . (d) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements . (e) For additional information on securities sold under agreements to repurchase, refer to Note 16 to the Consolidated Financial Statements . Gross amounts of recognized assets/(liabilities) Gross amounts offset in the Consolidated Balance Sheet Net amounts of assets/(liabilities) Gross amounts not offset in the Consolidated Balance Sheet December 31, 2015 ( $ in millions ) Financial instruments Collateral Net amount Assets Derivative assets in net asset positions $ 224 $ — $ 224 $ (69 ) $ (67 ) $ 88 Derivative assets in net liability positions 9 — 9 (9 ) — — Total assets (d) $ 233 $ — $ 233 $ (78 ) $ (67 ) $ 88 Liabilities Derivative liabilities in net liability positions $ (68 ) $ — $ (68 ) $ 9 $ 2 $ (57 ) Derivative liabilities in net asset positions (69 ) — (69 ) 69 — — Derivative liabilities with no offsetting arrangements (8 ) — (8 ) — — (8 ) Total derivative liabilities (d) (145 ) — (145 ) 78 2 (65 ) Securities sold under agreements to repurchase (e) (648 ) — (648 ) — 648 — Total liabilities $ (793 ) $ — $ (793 ) $ 78 $ 650 $ (65 ) (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. $7 million of noncash derivative collateral pledged to us was excluded at December 31, 2015. We do not record such collateral received on our Consolidated Balance Sheet unless certain conditions are met. (c) Certain agreements grant us the right to sell or pledge the noncash assets we receive as collateral. Noncash collateral pledged to us where the agreement grants us the right to sell or pledge the underlying assets had a fair value of $7 million at December 31, 2015. We have not sold or pledged any of the noncash collateral received under these agreements as of December 31, 2015. (d) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements . (e) For additional information on securities sold under agreements to repurchase, refer to Note 16 to the Consolidated Financial Statements .

Segment and Geographic Informat

Segment and Geographic Information	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segment Reporting Disclosure [Text Block]	Segment and Geographic 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 line-of-business 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 — Provides U.S.-based automotive financing services to consumers and automotive dealers, and automotive and equipment financing services to companies and municipalities. Our automotive finance services include providing retail installment sales contracts, loans, and leases, offering term loans to dealers, financing dealer floorplans and other lines of credit to dealers, fleet financing, providing financing to companies and municipalities for the purchase or lease of vehicles and equipment, and vehicle remarketing services. Insurance operations — Offers 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 selected commercial insurance coverages, which primarily insure dealers' wholesale vehicle inventory. Mortgage Finance operations — Primarily consists of the management of a held-for-investment consumer mortgage finance loan portfolio, which includes bulk purchases of high-quality jumbo and LMI mortgage loans originated by third parties. In late 2016, we also introduced limited direct mortgage originations consisting of jumbo and conforming mortgages through a third-party fulfillment partner, LenderLive. Under our current arrangement, conforming mortgages will be originated as held-for-sale and sold to LenderLive, while jumbo mortgages will be originated as held-for-investment. Servicing will be performed by a third party and no mortgage servicing rights will be created. Direct mortgage originations did not materially impact our results of operations for the year ended December 31, 2016. 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. Corporate and Other primarily consists of activity related to 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, the amortization of the discount associated with new debt issuances and bond exchanges, 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, beginning in June 2016, financial information related to TradeKing is 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 and geographic areas tables that follow are based in part on internal allocations, which involve management judgment. Financial information for our reportable operating segments is summarized as follows. Year ended December 31, ($ in millions) Automotive Finance operations Insurance operations Mortgage Finance operations Corporate Finance operations Corporate and Other Consolidated (a) 2016 Net financing revenue and other interest income (loss) $ 3,665 $ 61 $ 97 $ 121 $ (37 ) $ 3,907 Other revenue 306 1,036 — 26 162 1,530 Total net revenue 3,971 1,097 97 147 125 5,437 Provision for loan losses 924 — (4 ) 10 (13 ) 917 Total noninterest expense 1,667 940 67 66 199 2,939 Income (loss) from continuing operations before income tax expense $ 1,380 $ 157 $ 34 $ 71 $ (61 ) $ 1,581 Total assets $ 116,347 $ 7,172 $ 8,307 $ 3,183 $ 28,719 $ 163,728 2015 Net financing revenue and other interest income $ 3,429 $ 57 $ 57 $ 89 $ 87 $ 3,719 Other revenue (loss) 235 1,033 — 25 (151 ) 1,142 Total net revenue (loss) 3,664 1,090 57 114 (64 ) 4,861 Provision for loan losses 696 — 7 9 (5 ) 707 Total noninterest expense 1,633 879 39 55 155 2,761 Income (loss) from continuing operations before income tax expense $ 1,335 $ 211 $ 11 $ 50 $ (214 ) $ 1,393 Total assets $ 115,636 $ 7,053 $ 6,461 $ 2,677 $ 26,754 $ 158,581 2014 Net financing revenue and other interest income (loss) $ 3,321 $ 56 $ 36 $ 59 $ (97 ) $ 3,375 Other revenue (loss) 264 1,129 — 32 (149 ) 1,276 Total net revenue (loss) 3,585 1,185 36 91 (246 ) 4,651 Provision for loan losses 542 — 3 (16 ) (72 ) 457 Total noninterest expense 1,614 988 21 43 282 2,948 Income (loss) from continuing operations before income tax expense $ 1,429 $ 197 $ 12 $ 64 $ (456 ) $ 1,246 Total assets $ 113,188 $ 7,190 $ 3,542 $ 1,870 $ 25,841 $ 151,631 (a) Net financing revenue and other interest income after the provision for loan losses totaled $3.0 billion , for the years ended December 31, 2016 , and 2015 , and $2.9 billion for the year ended December 31, 2014 . Information concerning principal geographic areas was as follows. Year ended December 31, ($ in millions) Total net revenue Income from continuing operations before income tax expense Net income (loss) (b) Identifiable assets (c) Long-lived assets (d) 2016 Canada $ 90 $ 44 $ 32 $ 499 $ — Europe — — (1 ) 276 — Latin America — — (1 ) 23 — Asia-Pacific — — — 2 — Total foreign (e) 90 44 30 800 — Total domestic (f) 5,347 1,537 1,037 162,688 11,846 Total $ 5,437 $ 1,581 $ 1,067 $ 163,488 $ 11,846 2015 Canada $ 98 $ 47 $ 35 514 — Europe 1 4 27 325 — Latin America — — (2 ) 28 — Asia-Pacific — — 452 2 — Total foreign (e) 99 51 512 869 — Total domestic (f) 4,762 1,342 777 157,685 16,506 Total $ 4,861 $ 1,393 $ 1,289 $ 158,554 $ 16,506 2014 Canada $ 124 $ 54 $ 68 $ 590 $ — Europe 2 — 4 1,636 — Latin America — — (8 ) 29 — Asia-Pacific — — 122 636 — Total foreign (e) 126 54 186 2,891 — Total domestic (f) 4,525 1,192 964 148,713 19,735 Total $ 4,651 $ 1,246 $ 1,150 $ 151,604 $ 19,735 (a) Revenue consists of net financing revenue and other interest income and total other revenue as presented in our Consolidated Financial Statements . (b) Gain (loss) realized on sale of discontinued operations are allocated to the geographic area in which the business operated. (c) Identifiable assets consist of total assets excluding goodwill. (d) Long-lived assets consist of investments in operating leases, net, and net property and equipment. (e) Our foreign operations as of December 31, 2016 , 2015, and 2014, consist of our ongoing Insurance operations in Canada and our remaining international entities in wind-down. (f) Amounts include eliminations between our domestic and foreign operations.

Parent and Guarantor Consolidat

Parent and Guarantor Consolidating Financial Statements	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Financial Statements [Text Block]	Parent and Guarantor Consolidating Financial Statements Certain of our senior notes issued by the parent are guaranteed by 100% directly owned subsidiaries of Ally (the Guarantors). As of December 31, 2016 , 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) an elimination column for adjustments to arrive at (v) the information for the parent company, the Guarantors, and nonguarantors on a consolidated basis. Investments in subsidiaries are 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, investments in subsidiaries, and intercompany balances and transactions between the parent, the Guarantors, and nonguarantors. Condensed Consolidating Statements of Comprehensive Income Year ended December 31, 2016 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing (loss) revenue and other interest income Interest and fees on finance receivables and loans $ (104 ) $ — $ 5,266 $ — $ 5,162 Interest and fees on finance receivables and loans — intercompany 11 — 8 (19 ) — Interest and dividends on investment securities and other earning assets — — 421 (3 ) 418 Interest on cash and cash equivalents 5 — 9 — 14 Interest-bearing cash — intercompany — — 9 (9 ) — Operating leases 17 — 2,694 — 2,711 Total financing (loss) revenue and other interest income (71 ) — 8,407 (31 ) 8,305 Interest expense Interest on deposits 8 — 822 — 830 Interest on short-term borrowings 40 — 17 — 57 Interest on long-term debt 1,161 — 581 — 1,742 Interest on intercompany debt 20 — 11 (31 ) — Total interest expense 1,229 — 1,431 (31 ) 2,629 Net depreciation expense on operating lease assets 14 — 1,755 — 1,769 Net financing revenue (1,314 ) — 5,221 — 3,907 Cash dividends from subsidiaries Nonbank subsidiaries 965 — — (965 ) — Other revenue Insurance premiums and service revenue earned — — 945 — 945 (Loss) gain on mortgage and automotive loans, net (11 ) — 22 — 11 Loss on extinguishment of debt (3 ) — (2 ) — (5 ) Other gain on investments, net — — 176 9 185 Other income, net of losses 1,253 — 937 (1,796 ) 394 Total other revenue 1,239 — 2,078 (1,787 ) 1,530 Total net revenue 890 — 7,299 (2,752 ) 5,437 Provision for loan losses 408 — 509 — 917 Noninterest expense Compensation and benefits expense 573 — 419 — 992 Insurance losses and loss adjustment expenses — — 342 — 342 Other operating expenses 1,261 — 2,130 (1,786 ) 1,605 Total noninterest expense 1,834 — 2,891 (1,786 ) 2,939 (Loss) income from continuing operations before income tax (benefit) expense and undistributed income (loss) of subsidiaries (1,352 ) — 3,899 (966 ) 1,581 Income tax (benefit) expense from continuing operations (279 ) (82 ) 831 — 470 Net (loss) income from continuing operations (1,073 ) 82 3,068 (966 ) 1,111 Loss from discontinued operations, net of tax (39 ) — (5 ) — (44 ) Undistributed income (loss) of subsidiaries Bank subsidiary 1,273 1,273 — (2,546 ) — Nonbank subsidiaries 906 (2 ) — (904 ) — Net income 1,067 1,353 3,063 (4,416 ) 1,067 Other comprehensive loss, net of tax (110 ) (63 ) (106 ) 169 (110 ) Comprehensive income $ 957 $ 1,290 $ 2,957 $ (4,247 ) $ 957 Year ended December 31, 2015 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing (loss) revenue and other interest income Interest and fees on finance receivables and loans $ (83 ) $ — $ 4,653 $ — $ 4,570 Interest and fees on finance receivables and loans — intercompany 17 — 24 (41 ) — Interest on loans held-for-sale — — 40 — 40 Interest and dividends on investment securities and other earning assets — — 381 — 381 Interest on cash and cash equivalents 1 — 7 — 8 Interest-bearing cash — intercompany — — 8 (8 ) — Operating leases 9 — 3,389 — 3,398 Total financing (loss) revenue and other interest income (56 ) — 8,502 (49 ) 8,397 Interest expense Interest on deposits 10 — 708 — 718 Interest on short-term borrowings 40 — 9 — 49 Interest on long-term debt 1,121 — 541 — 1,662 Interest on intercompany debt 32 — 17 (49 ) — Total interest expense 1,203 — 1,275 (49 ) 2,429 Net depreciation expense on operating lease assets 7 — 2,242 — 2,249 Net financing revenue (1,266 ) — 4,985 — 3,719 Cash dividends from subsidiaries Bank subsidiaries 525 525 — (1,050 ) — Nonbank subsidiaries 1,123 — — (1,123 ) — Other revenue Insurance premiums and service revenue earned — — 940 — 940 (Loss) gain on mortgage and automotive loans, net (9 ) — 54 — 45 Loss on extinguishment of debt (355 ) — (2 ) — (357 ) Other gain on investments, net — — 155 — 155 Other income, net of losses 1,373 — 1,373 (2,387 ) 359 Total other revenue 1,009 — 2,520 (2,387 ) 1,142 Total net revenue 1,391 525 7,505 (4,560 ) 4,861 Provision for loan losses 157 — 550 — 707 Noninterest expense Compensation and benefits expense 571 — 842 (450 ) 963 Insurance losses and loss adjustment expenses — — 293 — 293 Other operating expenses 1,247 — 2,195 (1,937 ) 1,505 Total noninterest expense 1,818 — 3,330 (2,387 ) 2,761 (Loss) income from continuing operations before income tax (benefit) expense and undistributed income (loss) of subsidiaries (584 ) 525 3,625 (2,173 ) 1,393 Income tax (benefit) expense from continuing operations (267 ) — 763 — 496 Net (loss) income from continuing operations (317 ) 525 2,862 (2,173 ) 897 Income from discontinued operations, net of tax 356 — 36 — 392 Undistributed income (loss) of subsidiaries Bank subsidiary 581 581 — (1,162 ) — Nonbank subsidiaries 669 (1 ) — (668 ) — Net income 1,289 1,105 2,898 (4,003 ) 1,289 Other comprehensive loss, net of tax (165 ) (43 ) (172 ) 215 (165 ) Comprehensive income $ 1,124 $ 1,062 $ 2,726 $ (3,788 ) $ 1,124 Year ended December 31, 2014 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing revenue and other interest income Interest and fees on finance receivables and loans $ (14 ) $ — $ 4,471 $ — $ 4,457 Interest and fees on finance receivables and loans — intercompany 37 — 82 (119 ) — Interest on loans held-for-sale — — 1 — 1 Interest and dividends on investment securities and other earning assets — — 367 — 367 Interest on cash and cash equivalents 1 — 7 — 8 Interest-bearing cash — intercompany — — 6 (6 ) — Operating leases 269 — 3,289 — 3,558 Total financing revenue and other interest income 293 — 8,223 (125 ) 8,391 Interest expense Interest on deposits 15 — 649 — 664 Interest on short-term borrowings 43 — 9 — 52 Interest on long-term debt 1,492 — 575 — 2,067 Interest on intercompany debt 88 — 37 (125 ) — Total interest expense 1,638 — 1,270 (125 ) 2,783 Net depreciation expense on operating lease assets 161 — 2,072 — 2,233 Net financing revenue (1,506 ) — 4,881 — 3,375 Cash dividends from subsidiaries Bank subsidiaries 1,800 1,800 — (3,600 ) — Nonbank subsidiaries 651 — — (651 ) — Other revenue Insurance premiums and service revenue earned — — 979 — 979 (Loss) gain on mortgage and automotive loans, net (5 ) — 12 — 7 Loss on extinguishment of debt (202 ) — — — (202 ) Other gain on investments, net — — 181 — 181 Other income, net of losses 1,279 — 1,299 (2,267 ) 311 Total other revenue 1,072 — 2,471 (2,267 ) 1,276 Total net revenue 2,017 1,800 7,352 (6,518 ) 4,651 Provision for loan losses 250 — 207 — 457 Noninterest expense Compensation and benefits expense 586 — 793 (432 ) 947 Insurance losses and loss adjustment expenses — — 410 — 410 Other operating expenses 1,267 — 2,159 (1,835 ) 1,591 Total noninterest expense 1,853 — 3,362 (2,267 ) 2,948 (Loss) income from continuing operations before income tax (benefit) expense and undistributed (loss) income of subsidiaries (86 ) 1,800 3,783 (4,251 ) 1,246 Income tax (benefit) expense from continuing operations (457 ) — 778 — 321 Net income from continuing operations 371 1,800 3,005 (4,251 ) 925 Income from discontinued operations, net of tax 193 — 32 — 225 Undistributed (loss) income of subsidiaries Bank subsidiary (680 ) (680 ) — 1,360 — Nonbank subsidiaries 1,266 (1 ) — (1,265 ) — Net income 1,150 1,119 3,037 (4,156 ) 1,150 Other comprehensive income, net of tax 210 188 212 (400 ) 210 Comprehensive income $ 1,360 $ 1,307 $ 3,249 $ (4,556 ) $ 1,360 Condensed Consolidating Balance Sheet December 31, 2016 ($ in millions) Parent (a) Guarantors Nonguarantors (a) Consolidating adjustments Ally consolidated Assets Cash and cash equivalents Noninterest-bearing $ 720 $ — $ 827 $ — $ 1,547 Interest-bearing 100 — 4,287 — 4,387 Interest-bearing — intercompany — — 401 (401 ) — Total cash and cash equivalents 820 — 5,515 (401 ) 5,934 Trading securities — — 82 (82 ) — Available-for-sale securities — — 19,253 (327 ) 18,926 Held-to-maturity securities — — 839 — 839 Finance receivables and loans, net Finance receivables and loans, net 4,705 — 114,239 — 118,944 Intercompany loans to Bank subsidiary 1,125 — — (1,125 ) — Nonbank subsidiaries 1,779 — 626 (2,405 ) — Allowance for loan losses (115 ) — (1,029 ) — (1,144 ) Total finance receivables and loans, net 7,494 — 113,836 (3,530 ) 117,800 Investment in operating leases, net 42 — 11,428 — 11,470 Intercompany receivables from Bank subsidiary 299 — — (299 ) — Nonbank subsidiaries 107 — 67 (174 ) — Investment in subsidiaries Bank subsidiary 17,727 17,727 — (35,454 ) — Nonbank subsidiaries 10,318 — — (10,318 ) — Premiums receivable and other insurance assets — — 1,936 (31 ) 1,905 Other assets 4,347 — 5,085 (2,578 ) 6,854 Total assets $ 41,154 $ 17,727 $ 158,041 $ (53,194 ) $ 163,728 Liabilities Deposit liabilities Noninterest-bearing $ — $ — $ 84 $ — $ 84 Interest-bearing 167 — 78,771 — 78,938 Total deposit liabilities 167 — 78,855 — 79,022 Short-term borrowings 3,622 — 9,051 — 12,673 Long-term debt 21,798 — 32,330 — 54,128 Intercompany debt to Bank subsidiary 330 — — (330 ) — Nonbank subsidiaries 1,027 — 2,903 (3,930 ) — Intercompany payables to Nonbank subsidiaries 153 — 351 (504 ) — Interest payable 253 — 98 — 351 Unearned insurance premiums and service revenue — — 2,500 — 2,500 Accrued expenses and other liabilities 487 — 3,911 (2,661 ) 1,737 Total liabilities 27,837 — 129,999 (7,425 ) 150,411 Total equity 13,317 17,727 28,042 (45,769 ) 13,317 Total liabilities and equity $ 41,154 $ 17,727 $ 158,041 $ (53,194 ) $ 163,728 (a) Amounts presented are based upon the legal transfer of the underlying assets to VIEs in order to reflect legal ownership. December 31, 2015 ($ in millions) Parent (a) Guarantors Nonguarantors (a) Consolidating adjustments Ally consolidated Assets Cash and cash equivalents Noninterest-bearing $ 1,234 $ — $ 914 $ — $ 2,148 Interest-bearing 401 — 3,831 — 4,232 Interest-bearing — intercompany — — 850 (850 ) — Total cash and cash equivalents 1,635 — 5,595 (850 ) 6,380 Available-for-sale securities — — 17,157 — 17,157 Loans held-for-sale, net — — 105 — 105 Finance receivables and loans, net Finance receivables and loans, net 2,636 — 108,964 — 111,600 Intercompany loans to Bank subsidiary 600 — — (600 ) — Nonbank subsidiaries 3,277 — 559 (3,836 ) — Allowance for loan losses (72 ) — (982 ) — (1,054 ) Total finance receivables and loans, net 6,441 — 108,541 (4,436 ) 110,546 Investment in operating leases, net 81 — 16,190 — 16,271 Intercompany receivables from Bank subsidiary 186 — — (186 ) — Nonbank subsidiaries 259 — 282 (541 ) — Investment in subsidiaries Bank subsidiary 16,496 16,496 — (32,992 ) — Nonbank subsidiaries 10,902 11 — (10,913 ) — Premiums receivable and other insurance assets — — 1,827 (26 ) 1,801 Other assets 4,785 — 4,488 (2,952 ) 6,321 Total assets $ 40,785 $ 16,507 $ 154,185 $ (52,896 ) $ 158,581 Liabilities Deposit liabilities Noninterest-bearing $ — $ — $ 89 $ — $ 89 Interest-bearing 229 — 66,160 — 66,389 Total deposit liabilities 229 — 66,249 — 66,478 Short-term borrowings 3,453 — 4,648 — 8,101 Long-term debt 21,048 — 45,186 — 66,234 Intercompany debt to Nonbank subsidiaries 1,409 — 3,877 (5,286 ) — Intercompany payables to Bank subsidiary 142 — — (142 ) — Nonbank subsidiaries 420 — 191 (611 ) — Interest payable 258 — 92 — 350 Unearned insurance premiums and service revenue — — 2,434 — 2,434 Accrued expenses and other liabilities 387 82 4,028 (2,952 ) 1,545 Total liabilities 27,346 82 126,705 (8,991 ) 145,142 Total equity 13,439 16,425 27,480 (43,905 ) 13,439 Total liabilities and equity $ 40,785 $ 16,507 $ 154,185 $ (52,896 ) $ 158,581 (a) Amounts presented are based upon the legal transfer of the underlying assets to VIEs in order to reflect legal ownership. Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 241 $ 6 $ 5,383 $ (1,063 ) $ 4,567 Investing activities Purchases of available-for-sale securities — — (16,031 ) — (16,031 ) Proceeds from sales of available-for-sale securities — — 11,036 — 11,036 Proceeds from maturities and repayments of available-for-sale securities — — 3,379 — 3,379 Purchases of held-to-maturity securities — — (841 ) — (841 ) Purchases of loans held-for-investment (4 ) — (3,855 ) — (3,859 ) Proceeds from sales of finance receivables and loans originated as held-for-investment — — 4,285 — 4,285 Originations and repayments of loans held-for-investment and other 2,013 — (10,839 ) — (8,826 ) Net change in loans — intercompany 877 — (67 ) (810 ) — Purchases of operating lease assets — — (3,274 ) — (3,274 ) Disposals of operating lease assets 25 — 6,279 — 6,304 Acquisitions, net of cash acquired (309 ) — — — (309 ) Capital contributions to subsidiaries (3,908 ) — — 3,908 — Returns of contributed capital 3,678 8 — (3,686 ) — Net change in restricted cash (120 ) — 512 — 392 Net change in nonmarketable equity investments — — (628 ) — (628 ) Other, net (206 ) — (197 ) 91 (312 ) Net cash provided by (used in) investing activities 2,046 8 (10,241 ) (497 ) (8,684 ) Financing activities Net change in short-term borrowings — third party 169 — 4,395 — 4,564 Net (decrease) increase in deposits (61 ) — 12,569 — 12,508 Proceeds from issuance of long-term debt — third party 979 — 13,176 — 14,155 Repayments of long-term debt — third party (2,662 ) — (23,750 ) — (26,412 ) Net change in debt — intercompany (382 ) — (877 ) 1,259 — Redemption of preferred stock (696 ) — — — (696 ) Repurchase of common stock (341 ) — — — (341 ) Dividends paid — third party (108 ) — — — (108 ) Dividends paid and returns of contributed capital — intercompany — (14 ) (4,644 ) 4,658 — Capital contributions from parent — — 3,908 (3,908 ) — Net cash (used) in provided by financing activities (3,102 ) (14 ) 4,777 2,009 3,670 Effect of exchange-rate changes on cash and cash equivalents — — 1 — 1 Net decrease in cash and cash equivalents (815 ) — (80 ) 449 (446 ) Cash and cash equivalents at beginning of year 1,635 — 5,595 (850 ) 6,380 Cash and cash equivalents at end of year $ 820 $ — $ 5,515 $ (401 ) $ 5,934 Year ended December 31, 2015 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 370 $ 525 $ 6,390 $ (2,174 ) $ 5,111 Investing activities Purchases of available-for-sale securities — — (12,250 ) — (12,250 ) Proceeds from sales of available-for-sale securities — — 6,874 — 6,874 Proceeds from maturities and repayments of available-for-sale securities — — 4,255 — 4,255 Purchases of loans held-for-investment (169 ) — (4,332 ) — (4,501 ) Proceeds from sales of finance receivables and loans originated as held-for-investment — — 3,197 — 3,197 Originations and repayments of loans held-for-investment and other 1,954 — (11,298 ) — (9,344 ) Net change in loans — intercompany 240 — 1,211 (1,451 ) — Purchases of operating lease assets (94 ) — (4,591 ) — (4,685 ) Disposals of operating lease assets 7 — 5,539 — 5,546 Capital contributions to subsidiaries (796 ) (1 ) — 797 — Returns of contributed capital 1,444 — — (1,444 ) — Proceeds from sale of business units, net 1,049 — — — 1,049 Net change in restricted cash (7 ) — 271 — 264 Net change in nonmarketable equity investments — — (147 ) — (147 ) Other, net (47 ) — 42 — (5 ) Net cash provided by (used in) investing activities 3,581 (1 ) (11,229 ) (2,098 ) (9,747 ) Financing activities Net change in short-term borrowings — third party 115 — 913 — 1,028 Net (decrease) increase in deposits (91 ) — 8,338 — 8,247 Proceeds from issuance of long-term debt — third party 5,428 — 25,237 — 30,665 Repayments of long-term debt — third party (5,931 ) — (25,419 ) — (31,350 ) Net change in debt — intercompany (977 ) — (240 ) 1,217 — Repurchase and redemption of preferred stock (559 ) — — — (559 ) Repurchase of common stock (16 ) — — — (16 ) Dividends paid — third party (2,571 ) — — — (2,571 ) Dividends paid and returns of contributed capital — intercompany — (525 ) (3,092 ) 3,617 — Capital contributions from parent — 1 796 (797 ) — Net cash (used in) provided by financing activities (4,602 ) (524 ) 6,533 4,037 5,444 Effect of exchange-rate changes on cash and cash equivalents — — (4 ) — (4 ) Net (decrease) increase in cash and cash equivalents (651 ) — 1,690 (235 ) 804 Cash and cash equivalents at beginning of year 2,286 — 3,905 (615 ) 5,576 Cash and cash equivalents at end of year $ 1,635 $ — $ 5,595 $ (850 ) $ 6,380 Year ended December 31, 2014 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 330 $ 1,789 $ 5,533 $ (4,249 ) $ 3,403 Investing activities Purchases of available-for-sale securities — — (5,417 ) — (5,417 ) Proceeds from sales of available-for-sale securities — — 4,277 (17 ) 4,260 Proceeds from maturities and repayments of available-for-sale securities — — 2,657 — 2,657 Purchases of loans held-for-investment — — (894 ) 17 (877 ) Proceeds from sales of finance receivables and loans originated as held-for-investment — — 2,592 — 2,592 Originations and repayments of loans held-for-investment and other 1,900 — (6,047 ) — (4,147 ) Net change in loans — intercompany 1,428 — 154 (1,582 ) — Purchases of operating lease assets (2,337 ) — (7,547 ) — (9,884 ) Disposals of operating lease assets 3,053 — 2,807 — 5,860 Capital contributions to subsidiaries (1,179 ) — — 1,179 — Returns of contributed capital 1,422 — — (1,422 ) — Proceeds from sale of business units, net 46 — 1 — 47 Net change in restricted cash — — 1,625 — 1,625 Net change in nonmarketable equity investments — — 66 — 66 Other, net (29 ) — 35 — 6 Net cash provided by (used in) investing activities 4,304 — (5,691 ) (1,825 ) (3,212 ) Financing activities Net change in short-term borrowings — third party 113 — (1,607 ) — (1,494 ) Net (decrease) increase in deposits (121 ) — 4,972 — 4,851 Proceeds from issuance of long-term debt — third party 3,132 — 24,060 — 27,192 Repayments of long-term debt — third party (8,186 ) — (22,240 ) — (30,426 ) Net change in debt — intercompany 52 — (1,428 ) 1,376 — Dividends paid — third party (268 ) — — — (268 ) Dividends paid and returns of contributed capital — intercompany — (1,826 ) (3,846 ) 5,672 — Capital contributions from parent — — 1,179 (1,179 ) — Net cash (used in) provided by financing activities (5,278 ) (1,826 ) 1,090 5,869 (145 ) Effect of exchange-rate changes on cash and cash equivalents — — (1 ) — (1 ) Net (decrease) increase in cash and cash equivalents (644 ) (37 ) 931 (205 ) 45 Cash and cash equivalents at beginning of year 2,930 37 2,974 (410 ) 5,531 Cash and cash equivalents at end of year $ 2,286 $ — $ 3,905 $ (615 ) $ 5,576

Contingencies and Other Risks

Contingencies and Other Risks	12 Months Ended
	Dec. 31, 2016
Loss Contingency [Abstract]
Contingencies Disclosure [Text Block]	Contingencies and Other Risks Concentration with GM and Chrysler While we are continuing to diversify our automotive finance and insurance businesses and to expand into other financial services, General Motors Company (GM) and Fiat Chrysler Automobiles US LLC (Chrysler) dealers and their retail customers continue to constitute a significant portion of our customer base. GM, Chrysler, and their captive finance companies compete forcefully with us and could take further actions that negatively impact the amount of business that we do with GM and Chrysler dealers and their customers. Further, a significant adverse change in GM’s or Chrysler’s business—including, for example, in the production or sale of GM or Chrysler vehicles, the quality or resale value of GM or Chrysler vehicles, GM’s or Chrysler’s relationships with its key suppliers, or the rate or volume of recalls of GM or Chrysler vehicles—could negatively impact our GM and Chrysler dealer and retail customer bases. Any future reductions in GM and Chrysler business that we are not able to offset could adversely affect our business and financial results. Legal Matters Ally and its subsidiaries, including Ally Bank, are or may be subject to potential liability in connection with pending or threatened legal proceedings and other matters. These legal matters may be formal or informal and include litigation and arbitration with one or more identified claimants, certified or purported class actions with yet-to-be-identified claimants, and regulatory or other governmental information-gathering requests, examinations, investigations, and enforcement proceedings. Our legal matters exist in varying stages of adjudication, arbitration, negotiation, or investigation and span our lines of business and operations. Claims may be based in law or equity—such as those arising under contracts or in tort and those involving banking, consumer-protection, securities, tax, employment, and other laws—and some can present novel legal theories and allege substantial or indeterminate damages. We accrue for a legal matter when a loss becomes probable and the amount of loss can be reasonably estimated. Accruals are evaluated each quarter and may be adjusted, upward or downward, based on our best judgment after consultation with counsel. No assurance exists that our accruals will not need to be adjusted in the future. The course and outcome of legal matters are inherently unpredictable. This is especially so when a matter is still in its early stages, the damages sought are indeterminate or unsupported, significant facts are unclear or disputed, novel questions of law or other meaningful legal uncertainties exist, a request to certify a proceeding as a class action is outstanding or granted, multiple parties are named, or regulatory or other governmental entities are involved. As a result, we cannot state with confidence how or when threatened or pending legal matters will be resolved and what losses may be incurred. Actual losses may be higher or lower than any amounts accrued for those matters, possibly to a significant degree. On the basis of information currently available, advice of counsel, available insurance coverage, and established reserves, it is the opinion of management that, except as described in the next paragraph, the eventual outcome of our existing legal matters will not have a material adverse effect on our consolidated financial condition, results of operations, or cash flows. It is possible, however, that an unfavorable resolution of legal matters may be material to our consolidated financial condition, results of operations, or cash flows in a particular period. Descriptions of our material legal matters follow. In each case, the matter could have material adverse consequences for us, including substantial damages or settlements, injunctions, governmental fines or penalties, and reputational or operational risks. We do not believe, however, that an estimate of reasonably possible losses or a range of reasonably possible losses in excess of established reserves—whether in excess of any related accrual or where no accrual exists—can be made for any of these matters. Securities Litigation In October 2016, a purported class action—Bucks County Employees Retirement Fund v. Ally Financial Inc. et al.—was filed in the Circuit Court for Wayne County in the State of Michigan. This matter was removed to the U.S. District Court for the Eastern District of Michigan on November 18, 2016, and is currently pending there as Case No. 2:16-CV-14104. The complaint alleges material misstatements and omissions in connection with Ally’s initial public offering in April 2014, including a failure to adequately disclose the severity of rising subprime automotive loan delinquency rates, deficient underwriting measures employed in the origination of subprime automotive loans, and aggressive tactics used with low-income borrowers. The request for relief includes an indeterminate amount of damages, fees, and costs and other remedies. In January 2017, another purported class action—National Shopmen Pension Fund v. Ally Financial Inc. et al.—was filed in the Circuit Court for Oakland County in the State of Michigan. This matter was removed to the U.S. District Court for the Eastern District of Michigan on January 30, 2017, and is currently pending there as Case No. 2:17-CV-10289. The allegations and requested relief in the complaint are substantially similar to those included in the complaint filed by Bucks County Employees Retirement Fund. We intend to vigorously defend against these actions. Automotive Subprime Matters In October 2014, we received a document request from the SEC in connection with its investigation related to subprime automotive finance and related securitization activities. Separately, in December 2014, we received a subpoena from the DOJ requesting similar information. In May 2015 and December 2016, we received information requests from the New York Department of Financial Services requesting similar information. We have cooperated with each of these agencies with respect to these matters. Indirect Automotive Finance Matters In December 2013, Ally Financial Inc. and Ally Bank entered into a Consent Order issued by the U.S. Consumer Financial Protection Bureau (CFPB) and a Consent Order jointly submitted with the DOJ and entered by the U.S. District Court for the Eastern District of Michigan (United States v. Ally Financial Inc. and Ally Bank, Civil Action No. 13-15180), in each case, pertaining to allegations of discrimination involving the automotive finance business. The Consent Orders require Ally to create a compliance plan addressing, at a minimum, the communication of Ally’s expectations of Equal Credit Opportunity Act (ECOA) compliance to our automotive dealer clients, maintenance of Ally’s existing limits on dealer finance income for contracts acquired by Ally, and monitoring for potential discrimination both at the dealer level and within our portfolio of contracts acquired across all of our automotive dealer clients. Ally formed a compliance committee consisting of certain Ally Financial Inc. and Ally Bank directors to oversee Ally’s execution of the Consent Orders’ terms. Ally is required to meet certain stipulations under the Consent Orders, including a requirement to make monetary payments when ongoing remediation targets are not attained. Since 2013, Ally has recognized expenses of approximately $240 million for judgments, fines, and monetary remuneration payments to customers related to the Consent Orders. The Consent Orders terminate, according to their terms, in 2017, and preclude the CFPB and the DOJ from pursuing any potential violations of the ECOA against Ally Financial Inc. or Ally Bank for conduct undertaken pursuant to the Consent Orders during the period of the Consent Orders. If the CFPB or the DOJ were to assert that Ally Financial Inc. or Ally Bank is violating the ECOA after the Consent Orders terminate, further legal proceedings could occur. Mortgage Matters We previously disclosed investigations by the DOJ relating to residential mortgage-backed securities issued by our former mortgage subsidiary, Residential Capital, LLC and its subsidiaries (ResCap RMBS). The DOJ was investigating potential fraud and other potential legal claims related to ResCap RMBS, including potential claims under the Financial Institutions Reform, Recovery, and Enforcement Act of 1989, as well as potential claims under the False Claims Act related to representations made by us in connection with investments in Ally Financial Inc. made by the U.S. Department of the Treasury pursuant to the Troubled Asset Relief Program in 2008 and 2009 regarding certain claims against Residential Capital, LLC or its subsidiaries at that time. On November 21, 2016, we comprehensively resolved these investigations and potential claims with the DOJ and entered into a settlement agreement. Under the agreement, we in 2016 (1) paid $52 million to the DOJ, which is included in discontinued operations, (2) withdrew the broker-dealer registration for Ally Securities LLC (formerly known as Residential Funding Securities LLC) (Ally Securities), which is one of our wholly-owned subsidiaries, and (3) began to wind down the affairs of Ally Securities. Other Contingencies Ally and its subsidiaries, including Ally Bank, are or may be subject to potential liability under various other contingent exposures, including indemnification, tax, self-insurance, and other miscellaneous contingencies. We accrue for a contingent exposure when a loss becomes probable and the amount of loss can be reasonably estimated. Accruals are evaluated each quarter and may be adjusted, upward or downward, based on our best judgment. No assurance exists that our accruals will not need to be adjusted in the future, and actual losses may be higher or lower than any amounts accrued for those exposures, possibly to a significant degree. On the basis of information currently available, available insurance coverage, and established reserves, it is the opinion of management that the eventual outcome of our other contingent exposures will not have a material adverse effect on our consolidated financial condition, results of operations, or cash flows.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events Characterization of Variation Margin Payments On January 4, 2017, the International Swaps and Derivatives Association (ISDA) issued a confirmation letter related to its May 27, 2016, accounting committee whitepaper, “Accounting Impact of CCP’s Rulebook Changes to Financial Institutions and Corporates May 2016,” and the corresponding discussions held with the staff of the SEC’s Office of the Chief Accountant. We are still in the process of evaluating the legal and accounting impact of this confirmation letter and it may have an impact on how we record our variation margin payments on certain derivative positions. Declaration of Quarterly Dividend Payment On January 11, 2017 , the Ally Board of Directors declared a quarterly cash dividend payment of $0.08 per share on all common stock. The dividend was paid on February 15, 2017 , to shareholders of record at the close of business on February 1, 2017. Unsecured Credit Facility Draw On January 27, 2017, we borrowed $1.25 billion pursuant to the terms of our private unsecured committed credit facility. This debt is scheduled to mature in December 2017. Amounts drawn under this facility are used for working capital and other general corporate purposes.

Guarantees and Commitments Guar

Guarantees and Commitments Guarantees and Commitments (Notes)	12 Months Ended
	Dec. 31, 2016
Guarantees [Abstract]
Guarantees [Text Block]	Guarantees and Commitments Guarantees Guarantees are defined as contracts or indemnification agreements that contingently require us to make payments to third parties based on changes in the underlying agreements with the guaranteed parties. The following summarizes our outstanding guarantees, including those of our discontinued operations, made to third parties on our Consolidated Balance Sheet , for the periods shown. 2016 2015 December 31, ( $ in millions ) Maximum liability Carrying value of liability Maximum liability Carrying value of liability Standby letters of credit and other guarantees $ 175 $ 8 $ 208 $ 13 Corporate Finance has exposure to standby letters of credit that represent irrevocable guarantees of payment of specified financial obligations. Third-party beneficiaries primarily accept standby letters of credit as insurance in the event of nonperformance by our borrowers. Our borrowers may request letters of credit under their revolving loan facility up to a certain sub-limit amount. Expiration dates on letters of credit range from certain ongoing commitments that will expire during the upcoming year to terms of several years for certain letters of credit. If nonperformance occurs by a borrower for which we have issued a letter of credit, we can be liable for payment of the letter of credit to the beneficiary with our recourse being a charge to the borrower's loan facility. In connection with our TradeKing wealth management business, we introduce customer securities accounts to a clearing broker, which clears and maintains custody of all customer assets and account activity. We are responsible for obtaining from each customer such funds or securities as are required to be deposited or maintained in their accounts. As a result, we are liable for any loss, liability, damage, cost, or expense incurred or sustained by the clearing broker as a result of the failure of any customer to timely make payments or deposits of securities to satisfy their contractual obligations. In addition, customer securities activities are transacted on either a cash or margin basis. In margin transactions, we may extend credit to the customer, through our clearing broker, subject to various regulatory rules and margin lending practices, collateralized by cash and securities in the customer’s account. In connection with these activities, we also execute customer transactions involving the sale of securities not yet purchased. Such transactions may expose us to credit risk in the event the customer’s assets are not sufficient to fully cover losses, which the customer may incur. In the event the customer fails to satisfy its obligations, we will purchase or sell financial instruments in the customer’s account in order to fulfill the customer’s obligations. The maximum potential exposure under these arrangements is difficult to estimate; however, the potential for us to incur material losses pursuant to these arrangements is remote. Commitments Financing Commitments The contractual commitments were as follows. December 31, ( $ in millions ) 2016 2015 Commitments to provide capital to investees (a) $ 206 $ 132 Construction-lending commitments (b) 164 197 Home equity lines of credit (c) 356 358 Unused revolving credit line commitments and other (d) 1,995 1,445 (a) We are committed to contribute capital to certain investees. The fair value of these commitments is considered in the overall valuation of the underlying assets with which they are associated. (b) The fair value of these commitments is considered in the overall valuation of the related assets. (c) We are committed to fund the remaining unused balances on home equity lines of credit. (d) The unused portion of revolving lines of credit reset at prevailing market rates and, as such, approximate market value. Revolving credit line commitments contain an element of credit risk. Management reduces its credit risk for unused revolving credit line commitments by applying the same credit policies in making commitments as it does for extending loans. We typically require collateral as these commitments are drawn. Lease Commitments Future minimum rental payments required under operating leases, primarily for real property, with noncancelable lease terms expiring after December 31, 2016 , are as follows. Year ended December 31, ( $ in millions ) 2017 $ 36 2018 36 2019 35 2020 33 2021 25 2022 and thereafter 75 Total minimum payment required $ 240 Certain of the leases contain escalation clauses and renewal or purchase options. Rental expenses under operating leases were $51 million , $51 million , and $50 million in 2016 , 2015 , and 2014 , respectively. Contractual Commitments We have entered into multiple agreements for information technology, voice and communication technology, and related maintenance. Many of the agreements are subject to variable price provisions, fixed or minimum price provisions, and termination or renewal provisions. Year ended December 31, ( $ in millions ) 2017 $ 94 2018 and 2019 13 2020 and thereafter 4 Total future payment obligations $ 111

Quarterly Financial Statements

Quarterly Financial Statements (unaudited) Quarterly Financial Statements (unaudited)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Statements (unaudited) [Abstract]
Quarterly Financial Information [Text Block]	Quarterly Financial Statements (unaudited) ( $ in millions ) First quarter Second quarter Third quarter Fourth quarter 2016 Net financing revenue and other interest income $ 951 $ 984 $ 996 $ 976 Other revenue 376 374 388 392 Total net revenue 1,327 1,358 1,384 1,368 Provision for loan losses 220 172 258 267 Total noninterest expense 710 773 735 721 Income from continuing operations before income tax expense 397 413 391 380 Income tax expense from continuing operations 150 56 130 134 Net income from continuing operations 247 357 261 246 Income (loss) from discontinued operations, net of tax 3 3 (52 ) 2 Net income $ 250 $ 360 $ 209 $ 248 Basic earnings per common share Net income from continuing operations $ 0.48 $ 0.70 $ 0.54 $ 0.52 Net income 0.49 0.71 0.43 0.53 Diluted earnings per common share Net income from continuing operations $ 0.48 $ 0.70 $ 0.54 $ 0.52 Net income 0.49 0.71 0.43 0.52 Cash dividends per common share $ — $ — $ 0.08 $ 0.08 2015 Net financing revenue and other interest income $ 850 $ 916 $ 970 $ 983 Other revenue 243 211 332 356 Total net revenue 1,093 1,127 1,302 1,339 Provision for loan losses 116 140 211 240 Total noninterest expense 695 724 674 668 Income from continuing operations before income tax expense 282 263 417 431 Income tax expense from continuing operations 103 94 144 155 Net income from continuing operations 179 169 273 276 Income (loss) from discontinued operations, net of tax 397 13 (5 ) (13 ) Net income $ 576 $ 182 $ 268 $ 263 Basic earnings per common share Net income (loss) from continuing operations $ 0.23 $ (2.24 ) $ 0.49 $ (1.94 ) Net income (loss) 1.06 (2.22 ) 0.48 (1.97 ) Diluted earnings per common share Net income (loss) from continuing operations $ 0.23 $ (2.24 ) $ 0.49 $ (1.94 ) Net income (loss) 1.06 (2.22 ) 0.47 (1.97 )

