Ally Financial (ALLY) 8-K 5 May 16 2015 FY Other Events Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Feb. 23, 2016	Jun. 30, 2015
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	8-K
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		483,067,645
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 9,874,447,499

Consolidated Statement of Incom

Consolidated Statement of Income - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Revenue and Other Interest Income [Abstract]
Interest and fees on finance receivables and loans									$ 4,570	$ 4,457	$ 4,529
Interest on loans held-for-sale									40	1	20
Interest and dividends on available-for-sale investment securities									381	367	325
Interest-bearing cash									8	8	10
Operating leases									3,398	3,558	3,209
Total financing revenue and other interest income									8,397	8,391	8,093
Interest Expense [Abstract]
Interest on deposits									718	664	654
Interest on short-term borrowings									49	52	63
Interest on long-term debt									1,662	2,067	2,602
Total interest expense									2,429	2,783	3,319
Depreciation expense on operating lease assets									2,249	2,233	1,995
Net financing revenue (loss)	$ 983	$ 970	$ 916	$ 850	$ 799	$ 889	$ 866	$ 821	3,719	3,375	2,779
Other revenue [Abstract]
Servicing fees									45	31	126
Servicing asset valuation and hedge activities, net									0	0	(213)
Total servicing income, net									45	31	(87)
Insurance premiums and service revenue earned									940	979	1,012
Gain (loss) on mortgage and automotive loans, net									45	7	55
Gain (loss) on extinguishment of debt									(357)	(202)	(59)
Other gain (loss) on investments, net									155	181	180
Other income, net of losses									314	280	383
Total other revenue	356	332	211	243	215	375	365	321	1,142	1,276	1,484
Total net revenue (loss)	1,339	1,302	1,127	1,093	1,014	1,264	1,231	1,142	4,861	4,651	4,263
Provision for loan losses	240	211	140	116	155	102	63	137	707	457	501
Noninterest Expense [Abstract]
Compensation and benefits expense									963	947	1,019
Insurance losses and loss adjustment expenses									293	410	405
Other operating expenses									1,505	1,591	1,981
Total noninterest expense	668	674	724	695	672	742	821	713	2,761	2,948	3,405
Income (loss) from continuing operations before income tax expense	431	417	263	282	187	420	347	292	1,393	1,246	357
Income tax expense (benefit) from continuing operations	155	144	94	103	36	127	64	94	496	321	(59)
Net income (loss) from continuing operations	276	273	169	179	151	293	283	198	897	925	416
Income (loss) from discontinued operations, net of tax	(13)	(5)	13	397	26	130	40	29	392	225	(55)
Net income (loss)	$ 263	$ 268	$ 182	$ 576	$ 177	$ 423	$ 323	$ 227	$ 1,289	$ 1,150	$ 361
Earnings Per Share, Basic [Abstract]
Net income (loss) from continuing operations, Per Basic Share	$ (1.94)	$ 0.49	$ (2.24)	$ 0.23	$ 0.17	$ 0.47	$ 0.45	$ 0.27	$ (3.47)	$ 1.36	$ (1.51)
Income (Loss) from Discontinued Operations, Net of Tax, Per Basic Share									0.81	0.47	(0.13)
Net (loss) income, Basic	(1.97)	0.48	(2.22)	1.06	0.23	0.74	0.54	0.33	(2.66)	1.83	(1.64)
Earnings Per Share, Diluted [Abstract]
Net income (loss) from continuing operations, Per Diluted Share	(1.94)	0.49	(2.24)	0.23	0.17	0.47	0.45	0.27	(3.47)	1.36	(1.51)
Income (loss) from discontinued operations, net of tax									0.81	0.47	(0.13)
Net (loss) income, Diluted	$ (1.97)	$ 0.47	$ (2.22)	$ 1.06	$ 0.23	$ 0.74	$ 0.54	$ 0.33	$ (2.66)	$ 1.83	$ (1.64)

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Consolidated Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 1,289	$ 1,150	$ 361
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	(39)	415	(159)
Other Comprehensive Income (Loss), Reclassification Adjustment to Net Income for Sale of Securities, Net of Tax	99	167	186
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent	(138)	248	(345)
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	(26)	(17)	(80)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	22	20	429
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent	(48)	(37)	(509)
Other Comprehensive Income Unrealized Gain Loss On Net Investment Hedges Arising During the Period Net of Tax	18	8	37
Other Comprehensive Income (Loss), Reclassification Adjustment for Net Investment Hedges Included in Net Income, Discontinued Operation, Net of Tax	(3)	0	(169)
Other Comprehensive Income (Loss), Net Investment Hedges Attributable to Parent, Net of Tax	21	8	206
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustments and Net Investment Hedges, Adjustment, Net of Tax	(27)	(29)	(303)
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	1	2	(1)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	0	0	(4)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent	1	2	3
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	0	(15)	18
Other Comprehensive Income (Loss), Reclassification Adjustment to Net Income, Pension and Other Postretirement Benefit Plans, for Net (Gain) Loss, Net of Tax	1	(4)	(40)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent	(1)	(11)	58
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(165)	210	(587)
Comprehensive income (loss)	$ 1,124	$ 1,360	$ (226)

Consolidated Balance Sheet

Consolidated Balance Sheet - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Assets [Abstract]
Cash and Due from Banks	$ 2,148	$ 1,348
Interest-bearing Deposits in Banks and Other Financial Institutions	4,232	4,228
Total cash and cash equivalents	6,380	5,576
Investment securities	17,157	16,137
Loans held-for-sale, net	105	2,003
Finance receivables and loans, net [Abstract]
Finance receivables and loans, net	111,600	99,948
Allowance for loan losses	(1,054)	(977)
Total finance receivables and loans, net	110,546	98,971
Investment in operating leases, net	16,271	19,510
Premiums receivable and other insurance assets	1,801	1,695
Other Assets	6,321	7,105
Assets of operations held-for-sale	0	634
Total assets	158,581	151,631
Liabilities and Equity [Abstract]
Noninterest-bearing deposit liabilities	89	64
Interest-bearing deposit liabilities	66,389	58,139
Total deposit liabilities	66,478	58,203
Short-term borrowings	8,101	7,062
Long-term debt	66,234	66,380
Interest payable	350	477
Unearned insurance premiums and service revenue	2,434	2,375
Accrued expenses and other liabilities	1,545	1,735
Total liabilities	145,142	136,232
Equity [Abstract]
Common stock and paid-in capital	21,100	21,038
Preferred stock	696	1,255
Accumulated deficit	(8,110)	(6,828)
Accumulated other comprehensive income	(231)	(66)
Treasury Stock, Value	(16)	0
Total equity	13,439	15,399
Total liabilities and equity	158,581	151,631
Variable Interest Entity, Primary Beneficiary [Member]
Finance receivables and loans, net [Abstract]
Finance receivables and loans, net	27,929	30,081
Allowance for loan losses	(196)	(179)
Total finance receivables and loans, net	27,733	29,902
Investment in operating leases, net	4,791	5,595
Other Assets	1,624	1,964
Total assets	34,148	37,461
Liabilities and Equity [Abstract]
Long-term debt	20,267	24,297
Accrued expenses and other liabilities	22	173
Total liabilities	$ 20,289	$ 24,470

Consolidated Balance Sheet (Par

Consolidated Balance Sheet (Paranthetical) - $ / shares	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
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
Common Stock, Shares, Issued	482,790,696	480,136,039	479,767,470	412,600,700
Common Stock, Shares, Outstanding	481,980,111	480,094,891	479,767,470
Treasury Stock, Shares	810,585	41,148	0

Consolidated Statement Of Chang

Consolidated Statement Of Changes In Equity - USD ($) $ in Millions	Total	Common Stock Including Additional Paid in Capital [Member]	Mandatorily convertible preferred stock held by U.S. Department Of Treasury [Member]	Preferred stock [Member]	Retained earnings (accumulated deficit) [Member]	Accumulated Other Comprehensive Income [Member]	Treasury Stock [Member]
Beginning Balance at Dec. 31, 2012	$ 19,898	$ 19,668	$ 5,685	$ 1,255	$ (7,021)	$ 311	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	361				361
Preferred Stock Dividends Paid To the U.S. Department Of Treasury	(543)				(543)
Preferred stock dividends	(267)				(267)
Other comprehensive income (loss)	(587)					(587)
Adjustments to Additional Paid in Capital, Other	1	1
Stock Issued During Period, Value, New Issues	1,270	1,270
Stock Repurchased During Period, Value	(5,925)		(5,685)		(240)
Ending Balance at Dec. 31, 2013	14,208	20,939	0	1,255	(7,710)	(276)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred Stock Dividends paid to the U.S. Department Of Treasury related to the period from November 13, 2013 through November 20, 2013	8
Net income (loss)	1,150				1,150
Preferred Stock Dividends Paid To the U.S. Department Of Treasury	0
Preferred stock dividends	(268)				(268)
Other comprehensive income (loss)	210					210
Employee Benefits and Share-based Compensation	99	99
Ending Balance at Dec. 31, 2014	15,399	21,038	0	1,255	(6,828)	(66)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	1,289				1,289
Preferred Stock Dividends Paid To the U.S. Department Of Treasury	0
Preferred stock dividends	(2,571)				(2,571)
Other comprehensive income (loss)	(165)					(165)
Stock Repurchased During Period, Value	(325)			(325)
Preferred stock redemption	(234)			(234)
Employee Benefits and Share-based Compensation	62	62
Share repurchases related to employee stock-based compensation awards	(16)						(16)
Ending Balance at Dec. 31, 2015	13,439	$ 21,100	$ 0	$ 696	$ (8,110)	$ (231)	$ (16)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Repurchase and Redemption Premium	$ 2,364

Consolidated Statement Of Cash

Consolidated Statement Of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income (loss)	$ 1,289	$ 1,150	$ 361
Depreciation, Amortization and Accretion, Net	2,801	2,936	2,864
Changes In Fair Value Of Mortgage Servicing Rights	0	0	101
Provision for Loan Losses Expensed Including Discontinued Operations	707	457	570
Gain Loss on Sales of Loans Net Including Discontinued Operations	(45)	(7)	(55)
Available-for-sale Securities Gross Realized Gain Loss Excluding Otti Including Disc Ops	(155)	(181)	(182)
Gain (loss) on extinguishment of debt	357	202	59
Payments for Origination and Purchases of Loans Held-for-sale	(1,770)	0	(6,235)
Proceeds from Sale of Loans Held-for-sale	1,658	62	8,696
Total Charge Recorded Related to ResCap Bankruptcy	0	(150)	(600)
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	(452)	7	(666)
Deferred income taxes	565	117	(671)
Interest payable	(127)	(411)	(39)
Other assets	526	(132)	2,592
Other liabilities	(247)	(400)	(3,860)
Other, net	(12)	(247)	(434)
Net cash provided by (used in) operating activities	5,095	3,403	2,501
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of available-for-sale securities	(12,250)	(5,417)	(12,304)
Proceeds from sales of available-for-sale securities	6,874	4,260	3,627
Proceeds from maturities of available-for-sale securities	4,255	2,657	5,509
Net (increase) decrease in finance receivables and loans	(13,845)	(5,024)	(2,479)
Proceeds from Sale of Loans Held-for-investment	3,197	2,592	0
Purchases of operating lease assets	(4,685)	(9,884)	(9,196)
Disposals Of Operating Lease Assets	5,546	5,860	2,964
Proceeds from Sale of Mortgage Servicing Rights (MSR)	0	0	911
Proceeds from sale of business units, net	1,049	47	7,444
Increase (Decrease) in Restricted Cash	264	1,625	(70)
Other, net	(152)	72	51
Net cash (used in) provided by investing activities	(9,747)	(3,212)	(3,543)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Net change in short-term borrowings	1,028	(1,494)	1,591
Net increase in bank deposits	8,247	4,851	5,357
Proceeds from issuance of long-term debt	30,665	27,192	27,330
Repayments of long-term debt	(31,350)	(30,426)	(31,892)
Proceeds from Issuance of Common Stock	0	0	1,270
Payments for Repurchase of Redeemable Preferred Stock	(559)	0	0
Payments for Repurchase of Convertible Preferred Stock	0	0	(5,925)
Dividends paid	(2,571)	(268)	(810)
Net cash provided by (used in) financing activities	5,460	(145)	(3,079)
Effect of exchange-rate changes on cash and cash equivalents	(4)	(1)	45
Cash and Cash Equivalents, Period Increase (Decrease)	804	45	(4,076)
Net Cash Provided by (Used in) Discontinued Operations	0	0	2,094
Cash and cash equivalents at beginning of period	5,576	5,531	7,513
Cash and cash equivalents at end of period	6,380	5,576	5,531
Cash and cash equivalents of business units at the time of disposition			1,600
Supplemental Cash Flow Information [Abstract]
Interest	2,632	3,090	3,827
Income taxes	96	8	75
Transfer of Portfolio Loans and Leases to Held-for-sale	1,311	4,631	18
Proceeds from sales and repayments of mortgage loans held-for-investment originally designated as held-for-sale	$ 68	$ 38	$ 51

Description Of Business, Basis

Description Of Business, Basis Of Presentation, And Changes In Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
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. (referred to herein as Parent, Ally, we, our, or us) is a leading, independent, diversified, financial services firm. Founded in 1919, we are a leading financial services company with over 95 years of experience providing a broad array of financial products and services, primarily to automotive dealers and their retail customers. We operate as a financial holding company (FHC) and a bank holding company (BHC). Our banking subsidiary, Ally Bank, is an indirect, wholly-owned subsidiary of Ally Financial Inc. and a leading franchise in the growing direct (internet, telephone, mobile, and mail) banking market . 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 10 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.
Organization, Consolidation, Basis of Presentation, Business Description and 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. 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 currently includes securities classified as available-for-sale, which are carried at fair value with unrealized gains and losses included in accumulated other comprehensive income or loss. 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. 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 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. Noncredit component losses of a debt security are 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. 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 l ong 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 6 . In addition to our investment securities, we hold nonmarketable equity investments. Our nonmarketable equity investments are carried at cost less any previously recognized impairment, reported in other assets, and include Federal Home Loan Bank (FHLB) stock held to meet regulatory requirements, certain equity investments in low income housing tax credits, and other equity investments that are not publicly traded and therefore do not have a readily determinable fair value. As conditions warrant, we review our investments carried at cost for impairment and will adjust the carrying value of the investment if it is deemed to be impaired. No impairment was recognized in 2015 or 2014. For more information on our nonmarketable equity investments, refer to Note 25 . 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 8 . 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. • 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 or 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 are reported as nonperforming loans in Note 8 . 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 a reduction to provision 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 and 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 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 2015, 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 8 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, anticipated repossessions or foreclosures based on portfolio trends, and 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 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 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 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 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 10 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 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

Discontinued and Held-for-sale

Discontinued and Held-for-sale Operations	12 Months Ended
	Dec. 31, 2015
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	Discontinued and Held-for-sale Operations Discontinued Operations Prior to the adoption of ASU 2014-08, which was prospectively applied only to newly identified disposals that qualified as discontinued operations beginning after January 1, 2015, we 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 Insurance Operations During the first quarter of 2013, we completed the sale of our U.K.-based operations. During the second quarter of 2013, we sold our Mexican insurance business, ABA Seguros. Select Automotive Finance Operations During the fourth quarter of 2012, we committed to sell our operations in Europe and Latin America to General Motors Financial Company, Inc. (GMF). On the same date, we entered into an agreement with GMF to sell our 40% interest in a motor vehicle finance joint venture in China. During the first quarter of 2013, we sold our Canadian automotive finance operations, Ally Credit Canada Limited and ResMor Trust. During the second quarter of 2013, we completed the sale of our operations in Europe and the majority of Latin America. The transaction included European operations in Germany, the United Kingdom, Italy, Sweden, Switzerland, Austria, Belgium, France and the Netherlands, and Latin America operations in Mexico, Chile, and Colombia. During the fourth quarter of 2013, we completed the sale of our Latin American operations in Brazil. 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 $400 million was recorded. The tax expense included in this gain was reduced by the release of the valuation allowance on our capital loss carryforward deferred tax asset that was utilized to offset capital gains stemming from this sale. Select Corporate Finance Operations During the second quarter of 2014, we ceased operations of our Corporate Finance Group's Canadian operation, and classified this business as discontinued. Select Corporate and Other Operations During the first quarter of 2013, the operations of our former subsidiary Residential Capital, LLC (ResCap) were classified as discontinued. Select Financial Information Select financial information of discontinued operations is summarized below. The pretax income or loss, including direct costs to transact a sale, includes any impairment recognized to present the operations at the lower-of-cost or fair value. Fair value was based on the estimated sales price, which could differ from the ultimate sales price due to price volatility, changing interest rates, changing foreign-currency rates, and future economic conditions. Year ended December 31, ($ in millions) 2015 2014 2013 Select Insurance operations Total net revenue $ — $ — $ 190 Pretax income including direct costs to transact a sale (a) 3 6 319 (b) Tax expense (benefit) (c) 1 6 (14 ) Select Automotive Finance operations Total net revenue $ — $ 123 $ 572 Pretax income including direct costs to transact a sale (a) 452 129 660 (d) Tax expense (benefit) (c) 80 7 (101 ) Select Corporate Finance operations Total net revenue $ — $ — $ — Pretax income including direct costs to transact a sale (a) 22 23 — Tax expense (c) — 3 — Select Corporate and Other operations Total net revenue $ — $ — $ — Pretax loss (e) (9 ) (4 ) (1,741 ) Tax (benefit) (5 ) (87 ) (592 ) (a) Includes certain treasury and other corporate activity recognized by Corporate and Other. (b) Includes recognized pretax gain of $274 million in connection with the sale of our Mexican insurance business, ABA Seguros. (c) Includes certain income tax activity recognized by Corporate and Other. (d) Includes recognized pretax loss of $488 million in connection with the sale of our European and Latin American automotive finance operations and pretax gain of $888 million in connection with the sale of our Canadian automotive finance operations, Ally Credit Canada Limited and ResMor Trust. (e) Includes amounts related to our former ResCap subsidiary. Held-for-sale Operations Assets of operations held-for-sale consisted of $634 million in other assets at December 31, 2014 , related to the joint venture in China that was sold to GMF on January 2, 2015. No held-for-sale operations remain at December 31, 2015 .

Insurance Premiums and Service

Insurance Premiums and Service Revenue Earned	12 Months Ended
	Dec. 31, 2015
Premiums Written and 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. 2015 2014 2013 Year ended December 31, ($ in millions) Written Earned Written Earned Written Earned Insurance premiums Direct $ 313 $ 296 $ 294 $ 282 $ 270 $ 305 Assumed 2 16 43 54 61 58 Gross insurance premiums 315 312 337 336 331 363 Ceded (184 ) (125 ) (156 ) (117 ) (172 ) (120 ) Net insurance premiums 131 187 181 219 159 243 Service revenue 846 753 842 760 838 769 Insurance premiums and service revenue written and earned $ 977 $ 940 $ 1,023 $ 979 $ 997 $ 1,012

Other Income, Net Of Losses

Other Income, Net Of Losses	12 Months Ended
	Dec. 31, 2015
Other Nonoperating Income (Expense) [Abstract]
Other Income, Net of Losses [Text Block]	Other Income, Net of Losses Details of other income, net of losses, were as follows. Year ended December 31, ($ in millions) 2015 2014 2013 Remarketing fees $ 101 $ 112 $ 82 Late charges and other administrative fees 90 88 94 Income from equity-method investments 52 18 15 Mortgage processing fees and other mortgage income — — 81 Fair value adjustment on derivatives (a) (8 ) (31 ) 24 Other, net 79 93 87 Total other income, net of losses $ 314 $ 280 $ 383 (a) Refer to Note 22 for a description of derivative instruments and hedging activities.

Other Operating Expenses

Other Operating Expenses	12 Months Ended
	Dec. 31, 2015
Operating Expenses [Abstract]
Other Operating Expenses [Text Block]	Other Operating Expenses Details of other operating expenses were as follows. Year ended December 31, ($ in millions) 2015 2014 2013 Insurance commissions $ 378 $ 374 $ 370 Technology and communications 267 334 346 Lease and loan administration 126 122 173 Advertising and marketing 107 111 136 Professional services 93 100 176 Premises and equipment depreciation 82 81 81 Regulatory and licensing fees 79 87 116 Vehicle remarketing and repossession 78 83 60 Occupancy 50 47 44 Provision for legal and regulatory settlements (a) 45 4 105 Non-income taxes 29 40 35 Mortgage representation and warranty obligation, net (13 ) (10 ) 104 Other 184 218 235 Total other operating expenses $ 1,505 $ 1,591 $ 1,981 (a) Results for the year ended December 31, 2013, include a $98 million settlement charge related to Consent Orders issued by the Consumer Financial Protection Bureau (CFPB) and the U.S. Department of Justice (DOJ) pertaining to the allegation of disparate impact in the automotive finance business. Refer to Note 30 for additional details.