Description of Business, Basi40

Description of Business, Basis of Presentation, and Changes in Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Consolidation, Policy [Policy Text Block]	The Consolidated Financial Statements include the accounts of the parent and its consolidated subsidiaries, to which it is deemed to possess control, after eliminating intercompany balances and transactions, and include all variable interest entities (VIEs) in which we are the primary beneficiary. Other entities in which we have invested and have the ability to exercise significant influence over operating and financial policies of the investee, but upon which we do not possess control, are accounted for by the equity method of accounting within the financial statements and they are therefore not consolidated. Refer to Note 11 to the Consolidated Financial Statements for further details on our VIEs.
Basis of Accounting, Policy [Policy Text Block]	Our accounting and reporting policies conform to accounting principles generally accepted in the United States of America (GAAP). Additionally, where applicable, the policies conform to the accounting and reporting guidelines prescribed by bank regulatory authorities. Certain reclassifications may have been made to the prior periods’ financial statements and notes to conform to the current period’s presentation, which did not have a material impact on our Consolidated Financial Statements.
Use of Estimates, Policy [Policy Text Block]	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, legal and regulatory reserves, and the determination of the provision for income taxes.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and cash equivalents include cash on hand, cash on deposit at other financial institutions, cash items in process of collection, and certain highly liquid investments with maturities of three months or less from the date of purchase. Cash and cash equivalents that have restrictions on our ability to withdraw the funds are included in other assets on our Consolidated Balance Sheet. The book value of cash equivalents approximates fair value because of the short maturities of these instruments and the insignificant risk they present to changes in value with respect to changes in interest rates. Certain securities with original maturities of three months or less from the date of purchase that are held as a portion of longer-term investment portfolios, primarily held by our Insurance operations, are classified as investment securities.
Investment, Policy [Policy Text Block]	Our portfolio of investments includes various debt and marketable equity securities and nonmarketable equity investments. Debt and marketable equity securities are classified based on management’s intent to sell or hold the security. We classify debt securities as held-to-maturity only when we have both the intent and ability to hold the securities to maturity. We classify debt and marketable equity securities as trading when the securities are acquired for the purpose of selling or holding them for a short period of time. Securities not classified as either held-to-maturity or trading are classified as available-for-sale. Our debt and marketable equity securities include government securities, corporate bonds, asset-backed securities (ABS), mortgage-backed securities (MBS), equity securities and other investments. Our portfolio includes securities classified as available-for-sale and held-to-maturity. Our available-for-sale securities are carried at fair value with unrealized gains and losses included in accumulated other comprehensive income or loss and are subject to impairment. Our held-to-maturity securities are carried at amortized cost and are subject to impairment. We amortize premiums and discounts on debt securities as an adjustment to investment yield generally over the stated maturity of the security. For ABS and MBS where prepayments can be reasonably estimated, amortization is adjusted for expected prepayments. Additionally, we assess our debt and marketable equity securities for potential other-than-temporary impairment. We employ a methodology that considers available evidence in evaluating potential other-than-temporary impairment of our debt and marketable equity securities classified as available-for-sale and held-to-maturity. If the cost of an investment exceeds its fair value, we evaluate, among other factors, the magnitude and duration of the decline in fair value. We also evaluate the financial health of and business outlook for the issuer, the performance of the underlying assets for interests in securitized assets, and, for securities classified as available-for-sale, our intent and ability to hold the investment through recovery of its amortized cost basis. Once a decline in fair value of a debt security is determined to be other-than-temporary, an impairment charge for the credit component is recorded to other gain (loss) on investments, net, in our Consolidated Statement of Income, and a new cost basis in the investment is established. The noncredit loss component of a debt security is recorded in other comprehensive income (loss) when we do not intend to sell the security and it is not more likely than not that we will have to sell the security prior to the security's anticipated recovery. The credit and noncredit loss components are recorded in earnings when we intend to sell the security or it is more likely than not that we will have to sell the security prior to the security’s anticipated recovery. Unrealized losses that we have determined to be other-than-temporary on equity securities are recorded to other gain (loss) on investments, net in our Consolidated Statement of Income. Subsequent increases and decreases to the fair value of available-for-sale debt and equity securities are included in other comprehensive income (loss), so long as they are not attributable to another other-than-temporary impairment. Realized gains and losses on investment securities are reported in other gain (loss) on investments, net, and are determined using the specific identification method. For information on our debt and marketable equity securities, refer to Note 8 to the Consolidated Financial Statements . In addition to our investments in debt and marketable equity securities, we hold equity positions in other entities. These positions include Federal Home Loan Bank (FHLB) and Federal Reserve Bank (FRB) stock held to meet regulatory requirements, other equity investments that are not publicly traded and do not have a readily determinable fair value, equity investments in low income housing tax credits, and Community Reinvestment Act (CRA) equity investments, which are also not publicly traded and do not have a readily determinable fair value. Our investments in FHLB and FRB stock and other equity investments are accounted for using the cost method of accounting. Our low income housing tax credit investments are accounted for using the proportional amortization method of accounting for qualified affordable housing investments. Our obligations related to unfunded commitments for our low income housing tax credit investments are reported in other liabilities. Our CRA investments are accounted for using the equity method of accounting. Our FHLB and FRB stock and other equity investments carried at cost are included in nonmarketable equity investments in other assets. Our investments in low income housing tax credits and CRA are also included in other assets. As conditions warrant, we review our investments for impairment and will adjust the carrying value of the investment if it is deemed to be impaired. No impairment was recognized in 2016 or 2015. For more information on our nonmarketable equity investments, refer to Note 25 to the Consolidated Financial Statements
Finance, Loan and Lease Receivables Held-for-investment, Policy [Policy Text Block]	Finance receivables and loans are reported at their gross carrying value, which includes the principal amount outstanding, net of unamortized deferred fees and costs on originated loans, unamortized premiums and discounts on purchased loans, unamortized basis adjustments arising from the designation of finance receivables and loans as the hedged item in qualifying fair value hedge relationships, and cumulative principal charge-offs. We refer to the gross carrying value less the allowance for loan loss as the net carrying value in finance receivables and loans. Unearned rate support received from an automotive manufacturer on certain automotive loans, deferred origination fees and costs, and premiums and discounts on purchased loans, are amortized over the contractual life of the related finance receivable or loan using the effective interest method. We make various incentive payments for consumer automotive loan originations to automotive dealers and account for these payments as direct loan origination costs. Additionally, we make incentive payments to certain commercial automobile wholesale borrowers and account for these payments as a reduction to interest income in the period they are earned. Loan commitment fees are generally deferred and amortized over the commitment period. For information on finance receivables and loans, refer to Note 9 to the Consolidated Financial Statements . We initially classify finance receivables and loans as either loans held-for-sale or loans held-for-investment based on management's assessment of our intent and ability to hold loans for the foreseeable future or until maturity. Management's view of the foreseeable future is based on the longest reasonably reliable net income, liquidity, and capital forecast period. Management's intent and ability with respect to certain loans may change from time to time depending on a number of factors, for example economic, liquidity, and capital conditions. In order to reclassify loans to held-for-sale, management must have the intent to sell the loans and reasonably identify the specific loans to be sold. Loans classified as held-for-sale are carried at the lower of their net carrying value or fair value, unless the fair value option was elected, in which case those loans are carried at fair value. Interest income is recognized based upon the contractual rate of interest on the loan and the unpaid principal balance. We report accrued interest receivable on finance receivables and loans in other assets on the Consolidated Balance Sheet. Our portfolio segments are based on the level at which we develop and document our methodology for determining the allowance for loan losses. Additionally, the classes of finance receivables are based on several factors including the method for monitoring and assessing credit risk, the method of measuring carrying value, and the risk characteristics of the finance receivable. Based on an evaluation of our process for developing the allowance for loan losses including the nature and extent of exposure to credit risk arising from finance receivables, we have determined our portfolio segments to be consumer automotive, consumer mortgage, and commercial. • Consumer automotive — Consists of retail automotive financing for new and used vehicles. • Consumer mortgage — Consists of the following classes of finance receivables. • Mortgage Finance — Consists of consumer first mortgages from our ongoing mortgage operations including bulk acquisitions, originations, and refinancing of high-quality jumbo mortgages and low-to-moderate income (LMI) mortgages. In late 2016, we also introduced limited direct mortgage originations consisting of jumbo and conforming mortgages. Conforming mortgages will be originated as held-for-sale, while jumbo mortgages will be originated as held-for-investment. • Mortgage — Legacy — Consists of consumer mortgage assets originated prior to January 1, 2009, including first mortgages, subordinate-lien mortgages, and home equity mortgages. • Commercial — Consists of the following classes of finance receivables . • Commercial and Industrial • Automotive — Consists of financing operations to fund dealer purchases of new and used vehicles through wholesale floorplan financing. Additional commercial offerings include automotive dealer term loans, revolving lines of credit, and dealer fleet financing. • Other — Consists of senior secured leveraged cash flow and asset based loans. • Commercial Real Estate — Automotive — Consists of term loans to finance dealership land and buildings. Nonaccrual Loans Generally, we recognize loans of all classes as past due when they are 30 days delinquent on making a contractually required payment, and loans are placed on nonaccrual status when principal or interest has been delinquent for 90 days or when full collection is not expected. Interest income recognition is suspended when finance receivables and loans are placed on nonaccrual status. Additionally, amortization of premiums and discounts and deferred fees and costs ceases when finance receivables and loans are placed on nonaccrual. Exceptions include commercial real estate loans that are placed on nonaccrual status when delinquent for 60 days or when full collection is not probable, if sooner. Additionally, our policy is to generally place all loans that have been modified in troubled debt restructurings (TDRs) on nonaccrual status until the loan has been brought fully current, the collection of contractual principal and interest is reasonably assured, and six consecutive months of repayment performance is achieved. In certain cases, if a borrower has been current up to the time of the modification and repayment of the debt subsequent to the modification is reasonably assured, we may choose to continue to accrue interest on the loan. Loans on nonaccrual status are reported as nonperforming loans in Note 9 to the Consolidated Financial Statements . The receivable for interest income that is accrued, but not collected, at the date finance receivables and loans are placed on nonaccrual status is reversed against interest income and subsequently recognized only to the extent it is received in cash or until it qualifies for return to accrual status. However, where there is doubt regarding the ultimate collectability of loan principal, all cash received is applied to reduce the carrying value of such loans. Generally, finance receivables and loans are restored to accrual status only when contractually current and the collection of future payments is reasonably assured. Impaired Loans Loans of all classes are considered impaired when we determine it is probable that we will be unable to collect all amounts due (both principal and interest) according to the terms of the loan agreement. For all classes of consumer loans, impaired loans include all loans that have been modified in TDRs. Commercial loans of all classes are considered impaired on an individual basis and reported as impaired when we determine it is probable that we will be unable to collect all amounts due according to the terms of the loan agreement. With the exception of certain consumer TDRs that have been returned to accruing status, for all classes of impaired loans, income recognition is consistent with that of nonaccrual loans discussed above. Impaired loans may return to accrual status as discussed in the preceding nonaccrual loan section at which time, the normal accrual of interest income resumes. For collateral dependent loans, if the recorded investment in impaired loans exceeds the fair value of the collateral, a charge-off is recorded consistent with the TDR discussion below. Troubled Debt Restructurings When the terms of finance receivables or loans are modified, consideration must be given as to whether or not the modification results in a TDR. A modification is considered to be a TDR when both a) the borrower is experiencing financial difficulty and b) we grant a concession to the borrower. These considerations require significant judgment and vary by portfolio segment. In all cases, the cumulative impacts of all modifications are considered at the time of the most recent modification. For consumer loans of all classes, various qualitative factors are utilized for assessing the financial difficulty of the borrower. These include, but are not limited to, the borrower's default status on any of its debts, bankruptcy and recent changes in financial circumstances (loss of job, etc.). A concession has been granted when as a result of the modification we do not expect to collect all amounts due, including interest accrued at the original contract rate. Types of modifications that may be considered concessions include, but are not limited to, extensions of terms at a rate that does not constitute a market rate, a reduction, deferral or forgiveness of principal or interest owed and loans that have been discharged in a Chapter 7 Bankruptcy and have not been reaffirmed by the borrower. In addition to the modifications noted above, in our consumer automotive portfolio segment of loans we also provide extensions or deferrals of payments to borrowers whom we deem to be experiencing only temporary financial difficulty. In these cases, there are limits within our operational policies to minimize the number of times a loan can be extended, as well as limits to the length of each extension, including a cumulative cap over the life of the loan. Before offering an extension or deferral, we evaluate the capacity of the customer to make the scheduled payments after the deferral period. During the deferral period, we continue to accrue and collect interest on the loan as part of the deferral agreement. We grant these extensions or deferrals when we expect to collect all amounts due including interest accrued at the original contract rate. A restructuring that results in only a delay in payment that is deemed to be insignificant is not a concession and the modification is not considered to be a TDR. In order to assess whether a restructuring that results in a delay in payment is insignificant, we consider the amount of the restructured payments subject to delay in conjunction with the unpaid principal balance or the collateral value of the loan, whether or not the delay is significant with respect to the frequency of payments under the original contract, or the loan's original expected duration. In the cases where payment extensions on our automotive loan portfolio cumulatively extend beyond 90 days and are more than 10% of the original contractual term or where the cumulative payment extension is beyond 180 days, we deem the delay in payment to be more than insignificant, and as such, classify these types of modifications as TDRs. Otherwise, we believe that the modifications do not represent a concessionary modification and accordingly, they are not classified as TDRs. For commercial loans of all classes, similar qualitative factors are considered when assessing the financial difficulty of the borrower. In addition to the factors noted above, consideration is also given to the borrower's forecasted ability to service the debt in accordance with the contractual terms, possible regulatory actions and other potential business disruptions (e.g., the loss of a significant customer or other revenue stream). Consideration of a concession is also similar for commercial loans. In addition to the factors noted above, consideration is also given to whether additional guarantees or collateral have been provided. For all loans, TDR classification typically results from our loss mitigation activities. For loans held-for-investment that are not carried at fair value and are TDRs, impairment is typically measured based on the difference between the gross carrying value of the loan and the present value of the expected future cash flows of the loan. The loan may also be measured for impairment based on the fair value of the underlying collateral less costs to sell for loans that are collateral dependent. We recognize impairment by either establishing a valuation allowance or recording a charge-off. The financial impacts of modifications that meet the definition of a TDR are reported in the period in which they are identified as TDRs. Additionally, if a loan that is classified as a TDR redefaults within twelve months of the modification, we are required to disclose the instances of redefault. For the purpose of this disclosure, we have determined that a loan is considered to have redefaulted when the loan meets the requirements for evaluation under our charge-off policy except for commercial loans where redefault is defined as 90 days past due. Impaired loans may return to accrual status as discussed in the preceding nonaccrual loan section at which time, the normal accrual of interest income resumes. Net Charge-offs We disclose the measurement of net charge-offs as the amount of gross charge-offs recognized less recoveries received. Gross charge-offs reflect the amount of the gross carry value directly written-off. Generally, we recognize recoveries when they are received and record them as an increase to the allowance for loan losses. As a general rule, consumer automotive loans are written down to estimated collateral value, less costs to sell, once a loan becomes 120 days past due. In our consumer mortgage portfolio segment, first-lien mortgages and a subset of our home equity portfolio that are secured by real estate in a first-lien position are written down to the estimated fair value of the collateral, less costs to sell, once a mortgage loan becomes 180 days past due. Consumer mortgage loans that represent second-lien positions are charged off at 180 days past due. Consumer mortgage loans within our second-lien portfolio in bankruptcy that are 60 days past due are fully charged off within 60 days of receipt of notification of filing from the bankruptcy court. Consumer automotive and first-lien consumer mortgage loans in bankruptcy that are 60 days past due are written down to the estimated fair value of the collateral, less costs to sell, within 60 days of receipt of notification of filing from the bankruptcy court. Regardless of other timelines noted within this policy, loans are considered collateral dependent once foreclosure or repossession proceedings begin and are charged-off to the estimated fair value of the underlying collateral, less costs to sell at that time. Commercial loans are individually evaluated and where collectability of the recorded balance is in doubt are written down to the estimated fair value of the collateral less costs to sell. Generally, all commercial loans are charged-off when it becomes unlikely that the borrower is willing or able to repay the remaining balance of the loan and any underlying collateral is not sufficient to recover the outstanding principal. Collateral dependent loans are charged-off to the fair market value of collateral less costs to sell when appropriate. Noncollateral dependent loans are fully written-off.
Loans and Leases Receivable, Allowance for Loan Losses Policy [Policy Text Block]	The allowance for loan losses (the allowance) is management's estimate of incurred losses in the lending portfolios. We determine the amount of the allowance required for each of our portfolio segments based on its relative risk characteristics. The evaluation of these factors for both consumer and commercial finance receivables and loans involves quantitative analysis combined with sound management judgment. Additions to the allowance are charged to current period earnings through the provision for loan losses; amounts determined to be uncollectible are charged directly against the allowance, net of amounts recovered on previously charged-off accounts. The allowance is comprised of two components: specific reserves established for individual loans evaluated as impaired and portfolio-level reserves established for large groups of typically smaller balance homogeneous loans that are collectively evaluated for impairment. We evaluate the adequacy of the allowance based on the combined total of these two components. Determining the appropriateness of the allowance is complex and requires judgment by management about the effect of matters that are inherently uncertain. It is possible that others, given the same information, may at any point in time reach different reasonable conclusions. Measurement of impairment for specific reserves is generally determined on a loan-by-loan basis. Loans determined to be specifically impaired are measured based on the present value of expected future cash flows discounted at the loan's effective interest rate, an observable market price, or the estimated fair value of the collateral less estimated costs to sell when appropriate, whichever is determined to be the most appropriate. When these measurement values are lower than the net carrying value of that loan, impairment is recognized. Loans that are not identified as individually impaired are pooled with other loans with similar risk characteristics for evaluation of impairment for the portfolio-level allowance. For the purpose of calculating portfolio-level reserves, we have grouped our loans into three portfolio segments: consumer automotive, consumer mortgage, and commercial. The allowance consists of the combination of a quantitative assessment component based on statistical models, a retrospective evaluation of actual loss information to loss forecasts, and includes a qualitative component based on management judgment. Management takes into consideration relevant qualitative factors, including external and internal trends such as the impacts of changes in underwriting standards, collections and account management effectiveness, geographic concentrations, and economic events, among other factors, that have occurred but are not yet reflected in the quantitative assessment component. Qualitative adjustments are documented, reviewed, and approved through our established risk governance processes. During 2016, we did not substantively change any material aspect of our overall approach used to determine the allowance for loan losses for our portfolio segments. There were no material changes in criteria or estimation techniques as compared to prior periods that impacted the determination of the current period allowance for loan losses for our portfolio segments. Refer to Note 9 to the Consolidated Financial Statements for information on the allowance for loan losses. Consumer Loans Our consumer automotive and consumer mortgage portfolio segments are reviewed for impairment based on an analysis of loans that are grouped into common risk categories. We perform periodic and systematic detailed reviews of our lending portfolios to identify inherent risks and to assess the overall collectability of those portfolios. Loss models are utilized for these portfolios, which consider a variety of credit quality indicators including, but not limited to, historical loss experience, current economic conditions, credit scores, and expected loss factors by loan type. Consumer Automotive Portfolio Segment The allowance for loan losses within the consumer automotive portfolio segment is calculated using proprietary statistical models and other risk indicators applied to pools of loans with similar risk characteristics, including credit bureau score and loan-to-value ratios to arrive at an estimate of incurred losses in the portfolio. These statistical loss forecasting models are utilized to estimate incurred losses and consider a variety of factors including, but not limited to, historical loss experience, estimated defaults based on portfolio trends, and general economic and business trends. These statistical models predict forecasted losses inherent in the portfolio. The forecasted losses consider historical factors such as frequency (the number of contracts that we expect to default) and loss severity (the loss amount of contracts we expect to default). The loss severity within the consumer automotive portfolio segment is impacted by the market values of vehicles that are repossessed. Vehicle market values are affected by numerous factors including vehicle supply, the condition of the vehicle upon repossession, the overall price and volatility of gasoline or diesel fuel, consumer preference related to specific vehicle segments, and other factors. The quantitative assessment component of the allowance may be supplemented with qualitative reserves based on management's determination that such adjustments provide a better estimate of credit losses. This qualitative assessment takes into consideration relevant internal and external factors that have occurred but are not yet reflected in the forecasted losses and may affect the performance of the portfolio. Consumer Mortgage Portfolio Segment The allowance for loan losses within the consumer mortgage portfolio segment is calculated by using proprietary statistical models based on pools of loans with similar risk characteristics, including credit score, loan-to-value, loan age, documentation type, product type, and loan purpose, to arrive at an estimate of incurred losses in the portfolio. These statistical loss forecasting models are utilized to estimate incurred losses and consider a variety of factors including, but not limited to, historical loss experience, estimated foreclosures or defaults based on portfolio trends, delinquencies, and general economic and business trends. The forecasted losses are statistically derived based on a suite of behavioral based transition models. This transition framework predicts various stages of delinquency, default, and voluntary prepayment over the course of the life of the loan. The transition probability is a function of the loan and borrower characteristics and economic variables and considers historical factors such as frequency and loss severity. When a default event is predicted, a severity model is applied to estimate future loan losses. Loss severity within the consumer mortgage portfolio segment is impacted by the market values of foreclosed properties, which is affected by numerous factors, including geographic considerations and the condition of the foreclosed property. The quantitative assessment component of the allowance may be supplemented with qualitative reserves based on management's determination that such adjustments provide a better estimate of credit losses. This qualitative assessment takes into consideration relevant internal and external factors that have occurred but are not yet reflected in the forecasted losses and may affect the performance of the portfolio. Commercial Loans The allowance for loan losses within the commercial portfolio is comprised of reserves established for specific loans evaluated as impaired and portfolio-level reserves based on nonimpaired loans grouped into pools based on similar risk characteristics and collectively evaluated. A commercial loan is considered impaired when it is probable that we will be unable to collect all amounts due according to the contractual terms of the loan agreement based on current information and events. These loans are primarily evaluated individually and are risk-rated based on borrower, collateral, and industry-specific information that management believes is relevant in determining the occurrence of a loss event and measuring impairment. Management establishes specific allowances for commercial loans determined to be individually impaired based on the present value of expected future cash flows, discounted at the loan's effective interest rate, observable market price or the fair value of collateral, whichever is determined to be the most appropriate. Estimated costs to sell or realize the value of the collateral on a discounted basis are included in the impairment measurement, when appropriate. Loans not identified as impaired are grouped into pools based on similar risk characteristics and collectively evaluated. Our risk rating models use historical loss experience, concentrations, current economic conditions, and performance trends. The commercial historical loss experience is updated quarterly to incorporate the most recent data reflective of the current economic environment. The determination of the allowance is influenced by numerous assumptions and many factors that may materially affect estimates of loss, including volatility of loss given default, probability of default, and rating migration. In assessing the risk rating of a particular loan, several factors are considered including an evaluation of historical and current information involving subjective assessments and interpretations. In addition, the allowance related to the commercial portfolio segment is influenced by estimated recoveries from automotive manufacturers relative to guarantees or agreements with them to repurchase vehicles used as collateral to secure the loans. The quantitative assessment component of the allowance may be supplemented with qualitative reserves based on management's determination that such adjustments provide a better estimate of credit losses. This qualitative assessment takes into consideration relevant internal and external factors that have occurred but are not yet reflected in the forecasted losses and may affect the performance of the portfolio.
Consolidation, Variable Interest Entity, Policy [Policy Text Block]	We securitize, transfer, and service consumer and commercial automotive loans and operating leases. Securitization transactions typically involve the use of VIEs and are accounted for either as sales or secured borrowings. We may retain economic interests in the securitized and sold assets, which are generally retained in the form of senior or subordinated interests, interest- or principal-only strips, cash reserves, residual interests, and servicing rights. In order to conclude whether or not a variable interest entity is required to be consolidated, careful consideration and judgment must be given to our continuing involvement with the variable interest entity. In circumstances where we have both the power to direct the activities of the entity that most significantly impact the entity's performance and the obligation to absorb losses or the right to receive benefits of the entity that could be significant, we would conclude that we would consolidate the entity, which would also preclude us from recording an accounting sale on the transaction. In the case of a consolidated variable interest entity, the accounting is consistent with a secured borrowing, (e.g., we continue to carry the loans and we record the related securitized debt on our Consolidated Balance Sheet). In transactions where we are not determined to be the primary beneficiary of the VIE, we then must determine whether or not we achieve a sale for accounting purposes. In order to achieve a sale for accounting purposes, the assets being transferred must be legally isolated, not be constrained by restrictions from further transfer, and be deemed to be beyond our control. If we were to fail any of the three criteria for sale accounting, the accounting would be consistent with the preceding paragraph (i.e., a secured borrowing). Refer to Note 11 to the Consolidated Financial Statements for discussion on VIEs. Gains or losses on off-balance sheet securitizations take into consideration the fair value of the retained interests including the value of certain servicing assets or liabilities, if any, which are initially recorded at fair value at the date of sale. The estimate of the fair value of the retained interests and servicing requires us to exercise significant judgment about the timing and amount of future cash flows from the interests. Refer to Note 25 to the Consolidated Financial Statements for a discussion of fair value estimates. Gains or losses on off-balance sheet securitizations and sales are reported in gain (loss) on mortgage and automotive loans, net, in our Consolidated Statement of Income. Retained interests, as well as any purchased securities, are generally included in available-for-sale investment securities and follow the accounting as described above or are classified in other assets. Retained interests that are included in other assets are reported at fair value and include cash reserves and certain noncertificated residual interests. We retain servicing responsibilities for all of our consumer and commercial automotive loan and operating lease securitizations. We may receive servicing fees for off-balance sheet securitizations based on the securitized loan balances and certain ancillary fees, all of which are reported in servicing fees in the Consolidated Statement of Income. Typically, the fee we are paid for servicing consumer automotive finance receivables represents adequate compensation, and consequently, we do not recognize a servicing asset or liability. Whether on- or off-balance sheet, the investors in the securitization trusts generally have no recourse to our assets outside of protections afforded through customary market representation and warranty repurchase provisions.
Finance, Loan and Lease Receivables, Held for Investments, Foreclosed Assets Policy [Policy Text Block]	Assets are classified as repossessed and foreclosed and included in other assets when physical possession of the collateral is taken, which includes the transfer of title through foreclosure or other similar proceedings. Repossessed and foreclosed assets are carried at the lower of the outstanding balance at the time of repossession or foreclosure or the fair value of the asset less estimated costs to sell. Losses on the revaluation of repossessed and foreclosed assets are recognized as a charge-off of the allowance for loan losses at the time of repossession. Declines in value after repossession are charged to other operating expenses for loans and depreciation expense for operating lease assets as incurred.
Revenue Recognition Leases, Operating [Policy Text Block]	Investment in operating leases, net, represents the automobiles that are underlying the automotive lease contracts and is reported at cost, less accumulated depreciation and net of impairment charges and origination fees or costs. Depreciation of vehicles is recorded on a straight-line basis to an estimated residual value over the lease term. Manufacturer support payments that we receive upfront are treated as a reduction to the cost-basis in the underlying lease asset, which has the effect of reducing depreciation expense over the life of the contract. We periodically evaluate our depreciation rate for leased vehicles based on expected residual values and adjust depreciation expense over the remaining life of the lease if deemed appropriate. Income from operating lease assets that includes lease origination fees, net of lease origination costs, is recognized as operating lease revenue on a straight-line basis over the scheduled lease term. We have significant investments in the residual values of the assets in our operating lease portfolio. The residual values represent an estimate of the values of the assets at the end of the lease contracts. At contract inception, we determine pricing based on the projected residual value of the lease vehicle. This evaluation is primarily based on a proprietary model, which includes variables such as age, expected mileage, seasonality, segment factors, vehicle type, economic indicators, production cycle, automotive manufacturer incentives, and shifts in used vehicle supply. This internally-generated data is compared against third-party, independent data for reasonableness. Realization of the residual values is dependent on our future ability to market the vehicles under the prevailing market conditions. Over the life of the lease, we evaluate the adequacy of our estimate of the residual value and may make adjustments to the depreciation rates to the extent the expected value of the vehicle at lease termination changes. In addition to estimating the residual value at lease termination, we also evaluate the current value of the operating lease asset and test for impairment to the extent necessary based on market considerations and portfolio characteristics. Impairment is determined to exist if fair value of the leased asset is less than carrying value and it is determined that the net carrying value is not recoverable. The net carrying value of a leased asset is not recoverable if it exceeds the sum of the undiscounted expected future cash flows expected to result from the lease payments and the estimated residual value upon eventual disposition. No impairment was recognized in 2016 , 2015 , or 2014 . If our operating lease assets are considered to be impaired, the impairment is measured as the amount by which the carrying amount of the assets exceeds the fair value as estimated by discounted cash flows. We accrue rental income on our operating leases when collection is reasonably assured. We generally discontinue the accrual of revenue on operating leases at the time an account is determined to be uncollectible, at the earliest of time of repossession, within 60 days of bankruptcy notification and greater than 60 days past due, or greater than 120 days past due. When a lease vehicle is returned to us, the asset is reclassified from investment in operating leases, net, to other assets and recorded at the lower-of-cost or estimated fair value, less costs to sell, on our Consolidated Balance Sheet. Any losses recognized at this time are recorded as depreciation expense. Any gain or loss recognized at the time of sale of an off lease or repossessed lease vehicle is recognized as a remarketing gain or loss and presented as a component of depreciation expense.
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]	The net carrying value of long-lived assets (including property and equipment) are evaluated for impairment whenever events or changes in circumstances indicate that their net carrying values may not be recoverable from the estimated undiscounted future cash flows expected to result from their use and eventual disposition. Recoverability of assets to be held and used is measured by a comparison of their net carrying amount to future net undiscounted cash flows expected to be generated by the assets. If these assets are considered to be impaired, the impairment is measured as the amount by which the net carrying amount of the assets exceeds the fair value estimated using a discounted cash flow method. No material impairment was recognized in 2016 , 2015 , or 2014 . An impairment test on an asset group to be sold or otherwise disposed of is performed upon occurrence of a triggering event or when certain criteria are met (e.g., the asset is planned to be disposed of within twelve months, appropriate levels of authority have approved the sale, there is an active program to locate a buyer, etc.), which cause the disposal group to be classified as held-for-sale. Long-lived assets held-for-sale are recorded at the lower of their carrying amount or estimated fair value less cost to sell. If the net carrying value of the assets held-for-sale exceeds the fair value less cost to sell, we recognize an impairment loss based on the excess of the net carrying amount over the fair value of the assets less cost to sell. Refer to Note 3 to the Consolidated Financial Statements for a discussion of discontinued and held-for-sale operations.
Property, Plant and Equipment, Policy [Policy Text Block]	Property and equipment stated at cost, net of accumulated depreciation and amortization, are reported in other assets on our Consolidated Balance Sheet. Included in property and equipment are certain buildings, furniture and fixtures, leasehold improvements, company vehicles, IT hardware and software, capitalized software costs, and assets under construction. We begin depreciating these assets when they are ready for their intended use. Depreciation is recorded on a straight-line basis over the estimated useful lives of the assets, which generally ranges from three to thirty years. Capitalized software is generally amortized on a straight-line basis over its useful life, which generally ranges from three to five years. Capitalized software that is not expected to provide substantive service potential or for which development costs significantly exceed the amount originally expected is considered impaired and written down to fair value. Software expenditures that are considered general, administrative, or of a maintenance nature are expensed as incurred.
Business Combinations Policy [Policy Text Block]	We account for our business acquisitions using the acquisition method of accounting. Under this method, we generally record the initial carrying values of purchased assets, including identifiable intangible assets, and assumed liabilities at fair value on the acquisition date. We recognize goodwill when the acquisition price is greater than the fair value of the net assets acquired, including identifiable intangible assets. The initial fair value of recognized assets and liabilities are subject to refinement during the measurement period, a period up to one year after the closing date of an acquisition, as information relative to closing date fair values becomes available. Costs directly related to business combinations are recorded as expenses as they are incurred.
Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]	Goodwill and intangible assets, net of accumulated amortization, are reported in other assets. Our intangible assets primarily consist of acquired customer relationships and developed technology, and are amortized using a straight line methodology over their estimated useful lives. We review intangible assets for impairment at least annually, or whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable. If it is determined the carrying amount of the asset is not recoverable, an impairment charge is recorded. Refer to Note 2 to the Consolidated Financial Statements for further discussion on intangible assets. Goodwill represents the excess of the cost of an acquisition over the fair value of net assets acquired, including identifiable intangibles. We allocate goodwill to applicable reporting units based on the relative fair value of other net assets allocated to those reporting units at the time of the acquisition. In the event we restructure our business, we may reallocate goodwill. We test goodwill for impairment annually, or more frequently if events and changes in circumstances indicate that it is more likely than not that impairment exists. Our annual goodwill impairment test is performed as of August 31 of each year. In certain situations, we may perform a qualitative assessment to test goodwill for impairment. We may also decide to bypass the qualitative assessment and perform a quantitative assessment. If we perform the qualitative assessment to test goodwill for impairment and conclude that it is more likely than not that the reporting unit’s fair value is greater than its carrying value, then the quantitative assessment is not required. However, if we perform the qualitative assessment and determine that it is more likely than not that a reporting unit’s fair value is less than its carrying value, then we must perform the quantitative assessment. The quantitative assessment uses a two-step process. The first step of the assessment requires us to compare the fair value of each of the reporting units to their respective carrying value. The fair value of the reporting units in our quantitative assessment is determined based on various analyses including discounted cash flow projections using assumptions a market participant would use. If the carrying value is less than the fair value, no impairment exists, and the second step does not need to be completed. If the carrying value is higher than the fair value or there is an indication that impairment may exist, a second step must be performed where we determine the implied value of goodwill based on the individual fair values of the reporting unit's assets and liabilities, including unrecognized intangibles, to compute the amount of the impairment. Refer to Note 2 to the Consolidated Financial Statements for further discussion on goodwill.
Revenue Recognition, Deferred Revenue [Policy Text Block]	Insurance premiums, net of premiums ceded to reinsurers, and service revenue are earned over the terms of the policies. The portion of premiums and service revenue written applicable to the unexpired terms of the policies is recorded as unearned insurance premiums or unearned service revenue. For extended service and maintenance contracts, premiums and service revenues are earned on a basis proportionate to the anticipated cost emergence. For other short duration contracts, premiums and unearned service revenue are earned on a pro rata basis. For further information, refer to Note 4 to the Consolidated Financial Statements .
Deferred Charges, Policy [Policy Text Block]	Certain incremental direct costs incurred to originate a policy are deferred and recorded in other assets. These costs primarily include commissions paid to dealers to originate these policies and vary with the production of business. Deferred policy acquisition costs are amortized over the terms of the related policies and service contracts on the same basis as premiums and service revenue are earned. We group costs incurred for acquiring like contracts and consider anticipated investment income in determining the recoverability of these costs.
Unpaid Policy Claims and Claims Adjustment Expense, Policy [Policy Text Block]	Reserves for insurance losses and loss adjustment expenses are reported in accrued expenses and other liabilities on our Consolidated Balance Sheet. They are established for the unpaid cost of insured events that have occurred as of a point in time. More specifically, the reserves for insurance losses and loss adjustment expenses represent the accumulation of estimates for both reported losses and those incurred, but not reported, including loss adjustment expenses relating to direct insurance and assumed reinsurance agreements. We use a combination of methods, including the chain ladder development factor, expected loss, Bornhuetter Ferguson (BF), and frequency and severity methods to determine the ultimate losses for an individual line of business as well as accident year basis depending on the maturity of the accident period and line of business specifics. Development methods are used for more mature years where expected loss, BF, and frequency and severity methods are used for less mature years. Both paid and incurred loss and loss adjustment expenses are reviewed where available and a weighted average of estimates or a single method may be considered in selecting the final estimate for an individual accident period. We did not change our methodology for developing reserves for insurance losses for the year ended December 31, 2016 . Estimates for salvage and subrogation recoverable are recognized at the time losses are incurred and netted against the provision for insurance losses and loss adjustment expenses. Reserves are established for each business at the lowest meaningful level of homogeneous data. Since the reserves are based on estimates, the ultimate liability may vary from such estimates. The estimates are regularly reviewed and adjustments, which can potentially be significant, are included in earnings in the period in which they are deemed necessary.
Legal Costs, Policy [Policy Text Block]	Reserves for legal and regulatory matters are established when those matters present loss contingencies that are both probable and estimable, with a corresponding amount recorded to other operating expense. In cases where we have an accrual for losses, it is our policy to include an estimate for probable and estimable legal expenses related to the case. If, at the time of evaluation, the loss contingency related to a legal or regulatory matter is not both probable and estimable, we do not establish an accrued liability. We continue to monitor legal and regulatory matters for further developments that could affect the requirement to establish a liability or that may impact the amount of a previously established liability. There may be exposure to loss in excess of any amounts recognized. For certain other matters where the risk of loss is determined to be reasonably possible, estimable, and material to the financial statements, disclosure regarding details of the matter and an estimated range of loss is required. The estimated range of possible loss does not represent our maximum loss exposure. Financial statement disclosure is also required for matters that are deemed probable or reasonably possible, material to the financial statements, but for which an estimated range of loss is not possible to determine. While we believe our reserves are adequate, the outcome of legal and regulatory proceedings is extremely difficult to predict and we may settle claims or be subject to judgments for amounts that differ from our estimates. For information regarding the nature of all material contingencies, refer to Note 30 to the Consolidated Financial Statements .
Earnings Per Share, Policy [Policy Text Block]	We compute basic earnings (loss) per common share by dividing net income (loss) from continuing operations attributable to common shareholders after deducting dividends on preferred stock by the weighted-average number of common shares outstanding during the period. We compute diluted earnings (loss) per common share by dividing net income (loss) from continuing operations after deducting dividends on preferred stock by the weighted-average number of common shares outstanding during the period plus the dilution resulting from incremental shares that would have been outstanding if dilutive potential common shares had been issued (assuming it does not have the effect of antidilution), if applicable.
Derivatives, Policy [Policy Text Block]	We primarily use derivative instruments for risk management purposes. We do not use derivative instruments for speculative purposes. Some of our derivative instruments are designated in qualifying hedge accounting relationships; other derivative instruments do not qualify for hedge accounting or are not elected to be designated in a qualifying hedging relationship. In accordance with applicable accounting standards, all derivative instruments, whether designated for hedge accounting or not, are required to be recorded on the balance sheet as assets or liabilities and measured at fair value. Additionally, we have elected to report the fair value amounts recognized for derivative financial instruments, including the fair value amounts recognized for the right to reclaim cash collateral or the obligation to return cash collateral arising from derivative instruments recognized at fair value executed with the same counterparty under a master netting arrangement, on the Consolidated Balance Sheet on a gross basis where we do not have the intent to offset . For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements . At inception of a hedge accounting relationship, we designate each qualifying derivative financial instrument as a hedge of the fair value of a specifically identified asset or liability (fair value hedge); as a hedge of the variability of cash flows to be received or paid related to a recognized asset or liability (cash flow hedge); or as a hedge of the foreign-currency exposure of a net investment in a foreign operation (net investment hedge). We formally document all relationships between hedging instruments and hedged items and risk management objectives for undertaking various hedge transactions. Both at the hedge's inception and on an ongoing basis, we formally assess whether the derivatives that are used in hedging relationships are highly effective in offsetting changes in fair values or cash flows of hedged items. Changes in the fair value of derivative instruments that are designated and qualify as fair value hedges, along with the gain or loss on the hedged asset or liability attributable to the hedged risk, are recorded in current period earnings. For qualifying cash flow hedges, the effective portion of the change in the fair value of the derivative financial instruments is recorded in accumulated other comprehensive income, and recognized in the income statement when the hedged cash flows affect earnings. For a qualifying net investment hedge, the gain or loss is reported in accumulated other comprehensive income as part of the cumulative translation adjustment. The ineffective portions of fair value, cash flow, and net investment hedges are immediately recognized in earnings, along with the portion of the change in fair value that is excluded from the assessment of hedge effectiveness, if any. The hedge accounting treatment described herein is no longer applied if a derivative financial instrument is terminated or the hedge designation is removed or is assessed to be no longer highly effective. For these terminated fair value hedges, any changes to the hedged asset or liability remain as part of the basis of the hedged asset or liability and are recognized into income over the remaining life of the asset or liability. For terminated cash flow hedges, unless it is probable that the forecasted cash flows will not occur within a specified period, any changes in fair value of the derivative financial instrument previously recognized remain in accumulated other comprehensive income, and are reclassified into earnings in the same period that the hedged cash flows affect earnings. The previously recognized gain or loss for a net investment hedge continues to remain in accumulated other comprehensive income until earnings are impacted by sale or liquidation of the associated foreign operation. In all instances, after hedge accounting is no longer applied, any subsequent changes in fair value of the derivative instrument will be recorded into earnings. Changes in the fair value of derivative financial instruments held for risk management purposes that are not designated for hedge accounting under GAAP are reported in current period earnings.
Income Tax, Policy [Policy Text Block]	Our income tax expense, deferred tax assets and liabilities, and reserves for unrecognized tax benefits reflect management's best assessment of estimated future taxes to be paid. We are subject to income taxes predominantly in the United States. Significant judgments and estimates are required in determining the consolidated income tax expense. Deferred income taxes arise from temporary differences between the tax and financial statement recognition of revenue and expense. In evaluating our ability to recover our deferred tax assets within the jurisdiction from which they arise we consider all available positive and negative evidence including scheduled reversals of deferred tax liabilities, projected future taxable income, tax planning strategies and recent financial operations. In projecting future taxable income, we begin with historical results adjusted for the results of discontinued operations and changes in accounting policies and incorporate assumptions including the amount of future state, federal and foreign pretax operating income, the reversal of temporary differences, and the implementation of feasible and prudent tax planning strategies. We recognize the financial statement effects of uncertain income tax positions when it is more likely than not, based on the technical merits, that the position will be sustained upon examination. Also, we recognize accrued interest and penalties related to liabilities for uncertain income tax positions in interest expense and other operating expenses, respectively. For additional information regarding our provision for income taxes, refer to Note 23 to the Consolidated Financial Statements .
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	Under accounting guidance for share-based compensation, compensation cost recognized includes the cost of share-based awards. For equity classified share-based awards, compensation cost is ratably charged to expense based on the grant date fair value of the awards over the applicable service periods. For liability classified share-based awards, the associated liability is measured quarterly at fair value based on our share price and services rendered at the time of measurement until the awards are paid, with changes in fair value charged to compensation expense in the period in which the change occurs. As a result of the adoption of Accounting Standards Update (ASU) 2016-09, Stock Compensation — Improvements to Employee Share-Based Payment Accounting , we have made an accounting policy election to account for forfeitures of share-based awards as they occur. Refer to Note 24 to the Consolidated Financial Statements for a discussion of our share-based compensation plans.
Foreign Currency Transactions and Translations Policy [Policy Text Block]	Foreign-denominated assets and liabilities resulting from foreign-currency transactions are valued using period-end foreign-exchange rates and the results of operations and cash flows are determined using approximate weighted average exchange rates for the period. Translation adjustments are related to foreign subsidiaries using local currency as their functional currency and are reported as a separate component of accumulated other comprehensive income. Translation gains or losses are reclassified to earnings upon the substantial sale or liquidation of our investments in foreign operations. We may elect to enter into foreign-currency derivatives to mitigate our exposure to changes in foreign-exchange rates. Refer to the Derivative Instruments and Hedging Activities section above for a discussion of our hedging activities of the foreign-currency exposure of a net investment in a foreign operation.
New Accounting Pronouncements, Policy [Text Block]	Recently Adopted Accounting Standards Consolidation — Amendments to the Consolidation Analysis (ASU 2015-02) As of January 1, 2016, we adopted ASU 2015-02. The amendments in this update modify the requirements of consolidation with respect to entities that are or are similar in nature to limited partnerships or are variable interest entities (VIEs). For entities that are or are similar to limited partnerships, the guidance clarifies the evaluation of kick-out rights, removes the presumption that the general partner will consolidate and generally states that such entities will be presumed to be VIEs unless proven otherwise. For VIEs, the guidance modifies the analysis related to the evaluation of servicing fees, excludes servicing fees that are deemed commensurate with the level of service required from the determination of the primary beneficiary and clarifies certain considerations related to the consolidation analysis when performing a related party assessment. The amendments in this guidance did not impact our historical VIE and consolidation conclusions. No adjustments to our consolidated financial statements were required as a result of the adoption of this guidance. Stock Compensation — Improvements to Employee Share-Based Payment Accounting (ASU 2016-09) As of December 31, 2016, we adopted ASU 2016-09. The amendments in this update include changes to several aspects of share-based payment accounting. The amendments allow for an entity-wide accounting policy election to either account for forfeitures as they occur or estimate the number of awards that are expected to vest. We elected to account for forfeitures as they occur. The amendments modify the tax withholding requirements to allow entities to withhold an amount up to the employee’s maximum individual statutory tax rates without resulting in a liability classification of the award as opposed to limiting the withholding to the minimum statutory tax rates as required under previous accounting guidance. The amendments require that all excess tax benefits and tax deficiencies related to share-based payment awards should be recognized in income tax expense or benefit in the income statement in the period in which they occur. The adoption of these amendments did not have a material impact to the financial statements. The amendments also address the classification and presentation of certain items on the cash flow statement. Specifically, cash flows related to excess tax benefits should be classified as an operating activity instead of a financing activity and cash flows related to cash paid to a tax authority by an employer when withholding shares from an employee’s award for tax withholding purposes should be classified as a financing activity. The adoption of the amendment requiring excess tax benefits to be classified as an operating activity did not have a material impact to our consolidated statement of cash flows. The adoption of the amendment which requires amounts paid to a tax authority by an employer when withholding shares from an employee’s award for tax withholding purposes to be classified as a financing activity resulted in the reclassification of cash flows in our consolidated statement of cash flows for fiscal years ending December 31, 2016 , and 2015 , of $14 million and $16 million , respectively, from operating activities to financing activities. The impact for 2014 was not material to our consolidated statement of cash flows. Recently Issued Accounting Standards Revenue from Contracts with Customers (ASU 2014-09) and Revenue from Contracts with Customers — Deferral of the Effective Date (ASU 2015-14) In May 2014, the Financial Accounting Standards Board (FASB) issued ASU 2014-09. The purpose of this guidance is to streamline and consolidate existing revenue recognition principles in GAAP and to converge revenue recognition principles with International Financial Reporting Standards (IFRS). The core principle of the amendments is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to receive in exchange for those goods or services. The amendments include a five step process for consideration of the main principle, guidance on the accounting treatment for costs associated with a contract, and disclosure requirements related to the revenue process. As originally issued, the amendments in ASU 2014-09 were to be effective beginning on January 1, 2017. However, in August 2015, the FASB issued ASU 2015-14, which deferred the effective date of the guidance until January 1, 2018, and permitted early adoption as of the original effective date in ASU 2014-09. The FASB created a transition resource group to work with stakeholders and clarify the new guidance as necessary. The FASB has issued several additional ASUs to provide clarifying guidance and implementation support for ASU 2014-09. Management has considered these additional ASUs when assessing the overall impact of ASU 2014-09. The amendments to the revenue recognition principles can be applied on adoption either through a full retrospective application or on a modified basis with a cumulative effect adjustment on the date of initial adoption with certain practical expedients. A majority of our revenue streams are not in scope of this ASU as they are governed by other accounting standards. Management has determined that certain revenue streams and contractual arrangements are in scope of this guidance. Management does not expect these amendments to impact current revenue recognition patterns for a majority of the in scope revenue streams and contracts. However, we expect that the application of this guidance to noninsurance contracts within our insurance business will result in the deferral of certain amounts we currently recognize as revenue upon the origination of the contract. We do not expect the impact of the new guidance to these specific contracts to be material to the financial statements. Management has not yet determined whether we will adopt this guidance using the full retrospective approach or the modified retrospective approach. Financial Instruments — Recognition and Measurement of Financial Assets (ASU 2016-01) In January 2016, the FASB issued ASU 2016-01. The amendments in this update modify the requirements related to the measurement of certain financial instruments in the statement of financial condition and results of operation. For equity investments (other than investments accounted for using the equity method), entities must measure such instruments at fair value with changes in fair value recognized in net income. Changes in fair value for available-for-sale equity securities will no longer be recognized through other comprehensive income. Reporting entities may continue to elect to measure equity investments that do not have a readily determinable fair value at cost with adjustments for impairment and observable changes in price. In addition, for a liability (other than a derivative liability) that an entity measures at fair value, any change in fair value related to the instrument-specific credit risk, that is the entity’s own-credit, should be presented separately in other comprehensive income and not as a component of net income. The amendments are effective on January 1, 2018, with early adoption permitted solely for the provisions pertaining to instrument-specific credit risk for liabilities measured at fair value. The amendments must be applied on a modified retrospective basis with a cumulative effect adjustment as of the beginning of the fiscal year of initial adoption. The amendment requiring equity investments to be measured at fair value with changes in fair value recognized in net income will create additional volatility in our consolidated results of operations since changes in fair value for available-for-sale securities will be recognized in net income as opposed to other comprehensive income as required under existing accounting guidance. Management continues to evaluate the impact of the other amendments. However, we do not anticipate the other amendments to have a material impact to our financial statements. Leases (ASU 2016-02) In February 2016, the FASB issued ASU 2016-02. The amendments in this update primarily replace the existing accounting requirements for operating leases for lessees. Lessee accounting requirements for finance leases and lessor accounting requirements for both operating leases and sales type and direct financing leases (both of which were previously referred to as capital leases) are largely unchanged. The amendments require the lessee of an operating lease to record a balance sheet gross-up upon lease commencement by recognizing a right-of-use asset and lease liability equal to the present value of the lease payments. The right-of-use asset and lease liability should be derecognized in a manner that effectively yields a straight line lease expense over the lease term. In addition to the changes to the lessee operating lease accounting requirements, the amendments also change the types of costs that can be capitalized related to a lease agreement for both lessees and lessors for all types of leases. The amendments also require additional disclosures for all lease types for both lessees and lessors. The amendments are effective on January 1, 2019, with early adoption permitted. The amendments must be applied on a modified retrospective basis with a cumulative adjustment to the beginning of the earliest fiscal year presented in the financial statements in the period of adoption. Management is currently evaluating the impact of these amendments. Upon adoption, we expect to record a balance sheet gross up, reflecting our right-of-use asset and lease liability for our operating leases where we are the lessee (for example, our facility leases). We are currently reviewing our operating lease contracts where we are the lessee to determine the impact of the gross up and the changes to capitalizable costs. We are also reviewing our leases where we are the lessor to determine the impact of the changes to capitalizable costs. Financial Instruments — Credit Losses (ASU 2016-13) In June 2016, the FASB issued ASU 2016-13. The amendments in this update introduce a new accounting model to measure credit losses for financial assets measured at amortized cost. Credit losses for financial assets measured at amortized cost should be determined based on the total current expected credit losses over the life of the financial asset or group of financial assets. In effect, the financial asset or group of financial assets should be presented at the net amount expected to be collected. Credit losses will no longer be measured as they are incurred for financial assets measured at amortized cost. The amendments also modify the accounting for available-for-sale debt securities whereby credit losses will be recorded through an allowance for credit losses rather than a write-down to the security’s cost basis, which allows for reversals of credit losses when estimated credit losses decline. Credit losses for available-for-sale debt securities should be measured in a manner similar to current GAAP. The amendments are effective on January 1, 2020, with early adoption permitted as of January 1, 2019. The amendments must be applied using a modified retrospective approach with a cumulative-effect adjustment through retained earnings as of the beginning of the fiscal year upon adoption. The new accounting model for credit losses represents a significant departure from existing GAAP, and will likely materially increase the allowance for credit losses with a resulting negative adjustment to retained earnings. Management created a formal working group to govern the implementation of these amendments consisting of key stakeholders from finance, risk, and accounting and is currently evaluating the impact of the amendments.