Investment Securities

Investment Securities	12 Months Ended
	Dec. 31, 2015
Available-for-sale Securities [Abstract]
Investment Securities [Text Block]	Investment Securities Our portfolio of securities includes bonds, equity securities, asset- and mortgage-backed securities, and other investments. The cost, fair value, and gross unrealized gains and losses on available-for-sale securities were as follows. 2015 2014 Amortized cost Gross unrealized Fair 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 $ 1,760 $ — $ (19 ) $ 1,741 $ 1,195 $ 1 $ (18 ) $ 1,178 U.S. States and political subdivisions 693 24 (1 ) 716 389 17 — 406 Foreign government 169 8 — 177 224 8 — 232 Mortgage-backed residential (a) 10,459 52 (145 ) 10,366 10,431 119 (125 ) 10,425 Mortgage-backed commercial 486 — (5 ) 481 254 — (1 ) 253 Asset-backed 1,762 1 (8 ) 1,755 1,989 5 (3 ) 1,991 Corporate debt 1,213 8 (17 ) 1,204 734 14 (2 ) 746 Total debt securities (b) (c) 16,542 93 (195 ) 16,440 15,216 164 (149 ) 15,231 Equity securities 808 3 (94 ) 717 891 49 (34 ) 906 Total available-for-sale securities $ 17,350 $ 96 $ (289 ) $ 17,157 $ 16,107 $ 213 $ (183 ) $ 16,137 (a) Residential mortgage-backed securities include agency-backed bonds totaling $7,544 million and $7,557 million at December 31, 2015 , and December 31, 2014 , respectively. (b) Certain entities related to our Insurance operations are required to deposit securities with state regulatory authorities. These deposited securities totaled $14 million and $15 million at December 31, 2015 , and December 31, 2014 , respectively. (c) Investment securities with a fair value of $2,506 million and $801 million at December 31, 2015 , and December 31, 2014 , 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 $745 million of the underlying investment securities. The maturity distribution of available-for-sale debt securities outstanding is summarized in the following tables. Call or prepayment options may cause actual maturities to differ from contractual maturities. Total Due in one year or less Due after one year through five years Due after five years through ten years Due after ten years ($ in millions) Amount Yield Amount Yield Amount Yield Amount Yield Amount Yield December 31, 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 — — Mortgage-backed residential 10,366 2.9 — — 33 2.1 36 2.5 10,297 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 December 31, 2014 Fair value of available-for-sale debt securities (a) U.S. Treasury and federal agencies $ 1,178 1.5 % $ 7 3.0 % $ 677 1.2 % $ 494 1.9 % $ — — % U.S. States and political subdivisions 406 3.7 34 1.9 12 2.1 106 3.0 254 4.3 Foreign government 232 2.7 — — 128 2.5 104 2.9 — — Mortgage-backed residential 10,425 2.6 34 3.1 58 2.1 — — 10,333 2.6 Mortgage-backed commercial 253 1.5 — — 30 1.8 — — 223 1.4 Asset-backed 1,991 1.9 — — 1,311 1.9 463 2.0 217 2.2 Corporate debt 746 3.2 33 3.1 460 2.7 216 3.8 37 5.6 Total available-for-sale debt securities $ 15,231 2.5 $ 108 2.7 $ 2,676 1.9 $ 1,383 2.4 $ 11,064 2.6 Amortized cost of available-for-sale debt securities $ 15,216 $ 108 $ 2,674 $ 1,374 $ 11,060 (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 $1.0 billion and $2.0 billion at December 31, 2015 , and December 31, 2014 , respectively, and were composed primarily of money market accounts and short-term securities, including U.S. Treasury bills. The following table presents interest and dividends on available-for-sale securities. Year ended December 31, ($ in millions) 2015 2014 2013 Taxable interest $ 340 $ 336 $ 297 Taxable dividends 23 20 25 Interest and dividends exempt from U.S. federal income tax 18 11 3 Interest and dividends on available-for-sale securities $ 381 $ 367 $ 325 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) 2015 2014 2013 Gross realized gains $ 184 $ 209 $ 221 Gross realized losses (a) (15 ) (14 ) (21 ) Other-than-temporary impairment (14 ) (14 ) (20 ) Other gain on investments, net $ 155 $ 181 $ 180 (a) Certain available-for-sale securities were sold at a loss in 2015 , 2014 , and 2013 as a result of market conditions within these respective periods (e.g., a downgrade in the rating of a debt security), in accordance with our risk management policies and practices. 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 loses 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, 2015 , 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, 2015 , 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, 2015 . Refer to Note 1 for additional information related to investment securities and our methodology for evaluating potential other-than-temporary impairments. 2015 2014 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 $ 1,553 $ (17 ) $ 173 $ (2 ) $ 297 $ (3 ) $ 859 $ (15 ) U.S. States and political subdivisions 179 (1 ) — — 50 — — — Foreign government 2 — — — — — — — Mortgage-backed 4,096 (43 ) 2,453 (107 ) 1,172 (10 ) 3,098 (116 ) Asset-backed 1,402 (8 ) 64 — 819 (3 ) 8 — Corporate debt 745 (16 ) 12 (1 ) 132 (2 ) 11 — Total temporarily impaired debt securities 7,977 (85 ) 2,702 (110 ) 2,470 (18 ) 3,976 (131 ) Temporarily impaired equity securities 534 (54 ) 96 (40 ) 231 (24 ) 40 (10 ) Total temporarily impaired available-for-sale securities $ 8,511 $ (139 ) $ 2,798 $ (150 ) $ 2,701 $ (42 ) $ 4,016 $ (141 )

Loans Held-for-Sale, Net Loans

Loans Held-for-Sale, Net Loans Held-for-Sale, Net	12 Months Ended
	Dec. 31, 2015
Loans Held-for-Sale, Net [Abstract]
Loans Held-for-Sale, Net [Text Block]	Loans Held-for-Sale, Net Loans held-for-sale represent loans that we intend to sell. The composition of loans held-for-sale, net, was as follows. December 31, ( $ in millions ) 2015 2014 Consumer automotive $ — $ 1,515 Consumer mortgage Mortgage Finance — — Mortgage — Legacy — 452 Total consumer mortgage — 452 Total consumer — 1,967 Commercial and industrial — Other 105 36 Total loans held-for-sale, net $ 105 $ 2,003