Discontinued Operations Discont

Discontinued Operations Discontinued Operations (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Discontinued Operations, Policy [Policy Text Block]	Prior to the adoption of ASU 2014-08, which was prospectively applied only to newly identified disposals that qualify as discontinued operations beginning after January 1, 2015, we have classified operations as discontinued when operations and cash flows will be eliminated from our ongoing operations and we do not expect to retain any significant continuing involvement in their operations after the respective sale or disposal transactions. For all periods presented, the operating results for these discontinued operations have been removed from continuing operations and presented separately as discontinued operations, net of tax, in the Consolidated Statement of Income . The Notes to the Consolidated Financial Statements have been adjusted to exclude discontinued operations unless otherwise noted.

Acquisitions Acquisitions (Tabl

Acquisitions Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2016
Business Acquisition [Line Items]
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	The following table summarizes the allocation of cash consideration paid for TradeKing and the amounts of the identifiable assets acquired and liabilities assumed recognized at the acquisition date. ($ in millions) Purchase price Cash consideration $ 298 Allocation of purchase price to net assets acquired Intangible assets (a) 82 Cash and short-term investments (b) 50 Other assets 14 Deferred tax asset, net 4 Employee compensation and benefits (41 ) Other liabilities (4 ) Goodwill $ 193 (a) We recorded $6 million of amortization on these intangible assets during the year ended December 31, 2016. (b) Includes $40 million in cash proceeds from the acquisition transaction in order to pay employee compensation and benefits that vested upon acquisition as a result of the change in control.

Discontinued Operations (Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations [Table Text Block]	Select financial information of discontinued operations is summarized below. The pretax income or loss includes direct costs to transact a sale. Year ended December 31, ($ in millions) 2016 2015 2014 Select Automotive Finance operations Total net revenue $ — $ — $ 123 Pretax (loss) income (a) (2 ) 452 129 Tax expense (b) 2 80 7 Other operations Pretax (loss) income $ (41 ) $ 16 $ 25 Tax benefit (1 ) (4 ) (78 ) (a) Includes certain treasury and other corporate activity recognized by Corporate and Other. (b) Includes certain income tax activity recognized by Corporate and Other.

Insurance Premiums and Servic44

Insurance Premiums and Service Revenue Earned Insurance Premiums and Service Revenue Earned (Tables)	12 Months Ended
	Dec. 31, 2016
Insurance Premiums and Service Revenue Earned [Abstract]
Insurance Premiums and Service Revenue Earned [Table Text Block]	The following table is a summary of insurance premiums and service revenue written and earned. 2016 2015 2014 Year ended December 31, ($ in millions) Written Earned Written Earned Written Earned Insurance premiums Direct $ 317 $ 318 $ 313 $ 296 $ 294 $ 282 Assumed 3 5 2 16 43 54 Gross insurance premiums 320 323 315 312 337 336 Ceded (198 ) (141 ) (184 ) (125 ) (156 ) (117 ) Net insurance premiums 122 182 131 187 181 219 Service revenue 826 763 846 753 842 760 Insurance premiums and service revenue written and earned $ 948 $ 945 $ 977 $ 940 $ 1,023 $ 979

Other Income, Net of Losses (Ta

Other Income, Net of Losses (Tables)	12 Months Ended
	Dec. 31, 2016
Other Nonoperating Income (Expense) [Abstract]
Schedule of Other Nonoperating Income, by Component [Table Text Block]	Details of other income, net of losses, were as follows. Year ended December 31, ($ in millions) 2016 2015 2014 Remarketing fees $ 103 $ 101 $ 112 Late charges and other administrative fees 98 90 88 Servicing fees 64 45 31 Income from equity-method investments 18 52 18 Other, net 111 71 62 Total other income, net of losses $ 394 $ 359 $ 311

Reserves for Insurance Losses46

Reserves for Insurance Losses and Loss Adjustment Expenses Reserves for Insurance Losses and Loss Adjustment Expenses (Tables)	12 Months Ended
	Dec. 31, 2016
Insurance Liability for Unpaid Claims and Claims Adjustment Expenses [Abstract]
Short-duration Insurance Contracts, Claims Development [Table Text Block]	The following table shows cumulative incurred claims and allocated loss adjustment expenses, net of reinsurance. For the years ended December 31, ($ in millions) December 31, 2016 ($ in millions) Accident year (a) 2012 (b) 2013 (b) 2014 (b) 2015 (b) 2016 Total of incurred-but-not-reported liabilities plus expected development on reported claims (c) Cumulative number of reported claims (c) 2012 $ 435 $ 430 $ 423 $ 423 $ 423 $ 4 772,536 2013 376 365 370 370 2 672,247 2014 390 389 388 — 525,235 2015 274 271 — 342,054 2016 326 $ 24 453,807 Total $ 1,778 (a) Due to the discontinuation of various product lines and sale of certain international operations, information prior to 2012 has been excluded from the table in order to appropriately reflect the number of years for which claims are typically outstanding. In addition, given the short tail of our insurance contracts, the table above reflects the combined presentation of all business lines. (b) Information presented for the years 2012 through 2015 is unaudited supplementary information. (c) Claims are reported on a claimant basis. Claimant is defined as one vehicle for guaranteed asset protection (GAP) products, one repair visit for vehicle service contracts (VSCs) and vehicle maintenance contracts (VMCs), one dealership for dealer inventory products, and per individual/coverage for run-off personal auto products. The following table shows cumulative paid claims and allocated loss adjustment expenses, net of reinsurance. For the years ended December 31, ($ in millions) Accident year (a) 2012 (b) 2013 (b) 2014 (b) 2015 (b) 2016 2012 $ 391 $ 412 $ 416 $ 418 $ 419 2013 347 364 366 368 2014 369 388 388 2015 252 272 2016 302 Total 1,749 All outstanding liabilities for loss and allocated loss adjustment expenses before 2012, net of reinsurance 9 Reserves for insurance losses and allocated loss adjustment expenses, net of reinsurance $ 38 (a) Due to the discontinuation of various product lines and sale of certain international operations, information prior to 2012 has been excluded from the table in order to appropriately reflect the number of years for which claims are typically outstanding. In addition, given the short tail of our insurance contracts, the table above reflects the combined presentation of all business lines. (b) Information presented for the years 2012 through 2015 is unaudited supplementary information.
Short-duration Insurance Contracts, Schedule of Historical Claims Duration [Table Text Block]	The following table shows the average annual percentage payout of incurred claims by age, net of reinsurance. The information presented is unaudited supplementary information. Year 1 2 3 4 5 Percentage payout of incurred claims 93.4 % 5.5 % 0.4 % 0.5 % 0.1 %
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Table Text Block]	The following table shows a reconciliation of the disclosures of incurred and paid claims development to the reserves for insurance losses and loss adjustment expenses . December 31, ($ in millions) 2016 Reserves for insurance losses and loss adjustment expenses, net of reinsurance $ 38 Total reinsurance recoverable on unpaid claims 108 Unallocated loss adjustment expenses 3 Total gross reserves for insurance losses and loss adjustment expenses $ 149
Schedule of Liability for Unpaid Claims and Claims Adjustment Expense	The following table shows a rollforward of our reserves for insurance losses and loss adjustment expenses. ($ in millions) Total gross reserves for insurance losses and loss adjustment expenses at January 1, 2016 $ 169 Less: Reinsurance recoverable 120 Net reserves for insurance losses and loss adjustment expenses at January 1, 2016 49 Net insurance losses and loss adjustment expenses incurred related to: Current year 345 Prior years (a) (3 ) Total net insurance losses and loss adjustment expenses incurred 342 Net insurance losses and loss adjustment expenses paid or payable related to: Current year (320 ) Prior years (30 ) Total net insurance losses and loss adjustment expenses paid or payable (350 ) Net reserves for insurance losses and loss adjustment expenses at December 31, 2016 41 Plus: Reinsurance recoverable 108 Total gross reserves for insurance losses and loss adjustment expenses at December 31, 2016 $ 149 (a) There have been no material adverse changes to the reserve for prior years.

Other Operating Expenses (Table

Other Operating Expenses (Tables)	12 Months Ended
	Dec. 31, 2016
Operating Expenses [Abstract]
Schedule of Other Operating Cost and Expense, by Component [Table Text Block]	Details of other operating expenses were as follows. Year ended December 31, ($ in millions) 2016 2015 2014 Insurance commissions $ 389 $ 378 $ 374 Technology and communications 274 267 334 Lease and loan administration 136 126 122 Advertising and marketing 112 107 111 Professional services 103 93 100 Vehicle remarketing and repossession 95 78 83 Regulatory and licensing fees 94 79 87 Premises and equipment depreciation 84 82 81 Occupancy 51 50 47 Non-income taxes 25 29 40 Other 242 216 212 Total other operating expenses $ 1,605 $ 1,505 $ 1,591

Investment Securities (Tables)

Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Investment [Table Text Block]	Our portfolio of securities includes bonds, equity securities, asset-backed securities, commercial and residential mortgage-backed securities, and other investments. The cost, fair value, and gross unrealized gains and losses on investment securities were as follows. 2016 2015 Amortized cost Gross unrealized Fair value Amortized cost Gross unrealized Fair December 31, ($ in millions) gains losses gains losses Available-for-sale securities Debt securities U.S. Treasury and federal agencies $ 1,680 $ — $ (60 ) $ 1,620 $ 1,760 $ — $ (19 ) $ 1,741 U.S. States and political subdivisions 794 7 (19 ) 782 693 24 (1 ) 716 Foreign government 157 5 — 162 169 8 — 177 Agency mortgage-backed residential 10,473 29 (212 ) 10,290 7,553 46 (55 ) 7,544 Mortgage-backed residential 2,162 5 (70 ) 2,097 2,906 6 (90 ) 2,822 Mortgage-backed commercial 537 2 (2 ) 537 486 — (5 ) 481 Asset-backed 1,396 6 (2 ) 1,400 1,762 1 (8 ) 1,755 Corporate debt 1,452 7 (16 ) 1,443 1,213 8 (17 ) 1,204 Total debt securities (a) (b) 18,651 61 (381 ) 18,331 16,542 93 (195 ) 16,440 Equity securities 642 7 (54 ) 595 808 3 (94 ) 717 Total available-for-sale securities $ 19,293 $ 68 $ (435 ) $ 18,926 $ 17,350 $ 96 $ (289 ) $ 17,157 Total held-to-maturity securities (c) (d) $ 839 $ — $ (50 ) $ 789 $ — $ — $ — $ — (a) Certain entities related to our Insurance operations are required to deposit securities with state regulatory authorities. These deposited securities totaled $14 million at both December 31, 2016 , and December 31, 2015 . (b) Investment securities with a fair value of $4,881 million and $2,506 million at December 31, 2016 , and December 31, 2015 , were pledged to secure advances from the FHLB, short-term borrowings or repurchase agreements and for other purposes as required by contractual obligation or law. Under these agreements, Ally has granted the counterparty the right to sell or pledge $737 million and $745 million of the underlying investment securities at December 31, 2016 , and December 31, 2015 , respectively. (c) Held-to-maturity securities are recorded at amortized cost and consist of agency-backed residential mortgage-backed debt securities for liquidity purposes. (d) Held-to-maturity securities with a fair value of $87 million at December 31, 2016 , were pledged to secure advances from the FHLB.
Investments Classified by Contractual Maturity Date [Table Text Block]	The maturity distribution of investment securities outstanding is summarized in the following tables. Call or prepayment options may cause actual maturities to differ from contractual maturities. Total Due in one year or less Due after one year through five years Due after five years through ten years Due after ten years ($ in millions) Amount Yield Amount Yield Amount Yield Amount Yield Amount Yield December 31, 2016 Fair value of available-for-sale debt securities (a) U.S. Treasury and federal agencies $ 1,620 1.7 % $ 2 4.6 % $ 60 1.6 % $ 1,558 1.7 % $ — — % U.S. States and political subdivisions 782 3.1 64 1.7 29 2.3 172 2.8 517 3.4 Foreign government 162 2.6 — — 58 2.8 104 2.4 — — Agency mortgage-backed residential 10,290 2.9 — — — — 29 2.6 10,261 2.9 Mortgage-backed residential 2,097 2.9 — — — — — — 2,097 2.9 Mortgage-backed commercial 537 2.6 — — — — 3 2.8 534 2.6 Asset-backed 1,400 2.8 — — 1,059 2.8 143 3.2 198 2.6 Corporate debt 1,443 2.8 72 2.2 840 2.6 489 3.2 42 4.7 Total available-for-sale debt securities $ 18,331 2.8 $ 138 2.0 $ 2,046 2.7 $ 2,498 2.2 $ 13,649 2.9 Amortized cost of available-for-sale debt securities $ 18,651 $ 138 $ 2,040 $ 2,563 $ 13,910 Amortized cost of held-to-maturity securities $ 839 2.9 % $ — — % $ — — % $ — — % $ 839 2.9 % December 31, 2015 Fair value of available-for-sale debt securities (a) U.S. Treasury and federal agencies $ 1,741 1.8 % $ 6 5.1 % $ 510 1.2 % $ 1,225 2.1 % $ — — % U.S. States and political subdivisions 716 3.2 86 1.3 37 2.2 141 2.8 452 3.7 Foreign government 177 2.6 9 1.9 77 2.8 91 2.6 — — Agency mortgage-backed residential 7,544 2.9 — — 32 2.0 36 2.5 7,476 2.9 Mortgage-backed residential 2,822 2.9 — — 1 4.5 — — 2,821 2.9 Mortgage-backed commercial 481 2.0 — — — — 3 2.7 478 2.0 Asset-backed 1,755 2.3 6 1.4 1,027 2.1 518 2.6 204 2.2 Corporate debt 1,204 2.9 50 3.0 713 2.5 410 3.4 31 5.4 Total available-for-sale debt securities $ 16,440 2.7 $ 157 2.0 $ 2,397 2.1 $ 2,424 2.5 $ 11,462 2.9 Amortized cost of available-for-sale debt securities $ 16,542 $ 156 $ 2,404 $ 2,436 $ 11,546 (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 [Table Text Block]	The following table presents interest and dividends on investment securities. Year ended December 31, ($ in millions) 2016 2015 2014 Taxable interest $ 375 $ 340 $ 336 Taxable dividends 17 23 20 Interest and dividends exempt from U.S. federal income tax 19 18 11 Interest and dividends on investment securities $ 411 $ 381 $ 367
Schedule of Realized Gain (Loss) [Table Text Block]	The following table presents gross gains and losses realized upon the sales of available-for-sale securities and other-than-temporary impairment. Year ended December 31, ($ in millions) 2016 2015 2014 Gross realized gains $ 187 $ 184 $ 209 Gross realized losses (a) (2 ) (15 ) (14 ) Other-than-temporary impairment — (14 ) (14 ) Other gain on investments, net $ 185 $ 155 $ 181 (a) In accordance with our risk management policies and practice, certain available-for-sale securities were sold at a loss in 2016, 2015, and 2014 as a result of changing conditions within these respective periods (e.g., a downgrade in the rating of a debt security) or events outside of our control (such as issuer calls).
Schedule of Unrealized Loss on Investments [Table Text Block]	The table below summarizes available-for-sale securities in an unrealized loss position in accumulated other comprehensive income. Based on the assessment of whether such losses were deemed to be other-than-temporary, we believe that the unrealized losses are not indicative of an other-than-temporary impairment of these securities. As of December 31, 2016 , we did not have the intent to sell the debt securities with an unrealized loss position in accumulated other comprehensive income, it is not more likely than not that we will be required to sell these securities before recovery of their amortized cost basis, and we expect to recover the entire amortized cost basis of the securities. As of December 31, 2016 , we had the ability and intent to hold equity securities with an unrealized loss position in accumulated other comprehensive income, and it is not more likely than not that we will be required to sell these securities before recovery of their amortized cost basis. As a result, we believe that the securities with an unrealized loss position in accumulated other comprehensive income are not considered to be other-than-temporarily impaired at December 31, 2016 . Refer to Note 1 to the Consolidated Financial Statements for additional information related to investment securities and our methodology for evaluating potential other-than-temporary impairments. 2016 2015 Less than 12 months 12 months or longer Less than 12 months 12 months or longer December 31, ($ in millions) Fair value Unrealized loss Fair value Unrealized loss Fair value Unrealized loss Fair value Unrealized loss Available-for-sale securities Debt securities U.S. Treasury and federal agencies $ 1,612 $ (60 ) $ — $ — $ 1,553 $ (17 ) $ 173 $ (2 ) U.S. States and political subdivisions 524 (19 ) — — 179 (1 ) — — Foreign government 38 — — — 2 — — — Agency mortgage-backed residential 8,052 (196 ) 587 (16 ) 2,524 (21 ) 1,132 (34 ) Mortgage-backed residential 813 (17 ) 860 (53 ) 1,231 (19 ) 1,180 (71 ) Mortgage-backed commercial 47 (1 ) 149 (1 ) 341 (3 ) 141 (2 ) Asset-backed 375 (2 ) 127 — 1,402 (8 ) 64 — Corporate debt 744 (14 ) 46 (2 ) 745 (16 ) 12 (1 ) Total temporarily impaired debt securities 12,205 (309 ) 1,769 (72 ) 7,977 (85 ) 2,702 (110 ) Temporarily impaired equity securities 151 (8 ) 269 (46 ) 534 (54 ) 96 (40 ) Total temporarily impaired available-for-sale securities $ 12,356 $ (317 ) $ 2,038 $ (118 ) $ 8,511 $ (139 ) $ 2,798 $ (150 )

Finance Receivables and Loans49

Finance Receivables and Loans, Net (Tables)	12 Months Ended
	Dec. 31, 2016
Concentration Risk [Line Items]
Loans, Notes, Trade and Other Receivables Disclosure [Text Block]	Finance Receivables and Loans, Net The composition of finance receivables and loans reported at gross carrying value was as follows. December 31, ($ in millions) 2016 2015 Consumer automotive (a) $ 65,793 $ 64,292 Consumer mortgage Mortgage Finance (b) 8,294 6,413 Mortgage — Legacy (c) 2,756 3,360 Total consumer mortgage 11,050 9,773 Total consumer 76,843 74,065 Commercial Commercial and industrial Automotive 35,041 31,469 Other 3,248 2,640 Commercial real estate — Automotive 3,812 3,426 Total commercial 42,101 37,535 Total finance receivables and loans (d) $ 118,944 $ 111,600 (a) Includes $43 million and $66 million of fair value adjustment for loans in hedge accounting relationships at December 31, 2016 , and December 31, 2015 , respectively. Refer to Note 22 to the Consolidated Financial Statements for additional information. (b) Includes loans originated as interest-only mortgage loans of $30 million and $44 million at December 31, 2016 , and December 31, 2015 , respectively, 3% of which are expected to start principal amortization in 2017 , none in 2018 , 38% in 2019 , 39% in 2020 , and none thereafter. (c) Includes loans originated as interest-only mortgage loans of $714 million and $941 million at December 31, 2016 , and December 31, 2015 , respectively, 23% of which are expected to start principal amortization in 2017 , 2% in 2018 , none in 2019 , none in 2020 , and 1% thereafter. (d) Totals include net increases of $359 million and $110 million at December 31, 2016 , and December 31, 2015 , respectively, for unearned income, unamortized premiums and discounts, and deferred fees and costs. The following tables present an analysis of the activity in the allowance for loan losses on finance receivables and loans. ($ in millions) Consumer automotive Consumer mortgage Commercial Total Allowance at January 1, 2016 $ 834 $ 114 $ 106 $ 1,054 Charge-offs (a) (1,102 ) (39 ) (1 ) (1,142 ) Recoveries 307 32 2 341 Net charge-offs (795 ) (7 ) 1 (801 ) Provision for loan losses 919 (16 ) 14 917 Other (b) (26 ) — — (26 ) Allowance at December 31, 2016 $ 932 $ 91 $ 121 $ 1,144 Allowance for loan losses at December 31, 2016 Individually evaluated for impairment $ 28 $ 34 $ 23 $ 85 Collectively evaluated for impairment 904 57 98 1,059 Loans acquired with deteriorated credit quality — — — — Finance receivables and loans at gross carrying value Ending balance $ 65,793 $ 11,050 $ 42,101 $ 118,944 Individually evaluated for impairment 370 247 122 739 Collectively evaluated for impairment 65,423 10,803 41,979 118,205 Loans acquired with deteriorated credit quality — — — — (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 for more information regarding our charge-off policies. (b) Primarily related to the transfer of finance receivables and loans from held-for-investment to held-for-sale. ($ in millions) Consumer automotive Consumer mortgage Commercial Total Allowance at January 1, 2015 $ 685 $ 152 $ 140 $ 977 Charge-offs (a) (840 ) (48 ) (4 ) (892 ) Recoveries 262 17 4 283 Net charge-offs (578 ) (31 ) — (609 ) Provision for loan losses 739 1 (33 ) 707 Other (b) (12 ) (8 ) (1 ) (21 ) Allowance at December 31, 2015 $ 834 $ 114 $ 106 $ 1,054 Allowance for loan losses at December 31, 2015 Individually evaluated for impairment $ 22 $ 44 $ 20 $ 86 Collectively evaluated for impairment 812 70 86 968 Loans acquired with deteriorated credit quality — — — — Finance receivables and loans at gross carrying value Ending balance $ 64,292 $ 9,773 $ 37,535 $ 111,600 Individually evaluated for impairment 315 266 77 658 Collectively evaluated for impairment 63,977 9,507 37,458 110,942 Loans acquired with deteriorated credit quality — — — — (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 for more information regarding our charge-off policies. (b) Primarily related to the transfer of finance receivables and loans from held-for-investment to held-for-sale. The following table presents information about significant sales of finance receivables and loans and transfers of finance receivables and loans from held-for-investment to held-for-sale. December 31, ($ in millions) 2016 2015 Consumer automotive $ 4,267 $ 1,237 Consumer mortgage 15 78 Commercial 29 2 Total sales and transfers $ 4,311 $ 1,317 The following table presents information about significant purchases of finance receivables and loans. December 31, ($ in millions) 2016 2015 Consumer automotive $ 21 $ 272 Consumer mortgage 3,747 4,125 Total purchases of finance receivables and loans $ 3,768 $ 4,397 The following table presents an analysis of our past due finance receivables and loans recorded at gross carrying value. December 31, ($ in millions) 30–59 days past due 60–89 days past due 90 days or more past due Total past due Current Total finance receivables and loans 2016 Consumer automotive $ 1,850 $ 428 $ 302 $ 2,580 $ 63,213 $ 65,793 Consumer mortgage Mortgage Finance 39 6 4 49 8,245 8,294 Mortgage — Legacy 45 18 57 120 2,636 2,756 Total consumer mortgage 84 24 61 169 10,881 11,050 Total consumer 1,934 452 363 2,749 74,094 76,843 Commercial Commercial and industrial Automotive 3 — 7 10 35,031 35,041 Other — — — — 3,248 3,248 Commercial real estate — Automotive — — — — 3,812 3,812 Total commercial 3 — 7 10 42,091 42,101 Total consumer and commercial $ 1,937 $ 452 $ 370 $ 2,759 $ 116,185 $ 118,944 2015 Consumer automotive $ 1,618 $ 369 $ 222 $ 2,209 $ 62,083 $ 64,292 Consumer mortgage Mortgage Finance 44 5 10 59 6,354 6,413 Mortgage — Legacy 53 20 73 146 3,214 3,360 Total consumer mortgage 97 25 83 205 9,568 9,773 Total consumer 1,715 394 305 2,414 71,651 74,065 Commercial Commercial and industrial Automotive — — — — 31,469 31,469 Other — — — — 2,640 2,640 Commercial real estate — Automotive — — — — 3,426 3,426 Total commercial — — — — 37,535 37,535 Total consumer and commercial $ 1,715 $ 394 $ 305 $ 2,414 $ 109,186 $ 111,600 The following table presents the gross carrying value of our finance receivables and loans on nonaccrual status. December 31, ($ in millions) 2016 2015 Consumer automotive $ 598 $ 475 Consumer mortgage Mortgage Finance 10 15 Mortgage — Legacy 89 113 Total consumer mortgage 99 128 Total consumer 697 603 Commercial Commercial and industrial Automotive 33 25 Other 84 44 Commercial real estate — Automotive 5 8 Total commercial 122 77 Total consumer and commercial finance receivables and loans $ 819 $ 680 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 when full collection is not expected. Refer to Note 1 to the Consolidated Financial Statements for additional information. 2016 2015 December 31, ( $ in millions ) Performing Nonperforming Total Performing Nonperforming Total Consumer automotive $ 65,195 $ 598 $ 65,793 $ 63,817 $ 475 $ 64,292 Consumer mortgage Mortgage Finance 8,284 10 8,294 6,398 15 6,413 Mortgage — Legacy 2,667 89 2,756 3,247 113 3,360 Total consumer mortgage 10,951 99 11,050 9,645 128 9,773 Total consumer $ 76,146 $ 697 $ 76,843 $ 73,462 $ 603 $ 74,065 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. 2016 2015 December 31, ( $ in millions ) Pass Criticized (a) Total Pass Criticized (a) Total Commercial and industrial Automotive $ 33,160 $ 1,881 $ 35,041 $ 29,613 $ 1,856 $ 31,469 Other 2,597 651 3,248 2,122 518 2,640 Commercial real estate — Automotive 3,653 159 3,812 3,265 161 3,426 Total commercial $ 39,410 $ 2,691 $ 42,101 $ 35,000 $ 2,535 $ 37,535 (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 . The following table presents information about our impaired finance receivables and loans. December 31, ( $ in millions ) Unpaid principal balance (a) Gross carrying value Impaired with no allowance Impaired with an allowance Allowance for impaired loans 2016 Consumer automotive $ 407 $ 370 $ 131 $ 239 $ 28 Consumer mortgage Mortgage Finance 8 8 3 5 — Mortgage — Legacy 243 239 56 183 34 Total consumer mortgage 251 247 59 188 34 Total consumer 658 617 190 427 62 Commercial Commercial and industrial Automotive 33 33 7 26 3 Other 99 84 — 84 19 Commercial real estate — Automotive 5 5 2 3 1 Total commercial 137 122 9 113 23 Total consumer and commercial finance receivables and loans $ 795 $ 739 $ 199 $ 540 $ 85 2015 Consumer automotive $ 315 $ 315 $ — $ 315 $ 22 Consumer mortgage Mortgage Finance 9 9 5 4 1 Mortgage — Legacy 260 257 59 198 43 Total consumer mortgage 269 266 64 202 44 Total consumer 584 581 64 517 66 Commercial Commercial and industrial Automotive 25 25 4 21 3 Other 44 44 — 44 15 Commercial real estate — Automotive 8 8 1 7 2 Total commercial 77 77 5 72 20 Total consumer and commercial finance receivables and loans $ 661 $ 658 $ 69 $ 589 $ 86 (a) Adjusted for charge-offs. The following table presents average balance and interest income for our impaired finance receivables and loans. 2016 2015 2014 Year ended December 31, ($ in millions) Average balance Interest income Average balance Interest income Average balance Interest income Consumer automotive $ 344 $ 17 $ 295 $ 16 $ 317 $ 20 Consumer mortgage Mortgage Finance 8 — 8 — 12 — Mortgage — Legacy 248 9 272 9 861 12 Total consumer mortgage 256 9 280 9 873 12 Total consumer 600 26 575 25 1,190 32 Commercial Commercial and industrial Automotive 35 1 33 1 61 2 Other 60 1 41 3 59 3 Commercial real estate — Automotive 6 — 5 — 6 — Total commercial 101 2 79 4 126 5 Total consumer and commercial finance receivables and loans $ 701 $ 28 $ 654 $ 29 $ 1,316 $ 37 Troubled Debt Restructurings TDRs are loan modifications where concessions were granted to borrowers experiencing financial difficulties. For automotive loans, we may offer several types of assistance to aid our customers, including extension of the loan maturity date and rewriting the loan terms. Additionally, for mortgage loans, as part of certain programs, we offer mortgage loan modifications to qualified borrowers. Numerous initiatives 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 $663 million and $625 million at December 31, 2016 , and December 31, 2015 , respectively. Commercial commitments to lend additional funds to borrowers whose terms had been modified in a TDR were $2 million at both December 31, 2016 , and December 31, 2015 . Refer to Note 1 to the Consolidated Financial Statements for additional information. The following table presents information related to finance receivables and loans recorded at gross carrying value modified in connection with a TDR during the period. 2016 2015 Year ended December 31, ($ 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 20,227 $ 347 $ 293 17,222 $ 278 $ 237 Consumer mortgage Mortgage Finance 7 3 3 7 4 4 Mortgage — Legacy 120 18 18 197 42 40 Total consumer mortgage 127 21 21 204 46 44 Total consumer 20,354 368 314 17,426 324 281 Commercial Commercial and industrial Automotive 1 7 7 — — — Other — — — 1 21 21 Commercial real estate — Automotive — — — 1 3 3 Total commercial 1 7 7 2 24 24 Total consumer and commercial finance receivables and loans 20,355 $ 375 $ 321 17,428 $ 348 $ 305 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 12 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 for additional information) except for commercial finance receivables and loans, where redefault is defined as 90 days past due. 2016 2015 Year ended December 31, ($ in millions) Number of loans Gross carrying value Charge-off amount Number of loans Gross carrying value Charge-off amount Consumer automotive 7,800 $ 94 $ 56 6,836 $ 82 $ 47 Consumer mortgage Mortgage Finance — — — — — — Mortgage — Legacy 4 — — 10 1 — Total consumer finance receivables and loans 7,804 $ 94 $ 56 6,846 $ 83 $ 47 Concentration Risk Consumer We monitor our consumer loan portfolio for concentration risk across the states in which we lend. The highest concentrations of loans are in Texas and California, which represent an aggregate of 24.2% and 23.5% of our total outstanding consumer finance receivables and loans at December 31, 2016 , and December 31, 2015 , respectively. The following table shows the percentage of total consumer finance receivables and loans recorded at gross carrying value by state concentration. 2016 (a) 2015 December 31, Consumer automotive Consumer mortgage Consumer automotive Consumer mortgage Texas 13.6 % 6.6 % 13.7 % 6.2 % California 7.8 34.2 7.3 33.6 Florida 8.2 4.4 7.7 4.1 Pennsylvania 4.7 1.5 5.0 1.5 Illinois 4.3 3.4 4.4 4.1 Georgia 4.3 2.2 4.4 2.2 North Carolina 3.6 1.6 3.6 1.8 Ohio 3.5 0.5 3.7 0.6 New York 3.2 1.9 3.5 1.9 Michigan 2.7 1.9 3.1 2.4 Other United States 44.1 41.8 43.6 41.6 Total consumer loans 100.0 % 100.0 % 100.0 % 100.0 % (a) Presentation is in descending order as a percentage of total consumer finance receivables and loans at December 31, 2016. Commercial Real Estate The commercial real estate portfolio consists of loans issued primarily to automotive dealers. The following table shows the percentage of total commercial real estate finance receivables and loans reported at gross carrying value by state concentration. December 31, 2016 2015 Texas 16.1 % 17.7 % Florida 10.2 10.0 California 7.9 8.7 Michigan 7.6 8.9 New Jersey 4.2 2.1 Georgia 3.6 3.6 North Carolina 3.6 3.8 Pennsylvania 3.1 3.4 South Carolina 2.7 2.2 New York 2.6 3.1 Other United States 38.4 36.5 Total commercial real estate finance receivables and loans 100.0 % 100.0 % Commercial Criticized Exposure Finance receivables and loans classified as special mention, substandard, or doubtful are reported as criticized. These classifications are based on regulatory definitions and generally represent finance receivables and loans within our portfolio that have a higher default risk or have already defaulted. These finance receivables and loans require additional monitoring and review including specific actions to mitigate our potential loss. The following table presents the percentage of total commercial criticized finance receivables and loans reported at gross carrying value by industry concentrations. December 31, 2016 2015 Automotive 81.2 % 80.5 % Services 6.3 5.3 Electronics 4.2 3.3 Other 8.3 10.9 Total commercial criticized finance receivables and loans 100.0 % 100.0 %
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]	The composition of finance receivables and loans reported at gross carrying value was as follows. December 31, ($ in millions) 2016 2015 Consumer automotive (a) $ 65,793 $ 64,292 Consumer mortgage Mortgage Finance (b) 8,294 6,413 Mortgage — Legacy (c) 2,756 3,360 Total consumer mortgage 11,050 9,773 Total consumer 76,843 74,065 Commercial Commercial and industrial Automotive 35,041 31,469 Other 3,248 2,640 Commercial real estate — Automotive 3,812 3,426 Total commercial 42,101 37,535 Total finance receivables and loans (d) $ 118,944 $ 111,600 (a) Includes $43 million and $66 million of fair value adjustment for loans in hedge accounting relationships at December 31, 2016 , and December 31, 2015 , respectively. Refer to Note 22 to the Consolidated Financial Statements for additional information. (b) Includes loans originated as interest-only mortgage loans of $30 million and $44 million at December 31, 2016 , and December 31, 2015 , respectively, 3% of which are expected to start principal amortization in 2017 , none in 2018 , 38% in 2019 , 39% in 2020 , and none thereafter. (c) Includes loans originated as interest-only mortgage loans of $714 million and $941 million at December 31, 2016 , and December 31, 2015 , respectively, 23% of which are expected to start principal amortization in 2017 , 2% in 2018 , none in 2019 , none in 2020 , and 1% thereafter. (d) Totals include net increases of $359 million and $110 million at December 31, 2016 , and December 31, 2015 , respectively, for unearned income, unamortized premiums and discounts, and deferred fees and costs.
Allowance for Credit Losses on Financing Receivables [Table Text Block]	The following tables present an analysis of the activity in the allowance for loan losses on finance receivables and loans. ($ in millions) Consumer automotive Consumer mortgage Commercial Total Allowance at January 1, 2016 $ 834 $ 114 $ 106 $ 1,054 Charge-offs (a) (1,102 ) (39 ) (1 ) (1,142 ) Recoveries 307 32 2 341 Net charge-offs (795 ) (7 ) 1 (801 ) Provision for loan losses 919 (16 ) 14 917 Other (b) (26 ) — — (26 ) Allowance at December 31, 2016 $ 932 $ 91 $ 121 $ 1,144 Allowance for loan losses at December 31, 2016 Individually evaluated for impairment $ 28 $ 34 $ 23 $ 85 Collectively evaluated for impairment 904 57 98 1,059 Loans acquired with deteriorated credit quality — — — — Finance receivables and loans at gross carrying value Ending balance $ 65,793 $ 11,050 $ 42,101 $ 118,944 Individually evaluated for impairment 370 247 122 739 Collectively evaluated for impairment 65,423 10,803 41,979 118,205 Loans acquired with deteriorated credit quality — — — — (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 for more information regarding our charge-off policies. (b) Primarily related to the transfer of finance receivables and loans from held-for-investment to held-for-sale. ($ in millions) Consumer automotive Consumer mortgage Commercial Total Allowance at January 1, 2015 $ 685 $ 152 $ 140 $ 977 Charge-offs (a) (840 ) (48 ) (4 ) (892 ) Recoveries 262 17 4 283 Net charge-offs (578 ) (31 ) — (609 ) Provision for loan losses 739 1 (33 ) 707 Other (b) (12 ) (8 ) (1 ) (21 ) Allowance at December 31, 2015 $ 834 $ 114 $ 106 $ 1,054 Allowance for loan losses at December 31, 2015 Individually evaluated for impairment $ 22 $ 44 $ 20 $ 86 Collectively evaluated for impairment 812 70 86 968 Loans acquired with deteriorated credit quality — — — — Finance receivables and loans at gross carrying value Ending balance $ 64,292 $ 9,773 $ 37,535 $ 111,600 Individually evaluated for impairment 315 266 77 658 Collectively evaluated for impairment 63,977 9,507 37,458 110,942 Loans acquired with deteriorated credit quality — — — — (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 for more information regarding our charge-off policies. (b) Primarily related to the transfer of finance receivables and loans from held-for-investment to held-for-sale.
Schedule Of Sales Of Financing Receivables And Loans [Table Text Block]	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. December 31, ($ in millions) 2016 2015 Consumer automotive $ 4,267 $ 1,237 Consumer mortgage 15 78 Commercial 29 2 Total sales and transfers $ 4,311 $ 1,317
Schedule of Purchases of Financing Receivables and Loans [Table Text Block]	The following table presents information about significant purchases of finance receivables and loans. December 31, ($ in millions) 2016 2015 Consumer automotive $ 21 $ 272 Consumer mortgage 3,747 4,125 Total purchases of finance receivables and loans $ 3,768 $ 4,397
Past Due Financing Receivables [Table Text Block]	The following table presents an analysis of our past due finance receivables and loans recorded at gross carrying value. December 31, ($ in millions) 30–59 days past due 60–89 days past due 90 days or more past due Total past due Current Total finance receivables and loans 2016 Consumer automotive $ 1,850 $ 428 $ 302 $ 2,580 $ 63,213 $ 65,793 Consumer mortgage Mortgage Finance 39 6 4 49 8,245 8,294 Mortgage — Legacy 45 18 57 120 2,636 2,756 Total consumer mortgage 84 24 61 169 10,881 11,050 Total consumer 1,934 452 363 2,749 74,094 76,843 Commercial Commercial and industrial Automotive 3 — 7 10 35,031 35,041 Other — — — — 3,248 3,248 Commercial real estate — Automotive — — — — 3,812 3,812 Total commercial 3 — 7 10 42,091 42,101 Total consumer and commercial $ 1,937 $ 452 $ 370 $ 2,759 $ 116,185 $ 118,944 2015 Consumer automotive $ 1,618 $ 369 $ 222 $ 2,209 $ 62,083 $ 64,292 Consumer mortgage Mortgage Finance 44 5 10 59 6,354 6,413 Mortgage — Legacy 53 20 73 146 3,214 3,360 Total consumer mortgage 97 25 83 205 9,568 9,773 Total consumer 1,715 394 305 2,414 71,651 74,065 Commercial Commercial and industrial Automotive — — — — 31,469 31,469 Other — — — — 2,640 2,640 Commercial real estate — Automotive — — — — 3,426 3,426 Total commercial — — — — 37,535 37,535 Total consumer and commercial $ 1,715 $ 394 $ 305 $ 2,414 $ 109,186 $ 111,600
Schedule of Financing Receivables, Non Accrual Status [Table Text Block]	The following table presents the gross carrying value of our finance receivables and loans on nonaccrual status. December 31, ($ in millions) 2016 2015 Consumer automotive $ 598 $ 475 Consumer mortgage Mortgage Finance 10 15 Mortgage — Legacy 89 113 Total consumer mortgage 99 128 Total consumer 697 603 Commercial Commercial and industrial Automotive 33 25 Other 84 44 Commercial real estate — Automotive 5 8 Total commercial 122 77 Total consumer and commercial finance receivables and loans $ 819 $ 680
Financing Receivable Credit Quality Indicators - Performing and Nonperforming [Table Text Block]	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 when full collection is not expected. Refer to Note 1 to the Consolidated Financial Statements for additional information. 2016 2015 December 31, ( $ in millions ) Performing Nonperforming Total Performing Nonperforming Total Consumer automotive $ 65,195 $ 598 $ 65,793 $ 63,817 $ 475 $ 64,292 Consumer mortgage Mortgage Finance 8,284 10 8,294 6,398 15 6,413 Mortgage — Legacy 2,667 89 2,756 3,247 113 3,360 Total consumer mortgage 10,951 99 11,050 9,645 128 9,773 Total consumer $ 76,146 $ 697 $ 76,843 $ 73,462 $ 603 $ 74,065
Schedule Of Pass And Criticized Credit Quality Indicators Of Finance Receivables [Table Text Block]	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. 2016 2015 December 31, ( $ in millions ) Pass Criticized (a) Total Pass Criticized (a) Total Commercial and industrial Automotive $ 33,160 $ 1,881 $ 35,041 $ 29,613 $ 1,856 $ 31,469 Other 2,597 651 3,248 2,122 518 2,640 Commercial real estate — Automotive 3,653 159 3,812 3,265 161 3,426 Total commercial $ 39,410 $ 2,691 $ 42,101 $ 35,000 $ 2,535 $ 37,535 (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 [Table Text Block]	The following table presents information about our impaired finance receivables and loans. December 31, ( $ in millions ) Unpaid principal balance (a) Gross carrying value Impaired with no allowance Impaired with an allowance Allowance for impaired loans 2016 Consumer automotive $ 407 $ 370 $ 131 $ 239 $ 28 Consumer mortgage Mortgage Finance 8 8 3 5 — Mortgage — Legacy 243 239 56 183 34 Total consumer mortgage 251 247 59 188 34 Total consumer 658 617 190 427 62 Commercial Commercial and industrial Automotive 33 33 7 26 3 Other 99 84 — 84 19 Commercial real estate — Automotive 5 5 2 3 1 Total commercial 137 122 9 113 23 Total consumer and commercial finance receivables and loans $ 795 $ 739 $ 199 $ 540 $ 85 2015 Consumer automotive $ 315 $ 315 $ — $ 315 $ 22 Consumer mortgage Mortgage Finance 9 9 5 4 1 Mortgage — Legacy 260 257 59 198 43 Total consumer mortgage 269 266 64 202 44 Total consumer 584 581 64 517 66 Commercial Commercial and industrial Automotive 25 25 4 21 3 Other 44 44 — 44 15 Commercial real estate — Automotive 8 8 1 7 2 Total commercial 77 77 5 72 20 Total consumer and commercial finance receivables and loans $ 661 $ 658 $ 69 $ 589 $ 86 (a) Adjusted for charge-offs.
Schedule of Average Balance And Interest Income Of Impaired Finance Receivables [Table Text Block]	The following table presents average balance and interest income for our impaired finance receivables and loans. 2016 2015 2014 Year ended December 31, ($ in millions) Average balance Interest income Average balance Interest income Average balance Interest income Consumer automotive $ 344 $ 17 $ 295 $ 16 $ 317 $ 20 Consumer mortgage Mortgage Finance 8 — 8 — 12 — Mortgage — Legacy 248 9 272 9 861 12 Total consumer mortgage 256 9 280 9 873 12 Total consumer 600 26 575 25 1,190 32 Commercial Commercial and industrial Automotive 35 1 33 1 61 2 Other 60 1 41 3 59 3 Commercial real estate — Automotive 6 — 5 — 6 — Total commercial 101 2 79 4 126 5 Total consumer and commercial finance receivables and loans $ 701 $ 28 $ 654 $ 29 $ 1,316 $ 37
Troubled Debt Restructurings on Financing Receivables [Table Text Block]	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. 2016 2015 Year ended December 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 20,227 $ 347 $ 293 17,222 $ 278 $ 237 Consumer mortgage Mortgage Finance 7 3 3 7 4 4 Mortgage — Legacy 120 18 18 197 42 40 Total consumer mortgage 127 21 21 204 46 44 Total consumer 20,354 368 314 17,426 324 281 Commercial Commercial and industrial Automotive 1 7 7 — — — Other — — — 1 21 21 Commercial real estate — Automotive — — — 1 3 3 Total commercial 1 7 7 2 24 24 Total consumer and commercial finance receivables and loans 20,355 $ 375 $ 321 17,428 $ 348 $ 305
Finance receivables and loans redefaulted during the period [Table Text Block]	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 12 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 for additional information) except for commercial finance receivables and loans, where redefault is defined as 90 days past due. 2016 2015 Year ended December 31, ($ in millions) Number of loans Gross carrying value Charge-off amount Number of loans Gross carrying value Charge-off amount Consumer automotive 7,800 $ 94 $ 56 6,836 $ 82 $ 47 Consumer mortgage Mortgage Finance — — — — — — Mortgage — Legacy 4 — — 10 1 — Total consumer finance receivables and loans 7,804 $ 94 $ 56 6,846 $ 83 $ 47
Consumer Concentration Risk [Table Text Block]	The following table shows the percentage of total consumer finance receivables and loans recorded at gross carrying value by state concentration. 2016 (a) 2015 December 31, Consumer automotive Consumer mortgage Consumer automotive Consumer mortgage Texas 13.6 % 6.6 % 13.7 % 6.2 % California 7.8 34.2 7.3 33.6 Florida 8.2 4.4 7.7 4.1 Pennsylvania 4.7 1.5 5.0 1.5 Illinois 4.3 3.4 4.4 4.1 Georgia 4.3 2.2 4.4 2.2 North Carolina 3.6 1.6 3.6 1.8 Ohio 3.5 0.5 3.7 0.6 New York 3.2 1.9 3.5 1.9 Michigan 2.7 1.9 3.1 2.4 Other United States 44.1 41.8 43.6 41.6 Total consumer loans 100.0 % 100.0 % 100.0 % 100.0 % (a) Presentation is in descending order as a percentage of total consumer finance receivables and loans at December 31, 2016.
Commercial Concentration Risk [Table Text Block]	The following table shows the percentage of total commercial real estate finance receivables and loans reported at gross carrying value by state concentration. December 31, 2016 2015 Texas 16.1 % 17.7 % Florida 10.2 10.0 California 7.9 8.7 Michigan 7.6 8.9 New Jersey 4.2 2.1 Georgia 3.6 3.6 North Carolina 3.6 3.8 Pennsylvania 3.1 3.4 South Carolina 2.7 2.2 New York 2.6 3.1 Other United States 38.4 36.5 Total commercial real estate finance receivables and loans 100.0 % 100.0 %
Commercial Criticized Exposure [Table Text Block]	The following table presents the percentage of total commercial criticized finance receivables and loans reported at gross carrying value by industry concentrations. December 31, 2016 2015 Automotive 81.2 % 80.5 % Services 6.3 5.3 Electronics 4.2 3.3 Other 8.3 10.9 Total commercial criticized finance receivables and loans 100.0 % 100.0 %