Finance Receivables And Loans,

Finance Receivables And Loans, Net	12 Months Ended
	Dec. 31, 2015
Loans and Leases Receivable, Net Reported Amount, by Category Alternative [Abstract]
Loans, Notes, Trade and Other Receivables Disclosure [Text Block]	Finance Receivables and Loans, Net The composition of finance receivables and loans, net, reported at gross carrying value was as follows. December 31, ( $ in millions ) 2015 2014 Consumer automotive (a) $ 64,292 $ 56,570 Consumer mortgage Mortgage Finance (b) 6,413 3,504 Mortgage — Legacy (c) (d) 3,360 3,970 Total consumer mortgage 9,773 7,474 Total consumer 74,065 64,044 Commercial Commercial and industrial Automotive 31,469 30,871 Other 2,640 1,882 Commercial real estate — Automotive 3,426 3,151 Total commercial 37,535 35,904 Total finance receivables and loans (e) $ 111,600 $ 99,948 (a) Includes $66 million and $35 million of fair value adjustment for loans in hedge accounting relationships at December 31, 2015 , and December 31, 2014 , respectively. Refer to Note 22 for additional information. (b) Includes loans originated as interest-only mortgage loans of $44 million and $55 million at December 31, 2015 , and December 31, 2014 , respectively, 7% of which are expected to start principal amortization in 2016, 3% in 2017, none in 2018, 39% in 2019, and 38% thereafter. (c) Includes loans originated as interest-only mortgage loans of $941 million and $1.1 billion at December 31, 2015, and December 31, 2014, respectively, 35% of which are expected to start principal amortization in 2016, 22% in 2017, 2% in 2018, none in 2019, and 1% thereafter. (d) Includes consumer mortgages at a fair value of $1 million at December 31, 2014 , as a result of fair value option election. (e) Totals include a net increase of $110 million at December 31, 2015 , compared to a net reduction of $266 million at December 31, 2014 , 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, 2015 $ 685 $ 152 $ 140 $ 977 Charge-offs (840 ) (48 ) (4 ) (892 ) Recoveries 262 17 4 283 Net charge-offs (578 ) (31 ) — (609 ) Provision for loan losses 739 1 (33 ) 707 Other (a) (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) 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, 2014 $ 673 $ 389 $ 146 $ 1,208 Charge-offs (720 ) (51 ) (5 ) (776 ) Recoveries 219 8 12 239 Net charge-offs (501 ) (43 ) 7 (537 ) Provision for loan losses 540 (69 ) (14 ) 457 Other (a) (27 ) (125 ) 1 (151 ) Allowance at December 31, 2014 $ 685 $ 152 $ 140 $ 977 Allowance for loan losses Individually evaluated for impairment $ 23 $ 62 $ 21 $ 106 Collectively evaluated for impairment 662 90 119 871 Loans acquired with deteriorated credit quality — — — — Finance receivables and loans at gross carrying value Ending balance 56,570 7,473 35,904 99,947 Individually evaluated for impairment 282 336 82 700 Collectively evaluated for impairment 56,287 7,137 35,822 99,246 Loans acquired with deteriorated credit quality 1 — — 1 (a) 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 recorded at gross carrying value and transfers of finance receivables and loans from held-for-investment to held-for-sale. December 31, ( $ in millions ) 2015 2014 Consumer automotive $ 1,237 $ 4,106 Consumer mortgage 78 489 Commercial 2 36 Total sales and transfers $ 1,317 $ 4,631 The following table presents information about significant purchases of finance receivables and loans. December 31, ( $ in millions ) 2015 2014 Consumer automotive $ 272 $ — Consumer mortgage 4,125 857 Total purchases $ 4,397 $ 857 The following table presents an analysis of our past due finance receivables and loans, net, 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 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 2014 Consumer automotive $ 1,340 $ 293 $ 164 $ 1,797 $ 54,773 $ 56,570 Consumer mortgage Mortgage Finance 11 2 11 24 3,480 3,504 Mortgage — Legacy 65 23 113 201 3,768 3,969 Total consumer mortgage 76 25 124 225 7,248 7,473 Total consumer 1,416 318 288 2,022 62,021 64,043 Commercial Commercial and industrial Automotive — 9 — 9 30,862 30,871 Other — — — — 1,882 1,882 Commercial real estate — Automotive — — — — 3,151 3,151 Total commercial — 9 — 9 35,895 35,904 Total consumer and commercial $ 1,416 $ 327 $ 288 $ 2,031 $ 97,916 $ 99,947 The following table presents the gross carrying value of our finance receivables and loans on nonaccrual status. December 31, ( $ in millions ) 2015 2014 Consumer automotive $ 475 $ 386 Consumer mortgage Mortgage Finance 15 19 Mortgage — Legacy 113 158 Total consumer mortgage 128 177 Total consumer 603 563 Commercial Commercial and industrial Automotive 25 32 Other 44 46 Commercial real estate — Automotive 8 4 Total commercial 77 82 Total consumer and commercial finance receivables and loans $ 680 $ 645 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 for additional information. 2015 2014 December 31, ( $ in millions ) Performing Nonperforming Total Performing Nonperforming Total Consumer automotive $ 63,817 $ 475 $ 64,292 $ 56,184 $ 386 $ 56,570 Consumer mortgage Mortgage Finance 6,398 15 6,413 3,485 19 3,504 Mortgage — Legacy 3,247 113 3,360 3,811 158 3,969 Total consumer mortgage 9,645 128 9,773 7,296 177 7,473 Total consumer $ 73,462 $ 603 $ 74,065 $ 63,480 $ 563 $ 64,043 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. 2015 2014 December 31, ( $ in millions ) Pass Criticized (a) Total Pass Criticized (a) Total Commercial and industrial Automotive $ 29,613 $ 1,856 $ 31,469 $ 29,150 $ 1,721 $ 30,871 Other 2,122 518 2,640 1,509 373 1,882 Commercial real estate — Automotive 3,265 161 3,426 3,015 136 3,151 Total commercial $ 35,000 $ 2,535 $ 37,535 $ 33,674 $ 2,230 $ 35,904 (a) Includes loans classified as special mention, substandard, or doubtful. These classifications are based on regulatory definitions and generally represent loans within our portfolio that have a higher default risk or have already defaulted. Impaired Loans and Troubled Debt Restructurings Impaired Loans Loans are considered impaired when we determine it is probable that we will be unable to collect all amounts due according to the terms of the loan agreement. For more information on our impaired finance receivables and loans, refer to Note 1 . The following table presents information about our impaired finance receivables and loans recorded at gross carrying value. December 31, ( $ in millions ) Unpaid principal balance Gross carrying value Impaired with no allowance Impaired with an allowance Allowance for impaired loans 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 2014 Consumer automotive $ 282 $ 282 $ — $ 282 $ 23 Consumer mortgage Mortgage Finance 8 7 4 3 — Mortgage — Legacy 332 329 82 247 62 Total consumer mortgage 340 336 86 250 62 Total consumer 622 618 86 532 85 Commercial Commercial and industrial Automotive 32 32 4 28 5 Other 46 46 — 46 15 Commercial real estate — Automotive 4 4 1 3 1 Total commercial 82 82 5 77 21 Total consumer and commercial finance receivables and loans $ 704 $ 700 $ 91 $ 609 $ 106 The following table presents average balance and interest income for our impaired finance receivables and loans. 2015 2014 2013 Year ended December 31, ( $ in millions ) Average balance Interest income Average balance Interest income Average balance Interest income Consumer automotive $ 295 $ 16 $ 317 $ 20 $ 278 $ 18 Consumer mortgage Mortgage Finance 8 — 12 — 11 — Mortgage — Legacy 272 9 861 12 897 29 Total consumer mortgage 280 9 873 12 908 29 Total consumer 575 25 1,190 32 1,186 47 Commercial Commercial and industrial Automotive 33 1 61 2 152 6 Other 41 3 59 3 72 2 Commercial real estate — Automotive 5 — 6 — 29 1 Total commercial 79 4 126 5 253 9 Total consumer and commercial finance receivables and loans $ 654 $ 29 $ 1,316 $ 37 $ 1,439 $ 56 Troubled Debt Restructurings TDRs are loan modifications where concessions were granted to borrowers experiencing financial difficulties. 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. Additionally 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. Total TDRs recorded at gross carrying value were $625 million at December 31, 2015 , reflecting a decrease of $56 million from December 31, 2014 . Refer to Note 1 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. 2015 2014 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 17,222 $ 278 $ 237 17,511 $ 211 $ 187 Consumer mortgage Mortgage Finance 7 4 4 2 1 1 Mortgage — Legacy 197 42 40 394 79 73 Total consumer mortgage 204 46 44 396 80 74 Total consumer 17,426 324 281 17,907 291 261 Commercial Commercial and industrial Automotive — — — 3 23 23 Other 1 21 21 3 48 48 Commercial real estate — Automotive 1 3 3 — — — Total commercial 2 24 24 6 71 71 Total consumer and commercial finance receivables and loans 17,428 $ 348 $ 305 17,913 $ 362 $ 332 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 for additional information) except for commercial finance receivables and loans, where redefault is defined as 90 days past due. 2015 2014 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 6,836 $ 82 $ 47 7,117 $ 90 $ 47 Consumer mortgage Mortgage Finance — — — — — — Mortgage — Legacy 10 1 — 27 2 1 Total consumer finance receivables and loans 6,846 $ 83 $ 47 7,144 $ 92 $ 48 At December 31, 2015 , and December 31, 2014 , commercial commitments to lend additional funds to borrowers owing receivables whose terms had been modified in a TDR were $2 million and $4 million , respectively. Concentration Risk Consumer We monitor our consumer loan portfolio for concentration risk across the geographies in which we lend. The highest concentrations of loans are in Texas and California, which represent an aggregate of 23.5% of our total outstanding consumer finance receivables and loans at December 31, 2015 . Concentrations in our mortgage portfolio are closely monitored given the volatility of the housing markets, with special attention given to states with greater declines in real estate values. The following table shows the percentage of total consumer finance receivables and loans recorded at gross carrying value by state concentration. 2015 (a) 2014 December 31, Consumer automotive Consumer mortgage Consumer automotive Consumer mortgage Texas 13.7 % 6.2 % 13.6 % 6.0 % California 7.3 33.6 6.2 30.8 Florida 7.7 4.1 7.3 3.7 Pennsylvania 5.0 1.5 5.3 1.6 Illinois 4.4 4.1 4.4 4.2 Georgia 4.4 2.2 4.2 2.1 North Carolina 3.6 1.8 3.5 1.9 Ohio 3.7 0.6 3.9 0.6 New York 3.5 1.9 4.0 1.9 Michigan 3.1 2.4 3.8 3.1 Other United States 43.6 41.6 43.8 44.1 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, 2015 . 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, 2015 2014 Texas 17.7 % 13.8 % Florida 10.0 12.3 Michigan 8.9 9.9 California 8.7 9.0 North Carolina 3.8 3.9 Virginia 3.8 4.1 Georgia 3.6 3.7 Pennsylvania 3.4 3.8 New York 3.1 3.9 Illinois 2.9 2.7 Other United States 34.1 32.9 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 deemed 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. The following table presents the percentage of total commercial criticized finance receivables and loans reported at gross carrying value by industry concentrations. December 31, 2015 2014 Automotive 80.5 % 87.3 % Manufacturing 7.8 0.9 Services 5.3 2.0 Other 6.4 9.8 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, 2015
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 ) 2015 2014 Vehicles $ 20,211 $ 23,144 Accumulated depreciation (3,940 ) (3,634 ) Investment in operating leases, net $ 16,271 $ 19,510 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 ) 2015 2014 2013 Depreciation expense on operating lease assets (excluding remarketing gains) $ 2,600 $ 2,666 $ 2,327 Remarketing gains (351 ) (433 ) (332 ) Net depreciation expense on operating lease assets $ 2,249 $ 2,233 $ 1,995 The following table presents the future lease nonresidual rental payments due from customers for vehicles on operating leases. Year ended December 31, ( $ in millions ) 2016 $ 2,687 2017 1,445 2018 406 2019 57 2020 and thereafter 1 Total $ 4,596