Investment in Operating Lease50

Investment in Operating Leases, Net (Tables)	12 Months Ended
	Dec. 31, 2016
Leases, Operating [Abstract]
Schedule of Property Subject to or Available for Operating Lease [Table Text Block]	Investments in operating leases were as follows. December 31, ( $ in millions ) 2016 2015 Vehicles $ 14,584 $ 20,211 Accumulated depreciation (3,114 ) (3,940 ) Investment in operating leases, net $ 11,470 $ 16,271
Depreciation Expense On Operating Lease Assets [Table Text Block]	Depreciation expense on operating lease assets includes remarketing gains and losses recognized on the sale of operating lease assets. The following summarizes the components of depreciation expense on operating lease assets. Year ended December 31, ( $ in millions ) 2016 2015 2014 Depreciation expense on operating lease assets (excluding remarketing gains) $ 1,982 $ 2,600 $ 2,666 Remarketing gains (213 ) (351 ) (433 ) Net depreciation expense on operating lease assets $ 1,769 $ 2,249 $ 2,233
Schedule of Operating Leases of Lessor [Table Text Block]	The following table presents the future lease nonresidual rental payments due from customers for vehicles on operating leases. Year ended December 31, ( $ in millions ) 2017 $ 1,759 2018 821 2019 307 2020 44 2021 and thereafter 2 Total $ 2,933

Securitizations and Variable 51

Securitizations and Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2016
Securitizations And Variable Interest Entities [Abstract]
Schedule of Variable Interest Entities [Table Text Block]	The following table presents our involvement in consolidated and nonconsolidated VIEs in which we hold variable interests. For additional detail related to the assets and liabilities of consolidated variable interest entities refer to the Consolidated Balance Sheet. December 31, ($ in millions) Net carrying value of total assets Carrying value of total liabilities Assets sold to Maximum exposure to 2016 On-balance sheet variable interest entities Consumer automotive $ 20,869 (b) $ 8,557 (c) Commercial automotive 16,278 4,764 Off-balance sheet variable interest entities Consumer automotive 24 — $ 2,899 $ 2,923 (d) Commercial other 460 (e) 169 (f) — 651 (g) Total $ 37,631 $ 13,490 $ 2,899 $ 3,574 2015 On-balance sheet variable interest entities Consumer automotive $ 27,967 (b) $ 12,406 (c) Commercial automotive 16,763 7,982 Off-balance sheet variable interest entities Consumer automotive — — $ 3,034 $ 3,034 (d) Commercial other 210 (e) — — 493 (g) Total $ 44,940 $ 20,388 $ 3,034 $ 3,527 (a) Asset values represent the current unpaid principal balance of outstanding consumer finance receivables and loans within the VIEs. (b) Includes $9.6 billion and $10.6 billion of assets that are not encumbered by VIE beneficial interests held by third parties at December 31, 2016 , and December 31, 2015 , respectively. Ally or consolidated affiliates hold the interests in these assets, which eliminate in consolidation. (c) Includes $50 million and $99 million of liabilities due to consolidated affiliates at December 31, 2016 , and December 31, 2015 , respectively. These liabilities are not obligations to third-party beneficial interest holders. These liabilities are secured by a portion of the unencumbered assets and eliminate in consolidation. (d) Maximum exposure to loss represents the current unpaid principal balance of outstanding loans based on our customary representation and warranty provisions and certain noncertificated interests retained from the sale of automotive finance receivables. This measure is based on the unlikely event that all of the loans have underwriting defects or other defects that trigger a representation and warranty provision and the collateral supporting the loans are worthless. This required disclosure is not an indication of our expected loss. (e) Amounts are classified as other assets. (f) Amounts are classified as accrued expenses and other liabilities. (g) For certain nonconsolidated affordable housing entities, maximum exposure to loss represents the yield we guaranteed investors through long term guarantee contracts. The amount disclosed is based on the unlikely event that the underlying properties cease generating yield to investors and the yield delivered to investors in the form of low income tax housing credits is recaptured. For nonconsolidated equity investments, maximum exposure to loss represents our outstanding investment, additional committed capital, and low income housing tax credits subject to recapture. The amount disclosed is based on the unlikely event that our committed capital is funded, our investments become worthless, and the tax credits previously delivered to us are recaptured. This required disclosure is not an indication of our expected loss.
On-balance Sheet Variable Interest Entities [Table Text Block]	The consolidated VIEs included in the Consolidated Balance Sheet represent separate entities with which we are involved. The third-party investors in the obligations of consolidated VIEs have legal recourse only to the assets of the VIEs and do not have such recourse to us, except for the customary representation and warranty provisions. In addition, the cash flows from the assets are restricted only to pay such liabilities. Thus, our economic exposure to loss from outstanding third-party financing related to consolidated VIEs is significantly less than the carrying value of the consolidated VIE assets. All assets of consolidated VIEs, presented below based upon the legal transfer of the underlying assets in order to reflect legal ownership, are restricted for the benefit of the beneficial interest holders. December 31, ( $ in millions ) 2016 2015 Assets Finance receivables and loans, net Consumer $ 8,929 $ 11,682 Commercial 15,701 16,247 Allowance for loan losses (173 ) (196 ) Total finance receivables and loans, net 24,457 27,733 Investment in operating leases, net 1,745 4,791 Other assets 1,390 1,624 Total assets $ 27,592 $ 34,148 Liabilities Long-term debt 13,259 20,267 Accrued expenses and other liabilities 12 22 Total liabilities $ 13,271 $ 20,289
Schedule Of Cash Flow Received And Paid To Nonconsolidated Securitization Entities [Table Text Block]	The following table summarizes cash flows received and paid related to securitization entities and asset-backed financings where the transfer is accounted for as a sale and we have a continuing involvement with the transferred assets (e.g., servicing) that were outstanding during the years ended December 31, 2016 , 2015 , and 2014 . Additionally, this table contains information regarding cash flows received from and paid to nonconsolidated securitization entities that existed during each period. Year ended December 31, ($ in millions) Consumer automotive Consumer mortgage 2016 Cash proceeds from transfers completed during the period $ 1,715 $ — Servicing fees 35 — Other cash flows 8 — 2015 Cash proceeds from transfers completed during the period $ 1,551 $ — Servicing fees 28 — 2014 Cash proceeds from transfers completed during the period $ 2,594 $ — Servicing fees 11 — Representations and warranties obligations — (31 )
Schedule of Quantitative Information and Net Credit Losses about Securitized and Other Financial Assets Managed Together [Table Text Block]	The following table represents on-balance sheet loans held-for-sale and finance receivable and loans, off-balance sheet securitizations, and whole-loan sales where we have continuing involvement. The table presents quantitative information about delinquencies and net credit losses. Total Amount Amount 60 days or more Net credit losses December 31, ($ in millions) 2016 2015 2016 2015 2016 2015 On-balance sheet loans Consumer automotive $ 65,793 $ 64,292 $ 730 $ 591 $ 795 $ 578 Consumer mortgage 11,050 9,773 85 108 7 31 Commercial automotive 38,853 34,895 7 — 1 3 Commercial other 3,248 2,745 — — (2 ) (3 ) Total on-balance sheet loans 118,944 111,705 822 699 801 609 Off-balance sheet securitization entities Consumer automotive 2,392 2,529 13 9 8 5 Total off-balance sheet securitization entities 2,392 2,529 13 9 8 5 Whole-loan sales (a) 3,164 2,252 6 13 3 — Total $ 124,500 $ 116,486 $ 841 $ 721 $ 812 $ 614 (a) Whole-loan sales are not part of a securitization transaction, but represent consumer automotive pools of loans sold to third-party investors.

Servicing Activities (Tables)

Servicing Activities (Tables)	12 Months Ended
	Dec. 31, 2016
Servicing Asset [Abstract]
Schedule Of Total Serviced Automobile Loans Outstanding [Table Text Block]	The current unpaid principal balance and any related unamortized deferred fees and costs of total serviced automotive finance loans and leases outstanding were as follows. December 31, ($ in millions) 2016 2015 On-balance sheet automotive finance loans and leases Consumer automotive $ 65,646 $ 64,067 Commercial automotive 38,853 34,895 Operating leases 11,311 15,965 Other 67 72 Off-balance sheet automotive finance loans Securitizations 2,412 2,550 Whole-loan 3,191 2,259 Total serviced automotive finance loans and leases $ 121,480 $ 119,808

Premiums Receivable and Other53

Premiums Receivable and Other Insurance Assets Premiums Receivable and Other Insurance Assets (Tables)	12 Months Ended
	Dec. 31, 2016
Premiums Receivable and Other Insurance Assets [Abstract]
Premiums Receivable and Other Insurance Assets [Table Text Block]	Premiums receivable and other insurance assets consisted of the following. December 31, ( $ in millions ) 2016 2015 Prepaid reinsurance premiums $ 439 $ 382 Reinsurance recoverable on unpaid losses 108 120 Reinsurance recoverable on paid losses 20 18 Premiums receivable 80 82 Deferred policy acquisition costs 1,258 1,199 Total premiums receivable and other insurance assets $ 1,905 $ 1,801

Other Assets (Tables)

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2016
Other Assets [Abstract]
Schedule of Other Assets [Table Text Block]	The components of other assets were as follows. December 31, ($ in millions) 2016 2015 Property and equipment at cost $ 901 $ 691 Accumulated depreciation (525 ) (456 ) Net property and equipment 376 235 Restricted cash collections for securitization trusts (a) 1,694 2,010 Nonmarketable equity investments (b) 1,046 418 Net deferred tax assets 994 1,369 Accrued interest and rent receivables 476 402 Goodwill (c) 240 27 Cash reserve deposits held-for-securitization trusts (d) 184 252 Cash collateral placed with counterparties 167 125 Restricted cash and cash equivalents 111 120 Other accounts receivable 100 158 Fair value of derivative contracts in receivable position (e) 95 233 Other assets 1,371 972 Total other assets $ 6,854 $ 6,321 (a) Represents cash collections from customer payments on securitized receivables. These funds are distributed to investors as payments on the related secured debt. (b) Includes investments in FHLB stock of $577 million and $391 million and FRB stock of $435 million and $0 million at December 31, 2016 , and December 31, 2015 , respectively. (c) Includes goodwill of $27 million at our Insurance operations at both December 31, 2016 , and December 31, 2015 , $193 million and $0 million within Corporate and Other at December 31, 2016 , and December 31, 2015 , respectively, and $20 million and $0 million within Automotive Finance operations at December 31, 2016 , and December 31, 2015 , respectively. As a result of our acquisition of TradeKing, we recognized $193 million of goodwill within Corporate and Other on June 1, 2016 . On August 1, 2016, we purchased assets from Blue Yield. As a result of this purchase, we recognized $20 million of goodwill within Automotive Finance operations. No other changes in the carrying amount of goodwill were recorded during the year ended December 31, 2016 . (d) Represents credit enhancement in the form of cash reserves for various securitization transactions. (e) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements .

Deposit Liabilities (Tables)

Deposit Liabilities (Tables)	12 Months Ended
	Dec. 31, 2016
Deposits [Abstract]
Schedule of Deposit Liabilities [Table Text Block]	Deposit liabilities consisted of the following. December 31, ( $ in millions ) 2016 2015 Noninterest-bearing deposits $ 84 $ 89 Interest-bearing deposits Savings and money market checking accounts 46,976 36,386 Certificates of deposit 31,795 29,774 Dealer deposits 167 229 Total deposit liabilities $ 79,022 $ 66,478
Schedule Of Maturities For Total Time Deposits Text Block [Table Text Block]	The following table presents the scheduled maturity of total certificates of deposit. ( $ in millions ) Due in 2017 $ 16,206 Due in 2018 9,984 Due in 2019 3,041 Due in 2020 1,348 Due in 2021 1,216 Total certificates of deposit $ 31,795

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Schedule of Short-term Debt [Table Text Block]	The following table presents the composition of our short-term borrowings portfolio. 2016 2015 December 31, ($ in millions) Unsecured Secured (a) Total Unsecured Secured (a) Total Demand notes $ 3,622 $ — $ 3,622 $ 3,369 $ — $ 3,369 Federal Home Loan Bank — 7,875 7,875 — 4,000 4,000 Financial instruments sold under agreements to repurchase — 1,176 1,176 — 648 648 Other — — — 84 — 84 Total short-term borrowings $ 3,622 $ 9,051 $ 12,673 $ 3,453 $ 4,648 $ 8,101 Weighted average interest rate (b) 1.0 % 0.8 % (a) Refer to the section below titled Long-term Debt for further details on assets restricted as collateral for payment of the related debt. (b) Based on the debt outstanding and the interest rate at December 31 of each year.
Schedule of Long-term Debt Instruments [Table Text Block]	The following tables present the composition of our long-term debt portfolio. December 31, ($ in millions) Amount Interest rate Weighted-average interest rate (a) Due date range 2016 Unsecured debt Fixed rate (b) $ 17,155 Variable rate 1 Trust preferred securities 2,568 Fair value adjustment (c) 326 Total unsecured debt 20,050 0.68–8.00% 5.36 % 2017–2049 Secured debt Fixed rate 17,935 Variable rate 16,154 Fair value adjustment (11 ) Total secured debt (d) (e) (f) 34,078 0.63–4.55% 1.53 % 2017–2035 Total long-term debt $ 54,128 2015 Unsecured debt Fixed rate (b) $ 17,657 Variable rate 375 Trust preferred securities 2,600 Fair value adjustment (c) 334 Total unsecured debt 20,966 0.37–8.13% 5.40 % 2016–2049 Secured debt Fixed rate 20,511 Variable rate 24,760 Fair value adjustment (c) (3 ) Total secured debt (d) (e) (f) 45,268 0.48–4.06% 1.18 % 2016–2035 Total long-term debt $ 66,234 (a) Based on the debt outstanding and the interest rate at December 31 of each year excluding any impacts of interest rate hedges. (b) Includes subordinated debt of $1.4 billion and $1.1 billion at December 31, 2016 , and 2015 , respectively. (c) Represents the fair value adjustment associated with the application of hedge accounting on certain of our long-term debt positions. Refer to Note 22 to the Consolidated Financial Statements for additional information. (d) Includes $13.3 billion and $20.3 billion of VIE secured debt at December 31, 2016 , and 2015 , respectively. (e) Includes $14.8 billion and $19.9 billion of debt outstanding from the Automotive secured revolving credit facilities at December 31, 2016 , and 2015 , respectively. (f) Includes advances from the Federal Home Loan Bank of Pittsburgh of $6.1 billion and $ 5.4 billion at December 31, 2016 , and December 31, 2015 , respectively.
Long-term Debt Portfolio [Table Text Block]	2016 2015 December 31, ($ in millions) Unsecured Secured Total Unsecured Secured Total Long-term debt Due within one year $ 4,274 $ 10,279 $ 14,553 $ 1,829 $ 9,427 $ 11,256 Due after one year 15,450 23,810 39,260 18,803 35,844 54,647 Fair value adjustment 326 (11 ) 315 334 (3 ) 331 Total long-term debt $ 20,050 $ 34,078 $ 54,128 $ 20,966 $ 45,268 $ 66,234
Scheduled Remaining Maturity of Long-term Debt [Table Text Block]	The following table presents the scheduled remaining maturity of long-term debt at December 31, 2016 , assuming no early redemptions will occur. The actual payment of secured debt may vary based on the payment activity of the related pledged assets. ($ in millions) 2017 2018 2019 2020 2021 2022 and thereafter Fair value adjustment Total Unsecured Long-term debt $ 4,365 $ 3,700 $ 1,681 $ 2,212 $ 638 $ 8,454 $ 326 $ 21,376 Original issue discount (91 ) (101 ) (39 ) (39 ) (43 ) (1,013 ) — (1,326 ) Total unsecured 4,274 3,599 1,642 2,173 595 7,441 326 20,050 Secured Long-term debt 10,279 8,156 7,334 4,248 2,481 1,591 (11 ) 34,078 Total long-term debt $ 14,553 $ 11,755 $ 8,976 $ 6,421 $ 3,076 $ 9,032 $ 315 $ 54,128
Pledged assets for the payment of the related secured borrowings and repurchase agreements [Table Text Block]	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. 2016 2015 December 31, ($ in millions) Total Ally Bank (a) Total Ally Bank (a) Investment securities (b) $ 4,895 $ 4,231 $ 2,420 $ 1,761 Mortgage assets held-for-investment and lending receivables 10,954 10,954 9,743 9,743 Consumer automotive finance receivables (b) 27,846 5,751 34,324 9,167 Commercial automotive finance receivables 19,487 19,280 19,623 19,177 Investment in operating leases, net 2,040 913 5,539 3,205 Total assets restricted as collateral (c) (d) $ 65,222 $ 41,129 $ 71,649 $ 43,053 Secured debt $ 43,129 (e) $ 22,149 $ 49,916 (e) $ 24,787 (a) Ally Bank is a component of the total column. (b) A portion of the restricted investment securities and consumer automotive finance receivables are 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 $19.0 billion and $14.9 billion at December 31, 2016 , and December 31, 2015 , respectively. These assets were composed primarily of consumer mortgage finance receivables and loans, net, and investment securities. Ally Bank has access to the Federal Reserve Bank Discount Window. Ally Bank had assets pledged and restricted as collateral to the Federal Reserve Bank totaling $2.4 billion and $2.9 billion at December 31, 2016 , and December 31, 2015 , respectively. These assets were composed of consumer automotive finance receivables and loans, net, and investment in operating leases, net. Availability under these programs is only for the operations of Ally Bank and cannot be used to fund the operations or liabilities of Ally or its subsidiaries. (d) Excludes restricted cash and cash reserves for securitization trusts recorded within other assets on the Consolidated Balance Sheet . Refer to Note 14 to the Consolidated Financial Statements for additional information. (e) Includes $9.1 billion and $4.6 billion of short-term borrowings at December 31, 2016 , and December 31, 2015 , respectively.
Schedule Of Committed Funding Facilities [Table Text Block]	Committed Funding Facilities Outstanding Unused capacity (a) Total capacity December 31, ($ in millions) 2016 2015 2016 2015 2016 2015 Bank funding Secured (b) $ 3,250 $ 3,250 $ 350 $ — $ 3,600 $ 3,250 Parent funding Secured 11,550 16,914 1,975 251 13,525 17,165 Unsecured (c) — — 1,250 — 1,250 — Total committed facilities $ 14,800 $ 20,164 $ 3,575 $ 251 $ 18,375 $ 20,415 (a) Funding from committed secured facilities is available on request in the event excess collateral resides in certain facilities or is available to the extent incremental collateral is available and contributed to the facilities. (b) Excludes off-balance sheet credit facility amounts. (c) This facility was fully drawn in January 2017. Refer to Note 32 for further information.

Accrued Expenses and Other Li57

Accrued Expenses and Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2016
Accounts Payable and Accrued Liabilities [Abstract]
Schedule of Accrued Liabilities [Table Text Block]	The components of accrued expenses and other liabilities were as follows. December 31, ( $ in millions ) 2016 2015 Accounts payable $ 649 $ 391 Employee compensation and benefits 232 242 Reserves for insurance losses and loss adjustment expenses 149 169 Fair value of derivative contracts in payable position (a) 95 145 Deferred revenue 56 108 Cash collateral received from counterparties 10 82 Other liabilities 546 408 Total accrued expenses and other liabilities $ 1,737 $ 1,545 (a) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements .

Equity (Tables)

Equity (Tables)	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Schedule of Stockholders Equity [Table Text Block]	The following table presents changes in the number of shares issued and outstanding. Year ended December 31, ( shares in thousands ) (a) 2016 2015 2014 Common stock Total issued, January 1, 482,791 480,136 479,767 New issuances Employee benefits and compensation plans 2,917 2,655 369 Total issued, December 31, 485,708 482,791 480,136 Treasury balance, January 1, (811 ) (41 ) — Repurchase of common stock (b) (c) (17,897 ) (769 ) (41 ) Total treasury stock, December 31, (18,707 ) (811 ) (41 ) Total outstanding, December 31, 467,000 481,980 480,095 (a) Figures in the table may not recalculate exactly due to rounding. Number of shares issued, in treasury, and outstanding are calculated based on unrounded numbers. (b) Includes shares of common stock withheld to cover income taxes owed by participants in our share-based incentive plans. (c) On July 19, 2016, we announced a common stock repurchase program of up to $700 million . The program commenced in the third quarter of 2016 and will expire on June 30, 2017.

Accumulated Other Comprehensi59

Accumulated Other Comprehensive Loss (Tables)	12 Months Ended
	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table presents changes, net of tax, in each component of accumulated other comprehensive loss. ($ in millions) Unrealized (losses) gains on investment securities (a) Translation adjustments and net investment hedges (b) Cash flow hedges (b) Defined benefit pension plans Accumulated other comprehensive loss Balance at January 1, 2014 $ (269 ) $ 65 $ 5 $ (77 ) $ (276 ) 2014 net change 248 (29 ) 2 (11 ) 210 Balance at December 31, 2014 $ (21 ) $ 36 $ 7 $ (88 ) $ (66 ) 2015 net change (138 ) (27 ) 1 (1 ) (165 ) Balance at December 31, 2015 $ (159 ) $ 9 $ 8 $ (89 ) $ (231 ) 2016 net change (114 ) 5 — (1 ) (110 ) Balance at December 31, 2016 $ (273 ) $ 14 $ 8 $ (90 ) $ (341 ) (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 22 to the Consolidated Financial Statements .
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]	The following tables present the before- and after-tax changes in each component of accumulated other comprehensive loss. Year ended December 31, 2016 ($ in millions) Before tax Tax effect After tax Investment securities Net unrealized gains arising during the period $ 13 $ 20 $ 33 Less: Net realized gains reclassified to income from continuing operations 185 (a) (38 ) (b) 147 Net change (172 ) 58 (114 ) Translation adjustments Net unrealized gains arising during the period 5 (2 ) 3 Less: Net realized losses reclassified to income from discontinued operations, net of tax (1 ) — (1 ) Net change 6 (2 ) 4 Net investment hedges (c) Net unrealized gains arising during the period 1 — 1 Defined benefit pension plans Net unrealized losses arising during the period (5 ) 2 (3 ) Less: Net realized losses reclassified to income from continuing operations (4 ) (d) 2 (b) (2 ) Net change (1 ) — (1 ) Other comprehensive loss $ (166 ) $ 56 $ (110 ) (a) Includes gains reclassified to other gain on investments, net in our Consolidated Statement of Income . (b) Includes amounts reclassified to income tax expense from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements . (d) Includes gains reclassified to compensation and benefits expense in our Consolidated Statement of Income . Year ended December 31, 2015 ($ in millions) Before tax Tax effect After tax Investment securities Net unrealized losses arising during the period $ (65 ) $ 26 $ (39 ) Less: Net realized gains reclassified to income from continuing operations 155 (a) (56 ) (b) 99 Net change (220 ) 82 (138 ) Translation adjustments Net unrealized losses arising during the period (39 ) 13 (26 ) Less: Net realized gains reclassified to income from discontinued operations, net of tax 42 (20 ) 22 Net change (81 ) 33 (48 ) Net investment hedges (c) Net unrealized gains arising during the period 29 (11 ) 18 Less: Net realized losses reclassified to income from discontinued operations, net of tax (4 ) 1 (3 ) Net change 33 (12 ) 21 Cash flow hedges (c) Net unrealized gains arising during the period 2 (1 ) 1 Defined benefit pension plans Net unrealized gains (losses) arising during the period — — — Less: Net realized gains reclassified to income from continuing operations 1 (d) — (b) 1 Net change (1 ) — (1 ) Other comprehensive loss $ (267 ) $ 102 $ (165 ) (a) Includes gains reclassified to other gain on investments, net in our Consolidated Statement of Income . (b) Includes amounts reclassified to income tax expense from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements . (d) Includes gains reclassified to compensation and benefits expense in our Consolidated Statement of Income . Year ended December 31, 2014 ($ in millions) Before tax Tax effect After tax Investment securities Net unrealized gains arising during the period $ 557 $ (142 ) $ 415 Less: Net realized gains reclassified to income from continuing operations 181 (a) (14 ) (b) 167 Net change 376 (128 ) 248 Translation adjustments Net unrealized losses arising during the period (27 ) 10 (17 ) Less: Net realized gains reclassified to income from discontinued operations, net of tax 23 (3 ) 20 Net change (50 ) 13 (37 ) Net investment hedges (c) Net unrealized gains arising during the period 13 (5 ) 8 Cash flow hedges (c) Net unrealized gains arising during the period 2 — 2 Defined benefit pension plans Net unrealized losses arising during the period (24 ) 9 (15 ) Less: Net realized losses reclassified to income from continuing operations (7 ) (d) 3 (b) (4 ) Net change (17 ) 6 (11 ) Other comprehensive income $ 324 $ (114 ) $ 210 (a) Includes gains reclassified to other gain on investments, net in our Consolidated Statement of Income . (b) Includes amounts reclassified to income tax expense from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements . (d) Includes losses reclassified to compensation and benefits expense in our Consolidated Statement of Income .

Earnings per Common Share (Tabl

Earnings per Common Share (Tables)	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	The following table presents the calculation of basic and diluted earnings per common share. Year ended December 31, ( $ in millions, except per share data; shares in thousands ) (a) 2016 2015 2014 Net income from continuing operations $ 1,111 $ 897 $ 925 Preferred stock dividends (b) (30 ) (2,571 ) (268 ) Net income (loss) from continuing operations attributable to common shareholders 1,081 (1,674 ) 657 (Loss) income from discontinued operations, net of tax (44 ) 392 225 Net income (loss) attributable to common shareholders $ 1,037 $ (1,282 ) $ 882 Basic weighted-average common shares outstanding (c) 481,105 482,873 481,155 Diluted weighted-average common shares outstanding (c) (d) 482,182 482,873 481,934 Basic earnings per common share Net income (loss) from continuing operations $ 2.25 $ (3.47 ) $ 1.36 (Loss) income from discontinued operations, net of tax (0.09 ) 0.81 0.47 Net income (loss) $ 2.15 $ (2.66 ) $ 1.83 Diluted earnings per common share Net income (loss) from continuing operations $ 2.24 $ (3.47 ) $ 1.36 (Loss) income from discontinued operations, net of tax (0.09 ) 0.81 0.47 Net income (loss) $ 2.15 $ (2.66 ) $ 1.83 (a) Figures in the table may not recalculate exactly due to rounding. Earnings per share is calculated based on unrounded numbers. (b) Preferred stock dividends for the year ended December 31, 2015 , include $2,364 million recognized in connection with the partial redemption of the Series G Preferred Stock and the repurchase of the Series A Preferred Stock. These dividends represent an additional return to preferred shareholders calculated as the excess consideration paid over the carrying amount derecognized. (c) Includes shares related to share-based compensation that vested but were not yet issued for the years ended December 31, 2016 , 2015 , and 2014 , respectively. (d) Due to the antidilutive effect of the net loss from continuing operations attributable to common shareholders for the year ended December 31, 2015 , basic weighted-average common shares outstanding was used to calculate basic and diluted earnings per share.

Regulatory Capital and Other 61

Regulatory Capital and Other Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2016
Regulatory Capital Requirements [Abstract]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block]	The following table summarizes our capital ratios under the U.S. Basel III capital framework. December 31, 2016 December 31, 2015 Required Well-capitalized ( $ in millions ) Amount Ratio Amount Ratio Capital ratios Common Equity Tier 1 (to risk-weighted assets) Ally Financial Inc. $ 12,978 9.37 % $ 12,507 9.21 % 4.50 % (a) Ally Bank 17,888 16.70 16,594 17.05 4.50 6.50 % Tier 1 (to risk-weighted assets) Ally Financial Inc. $ 15,147 10.93 % $ 15,077 11.10 % 6.00 % 6.00 % Ally Bank 17,888 16.70 16,594 17.05 6.00 8.00 Total (to risk-weighted assets) Ally Financial Inc. $ 17,419 12.57 % $ 17,005 12.52 % 8.00 % 10.00 % Ally Bank 18,458 17.24 17,043 17.51 8.00 10.00 Tier 1 leverage (to adjusted quarterly average assets) (b) Ally Financial Inc. $ 15,147 9.54 % $ 15,077 9.73 % 4.00 % (a) Ally Bank 17,888 15.21 16,594 15.38 15.00 (c) 5.00 % (a) Currently, there is no ratio component for determining whether a BHC is "well-capitalized." (b) Federal regulatory reporting guidelines require the calculation of adjusted quarterly average assets using a daily average methodology. (c) Ally Bank has committed to the FRB to maintain a Tier 1 leverage ratio of at least 15% .

Derivative Instruments and He62

Derivative Instruments and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value Amounts of Derivative Instruments Reported On Our Condensed Consolidated Balance Sheet [Table Text Block]	The following table summarizes the fair value amounts of derivative instruments reported on our Consolidated Balance Sheet . The fair value 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. 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. 2016 2015 Derivative contracts in a Notional Derivative contracts in a Notional December 31, ($ in millions) receivable payable receivable payable Derivatives designated as accounting hedges Interest rate contracts Swaps (c) (d) (e) $ 19 $ 21 $ 4,731 $ 126 $ 9 $ 14,151 Foreign exchange contracts Forwards 1 — 171 — 1 189 Total derivatives designated as accounting hedges 20 21 4,902 126 10 14,340 Derivatives not designated as accounting hedges Interest rate contracts Swaps — — 137 30 51 6,101 Futures and forwards — — — 2 2 1,905 Written options — 73 14,518 — 72 18,220 Purchased options 73 — 14,517 73 — 18,240 Total interest rate risk 73 73 29,172 105 125 44,466 Foreign exchange contracts Futures and forwards 1 — 92 — — 278 Total foreign exchange risk 1 — 92 — — 278 Equity contracts Forwards — — — — 9 32 Written options — 1 — — 1 — Purchased options 1 — — 2 — — Total equity risk 1 1 — 2 10 32 Total derivatives not designated as accounting hedges 75 74 29,264 107 135 44,776 Total derivatives $ 95 $ 95 $ 34,166 $ 233 $ 145 $ 59,116 (a) Derivative contracts in a receivable position are classified as other assets on the Consolidated Balance Sheet , and include accrued interest of $7 million and $46 million at December 31, 2016 , and December 31, 2015 , respectively. (b) Derivative contracts in a liability position are classified as accrued expenses and other liabilities on the Consolidated Balance Sheet , and include accrued interest of $1 million and $12 million at December 31, 2016 , and December 31, 2015 , respectively. (c) Includes fair value hedges consisting of receive-fixed swaps on fixed-rate unsecured debt obligations with $8 million and $112 million in a receivable position, $14 million and $3 million in a payable position, and a $1.7 billion and $6.8 billion notional amount at December 31, 2016 , and December 31, 2015 , respectively. The hedge notional amount of $1.7 billion at December 31, 2016 , is associated with debt maturing in five or more years. (d) Includes fair value hedges consisting of receive-fixed swaps on fixed-rate secured debt obligations (FHLB Advances) with $0 million and $1 million in a receivable position, $7 million and $2 million in a payable position, and a $240 million and $500 million notional amount at December 31, 2016 , and December 31, 2015 , respectively. (e) Other fair value hedges include pay-fixed swaps on portfolios of held-for-investment automotive loan assets with $10 million and $13 million in a receivable position, $1 million and $3 million in a payable position, and a $2.8 billion and $6.8 billion notional amount at December 31, 2016 , and December 31, 2015 , respectively.
Gains and Losses On Derivative Instruments Reported in Statement of Comprehensive Income [Table Text Block]	The following table summarizes the location and amounts of gains and losses on derivative instruments reported in our Consolidated Statement of Income . Year ended December 31, ( $ in millions ) 2016 2015 2014 Derivatives qualifying for hedge accounting (Loss) gain recognized in earnings on derivatives Interest rate contracts Interest and fees on finance receivables and loans (a) $ (2 ) $ (9 ) $ 15 Interest on long-term debt (b) (c) 65 35 199 Gain (loss) recognized in earnings on hedged items Interest rate contracts Interest and fees on finance receivables and loans (d) — 39 34 Interest on long-term debt (e) (70 ) (30 ) (185 ) Total derivatives qualifying for hedge accounting (7 ) 35 63 Derivatives not designated as accounting hedges (Loss) gain recognized in earnings on derivatives Interest rate contracts Loss on mortgage and automotive loans, net — (2 ) — Other income, net of losses — (17 ) (37 ) Total interest rate contracts — (19 ) (37 ) Foreign exchange contracts (f) Interest on long-term debt (2 ) (139 ) (172 ) Other income, net of losses 1 12 12 Total foreign exchange contracts (1 ) (127 ) (160 ) Equity contracts Compensation and benefits expense — (10 ) (5 ) Total equity contracts — (10 ) (5 ) Loss recognized in earnings on derivatives $ (8 ) $ (121 ) $ (139 ) (a) Amounts exclude losses related to interest for qualifying accounting hedges of retail automotive loans held-for-investment, which are primarily offset by the fixed coupon payments of the loans. The losses were $18 million , $64 million , and $61 million for the years ended December 31, 2016 , 2015 , and 2014 respectively. (b) Amounts exclude gains related to interest for qualifying accounting hedges of unsecured debt, which are primarily offset by the fixed coupon payment on the long-term debt. The gains were $40 million , $97 million , and $112 million and for the years ended December 31, 2016 , 2015 , and 2014, respectively. (c) Amounts exclude gains related to interest for qualifying accounting hedges of secured debt (FHLB Advances), which are primarily offset by the fixed coupon payment on the long-term debt. The gains were $5 million and $1 million for the years ended December 31, 2016 , and 2015 , respectively. (d) Amounts exclude losses related to amortization of deferred loan basis adjustments on the de-designated hedged item of $20 million and $8 million for the year ended December 31, 2016 , and 2015 , respectively. (e) Amounts exclude gains related to amortization of deferred debt basis adjustments on the de-designated hedged item of $84 million , $73 million , and $155 million for the years ended December 31, 2016 , 2015 , and 2014 respectively. (f) Amounts exclude gains and losses related to the revaluation of the related foreign-denominated debt or receivable. Gains of $0 million , $132 million , and $165 million were recognized for the years ended December 31, 2016 , 2015 , and 2014, respectively.
Derivative Instruments Used in Cash Flow and Net Investment Hedge Accounting Relationships [Table Text Block]	The following table summarizes derivative instruments used in cash flow and net investment hedge accounting relationships. Year ended December 31, ( $ in millions ) 2016 2015 2014 Cash flow hedges Interest rate contracts Loss reclassified from accumulated other comprehensive loss to interest on long-term debt $ — $ — $ (2 ) Total interest on long-term debt $ — $ — $ (2 ) Gain recognized in other comprehensive loss $ — $ 2 $ 2 Net investment hedges Foreign exchange contracts Loss reclassified from accumulated other comprehensive loss to income from discontinued operations, net $ — $ (4 ) $ — Total loss from discontinued operations, net $ — $ (4 ) $ — Gain recognized in other comprehensive loss (a) $ 1 $ 33 $ 13 (a) The amounts represent the effective portion of net investment hedges. There are offsetting amounts recognized in accumulated other comprehensive loss related to the revaluation of the related net investment in foreign operations, including the tax impacts of the hedge and related net investment, as disclosed separately in Note 19 to the Consolidated Financial Statements . There were gains of $4 million for the year ended December 31, 2016 , and losses of $59 million , and $41 million for the years ended December 31, 2015 , and 2014, respectively.

Income Taxes Income Taxes (Tabl

Income Taxes Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	The significant components of income tax expense from continuing operations were as follows. Year ended December 31, ( $ in millions ) 2016 2015 2014 Current income tax expense U.S. federal $ — $ — $ (3 ) Foreign 8 6 8 State and local 9 3 5 Total current expense 17 9 10 Deferred income tax expense U.S. federal 423 454 270 Foreign — 1 2 State and local 30 32 39 Total deferred expense 453 487 311 Total income tax expense from continuing operations $ 470 $ 496 $ 321
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	A reconciliation of income tax expense from continuing operations with the amounts at the statutory U.S. federal income tax rate is shown in the following table. Year ended December 31, ( $ in millions ) 2016 2015 2014 Statutory U.S. federal tax expense $ 553 $ 488 $ 436 Change in tax resulting from Changes in unrecognized tax benefits (a) (161 ) (5 ) (63 ) Valuation allowance change, excluding expirations 51 (25 ) (47 ) State and local income taxes, net of federal income tax benefit 35 38 48 Tax credits, excluding expirations (15 ) (13 ) (27 ) Nondeductible expenses 7 14 31 Tax law enactment — — (39 ) Other, net — (1 ) (18 ) Total income tax expense from continuing operations $ 470 $ 496 $ 321 (a) Primarily the result of a Q2 2016 U.S. tax reserve release related to a prior year federal return.
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	The significant components of deferred tax assets and liabilities are reflected in the following table. December 31, ( $ in millions ) 2016 2015 Deferred tax assets Tax credit carryforwards $ 1,987 $ 1,941 Tax loss carryforwards 936 950 Adjustments to loan value 546 311 State and local taxes 162 194 Unearned insurance premiums 141 141 Hedging transactions 123 99 Other 208 212 Gross deferred tax assets 4,103 3,848 Valuation allowance (646 ) (582 ) Deferred tax assets, net of valuation allowance 3,457 3,266 Deferred tax liabilities Lease transactions 1,789 1,273 Deferred acquisition costs 424 403 Debt transactions 161 162 Other 107 69 Gross deferred tax liabilities 2,481 1,907 Net deferred tax assets (a) $ 976 $ 1,359 (a) Total net deferred tax assets include $994 million and $1,369 million of net deferred tax assets included in other assets on our Consolidated Balance Sheet for tax jurisdictions in a total net deferred tax asset position and $18 million and $10 million included in accrued expenses and other liabilities on our Consolidated Balance Sheet for tax jurisdictions in a total net deferred tax liability position at December 31, 2016, and 2015, respectively.
Schedule of Deferred tax assets and related valuation allowances recognized for the net operating and other loss carryforwards and tax credit carryforwards [Table Text Block]	The following table summarizes net deferred tax assets including related valuation allowances at December 31, 2016. ( $ in millions ) Deferred tax asset/(liability) Valuation allowance Net deferred tax asset/(liability) Years of expiration Tax credit carryforwards Foreign tax credits $ 1,771 $ (485 ) $ 1,286 2017–2026 General business credits 191 — 191 2023–2036 Alternative minimum tax (AMT) credits 25 — 25 n/a Total tax credit carryforwards 1,987 (485 ) 1,502 Tax loss carryforwards Net operating losses — federal 900 — 900 2027–2036 Net operating losses — state 193 (a) (83 ) 110 2017–2036 Capital losses — federal 36 (36 ) — 2017 Capital losses — state 9 (a) (9 ) — 2017–2027 Total tax loss carryforwards 1,138 (128 ) 1,010 Other deferred tax assets 978 (33 ) 945 n/a Deferred tax assets 4,103 (646 ) 3,457 Deferred tax liabilities (2,481 ) — (2,481 ) n/a Net deferred tax assets $ 1,622 $ (646 ) $ 976 (a) State net operating loss and capital loss carryforwards are included in the state and local taxes total disclosed in our deferred inventory table above.
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]	The following table provides a reconciliation of the beginning and ending amount of unrecognized tax benefits. ( $ in millions ) 2016 2015 2014 Balance at January 1, $ 185 $ 191 $ 262 Additions based on tax positions related to the current year — — — Additions for tax positions of prior years 12 7 9 Settlements (182 ) (10 ) (79 ) Expiration of statute of limitations (1 ) (3 ) (1 ) Balance at December 31, $ 14 $ 185 $ 191

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Measurements - Recurring Basis [Table Text Block]	The following tables display the assets and liabilities measured at fair value on a recurring basis including financial instruments elected for the fair value option. We often economically hedge the fair value change of our assets or liabilities with derivatives and other financial instruments. The tables below display the hedges separately from the hedged items; therefore, they do not directly display the impact of our risk management activities. Recurring fair value measurements December 31, 2016 ($ in millions) Level 1 Level 2 Level 3 Total Assets Investment securities Available-for-sale securities Debt securities U.S. Treasury and federal agencies $ 1,620 $ — $ — $ 1,620 U.S. States and political subdivisions — 782 — 782 Foreign government 11 151 — 162 Agency mortgage-backed residential — 10,290 — 10,290 Mortgage-backed residential — 2,097 — 2,097 Mortgage-backed commercial — 537 — 537 Asset-backed — 1,400 — 1,400 Corporate debt — 1,443 — 1,443 Total debt securities 1,631 16,700 — 18,331 Equity securities (a) 595 — — 595 Total available-for-sale securities 2,226 16,700 — 18,926 Other assets Interests retained in financial asset sales — — 29 29 Derivative contracts in a receivable position (b) Interest rate — 92 — 92 Foreign currency — 2 — 2 Other 1 — — 1 Total derivative contracts in a receivable position 1 94 — 95 Total assets $ 2,227 $ 16,794 $ 29 $ 19,050 Liabilities Accrued expenses and other liabilities Derivative contracts in a payable position (b) Interest rate $ — $ (94 ) $ — $ (94 ) Other (1 ) — — (1 ) Total derivative contracts in a payable position (1 ) (94 ) — (95 ) Total liabilities $ (1 ) $ (94 ) $ — $ (95 ) (a) Our investment in any one industry did not exceed 14% . (b) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements . Recurring fair value measurements December 31, 2015 ($ in millions) Level 1 Level 2 Level 3 Total Assets Investment securities Available-for-sale securities Debt securities U.S. Treasury and federal agencies $ 1,469 $ 272 $ — $ 1,741 U.S. States and political subdivisions — 716 — 716 Foreign government 10 167 — 177 Agency mortgage-backed residential — 7,544 — 7,544 Mortgage-backed residential — 2,822 — 2,822 Mortgage-backed commercial — 481 — 481 Asset-backed — 1,755 — 1,755 Corporate debt — 1,204 — 1,204 Total debt securities 1,479 14,961 — 16,440 Equity securities (a) 717 — — 717 Total available-for-sale securities 2,196 14,961 — 17,157 Other assets Interests retained in financial asset sales — — 40 40 Derivative contracts in a receivable position (b) Interest rate 2 229 — 231 Other 2 — — 2 Total derivative contracts in a receivable position 4 229 — 233 Total assets $ 2,200 $ 15,190 $ 40 $ 17,430 Liabilities Accrued expenses and other liabilities Derivative contracts in a payable position (b) Interest rate $ (2 ) $ (133 ) $ — $ (135 ) Foreign currency — (1 ) — (1 ) Other (1 ) (8 ) — (9 ) Total derivative contracts in a payable position (3 ) (142 ) — (145 ) Total liabilities $ (3 ) $ (142 ) $ — $ (145 ) (a) Our investment in any one industry did not exceed 14% . (b) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements .
Fair Value Measurements - Reconciliation of Level 3 Assets and Liabilities [Table Text Block]	The following tables present the reconciliation for all Level 3 assets and liabilities measured at fair value on a recurring basis. 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 Fair value at Net unrealized gains included in earnings ($ in millions) Fair value at Jan. 1, 2016 included in earnings included in OCI Purchases Sales Issuances Settlements Assets Other assets Interests retained in financial asset sales $ 40 $ 4 (a) $ — $ — $ 9 $ — $ (24 ) $ 29 $ — Total assets $ 40 $ 4 $ — $ — $ 9 $ — $ (24 ) $ 29 $ — (a) Reported as other income, net of losses, in the Consolidated Statement of Income . Level 3 recurring fair value measurements Fair value at Jan. 1, 2015 Net realized/unrealized Purchases Sales Issuances Settlements Fair value at Net unrealized gains included in earnings ($ in millions) included in earnings included in OCI Assets Mortgage loans held-for-sale, net $ 3 $ 1 $ — $ — $ (4 ) $ — $ — $ — $ — Other assets Interests retained in financial asset sales 47 9 (a) — — — 26 (42 ) 40 — Total assets $ 50 $ 10 $ — $ — $ (4 ) $ 26 $ (42 ) $ 40 $ — (a) Reported as other income, net of losses, in the Consolidated Statement of Income .
Fair Value Measurements - Nonrecurring Basis [Table Text Block]	The following tables display the assets and liabilities measured at fair value on a nonrecurring basis. Nonrecurring Lower-of-cost or Total (loss)gain included in earnings for the year ended December 31, 2016 ($ in millions) Level 1 Level 2 Level 3 Total Assets Commercial finance receivables and loans, net (a) Commercial and industrial Automotive $ — $ — $ 27 $ 27 $ (4 ) n/m (b) Other — — 65 65 (19 ) n/m (b) Total commercial finance receivables and loans, net — — 92 92 (23 ) n/m (b) Other assets Repossessed and foreclosed assets (c) — — 12 12 (4 ) n/m (b) Other — — 4 4 — n/m (b) Total assets $ — $ — $ 108 $ 108 $ (27 ) n/m n/m = not meaningful (a) Represents the portion of the portfolio specifically impaired during 2016 . The related valuation allowance represents the cumulative adjustment to fair value of those specific receivables. (b) We consider the applicable valuation or loan loss allowance to be the most relevant indicator of the impact on earnings caused by the fair value measurement. Accordingly, the table above excludes total gains and losses included in earnings for these items. The carrying values are inclusive of the respective valuation or loan loss allowance. (c) The allowance provided for repossessed and foreclosed assets represents any cumulative valuation adjustment recognized to adjust the assets to fair value. Nonrecurring Lower-of-cost or Total loss included in earnings for the year ended December 31, 2015 ($ in millions) Level 1 Level 2 Level 3 Total Assets Loans held-for-sale, net $ — $ — $ 105 $ 105 $ — n/m (a) Commercial finance receivables and loans, net (b) Commercial and industrial Automotive — — 19 19 (2 ) n/m (a) Other — — 29 29 (15 ) n/m (a) Commercial real estate — Automotive — — 4 4 (3 ) n/m (a) Total commercial finance receivables and loans, net — — 52 52 (20 ) n/m (a) Other assets Repossessed and foreclosed assets (c) — — 9 9 (3 ) n/m (a) Other — — 6 6 (2 ) n/m (a) Total assets $ — $ — $ 172 $ 172 $ (25 ) n/m n/m = not meaningful (a) We consider the applicable valuation or loan loss allowance to be the most relevant indicator of the impact on earnings caused by the fair value measurement. Accordingly, the table above excludes total gains and losses included in earnings for these items. The carrying values are inclusive of the respective valuation or loan loss allowance. (b) Represents the portion of the portfolio specifically impaired during 2015 . The related valuation allowance represents the cumulative adjustment to fair value of those specific receivables. (c) The allowance provided for repossessed and foreclosed assets represents any cumulative valuation adjustment recognized to adjust the assets to fair value.
Fair Value of Financial Intruments [Table Text Block]	The following table presents the carrying and estimated fair value of financial instruments, except for those recorded at fair value on a recurring basis presented in the previous section of this note titled Recurring Fair Value. When possible, we use quoted market prices to determine fair value. Where quoted market prices are not available, the fair value is internally derived based on appropriate valuation methodologies with respect to the amount and timing of future cash flows and estimated discount rates. However, considerable judgment is required in interpreting current market data to develop the market assumptions and inputs necessary to estimate fair value. As such, the actual amount received to sell an asset or the amount paid to settle a liability could differ from our estimates. Fair value information presented herein was based on information available at December 31, 2016 , and December 31, 2015 . Estimated fair value December 31, ($ in millions) Carrying value Level 1 Level 2 Level 3 Total 2016 Financial assets Held-to-maturity securities $ 839 $ — $ 789 $ — $ 789 Finance receivables and loans, net 117,800 — — 118,750 118,750 Nonmarketable equity investments 1,046 — 1,012 55 1,067 Financial liabilities Deposit liabilities $ 79,022 $ — $ — $ 78,469 $ 78,469 Short-term borrowings 12,673 — — 12,675 12,675 Long-term debt 54,128 — 22,036 34,084 56,120 2015 Financial assets Loans held-for-sale, net $ 105 $ — $ — $ 105 $ 105 Finance receivables and loans, net 110,546 — — 110,737 110,737 Nonmarketable equity investments 418 — 391 42 433 Financial liabilities Deposit liabilities $ 66,478 $ — $ — $ 66,889 $ 66,889 Short-term borrowings 8,101 — — 8,102 8,102 Long-term debt 66,234 — 23,018 45,157 68,175

Offsetting Assets and Liabili65

Offsetting Assets and Liabilities Offsetting Assets and Liabilities (Assets) (Tables)	12 Months Ended
	Dec. 31, 2016
Offsetting Assets and Liabilities [Abstract]
Offsetting Assets [Table Text Block]	The composition of offsetting derivative instruments, financial assets, and financial liabilities was as follows. Gross amounts of recognized assets/(liabilities) Gross amounts offset in the Consolidated Balance Sheet Net amounts of assets/(liabilities) Gross amounts not offset in the Consolidated Balance Sheet December 31, 2016 ($ in millions) Financial instruments Collateral Net amount Assets Derivative assets in net asset positions $ 87 $ — $ 87 $ (4 ) $ (9 ) $ 74 Derivative assets in net liability positions 8 — 8 (8 ) — — Total assets (d) $ 95 $ — $ 95 $ (12 ) $ (9 ) $ 74 Liabilities Derivative liabilities in net liability positions $ (91 ) $ — $ (91 ) $ 8 $ 13 $ (70 ) Derivative liabilities in net asset positions (4 ) — (4 ) 4 — — Total derivative liabilities (d) (95 ) — (95 ) 12 13 (70 ) Securities sold under agreements to repurchase (e) (676 ) — (676 ) — 676 — Total liabilities $ (771 ) $ — $ (771 ) $ 12 $ 689 $ (70 ) (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. $6 million of noncash derivative collateral pledged to us was excluded at December 31, 2016 . We do not record such collateral received on our Consolidated Balance Sheet unless certain conditions are met. (c) Certain agreements grant us the right to sell or pledge the noncash assets we receive as collateral. Noncash collateral pledged to us where the agreement grants us the right to sell or pledge the underlying assets had a fair value of $6 million at December 31, 2016 . We have not sold or pledged any of the noncash collateral received under these agreements as of December 31, 2016 . (d) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements . (e) For additional information on securities sold under agreements to repurchase, refer to Note 16 to the Consolidated Financial Statements . Gross amounts of recognized assets/(liabilities) Gross amounts offset in the Consolidated Balance Sheet Net amounts of assets/(liabilities) Gross amounts not offset in the Consolidated Balance Sheet December 31, 2015 ( $ in millions ) Financial instruments Collateral Net amount Assets Derivative assets in net asset positions $ 224 $ — $ 224 $ (69 ) $ (67 ) $ 88 Derivative assets in net liability positions 9 — 9 (9 ) — — Total assets (d) $ 233 $ — $ 233 $ (78 ) $ (67 ) $ 88 Liabilities Derivative liabilities in net liability positions $ (68 ) $ — $ (68 ) $ 9 $ 2 $ (57 ) Derivative liabilities in net asset positions (69 ) — (69 ) 69 — — Derivative liabilities with no offsetting arrangements (8 ) — (8 ) — — (8 ) Total derivative liabilities (d) (145 ) — (145 ) 78 2 (65 ) Securities sold under agreements to repurchase (e) (648 ) — (648 ) — 648 — Total liabilities $ (793 ) $ — $ (793 ) $ 78 $ 650 $ (65 ) (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. $7 million of noncash derivative collateral pledged to us was excluded at December 31, 2015. We do not record such collateral received on our Consolidated Balance Sheet unless certain conditions are met. (c) Certain agreements grant us the right to sell or pledge the noncash assets we receive as collateral. Noncash collateral pledged to us where the agreement grants us the right to sell or pledge the underlying assets had a fair value of $7 million at December 31, 2015. We have not sold or pledged any of the noncash collateral received under these agreements as of December 31, 2015. (d) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements . (e) For additional information on securities sold under agreements to repurchase, refer to Note 16 to the Consolidated Financial Statements .

Offsetting Assets and Liabili66

Offsetting Assets and Liabilities Offsetting Assets and Liabilities (Liabilities) (Tables)	12 Months Ended
	Dec. 31, 2016
Offsetting Liabilities [Abstract]
Offsetting Liabilities [Table Text Block]	The composition of offsetting derivative instruments, financial assets, and financial liabilities was as follows. Gross amounts of recognized assets/(liabilities) Gross amounts offset in the Consolidated Balance Sheet Net amounts of assets/(liabilities) Gross amounts not offset in the Consolidated Balance Sheet December 31, 2016 ($ in millions) Financial instruments Collateral Net amount Assets Derivative assets in net asset positions $ 87 $ — $ 87 $ (4 ) $ (9 ) $ 74 Derivative assets in net liability positions 8 — 8 (8 ) — — Total assets (d) $ 95 $ — $ 95 $ (12 ) $ (9 ) $ 74 Liabilities Derivative liabilities in net liability positions $ (91 ) $ — $ (91 ) $ 8 $ 13 $ (70 ) Derivative liabilities in net asset positions (4 ) — (4 ) 4 — — Total derivative liabilities (d) (95 ) — (95 ) 12 13 (70 ) Securities sold under agreements to repurchase (e) (676 ) — (676 ) — 676 — Total liabilities $ (771 ) $ — $ (771 ) $ 12 $ 689 $ (70 ) (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. $6 million of noncash derivative collateral pledged to us was excluded at December 31, 2016 . We do not record such collateral received on our Consolidated Balance Sheet unless certain conditions are met. (c) Certain agreements grant us the right to sell or pledge the noncash assets we receive as collateral. Noncash collateral pledged to us where the agreement grants us the right to sell or pledge the underlying assets had a fair value of $6 million at December 31, 2016 . We have not sold or pledged any of the noncash collateral received under these agreements as of December 31, 2016 . (d) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements . (e) For additional information on securities sold under agreements to repurchase, refer to Note 16 to the Consolidated Financial Statements . Gross amounts of recognized assets/(liabilities) Gross amounts offset in the Consolidated Balance Sheet Net amounts of assets/(liabilities) Gross amounts not offset in the Consolidated Balance Sheet December 31, 2015 ( $ in millions ) Financial instruments Collateral Net amount Assets Derivative assets in net asset positions $ 224 $ — $ 224 $ (69 ) $ (67 ) $ 88 Derivative assets in net liability positions 9 — 9 (9 ) — — Total assets (d) $ 233 $ — $ 233 $ (78 ) $ (67 ) $ 88 Liabilities Derivative liabilities in net liability positions $ (68 ) $ — $ (68 ) $ 9 $ 2 $ (57 ) Derivative liabilities in net asset positions (69 ) — (69 ) 69 — — Derivative liabilities with no offsetting arrangements (8 ) — (8 ) — — (8 ) Total derivative liabilities (d) (145 ) — (145 ) 78 2 (65 ) Securities sold under agreements to repurchase (e) (648 ) — (648 ) — 648 — Total liabilities $ (793 ) $ — $ (793 ) $ 78 $ 650 $ (65 ) (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. $7 million of noncash derivative collateral pledged to us was excluded at December 31, 2015. We do not record such collateral received on our Consolidated Balance Sheet unless certain conditions are met. (c) Certain agreements grant us the right to sell or pledge the noncash assets we receive as collateral. Noncash collateral pledged to us where the agreement grants us the right to sell or pledge the underlying assets had a fair value of $7 million at December 31, 2015. We have not sold or pledged any of the noncash collateral received under these agreements as of December 31, 2015. (d) For additional information on derivative instruments and hedging activities, refer to Note 22 to the Consolidated Financial Statements . (e) For additional information on securities sold under agreements to repurchase, refer to Note 16 to the Consolidated Financial Statements .

Segment and Geographic Inform67

Segment and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment [Table Text Block]	Financial information for our reportable operating segments is summarized as follows. Year ended December 31, ($ in millions) Automotive Finance operations Insurance operations Mortgage Finance operations Corporate Finance operations Corporate and Other Consolidated (a) 2016 Net financing revenue and other interest income (loss) $ 3,665 $ 61 $ 97 $ 121 $ (37 ) $ 3,907 Other revenue 306 1,036 — 26 162 1,530 Total net revenue 3,971 1,097 97 147 125 5,437 Provision for loan losses 924 — (4 ) 10 (13 ) 917 Total noninterest expense 1,667 940 67 66 199 2,939 Income (loss) from continuing operations before income tax expense $ 1,380 $ 157 $ 34 $ 71 $ (61 ) $ 1,581 Total assets $ 116,347 $ 7,172 $ 8,307 $ 3,183 $ 28,719 $ 163,728 2015 Net financing revenue and other interest income $ 3,429 $ 57 $ 57 $ 89 $ 87 $ 3,719 Other revenue (loss) 235 1,033 — 25 (151 ) 1,142 Total net revenue (loss) 3,664 1,090 57 114 (64 ) 4,861 Provision for loan losses 696 — 7 9 (5 ) 707 Total noninterest expense 1,633 879 39 55 155 2,761 Income (loss) from continuing operations before income tax expense $ 1,335 $ 211 $ 11 $ 50 $ (214 ) $ 1,393 Total assets $ 115,636 $ 7,053 $ 6,461 $ 2,677 $ 26,754 $ 158,581 2014 Net financing revenue and other interest income (loss) $ 3,321 $ 56 $ 36 $ 59 $ (97 ) $ 3,375 Other revenue (loss) 264 1,129 — 32 (149 ) 1,276 Total net revenue (loss) 3,585 1,185 36 91 (246 ) 4,651 Provision for loan losses 542 — 3 (16 ) (72 ) 457 Total noninterest expense 1,614 988 21 43 282 2,948 Income (loss) from continuing operations before income tax expense $ 1,429 $ 197 $ 12 $ 64 $ (456 ) $ 1,246 Total assets $ 113,188 $ 7,190 $ 3,542 $ 1,870 $ 25,841 $ 151,631 (a) Net financing revenue and other interest income after the provision for loan losses totaled $3.0 billion , for the years ended December 31, 2016 , and 2015 , and $2.9 billion for the year ended December 31, 2014 .
Information Concerning Principal Geographic Areas [Table Text Block]	Information concerning principal geographic areas was as follows. Year ended December 31, ($ in millions) Total net revenue Income from continuing operations before income tax expense Net income (loss) (b) Identifiable assets (c) Long-lived assets (d) 2016 Canada $ 90 $ 44 $ 32 $ 499 $ — Europe — — (1 ) 276 — Latin America — — (1 ) 23 — Asia-Pacific — — — 2 — Total foreign (e) 90 44 30 800 — Total domestic (f) 5,347 1,537 1,037 162,688 11,846 Total $ 5,437 $ 1,581 $ 1,067 $ 163,488 $ 11,846 2015 Canada $ 98 $ 47 $ 35 514 — Europe 1 4 27 325 — Latin America — — (2 ) 28 — Asia-Pacific — — 452 2 — Total foreign (e) 99 51 512 869 — Total domestic (f) 4,762 1,342 777 157,685 16,506 Total $ 4,861 $ 1,393 $ 1,289 $ 158,554 $ 16,506 2014 Canada $ 124 $ 54 $ 68 $ 590 $ — Europe 2 — 4 1,636 — Latin America — — (8 ) 29 — Asia-Pacific — — 122 636 — Total foreign (e) 126 54 186 2,891 — Total domestic (f) 4,525 1,192 964 148,713 19,735 Total $ 4,651 $ 1,246 $ 1,150 $ 151,604 $ 19,735 (a) Revenue consists of net financing revenue and other interest income and total other revenue as presented in our Consolidated Financial Statements . (b) Gain (loss) realized on sale of discontinued operations are allocated to the geographic area in which the business operated. (c) Identifiable assets consist of total assets excluding goodwill. (d) Long-lived assets consist of investments in operating leases, net, and net property and equipment. (e) Our foreign operations as of December 31, 2016 , 2015, and 2014, consist of our ongoing Insurance operations in Canada and our remaining international entities in wind-down. (f) Amounts include eliminations between our domestic and foreign operations.

Parent and Guarantor Consolid68

Parent and Guarantor Consolidating Financial Statements (Tables)	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Income Statement [Table Text Block]	Condensed Consolidating Statements of Comprehensive Income Year ended December 31, 2016 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing (loss) revenue and other interest income Interest and fees on finance receivables and loans $ (104 ) $ — $ 5,266 $ — $ 5,162 Interest and fees on finance receivables and loans — intercompany 11 — 8 (19 ) — Interest and dividends on investment securities and other earning assets — — 421 (3 ) 418 Interest on cash and cash equivalents 5 — 9 — 14 Interest-bearing cash — intercompany — — 9 (9 ) — Operating leases 17 — 2,694 — 2,711 Total financing (loss) revenue and other interest income (71 ) — 8,407 (31 ) 8,305 Interest expense Interest on deposits 8 — 822 — 830 Interest on short-term borrowings 40 — 17 — 57 Interest on long-term debt 1,161 — 581 — 1,742 Interest on intercompany debt 20 — 11 (31 ) — Total interest expense 1,229 — 1,431 (31 ) 2,629 Net depreciation expense on operating lease assets 14 — 1,755 — 1,769 Net financing revenue (1,314 ) — 5,221 — 3,907 Cash dividends from subsidiaries Nonbank subsidiaries 965 — — (965 ) — Other revenue Insurance premiums and service revenue earned — — 945 — 945 (Loss) gain on mortgage and automotive loans, net (11 ) — 22 — 11 Loss on extinguishment of debt (3 ) — (2 ) — (5 ) Other gain on investments, net — — 176 9 185 Other income, net of losses 1,253 — 937 (1,796 ) 394 Total other revenue 1,239 — 2,078 (1,787 ) 1,530 Total net revenue 890 — 7,299 (2,752 ) 5,437 Provision for loan losses 408 — 509 — 917 Noninterest expense Compensation and benefits expense 573 — 419 — 992 Insurance losses and loss adjustment expenses — — 342 — 342 Other operating expenses 1,261 — 2,130 (1,786 ) 1,605 Total noninterest expense 1,834 — 2,891 (1,786 ) 2,939 (Loss) income from continuing operations before income tax (benefit) expense and undistributed income (loss) of subsidiaries (1,352 ) — 3,899 (966 ) 1,581 Income tax (benefit) expense from continuing operations (279 ) (82 ) 831 — 470 Net (loss) income from continuing operations (1,073 ) 82 3,068 (966 ) 1,111 Loss from discontinued operations, net of tax (39 ) — (5 ) — (44 ) Undistributed income (loss) of subsidiaries Bank subsidiary 1,273 1,273 — (2,546 ) — Nonbank subsidiaries 906 (2 ) — (904 ) — Net income 1,067 1,353 3,063 (4,416 ) 1,067 Other comprehensive loss, net of tax (110 ) (63 ) (106 ) 169 (110 ) Comprehensive income $ 957 $ 1,290 $ 2,957 $ (4,247 ) $ 957 Year ended December 31, 2015 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing (loss) revenue and other interest income Interest and fees on finance receivables and loans $ (83 ) $ — $ 4,653 $ — $ 4,570 Interest and fees on finance receivables and loans — intercompany 17 — 24 (41 ) — Interest on loans held-for-sale — — 40 — 40 Interest and dividends on investment securities and other earning assets — — 381 — 381 Interest on cash and cash equivalents 1 — 7 — 8 Interest-bearing cash — intercompany — — 8 (8 ) — Operating leases 9 — 3,389 — 3,398 Total financing (loss) revenue and other interest income (56 ) — 8,502 (49 ) 8,397 Interest expense Interest on deposits 10 — 708 — 718 Interest on short-term borrowings 40 — 9 — 49 Interest on long-term debt 1,121 — 541 — 1,662 Interest on intercompany debt 32 — 17 (49 ) — Total interest expense 1,203 — 1,275 (49 ) 2,429 Net depreciation expense on operating lease assets 7 — 2,242 — 2,249 Net financing revenue (1,266 ) — 4,985 — 3,719 Cash dividends from subsidiaries Bank subsidiaries 525 525 — (1,050 ) — Nonbank subsidiaries 1,123 — — (1,123 ) — Other revenue Insurance premiums and service revenue earned — — 940 — 940 (Loss) gain on mortgage and automotive loans, net (9 ) — 54 — 45 Loss on extinguishment of debt (355 ) — (2 ) — (357 ) Other gain on investments, net — — 155 — 155 Other income, net of losses 1,373 — 1,373 (2,387 ) 359 Total other revenue 1,009 — 2,520 (2,387 ) 1,142 Total net revenue 1,391 525 7,505 (4,560 ) 4,861 Provision for loan losses 157 — 550 — 707 Noninterest expense Compensation and benefits expense 571 — 842 (450 ) 963 Insurance losses and loss adjustment expenses — — 293 — 293 Other operating expenses 1,247 — 2,195 (1,937 ) 1,505 Total noninterest expense 1,818 — 3,330 (2,387 ) 2,761 (Loss) income from continuing operations before income tax (benefit) expense and undistributed income (loss) of subsidiaries (584 ) 525 3,625 (2,173 ) 1,393 Income tax (benefit) expense from continuing operations (267 ) — 763 — 496 Net (loss) income from continuing operations (317 ) 525 2,862 (2,173 ) 897 Income from discontinued operations, net of tax 356 — 36 — 392 Undistributed income (loss) of subsidiaries Bank subsidiary 581 581 — (1,162 ) — Nonbank subsidiaries 669 (1 ) — (668 ) — Net income 1,289 1,105 2,898 (4,003 ) 1,289 Other comprehensive loss, net of tax (165 ) (43 ) (172 ) 215 (165 ) Comprehensive income $ 1,124 $ 1,062 $ 2,726 $ (3,788 ) $ 1,124 Year ended December 31, 2014 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing revenue and other interest income Interest and fees on finance receivables and loans $ (14 ) $ — $ 4,471 $ — $ 4,457 Interest and fees on finance receivables and loans — intercompany 37 — 82 (119 ) — Interest on loans held-for-sale — — 1 — 1 Interest and dividends on investment securities and other earning assets — — 367 — 367 Interest on cash and cash equivalents 1 — 7 — 8 Interest-bearing cash — intercompany — — 6 (6 ) — Operating leases 269 — 3,289 — 3,558 Total financing revenue and other interest income 293 — 8,223 (125 ) 8,391 Interest expense Interest on deposits 15 — 649 — 664 Interest on short-term borrowings 43 — 9 — 52 Interest on long-term debt 1,492 — 575 — 2,067 Interest on intercompany debt 88 — 37 (125 ) — Total interest expense 1,638 — 1,270 (125 ) 2,783 Net depreciation expense on operating lease assets 161 — 2,072 — 2,233 Net financing revenue (1,506 ) — 4,881 — 3,375 Cash dividends from subsidiaries Bank subsidiaries 1,800 1,800 — (3,600 ) — Nonbank subsidiaries 651 — — (651 ) — Other revenue Insurance premiums and service revenue earned — — 979 — 979 (Loss) gain on mortgage and automotive loans, net (5 ) — 12 — 7 Loss on extinguishment of debt (202 ) — — — (202 ) Other gain on investments, net — — 181 — 181 Other income, net of losses 1,279 — 1,299 (2,267 ) 311 Total other revenue 1,072 — 2,471 (2,267 ) 1,276 Total net revenue 2,017 1,800 7,352 (6,518 ) 4,651 Provision for loan losses 250 — 207 — 457 Noninterest expense Compensation and benefits expense 586 — 793 (432 ) 947 Insurance losses and loss adjustment expenses — — 410 — 410 Other operating expenses 1,267 — 2,159 (1,835 ) 1,591 Total noninterest expense 1,853 — 3,362 (2,267 ) 2,948 (Loss) income from continuing operations before income tax (benefit) expense and undistributed (loss) income of subsidiaries (86 ) 1,800 3,783 (4,251 ) 1,246 Income tax (benefit) expense from continuing operations (457 ) — 778 — 321 Net income from continuing operations 371 1,800 3,005 (4,251 ) 925 Income from discontinued operations, net of tax 193 — 32 — 225 Undistributed (loss) income of subsidiaries Bank subsidiary (680 ) (680 ) — 1,360 — Nonbank subsidiaries 1,266 (1 ) — (1,265 ) — Net income 1,150 1,119 3,037 (4,156 ) 1,150 Other comprehensive income, net of tax 210 188 212 (400 ) 210 Comprehensive income $ 1,360 $ 1,307 $ 3,249 $ (4,556 ) $ 1,360
Condensed Balance Sheet [Table Text Block]	Condensed Consolidating Balance Sheet December 31, 2016 ($ in millions) Parent (a) Guarantors Nonguarantors (a) Consolidating adjustments Ally consolidated Assets Cash and cash equivalents Noninterest-bearing $ 720 $ — $ 827 $ — $ 1,547 Interest-bearing 100 — 4,287 — 4,387 Interest-bearing — intercompany — — 401 (401 ) — Total cash and cash equivalents 820 — 5,515 (401 ) 5,934 Trading securities — — 82 (82 ) — Available-for-sale securities — — 19,253 (327 ) 18,926 Held-to-maturity securities — — 839 — 839 Finance receivables and loans, net Finance receivables and loans, net 4,705 — 114,239 — 118,944 Intercompany loans to Bank subsidiary 1,125 — — (1,125 ) — Nonbank subsidiaries 1,779 — 626 (2,405 ) — Allowance for loan losses (115 ) — (1,029 ) — (1,144 ) Total finance receivables and loans, net 7,494 — 113,836 (3,530 ) 117,800 Investment in operating leases, net 42 — 11,428 — 11,470 Intercompany receivables from Bank subsidiary 299 — — (299 ) — Nonbank subsidiaries 107 — 67 (174 ) — Investment in subsidiaries Bank subsidiary 17,727 17,727 — (35,454 ) — Nonbank subsidiaries 10,318 — — (10,318 ) — Premiums receivable and other insurance assets — — 1,936 (31 ) 1,905 Other assets 4,347 — 5,085 (2,578 ) 6,854 Total assets $ 41,154 $ 17,727 $ 158,041 $ (53,194 ) $ 163,728 Liabilities Deposit liabilities Noninterest-bearing $ — $ — $ 84 $ — $ 84 Interest-bearing 167 — 78,771 — 78,938 Total deposit liabilities 167 — 78,855 — 79,022 Short-term borrowings 3,622 — 9,051 — 12,673 Long-term debt 21,798 — 32,330 — 54,128 Intercompany debt to Bank subsidiary 330 — — (330 ) — Nonbank subsidiaries 1,027 — 2,903 (3,930 ) — Intercompany payables to Nonbank subsidiaries 153 — 351 (504 ) — Interest payable 253 — 98 — 351 Unearned insurance premiums and service revenue — — 2,500 — 2,500 Accrued expenses and other liabilities 487 — 3,911 (2,661 ) 1,737 Total liabilities 27,837 — 129,999 (7,425 ) 150,411 Total equity 13,317 17,727 28,042 (45,769 ) 13,317 Total liabilities and equity $ 41,154 $ 17,727 $ 158,041 $ (53,194 ) $ 163,728 (a) Amounts presented are based upon the legal transfer of the underlying assets to VIEs in order to reflect legal ownership. December 31, 2015 ($ in millions) Parent (a) Guarantors Nonguarantors (a) Consolidating adjustments Ally consolidated Assets Cash and cash equivalents Noninterest-bearing $ 1,234 $ — $ 914 $ — $ 2,148 Interest-bearing 401 — 3,831 — 4,232 Interest-bearing — intercompany — — 850 (850 ) — Total cash and cash equivalents 1,635 — 5,595 (850 ) 6,380 Available-for-sale securities — — 17,157 — 17,157 Loans held-for-sale, net — — 105 — 105 Finance receivables and loans, net Finance receivables and loans, net 2,636 — 108,964 — 111,600 Intercompany loans to Bank subsidiary 600 — — (600 ) — Nonbank subsidiaries 3,277 — 559 (3,836 ) — Allowance for loan losses (72 ) — (982 ) — (1,054 ) Total finance receivables and loans, net 6,441 — 108,541 (4,436 ) 110,546 Investment in operating leases, net 81 — 16,190 — 16,271 Intercompany receivables from Bank subsidiary 186 — — (186 ) — Nonbank subsidiaries 259 — 282 (541 ) — Investment in subsidiaries Bank subsidiary 16,496 16,496 — (32,992 ) — Nonbank subsidiaries 10,902 11 — (10,913 ) — Premiums receivable and other insurance assets — — 1,827 (26 ) 1,801 Other assets 4,785 — 4,488 (2,952 ) 6,321 Total assets $ 40,785 $ 16,507 $ 154,185 $ (52,896 ) $ 158,581 Liabilities Deposit liabilities Noninterest-bearing $ — $ — $ 89 $ — $ 89 Interest-bearing 229 — 66,160 — 66,389 Total deposit liabilities 229 — 66,249 — 66,478 Short-term borrowings 3,453 — 4,648 — 8,101 Long-term debt 21,048 — 45,186 — 66,234 Intercompany debt to Nonbank subsidiaries 1,409 — 3,877 (5,286 ) — Intercompany payables to Bank subsidiary 142 — — (142 ) — Nonbank subsidiaries 420 — 191 (611 ) — Interest payable 258 — 92 — 350 Unearned insurance premiums and service revenue — — 2,434 — 2,434 Accrued expenses and other liabilities 387 82 4,028 (2,952 ) 1,545 Total liabilities 27,346 82 126,705 (8,991 ) 145,142 Total equity 13,439 16,425 27,480 (43,905 ) 13,439 Total liabilities and equity $ 40,785 $ 16,507 $ 154,185 $ (52,896 ) $ 158,581 (a) Amounts presented are based upon the legal transfer of the underlying assets to VIEs in order to reflect legal ownership.
Condensed Cash Flow Statement [Table Text Block]	Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 241 $ 6 $ 5,383 $ (1,063 ) $ 4,567 Investing activities Purchases of available-for-sale securities — — (16,031 ) — (16,031 ) Proceeds from sales of available-for-sale securities — — 11,036 — 11,036 Proceeds from maturities and repayments of available-for-sale securities — — 3,379 — 3,379 Purchases of held-to-maturity securities — — (841 ) — (841 ) Purchases of loans held-for-investment (4 ) — (3,855 ) — (3,859 ) Proceeds from sales of finance receivables and loans originated as held-for-investment — — 4,285 — 4,285 Originations and repayments of loans held-for-investment and other 2,013 — (10,839 ) — (8,826 ) Net change in loans — intercompany 877 — (67 ) (810 ) — Purchases of operating lease assets — — (3,274 ) — (3,274 ) Disposals of operating lease assets 25 — 6,279 — 6,304 Acquisitions, net of cash acquired (309 ) — — — (309 ) Capital contributions to subsidiaries (3,908 ) — — 3,908 — Returns of contributed capital 3,678 8 — (3,686 ) — Net change in restricted cash (120 ) — 512 — 392 Net change in nonmarketable equity investments — — (628 ) — (628 ) Other, net (206 ) — (197 ) 91 (312 ) Net cash provided by (used in) investing activities 2,046 8 (10,241 ) (497 ) (8,684 ) Financing activities Net change in short-term borrowings — third party 169 — 4,395 — 4,564 Net (decrease) increase in deposits (61 ) — 12,569 — 12,508 Proceeds from issuance of long-term debt — third party 979 — 13,176 — 14,155 Repayments of long-term debt — third party (2,662 ) — (23,750 ) — (26,412 ) Net change in debt — intercompany (382 ) — (877 ) 1,259 — Redemption of preferred stock (696 ) — — — (696 ) Repurchase of common stock (341 ) — — — (341 ) Dividends paid — third party (108 ) — — — (108 ) Dividends paid and returns of contributed capital — intercompany — (14 ) (4,644 ) 4,658 — Capital contributions from parent — — 3,908 (3,908 ) — Net cash (used) in provided by financing activities (3,102 ) (14 ) 4,777 2,009 3,670 Effect of exchange-rate changes on cash and cash equivalents — — 1 — 1 Net decrease in cash and cash equivalents (815 ) — (80 ) 449 (446 ) Cash and cash equivalents at beginning of year 1,635 — 5,595 (850 ) 6,380 Cash and cash equivalents at end of year $ 820 $ — $ 5,515 $ (401 ) $ 5,934 Year ended December 31, 2015 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 370 $ 525 $ 6,390 $ (2,174 ) $ 5,111 Investing activities Purchases of available-for-sale securities — — (12,250 ) — (12,250 ) Proceeds from sales of available-for-sale securities — — 6,874 — 6,874 Proceeds from maturities and repayments of available-for-sale securities — — 4,255 — 4,255 Purchases of loans held-for-investment (169 ) — (4,332 ) — (4,501 ) Proceeds from sales of finance receivables and loans originated as held-for-investment — — 3,197 — 3,197 Originations and repayments of loans held-for-investment and other 1,954 — (11,298 ) — (9,344 ) Net change in loans — intercompany 240 — 1,211 (1,451 ) — Purchases of operating lease assets (94 ) — (4,591 ) — (4,685 ) Disposals of operating lease assets 7 — 5,539 — 5,546 Capital contributions to subsidiaries (796 ) (1 ) — 797 — Returns of contributed capital 1,444 — — (1,444 ) — Proceeds from sale of business units, net 1,049 — — — 1,049 Net change in restricted cash (7 ) — 271 — 264 Net change in nonmarketable equity investments — — (147 ) — (147 ) Other, net (47 ) — 42 — (5 ) Net cash provided by (used in) investing activities 3,581 (1 ) (11,229 ) (2,098 ) (9,747 ) Financing activities Net change in short-term borrowings — third party 115 — 913 — 1,028 Net (decrease) increase in deposits (91 ) — 8,338 — 8,247 Proceeds from issuance of long-term debt — third party 5,428 — 25,237 — 30,665 Repayments of long-term debt — third party (5,931 ) — (25,419 ) — (31,350 ) Net change in debt — intercompany (977 ) — (240 ) 1,217 — Repurchase and redemption of preferred stock (559 ) — — — (559 ) Repurchase of common stock (16 ) — — — (16 ) Dividends paid — third party (2,571 ) — — — (2,571 ) Dividends paid and returns of contributed capital — intercompany — (525 ) (3,092 ) 3,617 — Capital contributions from parent — 1 796 (797 ) — Net cash (used in) provided by financing activities (4,602 ) (524 ) 6,533 4,037 5,444 Effect of exchange-rate changes on cash and cash equivalents — — (4 ) — (4 ) Net (decrease) increase in cash and cash equivalents (651 ) — 1,690 (235 ) 804 Cash and cash equivalents at beginning of year 2,286 — 3,905 (615 ) 5,576 Cash and cash equivalents at end of year $ 1,635 $ — $ 5,595 $ (850 ) $ 6,380 Year ended December 31, 2014 ($ in millions) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 330 $ 1,789 $ 5,533 $ (4,249 ) $ 3,403 Investing activities Purchases of available-for-sale securities — — (5,417 ) — (5,417 ) Proceeds from sales of available-for-sale securities — — 4,277 (17 ) 4,260 Proceeds from maturities and repayments of available-for-sale securities — — 2,657 — 2,657 Purchases of loans held-for-investment — — (894 ) 17 (877 ) Proceeds from sales of finance receivables and loans originated as held-for-investment — — 2,592 — 2,592 Originations and repayments of loans held-for-investment and other 1,900 — (6,047 ) — (4,147 ) Net change in loans — intercompany 1,428 — 154 (1,582 ) — Purchases of operating lease assets (2,337 ) — (7,547 ) — (9,884 ) Disposals of operating lease assets 3,053 — 2,807 — 5,860 Capital contributions to subsidiaries (1,179 ) — — 1,179 — Returns of contributed capital 1,422 — — (1,422 ) — Proceeds from sale of business units, net 46 — 1 — 47 Net change in restricted cash — — 1,625 — 1,625 Net change in nonmarketable equity investments — — 66 — 66 Other, net (29 ) — 35 — 6 Net cash provided by (used in) investing activities 4,304 — (5,691 ) (1,825 ) (3,212 ) Financing activities Net change in short-term borrowings — third party 113 — (1,607 ) — (1,494 ) Net (decrease) increase in deposits (121 ) — 4,972 — 4,851 Proceeds from issuance of long-term debt — third party 3,132 — 24,060 — 27,192 Repayments of long-term debt — third party (8,186 ) — (22,240 ) — (30,426 ) Net change in debt — intercompany 52 — (1,428 ) 1,376 — Dividends paid — third party (268 ) — — — (268 ) Dividends paid and returns of contributed capital — intercompany — (1,826 ) (3,846 ) 5,672 — Capital contributions from parent — — 1,179 (1,179 ) — Net cash (used in) provided by financing activities (5,278 ) (1,826 ) 1,090 5,869 (145 ) Effect of exchange-rate changes on cash and cash equivalents — — (1 ) — (1 ) Net (decrease) increase in cash and cash equivalents (644 ) (37 ) 931 (205 ) 45 Cash and cash equivalents at beginning of year 2,930 37 2,974 (410 ) 5,531 Cash and cash equivalents at end of year $ 2,286 $ — $ 3,905 $ (615 ) $ 5,576

Guarantees and Commitments Gu69

Guarantees and Commitments Guarantees and Commitments (Tables)	12 Months Ended
	Dec. 31, 2016
Guarantees [Abstract]
Schedule of Guarantor Obligations [Table Text Block]	Guarantees are defined as contracts or indemnification agreements that contingently require us to make payments to third parties based on changes in the underlying agreements with the guaranteed parties. The following summarizes our outstanding guarantees, including those of our discontinued operations, made to third parties on our Consolidated Balance Sheet , for the periods shown. 2016 2015 December 31, ( $ in millions ) Maximum liability Carrying value of liability Maximum liability Carrying value of liability Standby letters of credit and other guarantees $ 175 $ 8 $ 208 $ 13
Financing Commitments [Table Text Block]	The contractual commitments were as follows. December 31, ( $ in millions ) 2016 2015 Commitments to provide capital to investees (a) $ 206 $ 132 Construction-lending commitments (b) 164 197 Home equity lines of credit (c) 356 358 Unused revolving credit line commitments and other (d) 1,995 1,445 (a) We are committed to contribute capital to certain investees. The fair value of these commitments is considered in the overall valuation of the underlying assets with which they are associated. (b) The fair value of these commitments is considered in the overall valuation of the related assets. (c) We are committed to fund the remaining unused balances on home equity lines of credit. (d) The unused portion of revolving lines of credit reset at prevailing market rates and, as such, approximate market value.
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Future minimum rental payments required under operating leases, primarily for real property, with noncancelable lease terms expiring after December 31, 2016 , are as follows. Year ended December 31, ( $ in millions ) 2017 $ 36 2018 36 2019 35 2020 33 2021 25 2022 and thereafter 75 Total minimum payment required $ 240
Long-term Purchase Commitment [Table Text Block]	We have entered into multiple agreements for information technology, voice and communication technology, and related maintenance. Many of the agreements are subject to variable price provisions, fixed or minimum price provisions, and termination or renewal provisions. Year ended December 31, ( $ in millions ) 2017 $ 94 2018 and 2019 13 2020 and thereafter 4 Total future payment obligations $ 111

Quarterly Financial Statement70

Quarterly Financial Statements (unaudited) Quarterly Financial Statements (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Statements (unaudited) [Abstract]
Quarterly Financial Information [Table Text Block]	( $ in millions ) First quarter Second quarter Third quarter Fourth quarter 2016 Net financing revenue and other interest income $ 951 $ 984 $ 996 $ 976 Other revenue 376 374 388 392 Total net revenue 1,327 1,358 1,384 1,368 Provision for loan losses 220 172 258 267 Total noninterest expense 710 773 735 721 Income from continuing operations before income tax expense 397 413 391 380 Income tax expense from continuing operations 150 56 130 134 Net income from continuing operations 247 357 261 246 Income (loss) from discontinued operations, net of tax 3 3 (52 ) 2 Net income $ 250 $ 360 $ 209 $ 248 Basic earnings per common share Net income from continuing operations $ 0.48 $ 0.70 $ 0.54 $ 0.52 Net income 0.49 0.71 0.43 0.53 Diluted earnings per common share Net income from continuing operations $ 0.48 $ 0.70 $ 0.54 $ 0.52 Net income 0.49 0.71 0.43 0.52 Cash dividends per common share $ — $ — $ 0.08 $ 0.08 2015 Net financing revenue and other interest income $ 850 $ 916 $ 970 $ 983 Other revenue 243 211 332 356 Total net revenue 1,093 1,127 1,302 1,339 Provision for loan losses 116 140 211 240 Total noninterest expense 695 724 674 668 Income from continuing operations before income tax expense 282 263 417 431 Income tax expense from continuing operations 103 94 144 155 Net income from continuing operations 179 169 273 276 Income (loss) from discontinued operations, net of tax 397 13 (5 ) (13 ) Net income $ 576 $ 182 $ 268 $ 263 Basic earnings per common share Net income (loss) from continuing operations $ 0.23 $ (2.24 ) $ 0.49 $ (1.94 ) Net income (loss) 1.06 (2.22 ) 0.48 (1.97 ) Diluted earnings per common share Net income (loss) from continuing operations $ 0.23 $ (2.24 ) $ 0.49 $ (1.94 ) Net income (loss) 1.06 (2.22 ) 0.47 (1.97 )

Description of Business, Basi71

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	Dec. 31, 2016	Dec. 31, 2015
Accounting Standards Adopted or Issued [Abstract]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 14	$ 16

Acquisitions Acquisitions (Deta

Acquisitions Acquisitions (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Aug. 01, 2016	Jun. 01, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross		$ 28,000,000	$ 298,000,000
Amortization of Intangible Assets	$ 6,000,000
Goodwill	240,000,000			$ 27,000,000
Business Acquisition, Goodwill, Expected Tax Deductible Amount			0
Other Intangible Assets [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill			82,000,000
Cash and Cash Equivalents [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents			50,000,000
Other Assets [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill			14,000,000
Deferred Tax Asset [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill			4,000,000
Employee compensation and benefits [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents			40,000,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities			(41,000,000)
Other Liabilities [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities			(4,000,000)
Corporate and Other [Member]
Business Acquisition [Line Items]
Goodwill	193,000,000		$ 193,000,000	0
Automotive Finance Operations [Member]
Business Acquisition [Line Items]
Goodwill	$ 20,000,000	$ 20,000,000		$ 0

Discontinued Operations (Detail

Discontinued Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Automotive Finance Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sold Interest in Joint Venture		40.00%
Equity Method Investment, Realized Gain (Loss) on Disposal		$ 400
Disposal Group, Including Discontinued Operation, Revenue	$ 0	0	$ 123
Disposal Group, Including Discontinued Operation, Operating Income (Loss)	(2)	452	129
Discontinued Operation, Tax Effect of Discontinued Operation	2	80	7
Other Segments [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Operating Income (Loss)	(41)	16	25
Discontinued Operation, Tax Effect of Discontinued Operation	$ (1)	$ (4)	$ (78)