Securitizations And Variable In

Securitizations And Variable Interest Entities	12 Months Ended
	Dec. 31, 2015
Securitizations And Variable Interest Entities [Abstract]
Securitizations And Variable Interest Entities 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, 2015 , 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. Our servicing responsibilities, which constitute continued involvement in the transferred financial assets, consist of primary servicing (i.e., servicing the underlying transferred financial assets) and master servicing (i.e., servicing the beneficial interests that result from the securitization transactions). 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. Additionally, the securitization agreements may require cash flows to be directed away from certain of our retained interests due to specific over-collateralization requirements, which may or may not be performance-driven. 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 2015 or 2014. 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 were no sales of financial assets into nonconsolidated securitization trusts and similar asset-backed financing entities for consumer mortgage GSEs for the years ended December 31, 2015 , and 2014 , while there were $112 million of pretax gains on sales for the year ended December 31, 2013 . The pretax loss recognized for consumer automotive 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 , and no pretax gains or losses for the year ended December 31, 2013 . We provide long-term guarantee contracts to investors in certain nonconsolidated affordable housing entities and have extended a line of credit to provide liquidity and minimize our exposure under these contracts. 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. Our involvement with consolidated and nonconsolidated VIEs in which we hold variable interests is presented below. December 31, ( $ in millions ) Consolidated involvement with VIEs Assets of nonconsolidated VIEs (a) Maximum exposure to loss in nonconsolidated VIEs 2015 On-balance sheet variable interest entities Consumer automotive $ 27,967 (b) Commercial automotive 16,763 Off-balance sheet variable interest entities Consumer automotive — $ 3,034 $ 3,034 (c) Commercial other 210 (d) — (e) 493 (f) Total $ 44,940 $ 3,034 $ 3,527 2014 On-balance sheet variable interest entities Consumer automotive $ 31,966 (b) Commercial automotive 18,153 Off-balance sheet variable interest entities Consumer automotive — $ 2,801 $ 2,801 (c) Commercial other 146 (d) — (e) 362 (f) Total $ 50,265 $ 2,801 $ 3,163 (a) Asset values represent the current unpaid principal balance of outstanding consumer finance receivables and loans within the VIEs. (b) Includes $10.6 billion and $12.7 billion of assets which are not encumbered by VIE beneficial interests held by third parties at December 31, 2015 , and December 31, 2014 , respectively. Ally or consolidated affiliates hold the interests in these assets which eliminate in consolidation. (c) Maximum exposure to loss represents the current unpaid principal balance of outstanding loans based on our customary representation and warranty provisions. 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. (d) Includes $222 million and $164 million classified as other assets, offset by $12 million and $18 million classified as accrued expenses and other liabilities at December 31, 2015 , and December 31, 2014 , respectively. (e) Includes a VIE for which we have no management oversight and therefore we are not able to provide the total assets of the VIEs. (f) 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 ) 2015 2014 Assets Finance receivables and loans, net Consumer $ 11,682 $ 12,594 Commercial 16,247 17,487 Allowance for loan losses (196 ) (179 ) Total finance receivables and loans, net 27,733 29,902 Investment in operating leases, net 4,791 5,595 Other assets 1,624 1,964 Total assets $ 34,148 $ 37,461 Liabilities Long-term debt 20,267 24,297 Accrued expenses and other liabilities 22 173 Total liabilities $ 20,289 $ 24,470 Cash Flows with Off-balance Sheet Variable Interest Entities The following table summarizes cash flows received and paid related to securitization entities, asset-backed financings, or other similar transfers of financial assets 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 in 2015 , 2014 , and 2013 . 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 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 ) 2013 Cash proceeds from transfers completed during the period $ — $ 8,676 Servicing fees 13 70 Representations and warranties obligations — (66 ) Other cash flows — 70 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 past due Net credit losses December 31, ( $ in millions ) 2015 2014 2015 2014 2015 2014 On-balance sheet loans Consumer automotive $ 64,292 $ 58,085 $ 591 $ 457 $ 578 $ 501 Consumer mortgage 9,773 7,926 108 151 31 43 Commercial automotive 34,895 34,022 — 9 3 1 Commercial other 2,745 1,918 — — (3 ) (8 ) Total on-balance sheet loans 111,705 101,951 699 617 609 537 Off-balance sheet securitization entities Consumer automotive 2,529 2,801 9 5 5 1 Total off-balance sheet securitization entities 2,529 2,801 9 5 5 1 Whole-loan transactions (a) 2,252 929 13 33 — 6 Total $ 116,486 $ 105,681 $ 721 $ 655 $ 614 $ 544 (a) Whole-loan transactions 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, 2015
Servicing Activities [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. Typically, we conclude 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 $45 million , $31 million , and $58 million during the years ended December 31, 2015 , 2014 , and 2013 , 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 ) 2015 2014 On-balance sheet automotive finance loans and leases Consumer automotive $ 64,067 $ 58,085 Commercial automotive 34,895 34,022 Operating leases 15,965 19,510 Other 72 55 Off-balance sheet automotive finance loans Loans sold to third-party investors Securitizations 2,550 2,832 Whole-loan 2,259 887 Total serviced automotive finance loans and leases $ 119,808 $ 115,391

Premiums Receivable and Other I

Premiums Receivable and Other Insurance Assets	12 Months Ended
	Dec. 31, 2015
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 ) 2015 2014 Prepaid reinsurance premiums $ 382 $ 326 Reinsurance recoverable on unpaid losses 120 143 Reinsurance recoverable on paid losses 18 12 Premiums receivable 82 90 Deferred policy acquisition costs 1,199 1,124 Total premiums receivable and other insurance assets $ 1,801 $ 1,695

Other Assets

Other Assets	12 Months Ended
	Dec. 31, 2015
Other Assets [Abstract]
Other Assets Disclosure [Text Block]	Other Assets The components of other assets were as follows. December 31, ( $ in millions ) 2015 2014 Property and equipment at cost $ 691 $ 775 Accumulated depreciation (456 ) (550 ) Net property and equipment 235 225 Restricted cash collections for securitization trusts (a) 2,010 2,221 Net deferred tax assets 1,369 1,812 Nonmarketable equity investments 418 271 Cash reserve deposits held-for-securitization trusts (b) 252 303 Fair value of derivative contracts in receivable position (c) 233 263 Other accounts receivable 158 298 Collateral placed with counterparties 125 236 Restricted cash and cash equivalents 120 122 Other assets 1,401 1,354 Total other assets $ 6,321 $ 7,105 (a) Represents cash collection from customer payments on securitized receivables. These funds are distributed to investors as payments on the related secured debt. (b) Represents credit enhancement in the form of cash reserves for various securitization transactions. (c) For additional information on derivative instruments and hedging activities, refer to Note 22 .

Deposit Liabilities

Deposit Liabilities	12 Months Ended
	Dec. 31, 2015
Deposits [Abstract]
Deposit Liabilities Disclosures [Text Block]	Deposit Liabilities Deposit liabilities consisted of the following. December 31, ( $ in millions ) 2015 2014 Noninterest-bearing deposits $ 89 $ 64 Interest-bearing deposits Savings and money market checking accounts 36,386 26,769 Certificates of deposit 29,774 31,051 Dealer deposits 229 319 Total deposit liabilities $ 66,478 $ 58,203 At December 31, 2015 , and December 31, 2014 , certificates of deposit included $11.5 billion and $13.0 billion , respectively, of certificates of deposit in denominations of $100 thousand or more. At December 31, 2015 , and December 31, 2014 , certificates of deposit included $3.2 billion and $3.7 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 2016 $ 16,313 Due in 2017 8,800 Due in 2018 3,068 Due in 2019 695 Due in 2020 898 Total certificates of deposit $ 29,774

Short-Term Borrowings

Short-Term Borrowings	12 Months Ended
	Dec. 31, 2015
Short-term Debt [Abstract]
Short-term Debt [Text Block]	Short-term Borrowings The following table presents the composition of our short-term borrowings portfolio. 2015 2014 December 31, ( $ in millions ) Unsecured Secured (a) Total Unsecured Secured (a) Total Demand notes $ 3,369 $ — $ 3,369 $ 3,338 $ — $ 3,338 Federal Home Loan Bank — 4,000 4,000 — 2,950 2,950 Securities sold under agreements to repurchase — 648 648 — 774 774 Other 84 — 84 — — — Total short-term borrowings $ 3,453 $ 4,648 $ 8,101 $ 3,338 $ 3,724 $ 7,062 Weighted average interest rate (b) 0.8 % 0.8 % (a) Refer to Note 16 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, 2015 , the financial instruments sold under agreements to repurchase consisted of mortgage-backed residential securities with the following maturities: $403 million within the next 30 days and $245 million within 31 to 60 days. Refer to Note 6 and Note 26 for further details on investment securities sold under agreements to repurchase. 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, Ally is 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, Ally may incur additional delays and costs. As of December 31, 2015 , we placed cash collateral totaling $21 million with counterparties under these collateral arrangements associated with our repurchase agreements.

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2015
Long-term Debt, Unclassified [Abstract]
Long-term Debt [Text Block]	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 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 2014 Unsecured debt Fixed rate (b) $ 18,858 Variable rate 374 Trust preferred securities 2,598 Fair value adjustment (c) 452 Total unsecured debt 22,282 0.33 - 8.30% 5.90 % 2015 - 2049 Secured debt Fixed rate 19,793 Variable rate 24,305 Total secured debt (d) (e) (f) 44,098 0.21 - 4.59% 0.94 % 2015 - 2023 Total long-term debt $ 66,380 (a) Based on the debt outstanding and the interest rate at December 31 of each year. (b) Includes subordinated debt of $1.1 billion and $296 million at December 31, 2015 , and 2014 , 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 for additional information. (d) Includes $20.3 billion and $ 24.3 billion of VIE secured debt outstanding at December 31, 2015 , and 2014 , respectively. (e) Includes $19.9 billion and $17.0 billion of debt outstanding from the Automotive secured revolving credit facilities at December 31, 2015 , and 2014 , respectively. (f) Includes advances from the FHLB of $5.4 billion and $2.8 billion at December 31, 2015 , and 2014 , respectively. 2015 2014 December 31, ( $ in millions ) Unsecured Secured Total Unsecured Secured Total Long-term debt Due within one year $ 1,829 $ 9,427 $ 11,256 $ 4,780 $ 12,603 $ 17,383 Due after one year 18,803 35,844 54,647 17,050 31,495 48,545 Fair value adjustment 334 (3 ) 331 452 — 452 Total long-term debt $ 20,966 $ 45,268 $ 66,234 $ 22,282 $ 44,098 $ 66,380 The following table presents the scheduled remaining maturity of long-term debt, assuming no early redemptions will occur. The actual payment of secured debt may vary based on the payment activity of the related pledged assets. Year ended December 31, ( $ in millions ) 2016 2017 2018 2019 2020 2021 and thereafter Fair value adjustment Total Unsecured Long-term debt $ 1,904 $ 4,371 $ 3,702 $ 1,615 $ 2,228 $ 8,203 $ 334 $ 22,357 Original issue discount (75 ) (87 ) (98 ) (35 ) (35 ) (1,061 ) — (1,391 ) Total unsecured 1,829 4,284 3,604 1,580 2,193 7,142 334 20,966 Secured Long-term debt 9,427 15,217 9,109 5,823 3,414 2,281 (3 ) 45,268 Total long-term debt $ 11,256 $ 19,501 $ 12,713 $ 7,403 $ 5,607 $ 9,423 $ 331 $ 66,234 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 $8.3 billion of our fixed-rate debt into variable-rate obligations and $0.9 billion of our variable-rate debt into fixed-rate obligations at December 31, 2015 . 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. 2015 2014 December 31, ( $ in millions ) Total Ally Bank (a) Total Ally Bank (a) Investment securities (b) $ 2,420 $ 1,761 $ 786 $ 786 Mortgage assets held-for-investment and lending receivables 9,743 9,743 7,541 7,541 Consumer automotive finance receivables 34,324 9,167 33,438 11,263 Commercial automotive finance receivables 19,623 19,177 20,605 20,083 Investment in operating leases, net 5,539 3,205 6,820 4,672 Total assets restricted as collateral (c) (d) $ 71,649 $ 43,053 $ 69,190 $ 44,345 Secured debt $ 49,916 (e) $ 24,787 $ 47,822 (e) $ 27,103 (a) Ally Bank is a component of the total column. (b) Certain investment securities are restricted under repurchase agreements. Refer to Note 15 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 $14.9 billion and $10.7 billion at December 31, 2015 , and 2014 , 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 $2.9 billion and $3.2 billion at December 31, 2015 , and 2014 , 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 13 for additional information. (e) Includes $4.6 billion and $3.7 billion of short-term borrowings at December 31, 2015 , and 2014 , respectively. Trust Preferred Securities At December 31, 2015 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) net of original issue discount and debt issuance costs. Each Series 2 TRUPS security has a liquidation amount of $25. Distributions are cumulative and are payable until redemption at the applicable coupon rate. Distributions are payable at an annual rate 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 2015 , there were no trigger events that resulted in the repayment of debt at an accelerated rate or impacted the usage of our credit facilities. 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, 2015 , Ally Bank had exclusive access to $3.25 billion of funding capacity from a committed credit facility. 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 and other financial institutions 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, 2015 , $20.1 billion of our $20.4 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, 2015 , we had $12.5 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 ) 2015 2014 2015 2014 2015 2014 Bank funding Secured (b) $ 3,250 $ 3,250 $ — $ 250 $ 3,250 $ 3,500 Parent funding Secured 16,914 15,030 251 3,425 17,165 18,455 Total committed facilities $ 20,164 $ 18,280 $ 251 $ 3,675 $ 20,415 $ 21,955 (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.