Insurance Premiums and Servic74

Insurance Premiums and Service Revenue Earned Insurance Premiums and Service Revenue Earned (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Insurance Premiums and Service Revenue Earned [Abstract]
Direct Premiums Written	$ 317	$ 313	$ 294
Direct Premiums Earned	318	296	282
Assumed Premiums Written	3	2	43
Assumed Premiums Earned	5	16	54
Premiums Written, Gross	320	315	337
Gross Insurance Premiums Earned	323	312	336
Ceded Premiums Written	(198)	(184)	(156)
Ceded Premiums Earned	(141)	(125)	(117)
Premiums Written, Net	122	131	181
Premiums Earned, Net, Property and Casualty	182	187	219
Insurance Commissions and Fees Written	826	846	842
Insurance Commissions and Fees	763	753	760
Insurance Services Revenue Written	948	977	1,023
Insurance Services Revenue	$ 945	$ 940	$ 979

Other Income, Net of Losses (Sc

Other Income, Net of Losses (Schedule of Other Income, Net of Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Nonoperating Income (Expense) [Abstract]
Remarketing Fees	$ 103	$ 101	$ 112
Fees and Commissions, Other	98	90	88
Contractually Specified Servicing Fees, Late Fees, and Ancillary Fees Earned in Exchange for Servicing Financial Assets	64	45	31
Income (Loss) from Equity Method Investments	18	52	18
Other Income	111	71	62
Noninterest Income, Other Operating Income	$ 394	$ 359	$ 311

Reserves for Insurance Losses76

Reserves for Insurance Losses and Loss Adjustment Expenses Reserves for Insurance Losses and Loss Adjustment Expenses (Short-duration Insurance Contracts, Claims Development) (Details) number in Millions, $ in Millions	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,778
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Separately Presented	1,749
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	9
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	38
Short-duration Insurance Contracts, Accident Year 2012 [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	423	$ 423	$ 423	$ 430	$ 435
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred but Not Reported (IBNR) Claims, Amount	$ 4
Short-duration Insurance Contracts, Number of Reported Claims	772,536
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 419	418	416	412	$ 391
Short-duration Insurance Contracts, Accident Year 2013 [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	370	370	365	376
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred but Not Reported (IBNR) Claims, Amount	$ 2
Short-duration Insurance Contracts, Number of Reported Claims	672,247
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 368	366	364	$ 347
Short-duration Insurance Contracts, Accident Year 2014 [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	388	389	390
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred but Not Reported (IBNR) Claims, Amount	$ 0
Short-duration Insurance Contracts, Number of Reported Claims	525,235
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 388	388	$ 369
Short-duration Insurance Contracts, Accident Year 2015 [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	271	274
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred but Not Reported (IBNR) Claims, Amount	$ 0
Short-duration Insurance Contracts, Number of Reported Claims	342,054
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 272	$ 252
Short-duration Insurance Contracts, Accident Year 2016 [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	326
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred but Not Reported (IBNR) Claims, Amount	$ 24
Short-duration Insurance Contracts, Number of Reported Claims	453,807
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 302

Reserves for Insurance Losses77

Reserves for Insurance Losses and Loss Adjustment Expenses Reserves for Insurance Losses and Loss Adjustment Expenses (Short-duration Contracts, Schedule of Historical Claims Duration) (Details)	Dec. 31, 2016
Short-duration Contracts, Schedule of Historical Claims Duration [Abstract]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	93.40%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	5.50%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	0.40%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	0.50%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	0.10%

Reserves for Insurance Losses78

Reserves for Insurance Losses and Loss Adjustment Expenses Reserves for Insurance Losses and Loss Adjustment Expenses (Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Abstract]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	$ 38
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	108	$ 120
Short-duration Insurance Contracts, Liability for Unpaid Claims and Claims Adjustment Expense, Accumulated Unallocated Claim Adjustment Expense	3
Liability for Claims and Claims Adjustment Expense	$ 149	$ 169

Reserves for Insurance Losses79

Reserves for Insurance Losses and Loss Adjustment Expenses Reserves for Insurance Losses and Loss Adjustment Expenses (Schedule of Liability for Unpaid Claims and Claims Adjustment Expense) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Liability for Claims and Claims Adjustment Expenses (Rollforward) [Abstract]
Liability for Claims and Claims Adjustment Expense	$ 169
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	120
Liability for Unpaid Claims and Claims Adjustment Expense, Net	49
Current Year Claims and Claims Adjustment Expense	345
Prior Year Claims and Claims Adjustment Expense	(3)
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims	342
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year	(320)
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years	30
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid	(350)
Liability for Unpaid Claims and Claims Adjustment Expense, Net	41
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	108
Liability for Claims and Claims Adjustment Expense	$ 149

Other Operating Expenses (Sched

Other Operating Expenses (Schedule Of Other Operating Expenses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Expenses [Abstract]
Insurance Commissions	$ 389	$ 378	$ 374
Communications and Information Technology	274	267	334
Lease And Loan Administration	136	126	122
Marketing and Advertising Expense	112	107	111
Professional Fees	103	93	100
Vehicle remarketing and repossession	95	78	83
Regulatory and licensing fees	94	79	87
Depreciation, Nonproduction	84	82	81
Occupancy, Net	51	50	47
Taxes, Miscellaneous	25	29	40
Other Cost and Expense, Operating	242	216	212
Other Noninterest Expense	$ 1,605	$ 1,505	$ 1,591

Investment Securities (Investme

Investment Securities (Investment Table) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Schedule of Investments [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 19,293	$ 17,350
Available-for-sale Securities, Gross Unrealized Gains	68	96
Available-for-sale Securities, Gross Unrealized Losses	(435)	(289)
Available-for-sale securities	18,926	17,157
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	839	0
Held-to-maturity Securities, Fair Value	789	0
Deposit Assets	14	14
Pledged Assets Separately Reported, Securities Pledged for Federal Home Loan Bank, at Fair Value	4,881	2,506
Financial Instruments Owned and Pledged as Collateral, Amount Eligible to be Repledged by Counterparty	737	745
Cash Equivalents, at Carrying Value	300	1,000
Held-to-maturity Securities [Member]
Schedule of Investments [Line Items]
Unrealized Gain on Securities	0	0
Unrealized Gain (Loss) on Investments	(50)	0
Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	18,651	16,542
Available-for-sale Debt Securities Gross Unrealized Gain	61	93
Available-for-sale Debt Securities, Gross Unrealized Loss	(381)	(195)
Available-for-sale Securities, Debt Securities	18,331	16,440
US Treasury and Government [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	1,680	1,760
Available-for-sale Debt Securities Gross Unrealized Gain	0	0
Available-for-sale Debt Securities, Gross Unrealized Loss	(60)	(19)
Available-for-sale Securities, Debt Securities	1,620	1,741
US States and Political Subdivisions Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	794	693
Available-for-sale Debt Securities Gross Unrealized Gain	7	24
Available-for-sale Debt Securities, Gross Unrealized Loss	(19)	(1)
Available-for-sale Securities, Debt Securities	782	716
Foreign Government Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	157	169
Available-for-sale Debt Securities Gross Unrealized Gain	5	8
Available-for-sale Debt Securities, Gross Unrealized Loss	0	0
Available-for-sale Securities, Debt Securities	162	177
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	10,473	7,553
Available-for-sale Debt Securities Gross Unrealized Gain	29	46
Available-for-sale Debt Securities, Gross Unrealized Loss	(212)	(55)
Available-for-sale Securities, Debt Securities	10,290	7,544
Residential Mortgage Backed Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	2,162	2,906
Available-for-sale Debt Securities Gross Unrealized Gain	5	6
Available-for-sale Debt Securities, Gross Unrealized Loss	(70)	(90)
Available-for-sale Securities, Debt Securities	2,097	2,822
Commercial Mortgage Backed Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	537	486
Available-for-sale Debt Securities Gross Unrealized Gain	2	0
Available-for-sale Debt Securities, Gross Unrealized Loss	(2)	(5)
Available-for-sale Securities, Debt Securities	537	481
Asset-backed Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	1,396	1,762
Available-for-sale Debt Securities Gross Unrealized Gain	6	1
Available-for-sale Debt Securities, Gross Unrealized Loss	(2)	(8)
Available-for-sale Securities, Debt Securities	1,400	1,755
Corporate Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	1,452	1,213
Available-for-sale Debt Securities Gross Unrealized Gain	7	8
Available-for-sale Debt Securities, Gross Unrealized Loss	(16)	(17)
Available-for-sale Securities, Debt Securities	1,443	1,204
Equity Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Equity Securities, Amortized Cost Basis	642	808
Available-for-sale Equity Securities, Gross Unrealized Gain	7	3
Available-for-sale Equity Securities, Gross Unrealized Loss	(54)	(94)
Available-for-sale Securities, Equity Securities	595	$ 717
Federal Home Loan Bank Certificates and Obligations (FHLB) [Member]
Schedule of Investments [Line Items]
Held-to-maturity Securities, Fair Value	$ 87

Investment Securities (Invest82

Investment Securities (Investments Classified by Contractual Maturity Date) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Schedule of Investments [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	$ 839	$ 0
Held-to-Maturity Debt Securities, Yield	2.90%
Held-to-maturity Securities, Debt Maturities, within One Year, Net Carrying Amount	$ 0
Held-to-Maturity Debt Securities, Due in One Year or Less, Yield	0.00%
Held-to-maturity Securities, Debt Maturities, after One Through Five Years, Net Carrying Amount	$ 0
Held-to-Maturity Debt Securities, Due After One Year Through Five Years, Yield	0.00%
Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount	$ 0
Held-to-Maturity Debt Securities, Due After Five Years Through Ten Years, Yield	0.00%
Held-to-maturity Securities, Debt Maturities, after Ten Years, Net Carrying Amount	$ 839
Held-to-Maturity Securities, Due After Ten Years, Yield	2.90%
Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Debt Securities	$ 18,331	$ 16,440
Available-for-sale debt securities, Yield	2.80%	2.70%
Available-for-sale Debt Securities, Amortized Cost Basis	$ 18,651	$ 16,542
Available-for-sale debt securities, Due in one year or less, Amount	$ 138	$ 157
Available-for-sale debt securities, Due in one year or less, Yield	2.00%	2.00%
Amortized cost of available-for-sale debt securities, Due in one year or less, Amount	$ 138	$ 156
Available-for-sale debt securities, Due after one year through five years, Amount	$ 2,046	$ 2,397
Available-for-sale debt securities, Due after one year through five years, Yield	2.70%	2.10%
Amortized cost of available-for-sale debt securities, Due after one year through five years, Amount	$ 2,040	$ 2,404
Available-for-sale debt securities, Due after five years through ten years, Amount	$ 2,498	$ 2,424
Available-for-sale debt securities, Due after five years through ten years, Yield	2.20%	2.50%
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Amortized Cost Basis	$ 2,563	$ 2,436
Available-for-sale debt securities, Due after ten years, Amount	$ 13,649	$ 11,462
Available-for-sale debt securities, Due after ten years, Yield	2.90%	2.90%
Amortized cost of available-for-sale debt securities, Due after ten years, Amount	$ 13,910	$ 11,546
US Treasury and Government [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Debt Securities	$ 1,620	$ 1,741
Available-for-sale debt securities, Yield	1.70%	1.80%
Available-for-sale Debt Securities, Amortized Cost Basis	$ 1,680	$ 1,760
Available-for-sale debt securities, Due in one year or less, Amount	$ 2	$ 6
Available-for-sale debt securities, Due in one year or less, Yield	4.60%	5.10%
Available-for-sale debt securities, Due after one year through five years, Amount	$ 60	$ 510
Available-for-sale debt securities, Due after one year through five years, Yield	1.60%	1.20%
Available-for-sale debt securities, Due after five years through ten years, Amount	$ 1,558	$ 1,225
Available-for-sale debt securities, Due after five years through ten years, Yield	1.70%	2.10%
Available-for-sale debt securities, Due after ten years, Amount	$ 0	$ 0
Available-for-sale debt securities, Due after ten years, Yield	0.00%	0.00%
US States and Political Subdivisions Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Debt Securities	$ 782	$ 716
Available-for-sale debt securities, Yield	3.10%	3.20%
Available-for-sale Debt Securities, Amortized Cost Basis	$ 794	$ 693
Available-for-sale debt securities, Due in one year or less, Amount	$ 64	$ 86
Available-for-sale debt securities, Due in one year or less, Yield	1.70%	1.30%
Available-for-sale debt securities, Due after one year through five years, Amount	$ 29	$ 37
Available-for-sale debt securities, Due after one year through five years, Yield	2.30%	2.20%
Available-for-sale debt securities, Due after five years through ten years, Amount	$ 172	$ 141
Available-for-sale debt securities, Due after five years through ten years, Yield	2.80%	2.80%
Available-for-sale debt securities, Due after ten years, Amount	$ 517	$ 452
Available-for-sale debt securities, Due after ten years, Yield	3.40%	3.70%
Foreign Government Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Debt Securities	$ 162	$ 177
Available-for-sale debt securities, Yield	2.60%	2.60%
Available-for-sale Debt Securities, Amortized Cost Basis	$ 157	$ 169
Available-for-sale debt securities, Due in one year or less, Amount	$ 0	$ 9
Available-for-sale debt securities, Due in one year or less, Yield	0.00%	1.90%
Available-for-sale debt securities, Due after one year through five years, Amount	$ 58	$ 77
Available-for-sale debt securities, Due after one year through five years, Yield	2.80%	2.80%
Available-for-sale debt securities, Due after five years through ten years, Amount	$ 104	$ 91
Available-for-sale debt securities, Due after five years through ten years, Yield	2.40%	2.60%
Available-for-sale debt securities, Due after ten years, Amount	$ 0	$ 0
Available-for-sale debt securities, Due after ten years, Yield	0.00%	0.00%
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Debt Securities	$ 10,290	$ 7,544
Available-for-sale debt securities, Yield	2.90%	2.90%
Available-for-sale Debt Securities, Amortized Cost Basis	$ 10,473	$ 7,553
Available-for-sale debt securities, Due in one year or less, Amount	$ 0	$ 0
Available-for-sale debt securities, Due in one year or less, Yield	0.00%	0.00%
Available-for-sale debt securities, Due after one year through five years, Amount	$ 0	$ 32
Available-for-sale debt securities, Due after one year through five years, Yield	0.00%	2.00%
Available-for-sale debt securities, Due after five years through ten years, Amount	$ 29	$ 36
Available-for-sale debt securities, Due after five years through ten years, Yield	2.60%	2.50%
Available-for-sale debt securities, Due after ten years, Amount	$ 10,261	$ 7,476
Available-for-sale debt securities, Due after ten years, Yield	2.90%	2.90%
Residential Mortgage Backed Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Debt Securities	$ 2,097	$ 2,822
Available-for-sale debt securities, Yield	2.90%	2.90%
Available-for-sale Debt Securities, Amortized Cost Basis	$ 2,162	$ 2,906
Available-for-sale debt securities, Due in one year or less, Amount	$ 0	$ 0
Available-for-sale debt securities, Due in one year or less, Yield	0.00%	0.00%
Available-for-sale debt securities, Due after one year through five years, Amount	$ 0	$ 1
Available-for-sale debt securities, Due after one year through five years, Yield	0.00%	4.50%
Available-for-sale debt securities, Due after five years through ten years, Amount	$ 0	$ 0
Available-for-sale debt securities, Due after five years through ten years, Yield	0.00%	0.00%
Available-for-sale debt securities, Due after ten years, Amount	$ 2,097	$ 2,821
Available-for-sale debt securities, Due after ten years, Yield	2.90%	2.90%
Commercial Mortgage Backed Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Debt Securities	$ 537	$ 481
Available-for-sale debt securities, Yield	2.60%	2.00%
Available-for-sale Debt Securities, Amortized Cost Basis	$ 537	$ 486
Available-for-sale debt securities, Due in one year or less, Amount	$ 0	$ 0
Available-for-sale debt securities, Due in one year or less, Yield	0.00%	0.00%
Available-for-sale debt securities, Due after one year through five years, Amount	$ 0	$ 0
Available-for-sale debt securities, Due after one year through five years, Yield	0.00%	0.00%
Available-for-sale debt securities, Due after five years through ten years, Amount	$ 3	$ 3
Available-for-sale debt securities, Due after five years through ten years, Yield	2.80%	2.70%
Available-for-sale debt securities, Due after ten years, Amount	$ 534	$ 478
Available-for-sale debt securities, Due after ten years, Yield	2.60%	2.00%
Asset-backed Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Debt Securities	$ 1,400	$ 1,755
Available-for-sale debt securities, Yield	2.80%	2.30%
Available-for-sale Debt Securities, Amortized Cost Basis	$ 1,396	$ 1,762
Available-for-sale debt securities, Due in one year or less, Amount	$ 0	$ 6
Available-for-sale debt securities, Due in one year or less, Yield	0.00%	1.40%
Available-for-sale debt securities, Due after one year through five years, Amount	$ 1,059	$ 1,027
Available-for-sale debt securities, Due after one year through five years, Yield	2.80%	2.10%
Available-for-sale debt securities, Due after five years through ten years, Amount	$ 143	$ 518
Available-for-sale debt securities, Due after five years through ten years, Yield	3.20%	2.60%
Available-for-sale debt securities, Due after ten years, Amount	$ 198	$ 204
Available-for-sale debt securities, Due after ten years, Yield	2.60%	2.20%
Corporate Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Debt Securities	$ 1,443	$ 1,204
Available-for-sale debt securities, Yield	2.80%	2.90%
Available-for-sale Debt Securities, Amortized Cost Basis	$ 1,452	$ 1,213
Available-for-sale debt securities, Due in one year or less, Amount	$ 72	$ 50
Available-for-sale debt securities, Due in one year or less, Yield	2.20%	3.00%
Available-for-sale debt securities, Due after one year through five years, Amount	$ 840	$ 713
Available-for-sale debt securities, Due after one year through five years, Yield	2.60%	2.50%
Available-for-sale debt securities, Due after five years through ten years, Amount	$ 489	$ 410
Available-for-sale debt securities, Due after five years through ten years, Yield	3.20%	3.40%
Available-for-sale debt securities, Due after ten years, Amount	$ 42	$ 31
Available-for-sale debt securities, Due after ten years, Yield	4.70%	5.40%

Investment Securities (Invest83

Investment Securities (Investment Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Interest and Dividend Income, Securities, Operating, Available-for-sale	$ 418	$ 381	$ 367
Taxable interest	375	340	336
Taxable dividends	17	23	20
Interest and dividends exempt from U.S. federal income tax	19	18	11
Interest and Dividend Income, Securities, Operating, Available-for-sale	418	$ 381	$ 367
Excludes Other Earning Assets [Member]
Interest and Dividend Income, Securities, Operating, Available-for-sale	411
Interest and Dividend Income, Securities, Operating, Available-for-sale	$ 411

Investment Securities (Schedule

Investment Securities (Schedule Of Realized Gain (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Available-for-sale Securities [Abstract]
Available-for-sale Securities, Gross Realized Gains	$ 187	$ 184	$ 209
Available-for-sale Securities, Gross Realized Losses	(2)	(15)	(14)
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	0	(14)	(14)
Available-for-sale Securities, Gross Realized Gain (Loss)	$ 185	$ 155	$ 181

Investment Securities (Schedu85

Investment Securities (Schedule of Unrealized Loss on Investments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	$ 12,356	$ 8,511
Available-for-sale Securities, Unrealized Loss Less than 12 months	(317)	(139)
Available-for-sale Securities, Fair value 12 months or longer	2,038	2,798
Available-for-sale Securities, Unrealized Loss 12 months or longer	(118)	(150)
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	12,205	7,977
Available-for-sale Securities, Unrealized Loss Less than 12 months	(309)	(85)
Available-for-sale Securities, Fair value 12 months or longer	1,769	2,702
Available-for-sale Securities, Unrealized Loss 12 months or longer	(72)	(110)
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	1,612	1,553
Available-for-sale Securities, Unrealized Loss Less than 12 months	(60)	(17)
Available-for-sale Securities, Fair value 12 months or longer	0	173
Available-for-sale Securities, Unrealized Loss 12 months or longer	0	(2)
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	524	179
Available-for-sale Securities, Unrealized Loss Less than 12 months	(19)	(1)
Available-for-sale Securities, Fair value 12 months or longer	0	0
Available-for-sale Securities, Unrealized Loss 12 months or longer	0	0
Foreign Government Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	38	2
Available-for-sale Securities, Unrealized Loss Less than 12 months	0	0
Available-for-sale Securities, Fair value 12 months or longer	0	0
Available-for-sale Securities, Unrealized Loss 12 months or longer	0	0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	8,052	2,524
Available-for-sale Securities, Unrealized Loss Less than 12 months	(196)	(21)
Available-for-sale Securities, Fair value 12 months or longer	587	1,132
Available-for-sale Securities, Unrealized Loss 12 months or longer	(16)	(34)
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	813	1,231
Available-for-sale Securities, Unrealized Loss Less than 12 months	(17)	(19)
Available-for-sale Securities, Fair value 12 months or longer	860	1,180
Available-for-sale Securities, Unrealized Loss 12 months or longer	(53)	(71)
Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	47	341
Available-for-sale Securities, Unrealized Loss Less than 12 months	(1)	(3)
Available-for-sale Securities, Fair value 12 months or longer	149	141
Available-for-sale Securities, Unrealized Loss 12 months or longer	(1)	(2)
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	375	1,402
Available-for-sale Securities, Unrealized Loss Less than 12 months	(2)	(8)
Available-for-sale Securities, Fair value 12 months or longer	127	64
Available-for-sale Securities, Unrealized Loss 12 months or longer	0	0
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	744	745
Available-for-sale Securities, Unrealized Loss Less than 12 months	(14)	(16)
Available-for-sale Securities, Fair value 12 months or longer	46	12
Available-for-sale Securities, Unrealized Loss 12 months or longer	(2)	(1)
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	151	534
Available-for-sale Securities, Unrealized Loss Less than 12 months	(8)	(54)
Available-for-sale Securities, Fair value 12 months or longer	269	96
Available-for-sale Securities, Unrealized Loss 12 months or longer	$ (46)	$ (40)

Finance Receivables and Loans86

Finance Receivables and Loans, Net (Schedule of Accounts, Notes, Loans and Financing Receivables) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	$ 118,944	$ 111,600
Derivative, Amount of Hedged Item	315	331
Loans and Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	359	110
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	76,843	74,065
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	65,793	64,292
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Derivative, Amount of Hedged Item	43	66
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	11,050	9,773
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	8,294	6,413
Held For Investment Mortgage Finance Receivables Interest Only Mortgage Loans	$ 30	44
Consumer Portfolio Segment [Member] | Mortgage Finance [Member] | One year, or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	3.00%
Consumer Portfolio Segment [Member] | Mortgage Finance [Member] | Three years, or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	38.00%
Consumer Portfolio Segment [Member] | Mortgage Finance [Member] | Four years, or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	39.00%
Consumer Portfolio Segment [Member] | Mortgage Finance [Member] | Two years, or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	0.00%
Consumer Portfolio Segment [Member] | Mortgage Finance [Member] | Five years, or greater [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	0.00%
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	$ 2,756	3,360
Held For Investment Mortgage Finance Receivables Interest Only Mortgage Loans	$ 714	941
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member] | One year, or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	23.00%
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member] | Four years, or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	0.00%
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member] | Two years, or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	2.00%
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member] | Five years, or greater [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	1.00%
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	$ 42,101	37,535
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	35,041	31,469
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	3,248	2,640
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	$ 3,812	$ 3,426

Finance Receivables and Loans87

Finance Receivables and Loans, Net (Allowance for Credit Losses on Financing Receivables) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance	$ 1,054	$ 977
Allowance for Loan and Lease Losses, Write-offs	(1,142)	(892)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	341	283
Allowance for Loan and Lease Losses Write-offs, Net	(801)	(609)
Allowance for Loan and Lease Losses, Provision for Loss, Net	(917)	(707)
Allowance for Loan and Lease Losses, Adjustments, Net	26	21
Loans and Leases Receivable, Allowance, Ending Balance	1,144	1,054
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	85	86
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	1,059	968
Loans and Leases Receivable, Gross	118,944	111,600
Financing Receivable, Individually Evaluated for Impairment	739	658
Financing Receivable, Collectively Evaluated for Impairment	118,205	110,942
Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Allowance for Credit Losses	0	0
Loans and Leases Receivable, Gross	0	0
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance	834	685
Allowance for Loan and Lease Losses, Write-offs	(1,102)	(840)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	307	262
Allowance for Loan and Lease Losses Write-offs, Net	(795)	(578)
Allowance for Loan and Lease Losses, Provision for Loss, Net	(919)	(739)
Allowance for Loan and Lease Losses, Adjustments, Net	26	12
Loans and Leases Receivable, Allowance, Ending Balance	932	834
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	28	22
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	904	812
Loans and Leases Receivable, Gross	65,793	64,292
Financing Receivable, Individually Evaluated for Impairment	370	315
Financing Receivable, Collectively Evaluated for Impairment	65,423	63,977
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Allowance for Credit Losses	0	0
Loans and Leases Receivable, Gross	0	0
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance	114	152
Allowance for Loan and Lease Losses, Write-offs	(39)	(48)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	32	17
Allowance for Loan and Lease Losses Write-offs, Net	(7)	(31)
Allowance for Loan and Lease Losses, Provision for Loss, Net	16	(1)
Allowance for Loan and Lease Losses, Adjustments, Net	0	8
Loans and Leases Receivable, Allowance, Ending Balance	91	114
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	34	44
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	57	70
Loans and Leases Receivable, Gross	11,050	9,773
Financing Receivable, Individually Evaluated for Impairment	247	266
Financing Receivable, Collectively Evaluated for Impairment	10,803	9,507
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Allowance for Credit Losses	0	0
Loans and Leases Receivable, Gross	0	0
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance	106	140
Allowance for Loan and Lease Losses, Write-offs	(1)	(4)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	2	4
Allowance for Loan and Lease Losses Write-offs, Net	1	0
Allowance for Loan and Lease Losses, Provision for Loss, Net	(14)	33
Allowance for Loan and Lease Losses, Adjustments, Net	0	1
Loans and Leases Receivable, Allowance, Ending Balance	121	106
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	23	20
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	98	86
Loans and Leases Receivable, Gross	42,101	37,535
Financing Receivable, Individually Evaluated for Impairment	122	77
Financing Receivable, Collectively Evaluated for Impairment	41,979	37,458
Commercial Portfolio Segment [Member] | Commercial Loan [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Allowance for Credit Losses	0	0
Loans and Leases Receivable, Gross	$ 0	$ 0

Finance Receivables and Loans88

Finance Receivables and Loans, Net (Schedule of Sales of Financing Receivables and Loans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Significant Sales and Transfers	$ 4,311	$ 1,317
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Significant Sales and Transfers	4,267	1,237
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Significant Sales and Transfers	15	78
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Significant Sales and Transfers	$ 29	$ 2

Finance Receivables and Loans89

Finance Receivables and Loans, Net Finance Receivables and Loans, Net (Schedule of Purchases of Financing Receivables and Loans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Significant Purchases	$ 3,768	$ 4,397
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Significant Purchases	21	272
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Significant Purchases	$ 3,747	$ 4,125

Finance Receivables and Loans90

Finance Receivables and Loans, Net (Past Due Financing Receivables and Loans) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	$ 2,759	$ 2,414
Current	116,185	109,186
Loans and Leases Receivable, Gross	118,944	111,600
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	2,749	2,414
Current	74,094	71,651
Loans and Leases Receivable, Gross	76,843	74,065
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	2,580	2,209
Current	63,213	62,083
Loans and Leases Receivable, Gross	65,793	64,292
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	169	205
Current	10,881	9,568
Loans and Leases Receivable, Gross	11,050	9,773
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	49	59
Current	8,245	6,354
Loans and Leases Receivable, Gross	8,294	6,413
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	120	146
Current	2,636	3,214
Loans and Leases Receivable, Gross	2,756	3,360
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	10	0
Current	42,091	37,535
Loans and Leases Receivable, Gross	42,101	37,535
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	10	0
Current	35,031	31,469
Loans and Leases Receivable, Gross	35,041	31,469
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Current	3,248	2,640
Loans and Leases Receivable, Gross	3,248	2,640
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Current	3,812	3,426
Loans and Leases Receivable, Gross	3,812	3,426
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,937	1,715
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,934	1,715
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,850	1,618
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	84	97
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	39	44
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	45	53
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	3	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	3	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	452	394
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	452	394
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	428	369
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	24	25
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	6	5
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	18	20
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	370	305
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	363	305
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	302	222
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	61	83
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	4	10
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	57	73
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	7	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	7	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	$ 0	$ 0

Finance Receivables and Loans91

Finance Receivables and Loans, Net (Schedule of Financing Receivables, Non Accrual Status) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	$ 819	$ 680
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	697	603
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	598	475
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	99	128
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	10	15
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	89	113
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	122	77
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	33	25
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	84	44
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	$ 5	$ 8

Finance Receivables and Loans92

Finance Receivables and Loans, Net (Financing Receivable Credit Quality Indicators - Performing and Nonperforming) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	$ 118,944	$ 111,600
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	76,843	74,065
Consumer Portfolio Segment [Member] | Consumer Loan [Member] | Performing Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	76,146	73,462
Consumer Portfolio Segment [Member] | Consumer Loan [Member] | Nonperforming Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	697	603
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	65,793	64,292
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Performing Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	65,195	63,817
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Nonperforming Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	598	475
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	11,050	9,773
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | Performing Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	10,951	9,645
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | Nonperforming Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	99	128
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	8,294	6,413
Consumer Portfolio Segment [Member] | Mortgage Finance [Member] | Performing Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	8,284	6,398
Consumer Portfolio Segment [Member] | Mortgage Finance [Member] | Nonperforming Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	10	15
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	2,756	3,360
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member] | Performing Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	2,667	3,247
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member] | Nonperforming Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	$ 89	$ 113

Finance Receivables and Loans93

Finance Receivables and Loans, Net (Schedule of Pass And Criticized Credit Quality Indicators of Finance Receivables) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	$ 118,944	$ 111,600
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	42,101	37,535
Commercial Portfolio Segment [Member] | Commercial Loan [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	39,410	35,000
Commercial Portfolio Segment [Member] | Commercial Loan [Member] | Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	2,691	2,535
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	35,041	31,469
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	33,160	29,613
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member] | Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,881	1,856
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	3,248	2,640
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	2,597	2,122
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member] | Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	651	518
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	3,812	3,426
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	3,653	3,265
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member] | Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	$ 159	$ 161

Finance Receivables and Loans94

Finance Receivables and Loans, Net (Impaired Financing Receivables) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	$ 795	$ 661
Carrying value before allowance	739	658
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	199	69
Impaired Financing Receivable, with Related Allowance, Recorded Investment	540	589
Impaired Financing Receivable, Related Allowance	85	86
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	658	584
Carrying value before allowance	617	581
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	190	64
Impaired Financing Receivable, with Related Allowance, Recorded Investment	427	517
Impaired Financing Receivable, Related Allowance	62	66
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	407	315
Carrying value before allowance	370	315
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	131	0
Impaired Financing Receivable, with Related Allowance, Recorded Investment	239	315
Impaired Financing Receivable, Related Allowance	28	22
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	251	269
Carrying value before allowance	247	266
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	59	64
Impaired Financing Receivable, with Related Allowance, Recorded Investment	188	202
Impaired Financing Receivable, Related Allowance	34	44
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	8	9
Carrying value before allowance	8	9
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	3	5
Impaired Financing Receivable, with Related Allowance, Recorded Investment	5	4
Impaired Financing Receivable, Related Allowance	0	1
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	243	260
Carrying value before allowance	239	257
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	56	59
Impaired Financing Receivable, with Related Allowance, Recorded Investment	183	198
Impaired Financing Receivable, Related Allowance	34	43
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	137	77
Carrying value before allowance	122	77
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	9	5
Impaired Financing Receivable, with Related Allowance, Recorded Investment	113	72
Impaired Financing Receivable, Related Allowance	23	20
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	33	25
Carrying value before allowance	33	25
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	7	4
Impaired Financing Receivable, with Related Allowance, Recorded Investment	26	21
Impaired Financing Receivable, Related Allowance	3	3
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	99	44
Carrying value before allowance	84	44
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	0	0
Impaired Financing Receivable, with Related Allowance, Recorded Investment	84	44
Impaired Financing Receivable, Related Allowance	19	15
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	5	8
Carrying value before allowance	5	8
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	2	1
Impaired Financing Receivable, with Related Allowance, Recorded Investment	3	7
Impaired Financing Receivable, Related Allowance	$ 1	$ 2

Finance Receivables and Loans95

Finance Receivables and Loans, Net (Schedule of Average Balance and Interest Income of Impaired Finance Receivables) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	$ 701	$ 654	$ 1,316
Impaired Financing Receivable, Interest Income, Accrual Method	28	29	37
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	600	575	1,190
Impaired Financing Receivable, Interest Income, Accrual Method	26	25	32
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	344	295	317
Impaired Financing Receivable, Interest Income, Accrual Method	17	16	20
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	256	280	873
Impaired Financing Receivable, Interest Income, Accrual Method	9	9	12
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	8	8	12
Impaired Financing Receivable, Interest Income, Accrual Method	0	0	0
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	248	272	861
Impaired Financing Receivable, Interest Income, Accrual Method	9	9	12
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	101	79	126
Impaired Financing Receivable, Interest Income, Accrual Method	2	4	5
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	35	33	61
Impaired Financing Receivable, Interest Income, Accrual Method	1	1	2
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	60	41	59
Impaired Financing Receivable, Interest Income, Accrual Method	1	3	3
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	6	5	6
Impaired Financing Receivable, Interest Income, Accrual Method	$ 0	$ 0	$ 0

Finance Receivables and Loans96

Finance Receivables and Loans, Net (Troubled Debt Restructurings) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 663	$ 625
Financing Receivable, Modifications, Number of Contracts	20,355	17,428,000,000
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 375	$ 348
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 321	$ 305
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	20,354	17,426,000,000
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 368	$ 324
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 314	$ 281
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	20,227	17,222,000,000
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 347	$ 278
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 293	$ 237
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	127	204,000,000
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 21	$ 46
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 21	$ 44
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	7	7,000,000
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 3	$ 4
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 3	$ 4
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	120	197,000,000
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 18	$ 42
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 18	40
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Impaired, Commitment to Lend		$ 2
Financing Receivable, Modifications, Number of Contracts	1	2,000,000
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 7	$ 24
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 7	$ 24
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	1	0
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 7	$ 0
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 7	$ 0
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	0	1,000,000
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 0	$ 21
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 0	$ 21
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	0	1,000,000
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 0	$ 3
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 0	$ 3

Finance Receivables and Loans97

Finance Receivables and Loans, Net (Redefaults) (Details) - Consumer Portfolio Segment [Member] $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts	7,804	6,846
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 94	$ 83
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	$ 56	$ 47
Automobile Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts	7,800	6,836
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 94	$ 82
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	$ 56	$ 47
Mortgage Finance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts	0	0
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 0	$ 0
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	$ 0	$ 0
Mortgage - Legacy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts	4	10
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 0	$ 1
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	$ 0	$ 0

Finance Receivables and Loans98

Finance Receivables and Loans, Net Finance Receivables and Loans, Net (Consumer Concentration Risk by State and Foreign Geographic Region (Details)	Dec. 31, 2016	Dec. 31, 2015
Texas and California [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	24.20%	23.50%
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	100.00%	100.00%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | TEXAS
Concentration Risk [Line Items]
Consumer Concentration Risk	13.60%	13.70%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | CALIFORNIA
Concentration Risk [Line Items]
Consumer Concentration Risk	7.80%	7.30%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | FLORIDA
Concentration Risk [Line Items]
Consumer Concentration Risk	8.20%	7.70%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | PENNSYLVANIA
Concentration Risk [Line Items]
Consumer Concentration Risk	4.70%	5.00%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | ILLINOIS
Concentration Risk [Line Items]
Consumer Concentration Risk	4.30%	4.40%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | GEORGIA
Concentration Risk [Line Items]
Consumer Concentration Risk	4.30%	4.40%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | NORTH CAROLINA
Concentration Risk [Line Items]
Consumer Concentration Risk	3.60%	3.60%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | OHIO
Concentration Risk [Line Items]
Consumer Concentration Risk	3.50%	3.70%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | NEW YORK
Concentration Risk [Line Items]
Consumer Concentration Risk	3.20%	3.50%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | MICHIGAN
Concentration Risk [Line Items]
Consumer Concentration Risk	2.70%	3.10%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Other United States [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	44.10%	43.60%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	100.00%	100.00%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | TEXAS
Concentration Risk [Line Items]
Consumer Concentration Risk	6.60%	6.20%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | CALIFORNIA
Concentration Risk [Line Items]
Consumer Concentration Risk	34.20%	33.60%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | FLORIDA
Concentration Risk [Line Items]
Consumer Concentration Risk	4.40%	4.10%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | PENNSYLVANIA
Concentration Risk [Line Items]
Consumer Concentration Risk	1.50%	1.50%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | ILLINOIS
Concentration Risk [Line Items]
Consumer Concentration Risk	3.40%	4.10%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | GEORGIA
Concentration Risk [Line Items]
Consumer Concentration Risk	2.20%	2.20%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | NORTH CAROLINA
Concentration Risk [Line Items]
Consumer Concentration Risk	1.60%	1.80%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | OHIO
Concentration Risk [Line Items]
Consumer Concentration Risk	0.50%	0.60%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | NEW YORK
Concentration Risk [Line Items]
Consumer Concentration Risk	1.90%	1.90%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | MICHIGAN
Concentration Risk [Line Items]
Consumer Concentration Risk	1.90%	2.40%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | Other United States [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	41.80%	41.60%

Finance Receivables and Loans99

Finance Receivables and Loans, Net Finance Receivables and Loans, Net (Commercial Concentration Risk) (Details)	Dec. 31, 2016	Dec. 31, 2015
Concentration Risk [Line Items]
Commercial Concentration Risk	100.00%	100.00%
TEXAS
Concentration Risk [Line Items]
Commercial Concentration Risk	16.10%	17.70%
FLORIDA
Concentration Risk [Line Items]
Commercial Concentration Risk	10.20%	10.00%
MICHIGAN
Concentration Risk [Line Items]
Commercial Concentration Risk	7.90%	8.70%
CALIFORNIA
Concentration Risk [Line Items]
Commercial Concentration Risk	7.60%	8.90%
NORTH CAROLINA
Concentration Risk [Line Items]
Commercial Concentration Risk	4.20%	2.10%
VIRGINIA
Concentration Risk [Line Items]
Commercial Concentration Risk	3.60%	3.60%
GEORGIA
Concentration Risk [Line Items]
Commercial Concentration Risk	3.60%	3.80%
PENNSYLVANIA
Concentration Risk [Line Items]
Commercial Concentration Risk	3.10%	3.40%
NEW YORK
Concentration Risk [Line Items]
Commercial Concentration Risk	2.70%	2.20%
ILLINOIS
Concentration Risk [Line Items]
Commercial Concentration Risk	2.60%	3.10%
Other United States [Member]
Concentration Risk [Line Items]
Commercial Concentration Risk	38.40%	36.50%

Finance Receivables and Loan100

Finance Receivables and Loans, Net Finance Receivables and Loans, Net (Commercial Criticized Exposure) (Details)	Dec. 31, 2016	Dec. 31, 2015
Concentration Risk [Line Items]
Commercial Criticized Finance Receivables and Loans	100.00%	100.00%
5500 Retail, Auto Dealers and Gasoline Stations [Member]
Concentration Risk [Line Items]
Commercial Criticized Finance Receivables and Loans	81.20%	80.50%
310000 to 330000 Manufacturing [Member]
Concentration Risk [Line Items]
Commercial Criticized Finance Receivables and Loans	6.30%	5.30%
540000 to 549999 Professional, Scientific, and Technical Services [Member]
Concentration Risk [Line Items]
Commercial Criticized Finance Receivables and Loans	4.20%	3.30%
810000 to 819999 Other Services (except Public Administration) [Member]
Concentration Risk [Line Items]
Commercial Criticized Finance Receivables and Loans	8.30%	10.90%

Investment in Operating Leas101

Investment in Operating Leases, Net (Investments In Operating Leases) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Leases, Operating [Abstract]
Property Subject to or Available for Operating Lease, Gross	$ 14,584	$ 20,211
Property Subject to or Available for Operating Lease, Accumulated Depreciation	(3,114)	(3,940)
Property Subject to or Available for Operating Lease, Net	$ 11,470	$ 16,271

Investment in Operating Leas102

Investment in Operating Leases, Net (Schedule Of Depreciation Expense On Operating Lease Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Leases, Operating [Abstract]
Depreciation Expense On Operating Lease Assets	$ 1,982	$ 2,600	$ 2,666
Gross Remarketing (Gains) Losses	(213)	(351)	(433)
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	$ 1,769	$ 2,249	$ 2,233

Investment in Operating Leas103

Investment in Operating Leases, Net Investment in Operating Leases, Net (Schedule of Operating Leases of Lessor) (Details) $ in Millions	Dec. 31, 2016USD ($)
Leases, Operating [Abstract]
Operating Leases, Future Minimum Payments Receivable, Current	$ 1,759
Operating Leases, Future Minimum Payments Receivable, in Two Years	821
Operating Leases, Future Minimum Payments Receivable, in Three Years	307
Operating Leases, Future Minimum Payments Receivable, in Four Years	44
Operating Leases, Future Minimum Payments Receivable, Thereafter	2
Operating Leases, Future Minimum Payments Receivable	$ 2,933

Securitizations and Variable104

Securitizations and Variable Interest Entities (Schedule of Variable Interest Entities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Carrying value of assets for VIEs for which we have continuing involvement	$ 37,631	$ 44,940
Carrying value of liabilities for VIEs for which we have continuing involvement	13,490	20,388
Assets of nonconsolidated variable interest entities	2,899	3,034
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	3,574	3,527
Qualitative and Quantitative Information, Transferor's Continuing Involvement, Arrangements of Financial Support, Amount	50	99
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Variable Interest Entity [Line Items]
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale, Gain (Loss) on Sale	0	(3)	$ 1
Variable Interest Entity, Consolidated, Carrying Amount, Assets	20,869	27,967
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	24	0
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	8,557	12,406
Variable Interest Entity, Nonconsolidated, Carrying Amount, Liabilities	0	0
Assets of nonconsolidated variable interest entities	2,899	3,034
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	2,923	3,034
Continuing Involvement with Continued to be Recognized Transferred Financial Assets, Amount Outstanding	9,600	10,600
Commercial Portfolio Segment [Member] | Automobile Loan [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	16,278	16,763
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	4,764	7,982
Commercial Portfolio Segment [Member] | Other Financing Receivables [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	460	210
Variable Interest Entity, Nonconsolidated, Carrying Amount, Liabilities	169	0
Assets of nonconsolidated variable interest entities	0	0
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	$ 651	$ 493

Securitizations and Variable105

Securitizations and Variable Interest Entities Securitizations and Variable Interest Entities (Schedule of On-balance Sheet Variable Interest Entities) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
On-balance Sheet Variable Interest Entities [Line Items]
Loans and Leases Receivable, Gross	$ 118,944	$ 111,600
Loans and Leases Receivable, Allowance	(1,144)	(1,054)	$ (977)
Loans and Leases Receivable, Net Amount	117,800	110,546
Property Subject to or Available for Operating Lease, Net	11,470	16,271
Other Assets	6,854	6,321
Assets	163,728	158,581	$ 151,631
Long-term Debt	54,128	66,234
Accounts Payable and Accrued Liabilities	1,737	1,545
Liabilities	150,411	145,142
Variable Interest Entity, Primary Beneficiary [Member]
On-balance Sheet Variable Interest Entities [Line Items]
Loans and Leases Receivable, Gross	24,630	27,929
Loans and Leases Receivable, Allowance	(173)	(196)
Loans and Leases Receivable, Net Amount	24,457	27,733
Property Subject to or Available for Operating Lease, Net	1,745	4,791
Other Assets	1,390	1,624
Assets	27,592	34,148
Long-term Debt	13,259	20,267
Accounts Payable and Accrued Liabilities	12	22
Liabilities	13,271	20,289
Variable Interest Entity, Primary Beneficiary [Member] | Consumer Portfolio Segment [Member]
On-balance Sheet Variable Interest Entities [Line Items]
Loans and Leases Receivable, Gross	8,929	11,682
Variable Interest Entity, Primary Beneficiary [Member] | Commercial Portfolio Segment [Member]
On-balance Sheet Variable Interest Entities [Line Items]
Loans and Leases Receivable, Gross	$ 15,701	$ 16,247

Securitizations and Variable106

Securitizations and Variable Interest Entities (Schedule of Cash Flow Received and Paid o Nonconsolidated Securitization Entities) (Details) - Consumer Portfolio Segment [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Residential Mortgage [Member]
Cash Flow Received and Paid to Nonconsolidated Securitization Entities [Line Items]
Cash Flows Between Transferor and Transferee, Proceeds from New Transfers	$ 0	$ 0	$ 0
Cash Flows Between Transferor and Transferee, Servicing Fees	0	0	0
Cash Flows Between Transferor and Transferee, Receipts on Transferor's Interest in Transferred Financial Assets, Other	0
Cash Flow Between Transferee and Transferor Representations And Warranties Obligations			(31)
Automobile Loan [Member]
Cash Flow Received and Paid to Nonconsolidated Securitization Entities [Line Items]
Cash Flows Between Transferor and Transferee, Proceeds from New Transfers	1,715	1,551	2,594
Cash Flows Between Transferor and Transferee, Servicing Fees	35	$ 28	11
Cash Flows Between Transferor and Transferee, Receipts on Transferor's Interest in Transferred Financial Assets, Other	$ 8
Cash Flow Between Transferee and Transferor Representations And Warranties Obligations			$ 0

Securitizations and Variable107

Securitizations and Variable Interest Entities (Schedule of Quantitative Information and Net Credit Losses about Securitized and Other Financial Assets Managed Together) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	$ 124,500	$ 116,486
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	841	721
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	812	614
On-Balance Sheet Loans [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	118,944	111,705
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	822	699
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	801	609
On-Balance Sheet Loans [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	65,793	64,292
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	730	591
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	795	578
On-Balance Sheet Loans [Member] | Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	11,050	9,773
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	85	108
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	7	31
On-Balance Sheet Loans [Member] | Commercial Portfolio Segment [Member] | Automobile Loan [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	38,853	34,895
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	7	0
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	1	3
On-Balance Sheet Loans [Member] | Commercial Portfolio Segment [Member] | Other Financing Receivables [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	3,248	2,745
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	0	0
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	(2)	(3)
Off-Balance Sheet Loans [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	2,392	2,529
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	13	9
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	8	5
Off-Balance Sheet Loans [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	2,392	2,529
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	13	9
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	8	5
Whole-Loan Transactions [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	3,164	2,252
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	6	13
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	$ 3	$ 0

Servicing Activities (Schedule

Servicing Activities (Schedule of Total Serviced Automobile Loans Outstanding) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Automobile Serviced Assets [Line Items]
Contractually Specified Servicing Fees, Late Fees, and Ancillary Fees Earned in Exchange for Servicing Financial Assets	$ 64	$ 45	$ 31
Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Contractually Specified Servicing Fees, Late Fees, and Ancillary Fees Earned in Exchange for Servicing Financial Assets	64	45	$ 31
Servicing Asset	121,480	119,808
Consumer Loan [Member] | On-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Servicing Asset	65,646	64,067
Commercial Loan [Member] | On-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Servicing Asset	38,853	34,895
Operating Leases [Member] | On-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Servicing Asset	11,311	15,965
Other Assets [Member] | On-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Servicing Asset	67	72
Securitizations [Member] | Off-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Servicing Asset	2,412	2,550
Whole-Loan Transactions [Member] | Off-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Servicing Asset	$ 3,191	$ 2,259

Premiums Receivable and Othe109

Premiums Receivable and Other Insurance Assets Premiums Receivable and Other Insurance Assets (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Premiums Receivable and Other Insurance Assets [Abstract]
Prepaid Reinsurance Premiums	$ 439	$ 382
Reinsurance Recoverables, Incurred but Not Reported Claims	108	120
Reinsurance Recoverables on Paid Losses, Gross	20	18
Premiums Receivable, Net	80	82
Deferred Policy Acquisition Costs	1,258	1,199
Premiums receivable and other insurance assets	$ 1,905	$ 1,801

Other Assets (Schedule of Other

Other Assets (Schedule of Other Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Aug. 01, 2016	Jun. 01, 2016	Dec. 31, 2015
Goodwill [Line Items]
Goodwill	$ 240			$ 27
Property, Plant and Equipment, Gross	901			691
Accumulated depreciation	(525)			(456)
Property, Plant and Equipment, Net	376			235
Restricted cash collections for securitization trusts	1,694			2,010
Nonmarketable equity investments	1,046			418
Deferred Tax Assets, State Taxes	994			1,369
Interest Receivable	476			402
Goodwill	240			27
Cash reserve deposits held for securitization trusts	184			252
Cash and securities collateral placed with counterparties	167			125
Restricted Cash and Cash Equivalents	111			120
Other accounts receivable	100			158
Derivative Asset, Fair Value, Gross Asset	95			233
Other Assets, Miscellaneous	1,371			972
Other Assets	6,854			6,321
Federal Home Loan Bank Stock	577			391
Federal Reserve Bank Stock	435			0
Insurance Operations Member
Goodwill [Line Items]
Goodwill	27			27
Goodwill	27			27
Corporate and Other [Member]
Goodwill [Line Items]
Goodwill	193		$ 193	0
Goodwill	193		$ 193	0
Automotive Finance Operations [Member]
Goodwill [Line Items]
Goodwill	20	$ 20		0
Goodwill	$ 20	$ 20		$ 0

Deposit Liabilities (Schedule o

Deposit Liabilities (Schedule of Deposit Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deposits [Abstract]
Noninterest-bearing deposit liabilities	$ 84	$ 89
Interest-bearing Deposit Liabilities, by Component [Abstract]
Deposits, Savings Deposits	46,976	36,386
Time Deposits	31,795	29,774
Deposits, Retail	167	229
Deposits	79,022	66,478
Time Deposits, $100,000 or More	12,100	11,500
Time Deposits, $250,000 or More, Domestic	$ 3,500	$ 3,200

Deposit Liabilities Deposit Lia

Deposit Liabilities Deposit Liabilities (Schedule of Maturities for Total Time Deposits) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Schedule of Maturities For Total Time Deposits [Line Items]
Time Deposits	$ 31,795	$ 29,774
One year, or less [Member]
Schedule of Maturities For Total Time Deposits [Line Items]
Time Deposits	16,206
Two years, or less [Member]
Schedule of Maturities For Total Time Deposits [Line Items]
Time Deposits	9,984
Three years, or less [Member]
Schedule of Maturities For Total Time Deposits [Line Items]
Time Deposits	3,041
Four years, or less [Member]
Schedule of Maturities For Total Time Deposits [Line Items]
Time Deposits	1,348
Five years or less [Member]
Schedule of Maturities For Total Time Deposits [Line Items]
Time Deposits	$ 1,216

Debt Debt (Schedule of Short-te

Debt Debt (Schedule of Short-term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Short-term Debt [Line Items]
Demand Notes	$ 3,622	$ 3,369
Federal Home Loan Bank, Advances, Maturities Summary, Due in Next Twelve Months	7,875	4,000
Securities Sold under Agreements to Repurchase, Gross	1,176	648
Other Short-term Borrowings	0	84
Short-term Debt	$ 12,673	$ 8,101
Short-term Debt, Weighted Average Interest Rate	1.00%	0.80%
Non-derivative Cash Collateral Placed with Counterparties Associated with the Repurchase Agreements	$ 45	$ 21
Unsecured Debt [Member]
Short-term Debt [Line Items]
Demand Notes	3,622	3,369
Federal Home Loan Bank, Advances, Maturities Summary, Due in Next Twelve Months	0	0
Securities Sold under Agreements to Repurchase, Gross	0	0
Other Short-term Borrowings	0	84
Short-term Debt	3,622	3,453
Secured Debt [Member]
Short-term Debt [Line Items]
Demand Notes	0	0
Federal Home Loan Bank, Advances, Maturities Summary, Due in Next Twelve Months	7,875	4,000
Securities Sold under Agreements to Repurchase, Gross	1,176	648
Other Short-term Borrowings	0	0
Short-term Debt	9,051	$ 4,648
Maturity 31 to 60 Days [Member] | Secured Debt [Member]
Short-term Debt [Line Items]
Mortgage-backed Residential Securities Sold under Agreements to Repurchase, Maturity Period	676
One year, or less [Member] | Secured Debt [Member]
Short-term Debt [Line Items]
Asset-backed Automotive Financial Securities Sold under Agreements to Repurchase, Maturity Period	$ 500

Debt Debt (Schedule of Long-ter

Debt Debt (Schedule of Long-term Debt Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Derivative, Amount of Hedged Item	$ 315	$ 331
Long-term Debt	54,128	66,234
Secured Debt	43,129	49,916
Fixed Income Interest Rate [Member]
Debt Instrument [Line Items]
Unsecured Debt	17,155	17,657
Trust preferred securities	2,568	2,600
Secured Debt	17,935	20,511
Variable Income Interest Rate [Member]
Debt Instrument [Line Items]
Unsecured Debt	1	375
Secured Debt	16,154	24,760
Unsecured Debt [Member]
Debt Instrument [Line Items]
Derivative, Amount of Hedged Item	326	334
Long-term Debt	$ 20,050	$ 20,966
Long-term Debt, Weighted Average Interest Rate	5.36%	5.40%
Secured Debt [Member]
Debt Instrument [Line Items]
Derivative, Amount of Hedged Item	$ (11)	$ (3)
Long-term Debt	$ 34,078	$ 45,268
Long-term Debt, Weighted Average Interest Rate	1.53%	1.18%
Variable Interest Entity Debt	$ 13,300	$ 20,300
Subordinated Debt [Member]
Debt Instrument [Line Items]
Unsecured Debt	1,400	1,100
Revolving secured funding facilities [Member]
Debt Instrument [Line Items]
Secured Debt	14,800	19,900
Federal Home Loan Bank Advances [Member]
Debt Instrument [Line Items]
Secured Debt	$ 6,100	$ 5,400

Debt (Long-term Debt Portfolio)

Debt (Long-term Debt Portfolio) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Long-term Debt, Current Maturities	$ 14,553	$ 11,256
Long-term Debt, Excluding Current Maturities	39,260	54,647
Derivative, Amount of Hedged Item	315	331
Long-term debt	54,128	66,234
Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Current Maturities	4,274	1,829
Long-term Debt, Excluding Current Maturities	15,450	18,803
Derivative, Amount of Hedged Item	326	334
Long-term debt	20,050	20,966
Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Current Maturities	10,279	9,427
Long-term Debt, Excluding Current Maturities	23,810	35,844
Derivative, Amount of Hedged Item	(11)	(3)
Long-term debt	$ 34,078	$ 45,268

Debt (Scheduled Remaining Matur

Debt (Scheduled Remaining Maturity of Long-term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
2,017	$ 14,553
2,018	11,755
2,019	8,976
2,020	6,421
2,021	3,076
2022 and thereafter	9,032
Derivative, Amount of Hedged Item	315	$ 331
Long-term debt	54,128	66,234
Derivative Instrument Converting Fixed-rate Debt into Variable-rate Obligations	2,100
Derivative Instrument Converting Variable-rate Debt into Fixed-rate Obligations	132
Unsecured Debt [Member]
Debt Instrument [Line Items]
2,017	4,274
2,018	3,599
2,019	1,642
2,020	2,173
2,021	595
2022 and thereafter	7,441
Derivative, Amount of Hedged Item	326	334
Long-term debt	20,050	20,966
Debt Instrument, Unamortized Discount	(91)
Debt Instrument, Unamortized Discount	(1,326)
Unsecured Debt [Member] | Debt Instrument, Redemption, Period One [Member]
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount, Noncurrent	(101)
Unsecured Debt [Member] | Debt Instrument, Redemption, Period Two [Member]
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount, Noncurrent	(39)
Unsecured Debt [Member] | Debt Instrument, Redemption, Period Three [Member]
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount, Noncurrent	(39)
Unsecured Debt [Member] | Debt Instrument, Redemption, Period Four [Member]
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount, Noncurrent	(43)
Unsecured Debt [Member] | Debt Instrument, Redemption, Period Five [Member]
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount, Noncurrent	(1,013)
Secured Debt [Member]
Debt Instrument [Line Items]
2,017	10,279
2,018	8,156
2,019	7,334
2,020	4,248
2,021	2,481
2022 and thereafter	1,591
Derivative, Amount of Hedged Item	(11)	(3)
Long-term debt	34,078	$ 45,268
Long-term Debt [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
2,017	4,365
2,018	3,700
2,019	1,681
2,020	2,212
2,021	638
2022 and thereafter	8,454
Derivative, Amount of Hedged Item	326
Long-term debt	21,376
original issue discount [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Derivative, Amount of Hedged Item	$ 0

Debt (Pledged Assets Related to

Debt (Pledged Assets Related to Secured Borrowings and Repurchase Agreement) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Pledged Assets related to secured borrowings [Line Items]
Pledged Financial Instruments, Not Separately Reported, Other Debt Securities Available-for-sale or Held-for-investment	$ 4,895	$ 2,420
Pledged Assets, Mortgage assets held for investment	10,954	9,743
Pledged Assets, Investment in operating leases	2,040	5,539
Pledged Assets, Other, Not Separately Reported on Statement of Financial Position	65,222	71,649
Secured Debt	43,129	49,916
Short-term Debt	12,673	8,101
Ally Bank [Member]
Pledged Assets related to secured borrowings [Line Items]
Pledged Financial Instruments, Not Separately Reported, Other Debt Securities Available-for-sale or Held-for-investment	4,231	1,761
Pledged Assets, Mortgage assets held for investment	10,954	9,743
Pledged Assets, Investment in operating leases	913	3,205
Pledged Assets, Other, Not Separately Reported on Statement of Financial Position	41,129	43,053
Secured Debt	22,149	24,787
Pledged assets for Federal Home Loan Bank [Member] | Ally Bank [Member]
Pledged Assets related to secured borrowings [Line Items]
Pledged Assets, Other, Not Separately Reported on Statement of Financial Position	19,000	14,900
Pledged assets for Federal Reserve Bank [Member] | Ally Bank [Member]
Pledged Assets related to secured borrowings [Line Items]
Pledged Assets, Other, Not Separately Reported on Statement of Financial Position	2,400	2,900
Secured Debt [Member]
Pledged Assets related to secured borrowings [Line Items]
Short-term Debt	9,051	4,648
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Pledged Assets related to secured borrowings [Line Items]
Pledged Assets, Not Separately Reported, Finance Receivables	27,846	34,324
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Ally Bank [Member]
Pledged Assets related to secured borrowings [Line Items]
Pledged Assets, Not Separately Reported, Finance Receivables	5,751	9,167
Commercial Portfolio Segment [Member] | Automobile Loan [Member]
Pledged Assets related to secured borrowings [Line Items]
Pledged Assets, Not Separately Reported, Finance Receivables	19,487	19,623
Commercial Portfolio Segment [Member] | Automobile Loan [Member] | Ally Bank [Member]
Pledged Assets related to secured borrowings [Line Items]
Pledged Assets, Not Separately Reported, Finance Receivables	$ 19,280	$ 19,177

Debt Debt (Narrative - Trust Pr

Debt Debt (Narrative - Trust Preferred Securities) (Details) $ / shares in Units, $ in Millions	Dec. 31, 2016USD ($)$ / shares	Dec. 31, 2015USD ($)
Narrative - Trust Preferred Securities [Line Items]
Preferred Stock, Liquidation Preference Per Share | $ / shares	$ 25
Debt Instrument, Interest Rate, Stated Percentage	8.13%
From and including February 15, 2016, to but excluding February 15, 2040, distributions will be payable at an annual rate equal to three-month London interbank offer rate plus:	5.79%
Ally has the right to defer payments of interest for a period not exceeding consecutive quarters of:	20
Percent of principle debt, plus accrued and unpaid interest is the redemption price if Ally redeems the Series 2 TRUPS on or after February 15, 2016.	100.00%
Fixed Income Interest Rate [Member]
Narrative - Trust Preferred Securities [Line Items]
Trust preferred securities | $	$ 2,568	$ 2,600

Debt (Committed Funding Facilit

Debt (Committed Funding Facilities) (Details) - Committed Funding Facilities Member - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 18,375	$ 20,415
Outstanding	14,800	20,164
Unused capacity	3,575	251
Bank Funding Member | Secured Debt [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	3,600	3,250
Outstanding	3,250	3,250
Unused capacity	350	0
Revolving secured funding facilities [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	17,500
Nonbank Funding [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	13,525	17,165
Outstanding	11,550	16,914
Unused capacity	1,975	251
Nonbank Funding [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	1,250	0
Outstanding	0	0
Unused capacity	1,250	$ 0
Revolving secured funding facilities 1 year or greater [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 14,100

Accrued Expenses and Other L120

Accrued Expenses and Other Liabilities (Schedule of Accrued Expenses and Other Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Accounts Payable and Accrued Liabilities [Abstract]
Accounts Payable	$ 649	$ 391
Accrued Employee Benefits	232	242
Liability for Claims and Claims Adjustment Expense	149	169
Derivative Liability, Fair Value, Gross Liability	95	145
Deferred Revenue	56	108
Cash and securities collateral placed with counterparties	10	82
Other Accrued Liabilities	546	408
Accounts Payable and Accrued Liabilities	$ 1,737	$ 1,545

Equity Equity (Schedule of Stoc

Equity Equity (Schedule of Stockholders Equity) (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015$ / sharesshares	Dec. 31, 2014shares	Jul. 19, 2016USD ($)	Dec. 31, 2013shares
Schedule of Stockholders Equity [Line Items]
Stockholders' Equity Note, Stock Split, Conversion Ratio			310
Common Stock, Par or Stated Value Per Share | $ / shares	$ 0.01	$ 0.01
Common Stock, Shares Authorized	1,100,000,000	1,100,000,000	1,100,000,000
Common Stock, Shares, Issued	485,707,644	482,790,696	480,136,000		479,767,000
Stock Issued During Period, Shares, New Issues	2,917,000	2,655,000	369,000
Treasury Stock, Shares	(18,707,338)	(810,585)	(41,000)		0
Treasury Stock, Shares, Acquired	(17,897,000)	(769,000)	(41,000)
Common Stock, Shares, Outstanding	467,000,306	481,980,111	480,095,000
Stock Repurchase Program, Authorized Amount | $	$ 700			$ 700

Equity (Schedule Of Preferred S

Equity (Schedule Of Preferred Stock) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Oct. 18, 2016	Jul. 18, 2016	May 16, 2016	Dec. 31, 2015
Schedule of Capitalization, Equity [Line Items]
Non U S Dept Of Treasury Held Preferred Stock And APIC	$ 0				$ 696
Dividends Payable, Amount Per Share	$ 0.08	$ 0.08	$ 0.08
Series A Preferred Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Non U S Dept Of Treasury Held Preferred Stock And APIC				$ 696	$ 696
Preferred Stock, Shares Issued and Outstanding					27,870,560
Stock Redeemed or Called During Period, Shares	27,870,560
Preferred Stock, Redemption Price Per Share				$ 25
Dividends Payable, Amount Per Share				$ 0.53
Preferred Stock Redemption, Aggregate Liquidation Preference	$ 697
Preferred Stock, Redemption Amount				$ 712
Preferred stock dividends paid for Series A redemption	$ 15

Accumulated Other Comprehens123

Accumulated Other Comprehensive Loss (Rollforward) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax [Abstract]
Beginning Balance Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	$ (159)	$ (21)	$ (269)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent	(114)	(138)	248
Ending Balance Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(273)	(159)	(21)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Beginning Balance Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	9	36	65
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	5	(27)	(29)
Ending Balance Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	14	9	36
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax [Abstract]
Beginning Balance Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	8	7	5
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent	0	1	2
Ending Balance Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	8	8	7
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Beginning Balance Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax	(89)	(88)	(77)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent	(1)	(1)	(11)
Ending Balance Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax	(90)	(89)	(88)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(231)	(66)	(276)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(110)	(165)	210
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (341)	$ (231)	$ (66)

Accumulated Other Comprehens124

Accumulated Other Comprehensive Loss (Before and After Tax) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, [Abstract]
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax			$ 13	$ (65)	$ 557
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax			185	155	181
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent			(172)	(220)	376
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax [Abstract]
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax			20	26	(142)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax			(38)	(56)	(14)
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax, Portion Attributable to Parent			58	82	(128)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax [Abstract]
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax			33	(39)	415
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax			147	99	167
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent			(114)	(138)	248
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax [Abstract]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax			5	(39)	(27)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax			(1)	42	23
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax, Portion Attributable to Parent	$ 6			(81)	(50)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax [Abstract]
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax			(2)	13	10
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Tax			0	(20)	(3)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax, Portion Attributable to Parent	(2)			33	13
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax			3	(26)	(17)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	(1)		1	22	20
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent	4		4	(48)	(37)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax [Abstract]
Other Comprehensive Income Unrealized Gain Loss On Net Investment Hedges Arising During the Period, Before Tax			1	29	13
Other Comprehensive Income (Loss), Reclassification Adjustment for Net Investment Hedges Included in Net Income, Discontinued Operation, before Tax				(4)
Other Comprehensive Income (Loss), Net Investment Hedges Attributable to Parent, before Tax				33
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax				2	2
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax Effect [Abstract]
Other Comprehensive Income Unrealized Gain Loss On Net Investment Hedges Arising During the Period, Tax			0	(11)	(5)
Other Comprehensive Income (Loss), Reclassification Adjustment for Net Investment Hedges Included in Net Income, Discontinued Operation, Tax				1
Other Comprehensive Income (Loss), Net Investment Hedges Attributable to Parent, Tax				(12)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax				(1)	0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax [Abstract]
Other Comprehensive Income Unrealized Gain Loss On Net Investment Hedges Arising During the Period Net of Tax			1	18	8
Other Comprehensive Income (Loss), Reclassification Adjustment for Net Investment Hedges Included in Net Income, Discontinued Operation, Net of Tax			0	(3)	0
Other Comprehensive Income (Loss), Net Investment Hedges Attributable to Parent, Net of Tax			1	21	8
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent			0	1	2
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax, [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax			(5)	0	(24)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax		$ (4)		1	(7)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax, Portion Attributable to Parent			(1)	(1)	(17)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Tax			2	0	9
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Tax		2		0	3
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax, Portion Attributable to Parent			0	0	6
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax	$ (3)		(3)	0	(15)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Net of Tax		$ (2)		1	(4)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent			1	1	11
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent			(166)	(267)	324
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent			56	102	(114)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent			$ (110)	$ (165)	$ 210

Earnings per Common Share (Sche

Earnings per Common Share (Schedule of Basic and Diluted Earnings per Common Share) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	$ 246	$ 261	$ 357	$ 247	$ 276	$ 273	$ 169	$ 179	$ 1,111	$ 897	$ 925
Dividends, Preferred Stock, Cash									(30)	(2,571)	(268)
Net income (loss) from continuing operations attributable to common shareholders									1,081	(1,674)	657
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	$ 2	$ (52)	$ 3	$ 3	$ (13)	$ (5)	$ 13	$ 397	(44)	392	225
Net Income (Loss) Available to Common Stockholders, Basic									$ 1,037	$ (1,282)	$ 882
Weighted Average Number of Shares Outstanding, Basic									481,104,533	482,873	481,155
Weighted Average Number of Shares Outstanding, Diluted									482,182,115	482,873	481,934
Stock Repurchase and Redemption Premium										$ 2,364
Earnings Per Share, Basic [Abstract]
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.52	$ 0.54	$ 0.70	$ 0.48	$ (1.94)	$ 0.49	$ (2.24)	$ 0.23	$ 2.25	$ (3.47)	$ 1.36
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	0.53	0.43	0.71	0.49	(1.97)	0.48	(2.22)	1.06	(0.09)	0.81	0.47
Earnings Per Share, Basic									2.15	(2.66)	1.83
Earnings Per Share, Diluted [Abstract]
Income (Loss) from Continuing Operations, Per Diluted Share	0.52	0.54	0.70	0.48	(1.94)	0.49	(2.24)	0.23	2.24	(3.47)	1.36
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	$ 0.52	$ 0.43	$ 0.71	$ 0.49	$ (1.97)	$ 0.47	$ (2.22)	$ 1.06	(0.09)	0.81	0.47
Earnings Per Share, Diluted									$ 2.15	$ (2.66)	$ 1.83

Regulatory Capital and Other126

Regulatory Capital and Other Regulatory Matters (Schedule of Regulatory Capital Amount and Ratios) (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Oct. 18, 2016	Jul. 19, 2016	Jul. 18, 2016	Dec. 31, 2014
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1 Capital Required for Capital Adequacy to Risk-weighted Assets	4.50%	4.50%
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	6.00%	6.00%
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%	8.00%
Common equity Tier 1 capital conservation buffer	2.50%	2.50%
Federal Reserve Bank Stock	$ 435	$ 435	$ 0
assets greater than $50 billion	$ 50,000	$ 50,000
Dividends Payable, Amount Per Share	$ 0.08	$ 0.08		$ 0.08		$ 0.08
Stock Repurchase Program, Authorized Amount	$ 700	$ 700			$ 700
Treasury Stock, Value, Acquired, Cost Method	$ 326	$ 341	$ 16
Treasury Stock, Common, Shares	17,043,021	17,043,021
Reduction in total shares outstanding	3.50%	3.50%
Common Stock, Shares, Outstanding	467,000,306	467,000,306	481,980,111				480,095,000
Assets	$ 163,728	$ 163,728	$ 158,581				$ 151,631
Parent Company [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1 Capital Required for Capital Adequacy to Risk-weighted Assets	4.50%	4.50%
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	6.00%	6.00%
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%	8.00%
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	4.00%	4.00%
Common Equity Tier 1 Capital	$ 12,978	$ 12,978	$ 12,507
Percentage of Common Equity Tier 1 Capital to Risk-weighted Assets	9.37%	9.37%	9.21%
Tier One Risk Based Capital	$ 15,147	$ 15,147	$ 15,077
Tier One Risk Based Capital to Risk Weighted Assets	10.93%	10.93%	11.10%
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	6.00%	6.00%
Capital	$ 17,419	$ 17,419	$ 17,005
Capital to Risk Weighted Assets	12.57%	12.57%	12.52%
Capital Required to be Well Capitalized to Risk Weighted Assets	10.00%	10.00%
Tier One Leverage Capital	$ 15,147	$ 15,147	$ 15,077
Tier One Leverage Capital to Average Assets	9.54%	9.54%	9.73%
Ally Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1 Capital Required for Capital Adequacy to Risk-weighted Assets	4.50%	4.50%
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	6.00%	6.00%
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%	8.00%
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	15.00%	15.00%
Common Equity Tier 1 Capital	$ 17,888	$ 17,888	$ 16,594
Percentage of Common Equity Tier 1 Capital to Risk-weighted Assets	16.70%	16.70%	17.05%
Common Equity Tier 1 Capital Required to be Well Capitalized to Risk-weighted Assets	6.50%	6.50%
Tier One Risk Based Capital	$ 17,888	$ 17,888	$ 16,594
Tier One Risk Based Capital to Risk Weighted Assets	16.70%	16.70%	17.05%
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	8.00%	8.00%
Capital	$ 18,458	$ 18,458	$ 17,043
Capital to Risk Weighted Assets	17.24%	17.24%	17.51%
Capital Required to be Well Capitalized to Risk Weighted Assets	10.00%	10.00%
Tier One Leverage Capital	$ 17,888	$ 17,888	$ 16,594
Tier One Leverage Capital to Average Assets	15.21%	15.21%	15.38%
Tier One Leverage Capital Required to be Well Capitalized to Average Assets	5.00%	5.00%
Assets	$ 123,500	$ 123,500	$ 111,300
Cash Dividends Paid to Parent Company		0	525
FRB required reserve balance	149	149	$ 216
Insurance Operations Member
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval	$ 75	$ 75

Derivative Instruments and H127

Derivative Instruments and Hedging Activities (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Forward Contract Indexed to Issuer's Equity [Line Items]
Derivative, Notional Amount	$ 34,166	$ 59,116
Cash Collateral Placed with Counterparties Excluding Cash Collateral Associated with Repurchase Agreements	122	103
Securities Collateral Placed with Counterparties	72	86
Non-derivative Cash Collateral Placed with Counterparties Associated with the Repurchase Agreements	45	21
Cash Collateral Received from Counterparties, Excluding Collateral Associated with Repurchase Agreements	10	82
Non-cash collateral received	6	7
Designated as Hedging Instrument [Member]
Forward Contract Indexed to Issuer's Equity [Line Items]
Derivative, Notional Amount	4,902	14,340
Designated as Hedging Instrument [Member] | Equity Contract [Member]
Forward Contract Indexed to Issuer's Equity [Line Items]
Derivative, Notional Amount	0	32
Designated as Hedging Instrument [Member] | Forward Contracts [Member] | Equity Contract [Member]
Forward Contract Indexed to Issuer's Equity [Line Items]
Derivative, Notional Amount	$ 0	$ 32

Derivative Instruments and H128

Derivative Instruments and Hedging Activities (Fair Value Amounts of Derivative Instruments Reported on our Condensed Consolidated Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 95	$ 233
Derivative Liability, Fair Value, Gross Liability	95	145
Derivative, Notional Amount	34,166	59,116
Interest Receivable	476	402
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	20	126
Derivative Liability, Fair Value, Gross Liability	21	10
Derivative, Notional Amount	4,902	14,340
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	19	126
Derivative Liability, Fair Value, Gross Liability	21	9
Derivative, Notional Amount	4,731	14,151
Hedge notional amount associated with debt maturing in five or more years	1,700
Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1	0
Derivative Liability, Fair Value, Gross Liability	0	1
Derivative, Notional Amount	171	189
Fair Value Hedging [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Receive-fixed Swaps, Fair Value, Gross Asset	8	112
Receive-fixed Swaps, Fair Value, Gross Liability	14	3
Receive-fixed Swaps, Notional Amount	1,700	6,800
Pay-fixed Swaps, Fair Value, Gross Asset	10	13
Pay-fixed Swaps, Fair Value, Gross Liability	1	3
Pay-fixed Swaps, Notional Amount	2,800	6,800
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	73	105
Derivative Liability, Fair Value, Gross Liability	73	125
Derivative, Notional Amount	29,172	44,466
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1	0
Derivative Liability, Fair Value, Gross Liability	0	0
Derivative, Notional Amount	92	278
Equity Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1	2
Derivative Liability, Fair Value, Gross Liability	1	10
Derivative, Notional Amount	0	32
Interest Rate Swap [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	30
Derivative Liability, Fair Value, Gross Liability	0	51
Derivative, Notional Amount	137	6,101
Foreign Exchange Forward [Member] | Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1	0
Derivative Liability, Fair Value, Gross Liability	0	0
Derivative, Notional Amount	92	278
Futures and Forwards [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	2
Derivative Liability, Fair Value, Gross Liability	0	2
Derivative, Notional Amount	0	1,905
Written Options [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	73	72
Derivative, Notional Amount	14,518	18,220
Written Options [Member] | Equity Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	1	1
Derivative, Notional Amount	0	0
Purchased Options [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	73	73
Derivative Liability, Fair Value, Gross Liability	0	0
Derivative, Notional Amount	14,517	18,240
Purchased Options [Member] | Equity Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1	2
Derivative Liability, Fair Value, Gross Liability	0	0
Derivative, Notional Amount	0	0
Forward Contracts [Member] | Equity Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	0	9
Derivative, Notional Amount	0	32
Other Trading [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	75	107
Derivative Liability, Fair Value, Gross Liability	74	135
Derivative, Notional Amount	29,264	44,776
Secured Debt [Member] | Fair Value Hedging [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Receive-fixed Swaps, Fair Value, Gross Asset	0	1
Receive-fixed Swaps, Fair Value, Gross Liability	7	2
Receive-fixed Swaps, Notional Amount	240	500
Derivative assets in net asset position [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	87	224
Interest Receivable	7	46
Derivative assets in net liability positions [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	8	9
Interest Receivable	$ 1	$ 12

Derivative Instruments and H129

Derivative Instruments and Hedging Activities (Statement of Gains and Losses on Derivative Instruments Reported in Statement of Comprehensive Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	$ (7)	$ 35	$ 63
Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	(8)	(121)	(139)
Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	0	(19)	(37)
Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	(1)	(127)	(160)
Equity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	(10)	(5)
Interest Income [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	(2)	(9)	15
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	0	(2)	0
Interest Income [Member] | Interest Rate Contract [Member] | Hedges of Retail Auto Loans Held for Investment [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	18	64	61
Interest Income [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	39	34
Interest Income [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Losses Related to Amortization of Deferred Basis Adjustments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	20	8
Interest Income [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Gains Related to Amortization of Deferred Basis Adjustments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	84	73	155
Interest Expense [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	65	35	199
Interest Expense [Member] | Interest Rate Contract [Member] | Hedges of Unsecured Debt Held for Investment [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	40	97	112
Interest Expense [Member] | Interest Rate Contract [Member] | Hedges of Secured Debt [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	5	1
Interest Expense [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	(70)	(30)	(185)
Interest Expense [Member] | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	(2)	(139)	(172)
Other Income [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	0	(17)	(37)
Other Income [Member] | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	1	12	12
Other Income [Member] | Foreign Exchange Contract [Member] | Revaluation of Foreign-Denominated Debt or Receivable [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	0	132	165
Employee compensation and benefits [Member] | Equity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	$ 0	$ (10)	$ (5)

Derivative Instruments and H130

Derivative Instruments and Hedging Activities (Derivative Instruments Used in Net Investment Hedge Accounting Relationships) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Cumulative Translation Adjustment, Net of Tax, Period Increase (Decrease)	$ 4	$ 59	$ 41
Interest Rate Contract [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	0	(2)
Cash flow hedges, total interest on long-term debt	0	0	(2)
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	0	2	2
Foreign Exchange Contract [Member] | Net Investment Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	(4)	0
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	1	33	13
Net Investment Hedges - Total Other Income, Net of Losses	$ 0	$ (4)	$ 0

Income Taxes Income Taxes (Sche

Income Taxes Income Taxes (Schedule of Significant Components of Income Tax Expense) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Current Federal Tax Expense (Benefit)									$ 0	$ 0	$ (3)
Current Foreign Tax Expense (Benefit)									8	6	8
Current State and Local Tax Expense (Benefit)									9	3	5
Current Income Tax Expense (Benefit)									17	9	10
Deferred Federal Income Tax Expense (Benefit)									423	454	270
Deferred Foreign Income Tax Expense (Benefit)									0	1	2
Deferred State and Local Income Tax Expense (Benefit)									30	32	39
Deferred Income Tax Expense (Benefit)									453	487	311
Income Tax Expense (Benefit)	$ 134	$ 130	$ 56	$ 150	$ 155	$ 144	$ 94	$ 103	$ 470	$ 496	$ 321

Income Taxes Income Taxes (S132

Income Taxes Income Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount									$ 553	$ 488	$ 436
Effective Income Tax Rate Reconciliation, Change in Unrecognized Tax Benefits									(161)	(5)	(63)
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount									51	(25)	(47)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount									35	38	48
Effective Income Tax Reconciliation, Foreign Capital Loss									(15)	(13)	(27)
Effective Income Tax Rate Reconciliation, Equity in Earnings (Losses) of Unconsolidated Subsidiary, Amount									7	14	31
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount									0	0	(39)
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount									0	(1)	(18)
Income Tax Expense (Benefit)	$ 134	$ 130	$ 56	$ 150	$ 155	$ 144	$ 94	$ 103	$ 470	$ 496	$ 321

Income Taxes Schedule of Deferr

Income Taxes Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deferred Tax Assets and Liabilities [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards	$ 1,987	$ 1,941
Deferred Tax Assets, Tax Loss Carryforward	936	950
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities	546	311
Deferred Tax Assets, State and local taxes	162	194
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Unearned Premiums Reserve	141	141
Deferred Tax Assets, Hedging Transactions	123	99
Deferred Tax Assets, Other	208	212
Deferred Tax Assets, Gross	4,103	3,848
Deferred Tax Assets, Valuation Allowance	(646)	(582)
Deferred Tax Assets, Net of Valuation Allowance	3,457	3,266
Deferred Tax Liabilities, Leasing Arrangements	1,789	1,273
Deferred tax liabilities, deferred expense, deferred acquisition cost	424	403
Deferred Tax Liabilities, Financing Arrangements	161	162
Deferred Tax Liabilities, Other	107	69
Deferred Tax Liabilities, Gross	2,481	1,907
Deferred Tax Assets, Net, Inclusive of Deferred Tax Liabilities	976	1,359
Other Assets	6,854	6,321
Accounts Payable and Accrued Liabilities	1,737	1,545
Deferred Tax Asset [Member]
Deferred Tax Assets and Liabilities [Line Items]
Other Assets	994	1,369
Deferred Tax Liability [Member]
Deferred Tax Assets and Liabilities [Line Items]
Accounts Payable and Accrued Liabilities	$ 18	$ 10

Income Taxes Income Taxes (S134

Income Taxes Income Taxes (Schedule of Deferred tax assets and related valuation allowances recognized for net operating and other loss carryforwards and tax carryforwards) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards	$ 1,987	$ 1,941
Tax Credit Carryforward, Valuation Allowance	(485)
Net Deferred Tax Assets, Tax Credit Carryforwards	1,502
Deferred Tax Assets, State and Local Tax Carryforwards	1,138
State and Local Tax Carryforwards, Valuation Allowance	(128)
Net Deferred Tax Assets, State and Local Tax Carryforwards	1,010
Deferred Tax Assets, Other Non-Attribute	978
Other Non-Attribute, Valuation Allowance	(33)
Net Deferred Tax Assets, Other Non-Attribute	945
Deferred Tax Assets, Gross	4,103	3,848
Deferred Tax Assets, Gross, Valuation Allowance	(646)
Deferred Tax Assets, Net of Valuation Allowance	3,457	3,266
Deferred Tax Liabilities, Gross	2,481	1,907
Deferred Tax Liabilities, Gross, Valuation Allowance	0
Deferred Tax Liabilities, Net	(2,481)
Deferred Tax Assets, Gross, Net of Deferred Tax Liabilities	1,622
Deferred Tax Assets, Valuation Allowance	(646)	$ (582)
Deferred Tax Assets, Net	976
Foreign Tax Credits [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards	1,771
Tax Credit Carryforward, Valuation Allowance	(485)
Net Deferred Tax Assets, Tax Credit Carryforwards	1,286
General Business Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards	191
Tax Credit Carryforward, Valuation Allowance	0
Net Deferred Tax Assets, Tax Credit Carryforwards	191
AMT credits [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards	25
Tax Credit Carryforward, Valuation Allowance	0
Net Deferred Tax Assets, Tax Credit Carryforwards	25
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	900
Operating Loss Carryforwards, Valuation Allowance	0
Net Deferred Tax Assets, Operating Loss Carryforwards	900
Deferred Tax Assets, Capital Loss Carryforwards	36
Capital Loss Carryforwards, Valuation Allowance	(36)
Net Deferred Tax Assets, Capital Loss Carryforwards	0
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	193
Operating Loss Carryforwards, Valuation Allowance	(83)
Net Deferred Tax Assets, Operating Loss Carryforwards	110
Deferred Tax Assets, Capital Loss Carryforwards	9
Capital Loss Carryforwards, Valuation Allowance	(9)
Net Deferred Tax Assets, Capital Loss Carryforwards	$ 0

Income Taxes Income Tax (Schedu

Income Taxes Income Tax (Schedule of Unrecognized Tax Benefits Roll Forward) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	$ 14	$ 185	$ 191	$ 262
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions	0	0	0
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions	12	7	9
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	(182)	(10)	(79)
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	$ (1)	$ (3)	$ (1)

Income Taxes Income Tax (Narrat

Income Taxes Income Tax (Narrative - Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 177	$ 182	$ 9
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	2	5	1
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	$ 1	$ 1
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit			$ 3

Share-based Compensation Pla137

Share-based Compensation Plans Share-based Compensation Plans (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Apr. 10, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Price	$ 19.02			$ 23.98
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	32,921,120
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	7,307,246	6,476,427
Share-based Compensation	$ 54	$ 49	$ 46
Deferred Stock Unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	356,979	1,395,105
Share-based Compensation	$ 1	$ 3	42
Incentive Restricted Stock Unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized		51,103
Share-based Compensation	$ 0	$ 1	$ (2)
Shares Awarded 2014 [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	253,461	1,691,509
Shares Awarded 2015 [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	3,687,361	4,530,768
Shares Awarded 2016 [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	3,366,424
Shares Awarded 2013 [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized		254,150

Fair Value (Fair Value Measurme

Fair Value (Fair Value Measurment - Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 18,926	$ 17,157
Derivative Assets	74	88
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	(70)	$ (65)
Available-for-sale, Equity Investment in Any One Industry Did Not Exceed Percentage		14.00%
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	18,926	$ 17,157
Retained Interest, Fair Value Disclosure	29	40
Derivative Assets	95	233
Assets, Fair Value Disclosure	19,050	17,430
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	(95)	(145)
Liabilities, Fair Value Disclosure	(95)	(145)
Fair Value, Measurements, Recurring [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	(94)	(135)
Fair Value, Measurements, Recurring [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure		(1)
Fair Value, Measurements, Recurring [Member] | Other Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	(1)	(9)
Fair Value, Measurements, Recurring [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	18,331	16,440
Fair Value, Measurements, Recurring [Member] | US Treasury and Government [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,620	1,741
Fair Value, Measurements, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	782	716
Fair Value, Measurements, Recurring [Member] | Foreign Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	162	177
Fair Value, Measurements, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	10,290	7,544
Fair Value, Measurements, Recurring [Member] | Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,097	2,822
Fair Value, Measurements, Recurring [Member] | Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	537	481
Fair Value, Measurements, Recurring [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,400	1,755
Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,443	1,204
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	595	717
Fair Value, Measurements, Recurring [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	92	231
Fair Value, Measurements, Recurring [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	2
Fair Value, Measurements, Recurring [Member] | Other Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	1	2
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,226	2,196
Retained Interest, Fair Value Disclosure	0	0
Derivative Assets	1	4
Assets, Fair Value Disclosure	2,227	2,200
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	(1)	(3)
Liabilities, Fair Value Disclosure	(1)	(3)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	0	(2)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	(1)	(1)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,631	1,479
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US Treasury and Government [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,620	1,469
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Foreign Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	11	10
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	595	717
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	0	2
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	1	2
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	16,700	14,961
Retained Interest, Fair Value Disclosure	0	0
Derivative Assets	94	229
Assets, Fair Value Disclosure	16,794	15,190
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	(94)	(142)
Liabilities, Fair Value Disclosure	(94)	(142)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	(94)	(133)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure		(1)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	0	(8)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	16,700	14,961
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US Treasury and Government [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	272
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	782	716
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	151	167
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	10,290	7,544
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,097	2,822
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	537	481
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,400	1,755
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,443	1,204
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	92	229
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	2
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Retained Interest, Fair Value Disclosure	29	40
Derivative Assets	0	0
Assets, Fair Value Disclosure	29	40
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US Treasury and Government [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Foreign Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	$ 0	$ 0

Fair Value (Fair Value Measurem

Fair Value (Fair Value Measurement - Reconciliation of Level 3 Assets And Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Assets, Beginning balance	$ 40	$ 50
Net realized/unrealized gains (losses) included in earnings, Assets	4	10
Net realized/unrealized gains (losses) included in other comprehensive income, Assets	0	0
Purchases, Assets	0	0
Sales, Assets	9	(4)
Issuances, Assets	0	26
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(24)	(42)
Fair Value, Assets, Ending balance	29	40
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0
Retained Interest [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Assets, Beginning balance	40	47
Net realized/unrealized gains (losses) included in earnings, Assets	4	9
Net realized/unrealized gains (losses) included in other comprehensive income, Assets	0	0
Purchases, Assets	0	0
Sales, Assets	9	0
Issuances, Assets	0	26
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(24)	(42)
Fair Value, Assets, Ending balance	29	40
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0
Mortgage Loans Held-for-Sale, Net [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Assets, Beginning balance	$ 0	3
Net realized/unrealized gains (losses) included in earnings, Assets		1
Net realized/unrealized gains (losses) included in other comprehensive income, Assets		0
Purchases, Assets		0
Sales, Assets		(4)
Issuances, Assets		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		0
Fair Value, Assets, Ending balance		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		$ 0

Fair Value (Fair Value Measu140

Fair Value (Fair Value Measurement - Nonrecurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group	$ 0	$ 105
Fair Value, Measurements, Nonrecurring [Member] | Loans held-for-sale, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		105
Lower of cost or fair value or valuation reserve allowance		0
Fair Value, Measurements, Nonrecurring [Member] | Commercial Finance Receivables And Loans, Automotive [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial Finance Receivables and Loans, Net, Fair Value	27	19
Lower of cost or fair value or valuation reserve allowance	(4)	(2)
Fair Value, Measurements, Nonrecurring [Member] | Commercial Finance Receivables And Loans, Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial Finance Receivables and Loans, Net, Fair Value	65	29
Lower of cost or fair value or valuation reserve allowance	(19)	(15)
Fair Value, Measurements, Nonrecurring [Member] | Commercial Finance Receivables And Loans, Commercial Real Estate Automotive [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial Finance Receivables and Loans, Net, Fair Value		4
Lower of cost or fair value or valuation reserve allowance		(3)
Fair Value, Measurements, Nonrecurring [Member] | Commercial Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial Finance Receivables and Loans, Net, Fair Value	92	52
Lower of cost or fair value or valuation reserve allowance	(23)	(20)
Fair Value, Measurements, Nonrecurring [Member] | Repossessed And Foreclosed Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	12	9
Lower of cost or fair value or valuation reserve allowance	(4)	(3)
Fair Value, Measurements, Nonrecurring [Member] | Other Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	4	6
Lower of cost or fair value or valuation reserve allowance	0	(2)
Fair Value, Measurements, Nonrecurring [Member] | Assets, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	108	172
Lower of cost or fair value or valuation reserve allowance	(27)	(25)
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member] | Loans held-for-sale, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial Finance Receivables And Loans, Automotive [Member]
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 [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial Finance Receivables And Loans, Other [Member]
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 [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial Finance Receivables And Loans, Commercial Real Estate Automotive [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial Finance Receivables and Loans, Net, Fair Value		0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial Loan [Member]
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 [Member] | Fair Value, Inputs, Level 1 [Member] | Repossessed And Foreclosed Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	0	0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	0	0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member] | Assets, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	0	0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member] | Loans held-for-sale, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial Finance Receivables And Loans, Automotive [Member]
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 [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial Finance Receivables And Loans, Other [Member]
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 [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial Finance Receivables And Loans, Commercial Real Estate Automotive [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial Finance Receivables and Loans, Net, Fair Value		0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial Loan [Member]
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 [Member] | Fair Value, Inputs, Level 2 [Member] | Repossessed And Foreclosed Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	0	0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	0	0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member] | Assets, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	0	0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Loans held-for-sale, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		105
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial Finance Receivables And Loans, Automotive [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial Finance Receivables and Loans, Net, Fair Value	27	19
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial Finance Receivables And Loans, Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial Finance Receivables and Loans, Net, Fair Value	65	29
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial Finance Receivables And Loans, Commercial Real Estate Automotive [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial Finance Receivables and Loans, Net, Fair Value		4
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial Finance Receivables and Loans, Net, Fair Value	92	52
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Repossessed And Foreclosed Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	12	9
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	4	6
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Assets, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	$ 108	$ 172