Accrued Expenses and Other Liab

Accrued Expenses and Other Liabilities	12 Months Ended
	Dec. 31, 2015
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 ) 2015 2014 Accounts payable $ 391 $ 298 Employee compensation and benefits 242 298 Reserves for insurance losses and loss adjustment expenses 169 208 Fair value of derivative contracts in payable position (a) 145 252 Deferred revenue 108 151 Collateral received from counterparties 82 71 Other liabilities 408 457 Total accrued expenses and other liabilities $ 1,545 $ 1,735 (a) For additional information on derivative instruments and hedging activities, refer to Note 22 .

Equity

Equity	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Equity Note [Text Block]	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, ( in shares ) 2015 2014 2013 Common stock Total issued, January 1, 480,136,039 479,767,470 412,600,700 New issuances Employee benefits and compensation plans 2,654,657 368,569 — Private placement (a) — — 67,166,770 Total issued, December 31, 482,790,696 480,136,039 479,767,470 Total treasury stock, December 31, (810,585 ) (41,148 ) — Total outstanding, December 31, 481,980,111 480,094,891 479,767,470 (a) On November 20, 2013, Ally completed its private placement of its common stock for an aggregate price of $1.3 billion . Preferred Stock Series A Preferred Stock Holders of the Series A Preferred Stock are entitled to receive, when, and if declared by Ally, noncumulative cash dividends. Beginning March 25, 2011, to but excluding May 15, 2016, dividends accrue at a fixed rate of 8.5% per annum. Beginning on May 15, 2016, dividends will accrue at a rate equal to three-month London interbank offer rate (LIBOR) plus 6.243% , commencing on August 15, 2016, in each case on the 15th day of February, May, August, and November. Dividends will be payable to holders of record at the close of business on the preceding February 1, May 1, August 1, or November 1, as the case may be, or on such other date, not more than seventy calendar days prior to the dividend payment date, as will be fixed by the Ally Board of Directors. In the event that dividends with respect to a dividend period have not been paid in full on the dividend payment date, we will be prohibited, subject to certain specified exceptions, from (i) redeeming, purchasing or otherwise acquiring, any stock that ranks on a parity basis with, or junior in interest to, the Series A Preferred Stock; (ii) paying any dividends or making any distributions with respect to any stock that ranks junior in interest to the Series A Preferred Stock, until such time as Ally has paid the dividends payable on shares of the Series A Preferred Stock with respect to a subsequent dividend period; and (iii) declaring or paying any dividend on any stock ranking on a parity basis with the Series A Preferred Stock, subject to certain exceptions. The holders of the Series A Preferred Stock do not have voting rights other than those set forth in the certificate of designations for the Series A Preferred Stock included in Ally's Certificate of Incorporation. Ally may not redeem the Series A Preferred Stock before May 15, 2016, and after such time the Series A Preferred Stock may be redeemed in certain circumstances. In the event of any liquidation, dissolution or winding up of the affairs of Ally, holders of the Series A Preferred Stock will be entitled to receive the liquidation amount per share of Series A Preferred Stock and an amount equal to all declared, but unpaid dividends declared prior to the date of payment out of assets available for distribution, before any distribution is made for holders of stock that ranks junior in interest to the Series A Preferred Stock, subject to the rights of Ally's creditors. On April 9, 2014, we decreased the number of shares authorized for issuance of Series A Preferred Stock to 40,870,560 . On April 23, 2015, we announced a tender offer to purchase up to 13,000,000 shares of our outstanding Series A preferred stock for $26.65 per Series A share, which included an amount to cover accrued and unpaid dividends through the settlement date. The tender offer expired on May 20, 2015. On May 22, 2015, we repurchased 13,000,000 Series A Preferred Shares with an aggregate liquidation preference of $325 million for $347 million in cash. Upon repurchase of the tendered Series A Preferred shares on May 22, 2015, we derecognized the carrying value of $325 million and recognized the excess consideration paid of $22 million as an additional return to preferred shareholders. The remaining 27,870,560 Series A Preferred Shares following the repurchase were not impacted as a result of this transaction. Series G Preferred Stock On March 11, 2015, we issued a Notice of Partial Redemption to the holders of the outstanding Series G Preferred Stock to redeem, on a pro-rata basis, 1,288,300 shares at a redemption price of $ 1,000 per share plus $10.50 per share of accrued and unpaid dividends through the redemption date. On April 10, 2015, we redeemed 1,288,300 shares of our outstanding Series G Preferred Stock, with an aggregate liquidation preference of approximately $1,288 million for approximately $1,302 million in cash, which included $14 million in accrued and unpaid dividends. Upon redemption of the Series G Preferred shares, we derecognized the carrying value of $117 million and recognized the excess consideration paid of $1,171 million as an additional return to preferred shareholders. On November 12, 2015, we issued a Notice of Redemption to the holders of the remaining outstanding Series G Preferred Stock to redeem, on a pro-rata basis, 1,288,301 shares at a redemption price of $1,000 per share plus $5.64 per share of accrued and unpaid dividends through the redemption date. On December 14, 2015, we redeemed 1,288,301 shares of our outstanding Series G Preferred Stock, with an aggregate liquidation preference of approximately $1,288 million for approximately $1,295 million in cash, which included $7 million in accrued and unpaid dividends. Upon redemption of the Series G Preferred shares, we derecognized the carrying value of $117 million and recognized the excess consideration paid of $1,171 million as an additional return to preferred shareholders. Effective December 14, 2015, the Series G Preferred Stock was retired. The following table summarizes information about our Series A and Series G preferred stock. December 31, 2015 December 31, 2014 Series A preferred stock (a) Carrying value ( $ in millions ) $ 696 $ 1,021 Par value ( per share ) 0.01 0.01 Liquidation preference ( per share ) 25 25 Number of shares authorized 40,870,560 40,870,560 Number of shares issued and outstanding 27,870,560 40,870,560 Dividend/coupon Prior to May 15, 2016 8.5 % 8.5 % On and after May 15, 2016 Three month Three month Series G preferred stock Carrying value ( $ in millions ) $ — $ 234 Par value ( per share ) — 0.01 Liquidation preference ( per share ) — 1,000 Number of shares authorized — 2,576,601 Number of shares issued and outstanding — 2,576,601 Dividend/coupon — % 7 % (a) Nonredeemable prior to May 15, 2016.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Abstract]
Comprehensive Income (Loss) Note [Text Block]	Accumulated Other Comprehensive Income (Loss) The following table presents changes, net of tax, in each component of accumulated other comprehensive (loss) income. ( $ in millions ) Unrealized gains (losses) on investment securities (a) Translation adjustments and net investment hedges (b) Cash flow hedges (b) Defined benefit pension plans Accumulated other comprehensive income (loss) Balance at January 1, 2013 $ 76 $ 368 $ 2 $ (135 ) $ 311 2013 net change (345 ) (303 ) 3 58 (587 ) Balance at December 31, 2013 (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 ) (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 . The following table presents the before- and after-tax changes in each component of accumulated other comprehensive (loss) income. Year ended December 31, 2015 ( $ in millions ) Before Tax Tax Effect After Tax Unrealized losses on 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 (benefit) from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 22 . (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 Unrealized gains on 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 (benefit) expense from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 22 . (d) Includes losses reclassified to compensation and benefits expense in our Consolidated Statement of Income . Year ended December 31, 2013 ( $ in millions ) Before Tax Tax Effect After Tax Unrealized losses on investment securities Net unrealized losses arising during the period $ (333 ) $ 174 $ (159 ) Less: Net realized gains reclassified to income from continuing operations 180 (a) (2 ) (b) 178 Less: Net realized gains reclassified to income from discontinued operations, net of tax 10 (2 ) 8 Net change (523 ) 178 (345 ) Translation adjustments Net unrealized losses arising during the period (104 ) 24 (80 ) Less: Net realized gains reclassified to income from discontinued operations, net of tax 337 92 429 Net change (441 ) (68 ) (509 ) Net investment hedges (c) Net unrealized gains arising during the period 59 (22 ) 37 Less: Net realized losses reclassified to income from discontinued operations, net of tax (250 ) 81 (169 ) Net change 309 (103 ) 206 Cash flow hedges (c) Net unrealized losses arising during the period (1 ) — (1 ) Less: Net realized losses reclassified to income from continuing operations (7 ) (d) 3 (b) (4 ) Net change 6 (3 ) 3 Defined benefit pension plans Net unrealized gains arising during the period 26 (8 ) 18 Less: Net realized losses reclassified to income from continuing operations (2 ) (e) — (b) (2 ) Less: Net realized losses reclassified to income from discontinued operations, net of tax (49 ) 11 (38 ) Net change 77 (19 ) 58 Other comprehensive loss $ (572 ) $ (15 ) $ (587 ) (a) Includes gains reclassified to other gain on investments, net in our Consolidated Statement of Income . (b) Includes amounts reclassified to income tax expense (benefit) from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 22 . (d) Includes losses reclassified to long-term debt in our Consolidated Statement of Income . (e) 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, 2015
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 ) (a) 2015 2014 2013 Net income from continuing operations $ 897 $ 925 $ 416 Preferred stock dividends — U.S. Department of the Treasury — — (543 ) Impact of repurchase of mandatorily convertible preferred stock held by U.S. Department of the Treasury and elimination of share adjustment right — — (240 ) Preferred stock dividends (b) (2,571 ) (268 ) (267 ) Net (loss) income from continuing operations attributable to common shareholders (1,674 ) 657 (634 ) Income (loss) from discontinued operations, net of tax 392 225 (55 ) Net (loss) income attributable to common shareholders $ (1,282 ) $ 882 $ (689 ) Basic weighted-average common shares outstanding (c) 482,873,120 481,154,609 420,166,188 Diluted weighted-average common shares outstanding (c) (d) 482,873,120 481,933,811 420,166,188 Basic earnings per common share Net (loss) income from continuing operations $ (3.47 ) $ 1.36 $ (1.51 ) Income (loss) from discontinued operations, net of tax 0.81 0.47 (0.13 ) Net (loss) income $ (2.66 ) $ 1.83 $ (1.64 ) Diluted earnings per common share Net (loss) income from continuing operations $ (3.47 ) $ 1.36 $ (1.51 ) Income (loss) from discontinued operations, net of tax 0.81 0.47 (0.13 ) Net (loss) income $ (2.66 ) $ 1.83 $ (1.64 ) (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 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. Refer to Note 18 for additional preferred stock information. (c) Includes shares related to share-based compensation that vested but were not yet issued for the years ended December 31, 2015 , and 2014 , respectively. (d) Due to antidilutive effect of the net loss from continuing operations attributable to common shareholders for the years ended December 31, 2015 , and 2013, respectively, basic weighted-average common shares outstanding were used to calculate basic and diluted earnings per share. The effects of converting the outstanding Fixed Rate Cumulative Mandatorily Convertible Preferred Stock into common shares are not included in the diluted earnings per share calculation for the year ended December 31, 2013, as the effects would be antidilutive for the period. As such, 89 million of potential common shares were excluded from the diluted earnings per share calculation for the year ended December 31, 2013.