Fair Value Fair Value (Fair Val

Fair Value Fair Value (Fair Value Measurements - Nonrecurring Fair Value Inputs) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group	$ 0	$ 105

Fair Value (Fair Value of Finan

Fair Value (Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	$ 839	$ 0
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group	0	105
Loans and Leases Receivable, Net Amount	117,800	110,546
Nonmarketable equity investments	1,046	418
Deposits	79,022	66,478
Short-term Debt	12,673	8,101
Long-term Debt	54,128	66,234
Portion at Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	789
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		105
Loans and Leases Receivable, Net Amount	118,750	110,737
Nonmarketable equity investments	1,067	433
Deposits	78,469	66,889
Short-term Debt	12,675	8,102
Long-term Debt	56,120	68,175
Portion at Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	0
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		0
Loans and Leases Receivable, Net Amount	0	0
Nonmarketable equity investments	0	0
Deposits	0	0
Short-term Debt	0	0
Long-term Debt	0	0
Portion at Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	789
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		0
Loans and Leases Receivable, Net Amount	0	0
Nonmarketable equity investments	1,012	391
Deposits	0	0
Short-term Debt	0	0
Long-term Debt	22,036	23,018
Portion at Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	0
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		105
Loans and Leases Receivable, Net Amount	118,750	110,737
Nonmarketable equity investments	55	42
Deposits	78,469	66,889
Short-term Debt	12,675	8,102
Long-term Debt	34,084	45,157
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	839
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		105
Loans and Leases Receivable, Net Amount	117,800	110,546
Nonmarketable equity investments	1,046	418
Deposits	79,022	66,478
Short-term Debt	12,673	8,101
Long-term Debt	$ 54,128	$ 66,234

Offsetting Assets and Liabil143

Offsetting Assets and Liabilities Offsetting Assets and Liabilities (Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Offsetting Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 95	$ 233
Gross Amounts Offset in the Condensed Consolidated Balance Sheet	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	95	233
Derivative Asset, Not Subject to Master Netting Arrangement	(12)	(78)
Derivative, Collateral, Obligation to Return Cash	(9)	(67)
Derivative Asset	74	88
Customer Securities for which Entity has Right to Sell or Repledge, Fair Value	6	7
Derivative assets in net liability positions [Member]
Offsetting Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset	8	9
Gross Amounts Offset in the Condensed Consolidated Balance Sheet	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	8	9
Derivative Asset, Not Subject to Master Netting Arrangement	(8)	(9)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset	0	0
Derivative assets in net asset position [Member]
Offsetting Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset	87	224
Gross Amounts Offset in the Condensed Consolidated Balance Sheet	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	87	224
Derivative Asset, Not Subject to Master Netting Arrangement	(4)	(69)
Derivative, Collateral, Obligation to Return Cash	(9)	(67)
Derivative Asset	$ 74	$ 88

Offsetting Assets and Liabil144

Offsetting Assets and Liabilities Offsetting Assets and Liabilities (Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability	$ (95)	$ (145)
Gross Amounts Offset in the Condensed Consolidated Balance Sheet	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	(95)	(145)
Derivative Liability, Not Subject to Master Netting Arrangement Deduction	12	78
Derivative, Collateral, Right to Reclaim Cash	13	2
Derivative Liability	(70)	(65)
Customer Securities for which Entity has Right to Sell or Repledge, Fair Value	6	7
Derivative Liabilities in Net Liability Positions [Member]
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability	(91)	(68)
Gross Amounts Offset in the Condensed Consolidated Balance Sheet	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	(91)	(68)
Derivative Liability, Not Subject to Master Netting Arrangement Deduction	8	9
Derivative, Collateral, Right to Reclaim Cash	13	2
Derivative Liability	(70)	(57)
Derivative liabilities in net asset positions [Member]
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability	(4)	(69)
Gross Amounts Offset in the Condensed Consolidated Balance Sheet	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	(4)	(69)
Derivative Liability, Not Subject to Master Netting Arrangement Deduction	4	69
Derivative, Collateral, Right to Reclaim Cash	0	0
Derivative Liability	0	0
Derivative liabilities with no offsetting arrangements [Member]
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability		(8)
Gross Amounts Offset in the Condensed Consolidated Balance Sheet		0
Derivative Liability, Fair Value, Amount Offset Against Collateral		(8)
Derivative Liability, Not Subject to Master Netting Arrangement Deduction		0
Derivative, Collateral, Right to Reclaim Cash		0
Derivative Liability		(8)
Securities sold under agreement to repurchase [Member]
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability	(676)	(648)
Gross Amounts Offset in the Condensed Consolidated Balance Sheet	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	(676)	(648)
Derivative Liability, Not Subject to Master Netting Arrangement Deduction	0	0
Derivative, Collateral, Right to Reclaim Cash	676	648
Derivative Liability	0	0
Total Derivative Liabilities [Member]
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability	(771)	(793)
Gross Amounts Offset in the Condensed Consolidated Balance Sheet	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	(771)	(793)
Derivative Liability, Not Subject to Master Netting Arrangement Deduction	12	78
Derivative, Collateral, Right to Reclaim Cash	689	650
Derivative Liability	$ (70)	$ (65)

Segment and Geographic Infor145

Segment and Geographic Information (Financial Information Operating Segments) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Net Financing Revenue	$ 976	$ 996	$ 984	$ 951	$ 983	$ 970	$ 916	$ 850	$ 3,907	$ 3,719	$ 3,375
Nonoperating Income (Expense)	392	388	374	376	356	332	211	243	1,530	1,142	1,276
Revenues									5,437	4,861	4,651
Provision for Loan Losses Expensed	267	258	172	220	240	211	140	116	917	707	457
Noninterest Expense	721	735	773	710	668	674	724	695	2,939	2,761	2,948
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	380	$ 391	$ 413	$ 397	431	$ 417	$ 263	$ 282	1,581	1,393	1,246
Assets	163,728				158,581				163,728	158,581	151,631
Net Interest Income (Loss) after Provision for Loan Losses										3,012	2,918
Automotive Finance Operations [Member]
Segment Reporting Information [Line Items]
Net Financing Revenue									3,665	3,429	3,321
Nonoperating Income (Expense)									306	235	264
Revenues									3,971	3,664	3,585
Provision for Loan Losses Expensed									924	696	542
Noninterest Expense									1,667	1,633	1,614
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									1,380	1,335	1,429
Assets	116,347				115,636				116,347	115,636	113,188
Insurance Operations Member
Segment Reporting Information [Line Items]
Net Financing Revenue									61	57	56
Nonoperating Income (Expense)									1,036	1,033	1,129
Revenues									1,097	1,090	1,185
Provision for Loan Losses Expensed									0	0	0
Noninterest Expense									940	879	988
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									157	211	197
Assets	7,172				7,053				7,172	7,053	7,190
Mortgage Finance Operations [Member]
Segment Reporting Information [Line Items]
Net Financing Revenue									97	57	36
Nonoperating Income (Expense)									0	0	0
Revenues									97	57	36
Provision for Loan Losses Expensed									(4)	7	3
Noninterest Expense									67	39	21
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									34	11	12
Assets	8,307				6,461				8,307	6,461	3,542
Corporate Finance Operations [Member]
Segment Reporting Information [Line Items]
Net Financing Revenue									121	89	59
Nonoperating Income (Expense)									26	25	32
Revenues									147	114	91
Provision for Loan Losses Expensed									10	9	(16)
Noninterest Expense									66	55	43
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									71	50	64
Assets	3,183				2,677				3,183	2,677	1,870
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Net Financing Revenue									(37)	87	(97)
Nonoperating Income (Expense)									162	(151)	(149)
Revenues									125	(64)	(246)
Provision for Loan Losses Expensed									(13)	(5)	(72)
Noninterest Expense									199	155	282
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									(61)	(214)	(456)
Assets	$ 28,719				$ 26,754				$ 28,719	$ 26,754	$ 25,841

Segment and Geographic Infor146

Segment and Geographic Information (Information Concerning Principal Geographic Areas) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									$ 5,437	$ 4,861	$ 4,651
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	$ 380	$ 391	$ 413	$ 397	$ 431	$ 417	$ 263	$ 282	1,581	1,393	1,246
Net Income (Loss) Attributable to Parent	248	$ 209	$ 360	$ 250	263	$ 268	$ 182	$ 576	1,067	1,289	1,150
Identifiable Assets	163,488				158,554				163,488	158,554	151,604
Long-Lived Assets	11,846				16,506				11,846	16,506	19,735
Foreign [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									90	99	126
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									44	51	54
Net Income (Loss) Attributable to Parent									30	512	186
Identifiable Assets	800				869				800	869	2,891
Long-Lived Assets	0				0				0	0	0
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									90	98	124
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									44	47	54
Net Income (Loss) Attributable to Parent									32	35	68
Identifiable Assets	499				514				499	514	590
Long-Lived Assets	0				0				0	0	0
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									0	1	2
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									0	4	0
Net Income (Loss) Attributable to Parent									(1)	27	4
Identifiable Assets	276				325				276	325	1,636
Long-Lived Assets	0				0				0	0	0
Latin America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									0	0	0
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									0	0	0
Net Income (Loss) Attributable to Parent									(1)	(2)	(8)
Identifiable Assets	23				28				23	28	29
Long-Lived Assets	0				0				0	0	0
Asia-Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									0	0	0
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									0	0	0
Net Income (Loss) Attributable to Parent									0	452	122
Identifiable Assets	2				2				2	2	636
Long-Lived Assets	0				0				0	0	0
Domestic [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									5,347	4,762	4,525
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									1,537	1,342	1,192
Net Income (Loss) Attributable to Parent									1,037	777	964
Identifiable Assets	162,688				157,685				162,688	157,685	148,713
Long-Lived Assets	$ 11,846				$ 16,506				$ 11,846	$ 16,506	$ 19,735

Parent and Guarantor Consoli147

Parent and Guarantor Consolidating Financial Statements (Schedule of Condensed Consolidating Statement of Income) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Income Statements, Captions [Line Items]
Interest and Fee Income, Loans and Leases									$ 5,162	$ 4,570	$ 4,457
Interest and Fee Income, Loans and Leases Held-for-sale									0	40	1
Interest and Dividend Income, Securities, Operating, Available-for-sale									418	381	367
Interest Income, Deposits with Financial Institutions									14	8	8
Operating Leases, Income Statement, Lease Revenue									2,711	3,398	3,558
Total financing revenue and other interest income									8,305	8,397	8,391
Interest Expense, Deposits									830	718	664
Interest Expense, Short-term Borrowings									57	49	52
Interest Expense, Long-term Debt									1,742	1,662	2,067
Interest Expense, Related Party									0	0	0
Interest Expense									2,629	2,429	2,783
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease									1,769	2,249	2,233
Net Financing Revenue	$ 976	$ 996	$ 984	$ 951	$ 983	$ 970	$ 916	$ 850	3,907	3,719	3,375
Dividends from Bank Subsidiary										0	0
Dividends From Non Bank Subsidiary									0	0	0
Insurance Services Revenue									945	940	979
Gain (Loss) on Sales of Loans, Net									11	45	7
Gain (Loss) on Extinguishment of Debt									(5)	(357)	(202)
Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments									185	155	181
Noninterest Income, Other Operating Income									394	359	311
Nonoperating Income (Expense)	392	388	374	376	356	332	211	243	1,530	1,142	1,276
Revenues									5,437	4,861	4,651
Provision for Loan Losses Expensed	267	258	172	220	240	211	140	116	917	707	457
Labor and Related Expense									992	963	947
Policyholder Benefits and Claims Incurred, Net									342	293	410
Other Noninterest Expense									1,605	1,505	1,591
Noninterest Expense	721	735	773	710	668	674	724	695	2,939	2,761	2,948
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	380	391	413	397	431	417	263	282	1,581	1,393	1,246
Income Tax Expense (Benefit)	134	130	56	150	155	144	94	103	470	496	321
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	246	261	357	247	276	273	169	179	1,111	897	925
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	2	(52)	3	3	(13)	(5)	13	397	(44)	392	225
Undistributed income of bank subsidiaries									0	0	0
Undistributed income of nonbank subsidiaries									0	0	0
Net Income (Loss) Attributable to Parent	$ 248	$ 209	$ 360	$ 250	$ 263	$ 268	$ 182	$ 576	1,067	1,289	1,150
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									(110)	(165)	210
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									957	1,124	1,360
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Interest and Fee Income, Loans and Leases									(104)	(83)	(14)
Interest and Fee Income, Loans and Leases Held-for-sale										0	0
Interest and Dividend Income, Securities, Operating, Available-for-sale									0	0	0
Interest Income, Deposits with Financial Institutions									5	1	1
Operating Leases, Income Statement, Lease Revenue									17	9	269
Total financing revenue and other interest income									(71)	(56)	293
Interest Expense, Deposits									8	10	15
Interest Expense, Short-term Borrowings									40	40	43
Interest Expense, Long-term Debt									1,161	1,121	1,492
Interest Expense, Related Party									20	32	88
Interest Expense									1,229	1,203	1,638
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease									14	7	161
Net Financing Revenue									(1,314)	(1,266)	(1,506)
Dividends from Bank Subsidiary										525	1,800
Dividends From Non Bank Subsidiary									965	1,123	651
Insurance Services Revenue									0	0	0
Gain (Loss) on Sales of Loans, Net									(11)	(9)	(5)
Gain (Loss) on Extinguishment of Debt									(3)	(355)	(202)
Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments									0	0	0
Noninterest Income, Other Operating Income									1,253	1,373	1,279
Nonoperating Income (Expense)									1,239	1,009	1,072
Revenues									890	1,391	2,017
Provision for Loan Losses Expensed									408	157	250
Labor and Related Expense									573	571	586
Policyholder Benefits and Claims Incurred, Net									0	0	0
Other Noninterest Expense									1,261	1,247	1,267
Noninterest Expense									1,834	1,818	1,853
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									(1,352)	(584)	(86)
Income Tax Expense (Benefit)									(279)	(267)	(457)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent									(1,073)	(317)	371
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent									(39)	356	193
Undistributed income of bank subsidiaries									1,273	581	(680)
Undistributed income of nonbank subsidiaries									906	669	1,266
Net Income (Loss) Attributable to Parent									1,067	1,289	1,150
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									(110)	(165)	210
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									957	1,124	1,360
Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Interest and Fee Income, Loans and Leases									0	0	0
Interest and Fee Income, Loans and Leases Held-for-sale										0	0
Interest and Dividend Income, Securities, Operating, Available-for-sale									0	0	0
Interest Income, Deposits with Financial Institutions									0	0	0
Operating Leases, Income Statement, Lease Revenue									0	0	0
Total financing revenue and other interest income									0	0	0
Interest Expense, Deposits									0	0	0
Interest Expense, Short-term Borrowings									0	0	0
Interest Expense, Long-term Debt									0	0	0
Interest Expense, Related Party									0	0	0
Interest Expense									0	0	0
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease									0	0	0
Net Financing Revenue									0	0	0
Dividends from Bank Subsidiary										525	1,800
Dividends From Non Bank Subsidiary									0	0	0
Insurance Services Revenue									0	0	0
Gain (Loss) on Sales of Loans, Net									0	0	0
Gain (Loss) on Extinguishment of Debt									0	0	0
Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments									0	0	0
Noninterest Income, Other Operating Income									0	0	0
Nonoperating Income (Expense)									0	0	0
Revenues									0	525	1,800
Provision for Loan Losses Expensed									0	0	0
Labor and Related Expense									0	0	0
Policyholder Benefits and Claims Incurred, Net									0	0	0
Other Noninterest Expense									0	0	0
Noninterest Expense									0	0	0
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									0	525	1,800
Income Tax Expense (Benefit)									(82)	0	0
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent									82	525	1,800
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent									0	0	0
Undistributed income of bank subsidiaries									1,273	581	(680)
Undistributed income of nonbank subsidiaries									(2)	(1)	(1)
Net Income (Loss) Attributable to Parent									1,353	1,105	1,119
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									(63)	(43)	188
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									1,290	1,062	1,307
Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Interest and Fee Income, Loans and Leases									5,266	4,653	4,471
Interest and Fee Income, Loans and Leases Held-for-sale										40	1
Interest and Dividend Income, Securities, Operating, Available-for-sale									421	381	367
Interest Income, Deposits with Financial Institutions									9	7	7
Operating Leases, Income Statement, Lease Revenue									2,694	3,389	3,289
Total financing revenue and other interest income									8,407	8,502	8,223
Interest Expense, Deposits									822	708	649
Interest Expense, Short-term Borrowings									17	9	9
Interest Expense, Long-term Debt									581	541	575
Interest Expense, Related Party									11	17	37
Interest Expense									1,431	1,275	1,270
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease									1,755	2,242	2,072
Net Financing Revenue									5,221	4,985	4,881
Dividends from Bank Subsidiary										0	0
Dividends From Non Bank Subsidiary									0	0	0
Insurance Services Revenue									945	940	979
Gain (Loss) on Sales of Loans, Net									22	54	12
Gain (Loss) on Extinguishment of Debt									(2)	(2)	0
Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments									176	155	181
Noninterest Income, Other Operating Income									937	1,373	1,299
Nonoperating Income (Expense)									2,078	2,520	2,471
Revenues									7,299	7,505	7,352
Provision for Loan Losses Expensed									509	550	207
Labor and Related Expense									419	842	793
Policyholder Benefits and Claims Incurred, Net									342	293	410
Other Noninterest Expense									2,130	2,195	2,159
Noninterest Expense									2,891	3,330	3,362
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									3,899	3,625	3,783
Income Tax Expense (Benefit)									831	763	778
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent									3,068	2,862	3,005
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent									(5)	36	32
Undistributed income of bank subsidiaries									0	0	0
Undistributed income of nonbank subsidiaries									0	0	0
Net Income (Loss) Attributable to Parent									3,063	2,898	3,037
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									(106)	(172)	212
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									2,957	2,726	3,249
Affiliated Entity [Member]
Condensed Income Statements, Captions [Line Items]
Interest and Fee Income, Loans and Leases									0	0	0
Interest Income, Deposits with Financial Institutions									0	0	0
Affiliated Entity [Member] | Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Interest and Fee Income, Loans and Leases									11	17	37
Interest Income, Deposits with Financial Institutions									0	0	0
Affiliated Entity [Member] | Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Interest and Fee Income, Loans and Leases									0	0	0
Interest Income, Deposits with Financial Institutions									0	0	0
Affiliated Entity [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Interest and Fee Income, Loans and Leases									8	24	82
Interest Income, Deposits with Financial Institutions									9	8	6
Consolidation, Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Interest and Fee Income, Loans and Leases									0	0	0
Interest and Fee Income, Loans and Leases Held-for-sale										0	0
Interest and Dividend Income, Securities, Operating, Available-for-sale									(3)	0	0
Interest Income, Deposits with Financial Institutions									0	0	0
Operating Leases, Income Statement, Lease Revenue									0	0	0
Total financing revenue and other interest income									(31)	(49)	(125)
Interest Expense, Deposits									0	0	0
Interest Expense, Short-term Borrowings									0	0	0
Interest Expense, Long-term Debt									0	0	0
Interest Expense, Related Party									(31)	(49)	(125)
Interest Expense									(31)	(49)	(125)
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease									0	0	0
Net Financing Revenue									0	0	0
Dividends from Bank Subsidiary										(1,050)	(3,600)
Dividends From Non Bank Subsidiary									(965)	(1,123)	(651)
Insurance Services Revenue									0	0	0
Gain (Loss) on Sales of Loans, Net									0	0	0
Gain (Loss) on Extinguishment of Debt									0	0	0
Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments									9	0	0
Noninterest Income, Other Operating Income									(1,796)	(2,387)	(2,267)
Nonoperating Income (Expense)									(1,787)	(2,387)	(2,267)
Revenues									(2,752)	(4,560)	(6,518)
Provision for Loan Losses Expensed									0	0	0
Labor and Related Expense									0	(450)	(432)
Policyholder Benefits and Claims Incurred, Net									0	0	0
Other Noninterest Expense									(1,786)	(1,937)	(1,835)
Noninterest Expense									(1,786)	(2,387)	(2,267)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									(966)	(2,173)	(4,251)
Income Tax Expense (Benefit)									0	0	0
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent									(966)	(2,173)	(4,251)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent									0	0	0
Undistributed income of bank subsidiaries									(2,546)	(1,162)	1,360
Undistributed income of nonbank subsidiaries									(904)	(668)	(1,265)
Net Income (Loss) Attributable to Parent									(4,416)	(4,003)	(4,156)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									169	215	(400)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									(4,247)	(3,788)	(4,556)
Consolidation, Eliminations [Member] | Affiliated Entity [Member]
Condensed Income Statements, Captions [Line Items]
Interest and Fee Income, Loans and Leases									(19)	(41)	(119)
Interest Income, Deposits with Financial Institutions									$ (9)	$ (8)	$ (6)

Parent and Guarantor Consoli148

Parent and Guarantor Consolidating Financial Statements (Schedule of Condensed Consolidating Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and Due from Banks	$ 1,547	$ 2,148
Interest-bearing Deposits in Banks and Other Financial Institutions	4,387	4,232
Cash and Cash Equivalents, at Carrying Value	5,934	6,380	$ 5,576	$ 5,531
Trading Securities	0
Available-for-sale securities	18,926	17,157
Held-to-maturity securities	839	0
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group	0	105
Loans and Leases Receivable, Gross	118,944	111,600
Loans to bank subsidiary	0	0
Loans to nonbank subsidiary	0	0
Loans and Leases Receivable, Allowance	(1,144)	(1,054)	(977)
Loans and Leases Receivable, Net Amount	117,800	110,546
Property Subject to or Available for Operating Lease, Net	11,470	16,271
Receivables from bank subsidiary	0	0
Receivables from nonbank subsidiary	0	0
Investment in bank subsidiaries	0	0
Investment in nonbank subsidiaries	0	0
Premiums receivable and other insurance assets	1,905	1,801
Other Assets	6,854	6,321
Assets	163,728	158,581	151,631
Noninterest-bearing deposit liabilities	84	89
Interest-bearing Deposit Liabilities	78,938	66,389
Deposits	79,022	66,478
Short-term Debt	12,673	8,101
Long-term Debt	54,128	66,234
Debt Payable To Bank Subsidiaries	0
Debt Payable To Nonbank Subsidiaries	0	0
Payables to Bank Subsidiaries		0
Payables to Nonbank Subsidiaries	0	0
Interest payable	351	350
Unearned Premiums	2,500	2,434
Accounts Payable and Accrued Liabilities	1,737	1,545
Liabilities	150,411	145,142
Stockholders' Equity Attributable to Parent	13,317	13,439	15,399	14,208
Liabilities and Equity	163,728	158,581
Parent Company [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and Due from Banks	720	1,234
Interest-bearing Deposits in Banks and Other Financial Institutions	100	401
Cash and Cash Equivalents, at Carrying Value	820	1,635	2,286	2,930
Trading Securities	0
Available-for-sale securities	0	0
Held-to-maturity securities	0
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		0
Loans and Leases Receivable, Gross	4,705	2,636
Loans to bank subsidiary	1,125	600
Loans to nonbank subsidiary	1,779	3,277
Loans and Leases Receivable, Allowance	(115)	(72)
Loans and Leases Receivable, Net Amount	7,494	6,441
Property Subject to or Available for Operating Lease, Net	42	81
Receivables from bank subsidiary	299	186
Receivables from nonbank subsidiary	107	259
Investment in bank subsidiaries	17,727	16,496
Investment in nonbank subsidiaries	10,318	10,902
Premiums receivable and other insurance assets	0	0
Other Assets	4,347	4,785
Assets	41,154	40,785
Noninterest-bearing deposit liabilities	0	0
Interest-bearing Deposit Liabilities	167	229
Deposits	167	229
Short-term Debt	3,622	3,453
Long-term Debt	21,798	21,048
Debt Payable To Bank Subsidiaries	330
Debt Payable To Nonbank Subsidiaries	1,027	1,409
Payables to Bank Subsidiaries		142
Payables to Nonbank Subsidiaries	153	420
Interest payable	253	258
Unearned Premiums	0	0
Accounts Payable and Accrued Liabilities	487	387
Liabilities	27,837	27,346
Stockholders' Equity Attributable to Parent	13,317	13,439
Liabilities and Equity	41,154	40,785
Guarantor Subsidiaries [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and Due from Banks	0	0
Interest-bearing Deposits in Banks and Other Financial Institutions	0	0
Cash and Cash Equivalents, at Carrying Value	0	0	0	37
Trading Securities	0
Available-for-sale securities	0	0
Held-to-maturity securities	0
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		0
Loans and Leases Receivable, Gross	0	0
Loans to bank subsidiary	0	0
Loans to nonbank subsidiary	0	0
Loans and Leases Receivable, Allowance	0	0
Loans and Leases Receivable, Net Amount	0	0
Property Subject to or Available for Operating Lease, Net	0	0
Receivables from bank subsidiary	0	0
Receivables from nonbank subsidiary	0	0
Investment in bank subsidiaries	17,727	16,496
Investment in nonbank subsidiaries	0	11
Premiums receivable and other insurance assets	0	0
Other Assets	0	0
Assets	17,727	16,507
Noninterest-bearing deposit liabilities	0	0
Interest-bearing Deposit Liabilities	0	0
Deposits	0	0
Short-term Debt	0	0
Long-term Debt	0	0
Debt Payable To Bank Subsidiaries	0
Debt Payable To Nonbank Subsidiaries	0	0
Payables to Bank Subsidiaries		0
Payables to Nonbank Subsidiaries	0	0
Interest payable	0	0
Unearned Premiums	0	0
Accounts Payable and Accrued Liabilities	0	82
Liabilities	0	82
Stockholders' Equity Attributable to Parent	17,727	16,425
Liabilities and Equity	17,727	16,507
Non-Guarantor Subsidiaries [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and Due from Banks	827	914
Interest-bearing Deposits in Banks and Other Financial Institutions	4,287	3,831
Cash and Cash Equivalents, at Carrying Value	5,515	5,595	3,905	2,974
Trading Securities	82
Available-for-sale securities	19,253	17,157
Held-to-maturity securities	839
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		105
Loans and Leases Receivable, Gross	114,239	108,964
Loans to bank subsidiary	0	0
Loans to nonbank subsidiary	626	559
Loans and Leases Receivable, Allowance	(1,029)	(982)
Loans and Leases Receivable, Net Amount	113,836	108,541
Property Subject to or Available for Operating Lease, Net	11,428	16,190
Receivables from bank subsidiary	0	0
Receivables from nonbank subsidiary	67	282
Investment in bank subsidiaries	0	0
Investment in nonbank subsidiaries	0	0
Premiums receivable and other insurance assets	1,936	1,827
Other Assets	5,085	4,488
Assets	158,041	154,185
Noninterest-bearing deposit liabilities	84	89
Interest-bearing Deposit Liabilities	78,771	66,160
Deposits	78,855	66,249
Short-term Debt	9,051	4,648
Long-term Debt	32,330	45,186
Debt Payable To Bank Subsidiaries	0
Debt Payable To Nonbank Subsidiaries	2,903	3,877
Payables to Bank Subsidiaries		0
Payables to Nonbank Subsidiaries	351	191
Interest payable	98	92
Unearned Premiums	2,500	2,434
Accounts Payable and Accrued Liabilities	3,911	4,028
Liabilities	129,999	126,705
Stockholders' Equity Attributable to Parent	28,042	27,480
Liabilities and Equity	158,041	154,185
Affiliated Entity [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Interest-bearing Deposits in Banks and Other Financial Institutions	0	0
Affiliated Entity [Member] | Parent Company [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Interest-bearing Deposits in Banks and Other Financial Institutions	0	0
Affiliated Entity [Member] | Guarantor Subsidiaries [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Interest-bearing Deposits in Banks and Other Financial Institutions	0	0
Affiliated Entity [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Interest-bearing Deposits in Banks and Other Financial Institutions	401	850
Consolidation, Eliminations [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and Due from Banks	0	0
Interest-bearing Deposits in Banks and Other Financial Institutions	0	0
Cash and Cash Equivalents, at Carrying Value	(401)	(850)	$ (615)	$ (410)
Trading Securities	(82)
Available-for-sale securities	(327)	0
Held-to-maturity securities	0
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		0
Loans and Leases Receivable, Gross	0	0
Loans to bank subsidiary	(1,125)	(600)
Loans to nonbank subsidiary	(2,405)	(3,836)
Loans and Leases Receivable, Allowance	0	0
Loans and Leases Receivable, Net Amount	(3,530)	(4,436)
Property Subject to or Available for Operating Lease, Net	0	0
Receivables from bank subsidiary	(299)	(186)
Receivables from nonbank subsidiary	(174)	(541)
Investment in bank subsidiaries	(35,454)	(32,992)
Investment in nonbank subsidiaries	(10,318)	(10,913)
Premiums receivable and other insurance assets	(31)	(26)
Other Assets	(2,578)	(2,952)
Assets	(53,194)	(52,896)
Noninterest-bearing deposit liabilities	0	0
Interest-bearing Deposit Liabilities	0	0
Deposits	0	0
Short-term Debt	0	0
Long-term Debt	0	0
Debt Payable To Bank Subsidiaries	(330)
Debt Payable To Nonbank Subsidiaries	(3,930)	(5,286)
Payables to Bank Subsidiaries		(142)
Payables to Nonbank Subsidiaries	(504)	(611)
Interest payable	0	0
Unearned Premiums	0	0
Accounts Payable and Accrued Liabilities	(2,661)	(2,952)
Liabilities	(7,425)	(8,991)
Stockholders' Equity Attributable to Parent	(45,769)	(43,905)
Liabilities and Equity	(53,194)	(52,896)
Consolidation, Eliminations [Member] | Affiliated Entity [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Interest-bearing Deposits in Banks and Other Financial Institutions	$ (401)	$ (850)

Parent and Guarantor Consoli149

Parent and Guarantor Consolidating Financial Statements (Schedule of Condensed Consolidating Statement of Cash Flows) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 4,567	$ 5,111	$ 3,403
Payments to Acquire Available-for-sale Securities	(16,031)	(12,250)	(5,417)
Proceeds from sales of available-for-sale securities	11,036	6,874	4,260
Proceeds from maturities and repayment of available-for-sale securities	3,379	4,255	2,657
Payments to Acquire Held-to-maturity Securities	(841)	0	0
Payments to Acquire Loans Held-for-investment	3,859	4,501	877
Proceeds from Sale of Loans Held-for-sale	4,285	3,197	2,592
Originations and repayments of loans held-for-investment and other	(8,826)	(9,344)	(4,147)
Purchases of operating lease assets	(3,274)	(4,685)	(9,884)
Disposals of operating lease assets	6,304	5,546	5,860
Payments to Acquire Interest in Subsidiaries and Affiliates	(309)	0	0
Capital contributions to subsidiaries	0	0	0
Returns of contributed capital	0	0	0
Proceeds from Divestiture of Businesses	0	1,049	47
Increase (Decrease) in Restricted Cash	392	264	1,625
Increase (Decrease) in Non marketable equity securities	(628)	(147)	66
Payments for (Proceeds from) Other Investing Activities	(312)	(5)	6
Net cash provided by investing activities	(8,684)	(9,747)	(3,212)
Proceeds from (Repayments of) Short-term Debt	4,564	1,028	(1,494)
Increase (Decrease) in Deposits	12,508	8,247	4,851
Proceeds from issuance of long-term debt	14,155	30,665	27,192
Repayments of long-term debt	(26,412)	(31,350)	(30,426)
Net Change in Debt, Intercompany	0	0	0
Payments for Repurchase of Redeemable Preferred Stock	(696)	(559)	0
Payments for Repurchase of Common Stock	(341)	(16)	0
Payments of Dividends	(108)	(2,571)	(268)
Dividends paid and returns of contributed capital, Intercompany	0	0	0
Capital contributions from parent	0	0	0
Net cash (used in) provided by financing activities	3,670	5,444	(145)
Effect of exchange-rate changes on cash and cash equivalents	1	(4)	(1)
Cash and Cash Equivalents, Period Increase (Decrease)	(446)	804	45
Cash and Cash Equivalents, at Carrying Value	6,380	5,576	5,531
Cash and Cash Equivalents, at Carrying Value	5,934	6,380	5,576
Parent Company [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	241	370	330
Payments to Acquire Available-for-sale Securities	0	0	0
Proceeds from sales of available-for-sale securities	0	0	0
Proceeds from maturities and repayment of available-for-sale securities	0	0	0
Payments to Acquire Held-to-maturity Securities	0
Payments to Acquire Loans Held-for-investment	4	169	0
Proceeds from Sale of Loans Held-for-sale	0	0	0
Originations and repayments of loans held-for-investment and other	2,013	1,954	1,900
Purchases of operating lease assets	0	(94)	(2,337)
Disposals of operating lease assets	25	7	3,053
Payments to Acquire Interest in Subsidiaries and Affiliates	(309)
Capital contributions to subsidiaries	(3,908)	(796)	(1,179)
Returns of contributed capital	3,678	1,444	1,422
Proceeds from Divestiture of Businesses		1,049	46
Increase (Decrease) in Restricted Cash	(120)	(7)	0
Increase (Decrease) in Non marketable equity securities	0	0	0
Payments for (Proceeds from) Other Investing Activities	(206)	(47)	(29)
Net cash provided by investing activities	2,046	3,581	4,304
Proceeds from (Repayments of) Short-term Debt	169	115	113
Increase (Decrease) in Deposits	(61)	(91)	(121)
Proceeds from issuance of long-term debt	979	5,428	3,132
Repayments of long-term debt	(2,662)	(5,931)	(8,186)
Net Change in Debt, Intercompany	(382)	(977)	52
Payments for Repurchase of Redeemable Preferred Stock	(696)	(559)
Payments for Repurchase of Common Stock	(341)	(16)
Payments of Dividends	(108)	(2,571)	(268)
Dividends paid and returns of contributed capital, Intercompany	0	0	0
Capital contributions from parent	0	0	0
Net cash (used in) provided by financing activities	(3,102)	(4,602)	(5,278)
Effect of exchange-rate changes on cash and cash equivalents	0	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	(815)	(651)	(644)
Cash and Cash Equivalents, at Carrying Value	1,635	2,286	2,930
Cash and Cash Equivalents, at Carrying Value	820	1,635	2,286
Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	6	525	1,789
Payments to Acquire Available-for-sale Securities	0	0	0
Proceeds from sales of available-for-sale securities	0	0	0
Proceeds from maturities and repayment of available-for-sale securities	0	0	0
Payments to Acquire Held-to-maturity Securities	0
Payments to Acquire Loans Held-for-investment	0	0	0
Proceeds from Sale of Loans Held-for-sale	0	0	0
Originations and repayments of loans held-for-investment and other	0	0	0
Purchases of operating lease assets	0	0	0
Disposals of operating lease assets	0	0	0
Payments to Acquire Interest in Subsidiaries and Affiliates	0
Capital contributions to subsidiaries	0	(1)	0
Returns of contributed capital	8	0	0
Proceeds from Divestiture of Businesses		0	0
Increase (Decrease) in Restricted Cash	0	0	0
Increase (Decrease) in Non marketable equity securities	0	0	0
Payments for (Proceeds from) Other Investing Activities	0	0	0
Net cash provided by investing activities	8	(1)	0
Proceeds from (Repayments of) Short-term Debt	0	0	0
Increase (Decrease) in Deposits	0	0	0
Proceeds from issuance of long-term debt	0	0	0
Repayments of long-term debt	0	0	0
Net Change in Debt, Intercompany	0	0	0
Payments for Repurchase of Redeemable Preferred Stock	0	0
Payments for Repurchase of Common Stock	0	0
Payments of Dividends	0	0	0
Dividends paid and returns of contributed capital, Intercompany	(14)	(525)	(1,826)
Capital contributions from parent	0	1	0
Net cash (used in) provided by financing activities	(14)	(524)	(1,826)
Effect of exchange-rate changes on cash and cash equivalents	0	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	0	0	(37)
Cash and Cash Equivalents, at Carrying Value	0	0	37
Cash and Cash Equivalents, at Carrying Value	0	0	0
Non-Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	5,383	6,390	5,533
Payments to Acquire Available-for-sale Securities	(16,031)	(12,250)	(5,417)
Proceeds from sales of available-for-sale securities	11,036	6,874	4,277
Proceeds from maturities and repayment of available-for-sale securities	3,379	4,255	2,657
Payments to Acquire Held-to-maturity Securities	(841)
Payments to Acquire Loans Held-for-investment	3,855	4,332	894
Proceeds from Sale of Loans Held-for-sale	4,285	3,197	2,592
Originations and repayments of loans held-for-investment and other	(10,839)	(11,298)	(6,047)
Purchases of operating lease assets	(3,274)	(4,591)	(7,547)
Disposals of operating lease assets	6,279	5,539	2,807
Payments to Acquire Interest in Subsidiaries and Affiliates	0
Capital contributions to subsidiaries	0	0	0
Returns of contributed capital	0	0	0
Proceeds from Divestiture of Businesses		0	1
Increase (Decrease) in Restricted Cash	512	271	1,625
Increase (Decrease) in Non marketable equity securities	(628)	(147)	66
Payments for (Proceeds from) Other Investing Activities	(197)	42	35
Net cash provided by investing activities	(10,241)	(11,229)	(5,691)
Proceeds from (Repayments of) Short-term Debt	4,395	913	(1,607)
Increase (Decrease) in Deposits	12,569	8,338	4,972
Proceeds from issuance of long-term debt	13,176	25,237	24,060
Repayments of long-term debt	(23,750)	(25,419)	(22,240)
Net Change in Debt, Intercompany	(877)	(240)	(1,428)
Payments for Repurchase of Redeemable Preferred Stock	0	0
Payments for Repurchase of Common Stock	0	0
Payments of Dividends	0	0	0
Dividends paid and returns of contributed capital, Intercompany	(4,644)	(3,092)	(3,846)
Capital contributions from parent	3,908	796	1,179
Net cash (used in) provided by financing activities	4,777	6,533	1,090
Effect of exchange-rate changes on cash and cash equivalents	1	(4)	(1)
Cash and Cash Equivalents, Period Increase (Decrease)	(80)	1,690	931
Cash and Cash Equivalents, at Carrying Value	5,595	3,905	2,974
Cash and Cash Equivalents, at Carrying Value	5,515	5,595	3,905
Affiliated Entity [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Payments for (Proceeds from) Loans and Leases	0	0	0
Affiliated Entity [Member] | Parent Company [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Payments for (Proceeds from) Loans and Leases	877	240	1,428
Affiliated Entity [Member] | Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Payments for (Proceeds from) Loans and Leases	0	0	0
Affiliated Entity [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Payments for (Proceeds from) Loans and Leases	(67)	1,211	154
Consolidation, Eliminations [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(1,063)	(2,174)	(4,249)
Payments to Acquire Available-for-sale Securities	0	0	0
Proceeds from sales of available-for-sale securities	0	0	(17)
Proceeds from maturities and repayment of available-for-sale securities	0	0	0
Payments to Acquire Held-to-maturity Securities	0
Payments to Acquire Loans Held-for-investment	0	0	(17)
Proceeds from Sale of Loans Held-for-sale	0	0	0
Originations and repayments of loans held-for-investment and other	0	0	0
Purchases of operating lease assets	0	0	0
Disposals of operating lease assets	0	0	0
Payments to Acquire Interest in Subsidiaries and Affiliates	0
Capital contributions to subsidiaries	3,908	797	1,179
Returns of contributed capital	(3,686)	(1,444)	(1,422)
Proceeds from Divestiture of Businesses		0	0
Increase (Decrease) in Restricted Cash	0	0	0
Increase (Decrease) in Non marketable equity securities	0	0	0
Payments for (Proceeds from) Other Investing Activities	91	0	0
Net cash provided by investing activities	(497)	(2,098)	(1,825)
Proceeds from (Repayments of) Short-term Debt	0	0	0
Increase (Decrease) in Deposits	0	0	0
Proceeds from issuance of long-term debt	0	0	0
Repayments of long-term debt	0	0	0
Net Change in Debt, Intercompany	1,259	1,217	1,376
Payments for Repurchase of Redeemable Preferred Stock	0	0
Payments for Repurchase of Common Stock	0	0
Payments of Dividends	0	0	0
Dividends paid and returns of contributed capital, Intercompany	4,658	3,617	5,672
Capital contributions from parent	(3,908)	(797)	(1,179)
Net cash (used in) provided by financing activities	2,009	4,037	5,869
Effect of exchange-rate changes on cash and cash equivalents	0	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	449	(235)	(205)
Cash and Cash Equivalents, at Carrying Value	(850)	(615)	(410)
Cash and Cash Equivalents, at Carrying Value	(401)	(850)	(615)
Consolidation, Eliminations [Member] | Affiliated Entity [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Payments for (Proceeds from) Loans and Leases	$ (810)	$ (1,451)	$ (1,582)

Contingencies and Other Risks (

Contingencies and Other Risks (Details) - USD ($) $ in Millions	12 Months Ended	48 Months Ended
	Dec. 31, 2016	Dec. 31, 2016
Loss Contingency [Abstract]
Consent Order Fees and Expenses		$ 240
Litigation Settlement, Amount	$ 52

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions	Jan. 27, 2017	Jan. 11, 2017	Dec. 31, 2016	Oct. 18, 2016	Jul. 18, 2016	Dec. 31, 2015
Subsequent Event [Line Items]
Dividends Payable, Amount Per Share			$ 0.08	$ 0.08	$ 0.08
Short-term Debt			$ 12,673			$ 8,101
Unsecured Debt [Member]
Subsequent Event [Line Items]
Short-term Debt			$ 3,622			$ 3,453
Subsequent Event [Member]
Subsequent Event [Line Items]
Dividends Payable, Amount Per Share		$ 0.08
Subsequent Event [Member] | Unsecured Debt [Member] | Committed Funding Facilities Member
Subsequent Event [Line Items]
Short-term Debt	$ 1,300

Guarantees and Commitments G152

Guarantees and Commitments Guarantees and Commitments (Guarantees to third parties) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Guarantor Obligations [Line Items]
Standby letters of credit and other guarantees	$ 8	$ 13
Maximum [Member]
Guarantor Obligations [Line Items]
Standby letters of credit and other guarantees	$ 175	$ 208

Guarantees and Commitments G153

Guarantees and Commitments Guarantees and Commitments (Contractual financing commitments) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Guarantees [Abstract]
Commitment to provide capital to investees	$ 206	$ 132
Warehouse and construction lending commitments	164	197
Commitment to fund remaining unused balances on home equity lines of credit	356	358
Unused revolving credit line commitments and other	$ 1,995	$ 1,445

Guarantees and Commitments G154

Guarantees and Commitments Guarantees and Commitments (Schedule of Lease Commitments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Guarantees [Abstract]
Operating Leases, Rent Expense	$ 51	$ 51	$ 50
Operating Leases, Future Minimum Payments Due, Next Twelve Months	36
Operating Leases, Future Minimum Payments, Due in Two Years	36
Operating Leases, Future Minimum Payments, Due in Three Years	35
Operating Leases, Future Minimum Payments, Due in Four Years	33
Operating Leases, Future Minimum Payments, Due in Five Years	25
Operating Leases, Future Minimum Payments, Due Thereafter	75
Operating Leases, Rent Expense	$ 240

Guarantees and Commitments G155

Guarantees and Commitments Guarantees and Commitments (Other Purchase Commitments) (Details) $ in Millions	Dec. 31, 2016USD ($)
Guarantees [Abstract]
Other Commitment, Due in Next Twelve Months	$ 94
Other Commitment, Due in Second and Third Year	13
Other Commitment, Due in Fourth Year	4
Other Commitment	$ 111

Quarterly Financial Statemen156

Quarterly Financial Statements (unaudited) Quarterly Financial Statements (unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Statements (unaudited) [Abstract]
Net Financing Revenue	$ 976	$ 996	$ 984	$ 951	$ 983	$ 970	$ 916	$ 850	$ 3,907	$ 3,719	$ 3,375
Nonoperating Income (Expense)	392	388	374	376	356	332	211	243	1,530	1,142	1,276
Revenue, Net	1,368	1,384	1,358	1,327	1,339	1,302	1,127	1,093
Provision for Loan Losses Expensed	267	258	172	220	240	211	140	116	917	707	457
Noninterest Expense	721	735	773	710	668	674	724	695	2,939	2,761	2,948
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	380	391	413	397	431	417	263	282	1,581	1,393	1,246
Income Tax Expense (Benefit)	134	130	56	150	155	144	94	103	470	496	321
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	246	261	357	247	276	273	169	179	1,111	897	925
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	2	(52)	3	3	(13)	(5)	13	397	(44)	392	225
Net Income (Loss) Attributable to Parent	$ 248	$ 209	$ 360	$ 250	$ 263	$ 268	$ 182	$ 576	$ 1,067	$ 1,289	$ 1,150
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.52	$ 0.54	$ 0.70	$ 0.48	$ (1.94)	$ 0.49	$ (2.24)	$ 0.23	$ 2.25	$ (3.47)	$ 1.36
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	0.53	0.43	0.71	0.49	(1.97)	0.48	(2.22)	1.06	(0.09)	0.81	0.47
Income (Loss) from Continuing Operations, Per Diluted Share	0.52	0.54	0.70	0.48	(1.94)	0.49	(2.24)	0.23	2.24	(3.47)	1.36
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	0.52	0.43	0.71	0.49	$ (1.97)	$ 0.47	$ (2.22)	$ 1.06	(0.09)	0.81	0.47
Common Stock, Dividends, Per Share, Declared	$ 0.08	$ 0.08	$ 0	$ 0					$ 0.16	$ 0	$ 0