Regulatory Capital

Regulatory Capital	12 Months Ended
	Dec. 31, 2015
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 reflect new and higher capital requirements, capital buffers, and new regulatory capital definitions, deductions and adjustments. Certain aspects of U.S. Basel III, including the new capital buffers and 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 new and higher 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. In addition to introducing new capital ratios, U.S. Basel III revises 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 the new 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 new items are deducted from Common Equity Tier 1 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 revises the standardized approach for calculating risk-weighted assets by, among other things, modifying certain risk weights and introducing new 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. During 2010, Ally, IB Finance Holding Company, LLC (IB Finance), Ally Bank, and the Federal Deposit Insurance Corporation (FDIC) entered into a Capital and Liquidity Maintenance Agreement (CLMA). The CLMA was restated on July 13, 2015. The CLMA requires capital at Ally Bank to be maintained 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 FDIC's regulations related to capital maintenance. 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. Under Basel III Under Basel I December 31, 2015 (a) December 31, 2014 (b) Required minimum Well-capitalized minimum ( $ in millions ) Amount Ratio Amount Ratio Risk-based capital Common Equity Tier 1 (to risk-weighted assets) (c) Ally Financial Inc. $ 12,507 9.21 % $ 12,588 9.64 % 4.50 % (d) Ally Bank 16,594 17.05 16,022 16.89 4.50 6.50 % Tier 1 (to risk-weighted assets) Ally Financial Inc. $ 15,077 11.10 % $ 16,389 12.55 % 6.00 % 6.00 % Ally Bank 16,594 17.05 16,022 16.89 6.00 8.00 Total (to risk-weighted assets) Ally Financial Inc. $ 17,005 12.52 % $ 17,294 13.24 % 8.00 % 10.00 % Ally Bank 17,043 17.51 16,468 17.36 8.00 10.00 Tier 1 leverage (to adjusted quarterly average assets) (e) Ally Financial Inc. $ 15,077 9.73 % $ 16,389 10.94 % 4.00 % (d) Ally Bank 16,594 15.38 16,022 15.44 15.00 (f) 5.00 % (a) U.S. Basel III became effective for us on January 1, 2015, subject to transitional provisions primarily related to deductions and adjustments impacting Common Equity Tier 1 capital and Tier 1 capital. (b) Capital ratios as of December 31, 2014, are presented under the U.S. Basel I capital framework. (c) Previously referred to as Tier 1 Common Equity under the U.S. Basel I capital framework. (d) Currently, there is no ratio component for determining whether a BHC is "well-capitalized." (e) Federal regulatory reporting guidelines require the calculation of adjusted quarterly average assets using a daily average methodology. (f) Ally Bank, in accordance with the CLMA, is required to maintain a Tier 1 leverage ratio of at least 15% . At December 31, 2015 , 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 periodic company-run stress tests, is subject to an annual supervisory stress test conducted by the Board of Governors of the Federal Reserve System (FRB), and must submit an annual capital plan to the FRB. In addition, as an insured state nonmember bank with $50 billion or more in total consolidated assets, Ally Bank is required to conduct annual company-run stress tests. 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 January 5, 2015, Ally submitted the results of its semi-annual stress test and its proposed capital actions to the FRB, and Ally Bank submitted the results of its annual company-run stress test to the FDIC. On March 6, 2015, Ally and Ally Bank publicly disclosed summary results of the stress test under the most severe scenario in accordance with regulatory requirements. On March 11, 2015, Ally received a non-objection to its capital plan from the FRB, including the proposed capital actions contained in our submission. As a result, we redeemed $1.3 billion in Series G preferred securities in April 2015, and repurchased $325 million in Series A preferred securities in May 2015, pursuant to a tender offer. In addition, on July 6, 2015, Ally submitted to the FRB the results of our company-run mid-year stress test conducted under multiple macroeconomic scenarios. We disclosed the results of this stress test under the most severe scenario on July 15, 2015, in accordance with regulatory requirements. On November 12, 2015, we received approval from the FRB to redeem the remaining 1,288,301 shares of our outstanding Series G Preferred Stock, which was then redeemed and retired on December 14, 2015. Under a new rule effective for the 2016 capital planning cycle and subsequent cycles, Ally expects to submit its 2016 capital plan by April 5, 2016, with a response expected from the FRB by June 30, 2016. Depository Institutions Ally Bank is a state nonmember bank, chartered by the State of Utah, and subject to the supervision of the FDIC and the Utah Department of Financial Institutions (Utah DFI). 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 $111.3 billion and $104.4 billion at December 31, 2015 , and 2014 , 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 and $1.8 billion in 2015 and 2014 , respectively. Ally Bank did not make any dividend or other distributions to Ally in 2013 . The FRB requires banks to maintain minimum average reserve balances. The amount of the required reserve balance for Ally Bank was $216 million and $313 million at December 31, 2015 , and 2014 , respectively. 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 and interest payments on escrow accounts. 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, 2015 . 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, 2015 , the maximum dividend that could be paid by the U.S. insurance subsidiaries over the next twelve months without prior statutory approval was $93 million .

Derivative Instruments And Hedg

Derivative Instruments And Hedging Activities	12 Months Ended
	Dec. 31, 2015
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 Federal Home Loan Bank Advances, pay-fixed swaps designated as fair value hedges of specific portfolios of fixed-rate held-for-investment retail automotive loan assets, and pay-fixed swaps designated as cash flow hedges of the expected future cash flows in the form of interest payments on certain outstanding variable-rate borrowings associated with our secured debt. 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 income (loss). Our remaining foreign subsidiaries in wind-down maintain both assets and liabilities in local currencies. These local currencies are generally the subsidiaries' functional currencies for accounting purposes. Foreign-currency-exchange-rate gains and losses arise when the assets or liabilities of our subsidiaries are denominated in currencies that differ from its functional currency. We enter into economic hedges to mitigate this risk. We also enter into foreign currency forwards to economically hedge our foreign denominated debt, our centralized lending program, and foreign-denominated third party loans. The hedge of foreign denominated debt was entered into concurrent with the debt issuance with the terms of the derivative matching the terms of the underlying debt. The centralized lending program manages liquidity for our subsidiary businesses, but as of December 31, 2015 , this activity is immaterial. Foreign-currency-denominated loan agreements are executed with our foreign subsidiaries in their local currencies. We evaluate our foreign-currency exposure resulting from intercompany lending and manage our currency risk exposure by entering into foreign-currency derivatives with external counterparties. Our remaining foreign-currency derivatives, such as hedges of foreign-denominated third party loans, 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 was entered into concurrent with the debt issuance with the terms of the derivative matching the terms of the underlying debt. 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 $32 million as of December 31, 2015 , and was recorded within other assets on the Consolidated Balance Sheet . 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, net 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 in 2015. We placed cash collateral totaling $103 million and securities collateral totaling $86 million at December 31, 2015 , and $221 million and $15 million at December 31, 2014 , 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, 2015 , we placed cash collateral totaling $21 million with counterparties under collateral arrangements associated with repurchase agreements. Refer to Note 15 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 $82 million at December 31, 2015 , to support these derivative positions. We received cash collateral from counterparties totaling $71 million at December 31, 2014 . 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 such collateral received on our Consolidated Balance Sheet unless certain conditions are met. At December 31, 2015 , and 2014 , we received noncash collateral of $7 million and $15 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. 2015 2014 Derivative contracts in a Notional amount Derivative contracts in a Notional amount December 31, ( $ in millions ) receivable position (a) payable position (b) receivable position (a) payable position (b) Derivatives qualifying for hedge accounting Interest rate contracts Swaps (c) (d) (e) $ 126 $ 9 $ 14,151 $ 118 $ 7 $ 18,554 Foreign exchange contracts Forwards — 1 189 — — 210 Total derivatives qualifying for hedge accounting 126 10 14,340 118 7 18,764 Economic hedges Interest rate contracts Swaps 30 51 6,101 40 65 11,979 Futures and forwards 2 2 1,905 4 2 18,886 Written options — 72 18,220 — 94 14,823 Purchased options 73 — 18,240 94 — 15,159 Total interest rate risk 105 125 44,466 138 161 60,847 Foreign exchange contracts Swaps — — — — 74 1,210 Futures and forwards — — 278 5 4 304 Total foreign exchange risk — — 278 5 78 1,514 Equity contracts Forwards — 9 32 — 3 74 Written options — 1 — — 3 1 Purchased options 2 — — 2 — — Total equity risk 2 10 32 2 6 75 Total economic hedges 107 135 44,776 145 245 62,436 Total derivatives $ 233 $ 145 $ 59,116 $ 263 $ 252 $ 81,200 (a) Derivative contracts in a receivable position are classified as other assets on the Consolidated Balance Sheet, and includes accrued interest of $46 million and $50 million at December 31, 2015 , and 2014 , respectively. (b) Derivative contracts in a liability position are classified as accrued expenses and other liabilities on the Consolidated Balance Sheet, and includes accrued interest of $12 million and $17 million at December 31, 2015 , and 2014 , respectively. (c) Includes fair value hedges consisting of receive-fixed swaps on fixed-rate debt obligations with $112 million and $97 million in a receivable position, $3 million and $1 million in a payable position, and a $6.8 billion and $4.7 billion notional amount at December 31, 2015 , and December 31, 2014 , respectively. Of the hedge notional amount at December 31, 2015 , $2.6 billion is associated with debt maturing in five or more years. (d) Other fair value hedges include pay-fixed swaps on portfolios of held-for-investment automotive loan assets with $13 million and $21 million in a receivable position, $3 million and $6 million in a payable position, and a $6.8 billion and $13.9 billion notional amount at December 31, 2015 , and December 31, 2014 , respectively. (e) Fair value hedges were executed during the fourth quarter consisting of receive-fixed swaps on fixed-rate secured debt obligations (FHLB Advances) with $1 million in a receivable position, $2 million in a payable position, and a $500 million notional amount at December 31, 2015 . 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 ) 2015 2014 2013 Derivatives qualifying for hedge accounting (Loss) gain recognized in earnings on derivatives Interest rate contracts Interest and fees on finance receivables and loans (a) $ (9 ) $ 15 $ 7 Interest on long-term debt (b) (c) 35 199 (389 ) Gain (loss) recognized in earnings on hedged items Interest rate contracts Interest and fees on finance receivables and loans (d) 39 34 2 Interest on long-term debt (e) (30 ) (185 ) 402 Total derivatives qualifying for hedge accounting 35 63 22 Economic derivatives (Loss) gain recognized in earnings on derivatives Interest rate contracts Servicing asset valuation and hedge activities, net — — (112 ) Loss on mortgage and automotive loans, net (2 ) — (37 ) Other income, net of losses (17 ) (37 ) 14 Total interest rate contracts (19 ) (37 ) (135 ) Foreign exchange contracts (f) Interest on long-term debt (139 ) (172 ) 94 Other income, net of losses 12 12 24 Total foreign exchange contracts (127 ) (160 ) 118 Equity contracts Compensation and benefits expense (10 ) (5 ) — Total equity contracts (10 ) (5 ) — (Loss) gain recognized in earnings on derivatives $ (121 ) $ (139 ) $ 5 (a) Amounts exclude losses related to interest for qualifying accounting hedges of portfolios of retail automotive loans held-for-investment, which are primarily offset by the fixed coupon payments of the loans. The losses were $64 million , $61 million , and $9 million for the years ended December 31, 2015 , and 2014 , and 2013 , respectively. (b) Amounts exclude gains related to interest for qualifying accounting hedges of debt, which are primarily offset by the fixed coupon payment on the long-term debt. The gains were $97 million , $112 million , and $131 million for the years ended December 31, 2015 , 2014 , and 2013 , 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 $1 million for the year ended December 31, 2015. (d) Amounts exclude losses related to amortization of deferred loan basis adjustments on the de-designated hedged item of $8 million for the year ended December 31, 2015 . (e) Amounts exclude gains related to amortization of deferred basis adjustments on the de-designated hedged item of $73 million , $155 million , and $247 million for the years ended December 31, 2015 , 2014 , and 2013 , respectively. (f) Amounts exclude gains and losses related to the revaluation of the related foreign-denominated debt or receivable. Gains of $132 million , and $165 million , and losses of $117 million , were recognized for the years ended December 31, 2015 , 2014 , and 2013 , respectively. The following table summarizes derivative instruments used in cash flow and net investment hedge accounting relationships. Year ended December 31, ( $ in millions ) 2015 2014 2013 Cash flow hedges Interest rate contracts Loss reclassified from accumulated other comprehensive income to interest on long-term debt $ — $ (2 ) $ (7 ) Total interest on long-term debt $ — $ (2 ) $ (7 ) Gain recognized in other comprehensive income $ 2 $ 2 $ 6 Net investment hedges Foreign exchange contracts Loss reclassified from accumulated other comprehensive income to income (loss) from discontinued operations, net $ (4 ) $ — $ (250 ) Total loss from discontinued operations, net $ (4 ) $ — $ (250 ) Gain recognized in other comprehensive income (a) $ 33 $ 13 $ 309 (a) The amounts represent the effective portion of net investment hedges. There are offsetting amounts recognized in accumulated other comprehensive income 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 . There were losses of $59 million , $41 million , and $582 million for the years ended December 31, 2015 , 2014 , and 2013 , respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	Income Taxes The significant components of income tax expense (benefit) from continuing operations were as follows. Year ended December 31, ( $ in millions ) 2015 2014 2013 Current income tax expense (benefit) U.S. federal $ — $ (3 ) $ — Foreign 6 8 4 State and local 3 5 — Total current expense 9 10 4 Deferred income tax expense (benefit) U.S. federal 454 270 (67 ) Foreign 1 2 (1 ) State and local 32 39 5 Total deferred expense (benefit) 487 311 (63 ) Total income tax expense (benefit) from continuing operations $ 496 $ 321 $ (59 ) A reconciliation of income tax expense (benefit) 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 ) 2015 2014 2013 Statutory U.S. federal tax expense $ 488 $ 436 $ 125 Change in tax resulting from State and local income taxes, net of federal income tax benefit 38 48 16 Effect of valuation allowance change (26 ) (64 ) (154 ) Nondeductible expenses 14 31 26 Tax credits (12 ) (10 ) (45 ) Changes in unrecognized tax benefits (5 ) (63 ) (10 ) Tax law enactment — (39 ) (44 ) Other, net (1 ) (18 ) 27 Total income tax expense (benefit) from continuing operations $ 496 $ 321 $ (59 ) 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. For the year ended December 31, 2013, consolidated income tax benefit from continuing operations was largely driven by a release of a portion of our valuation allowance related to the measurement of foreign tax credit carryforwards anticipated to be utilized in the future and release of our valuation allowance on capital loss carryforwards utilized against 2013 capital gains. Additional benefit was also recognized from a tax law enactment that retroactively reinstated the active financing exception. As of each reporting date, we consider existing evidence, both positive and negative, that could impact our view with regard to future realization of deferred tax assets. We continue to believe it is more likely than not that the benefit for certain foreign tax credit, state net operating loss, 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. The sale of our joint venture in China, which was completed in January 2015, resulted in additional capital gains that allowed us to realize our remaining U.S. federal capital loss carryforwards. This resulted in an income tax benefit upon the reversal of the valuation allowance on the related deferred tax asset. The significant components of deferred tax assets and liabilities are reflected in the following table. December 31, ( $ in millions ) 2015 2014 Deferred tax assets Tax credit carryforwards $ 1,941 $ 1,911 Tax loss carryforwards 950 1,158 Adjustments to loan value 311 520 State and local taxes 194 227 Unearned insurance premiums 141 141 Hedging transactions 99 139 Other 212 210 Gross deferred tax assets 3,848 4,306 Valuation allowance (582 ) (734 ) Deferred tax assets, net of valuation allowance 3,266 3,572 Deferred tax liabilities Lease transactions 1,273 1,148 Deferred acquisition costs 403 378 Debt transactions 162 161 Other 69 78 Gross deferred tax liabilities 1,907 1,765 Net deferred tax assets (a) $ 1,359 $ 1,807 (a) Total net deferred tax assets includes $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 $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, 2015 . The following table summarizes net deferred tax assets including related valuation allowances at December 31, 2015 . ( $ in millions ) Deferred Tax Asset/(Liability) Valuation Allowance Net Deferred Tax Asset/(Liability) Years of Expiration Tax credit carryforwards Foreign tax credits $ 1,748 $ (472 ) $ 1,276 2016 - 2025 General business credits 173 — 173 2032 - 2035 AMT credits 20 — 20 n/a Total tax credit carryforwards 1,941 (472 ) 1,469 Tax loss carryforwards Net operating losses — federal 950 — 950 2031 - 2033 Net operating losses — state 208 (a) (77 ) 131 2016 - 2035 Capital losses — state 28 (a) (28 ) — 2016 - 2017 Total tax loss carryforwards 1,186 (105 ) 1,081 Other deferred tax assets 721 (5 ) 716 n/a Deferred tax assets 3,848 (582 ) 3,266 Deferred tax liabilities (1,907 ) — (1,907 ) n/a Net deferred tax assets $ 1,941 $ (582 ) $ 1,359 (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, 2015 , we do not assert that any foreign earnings are indefinitely reinvested outside of the United States. As a result, all 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, 2015 . The following table provides a reconciliation of the beginning and ending amount of unrecognized tax benefits. ( $ in millions ) 2015 2014 2013 Balance at January 1, $ 191 $ 262 $ 102 Additions based on tax positions related to the current year — — 174 Additions for tax positions of prior years 7 9 1 Settlements (10 ) (79 ) (14 ) Expiration of statute of limitations (3 ) (1 ) (1 ) Balance at December 31, $ 185 $ 191 $ 262 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, 2015 , 2014 , and 2013 , the balance of unrecognized tax benefits that, if recognized, would affect our effective tax rate is $177 million , $182 million , and $240 million , respectively. We recognize accrued interest and penalties related to uncertain income tax positions in interest expense and other operating expenses, respectively. For the years ended December 31, 2015 , 2014 , and 2013 , less than $1 million , $1 million , and $2 million , respectively, were accrued for interest and penalties with the cumulative accrued balance totaling $2 million at December 31, 2015 , $5 million at December 31, 2014 , and $7 million at December 31, 2013 . It is reasonably possible that the unrecognized tax benefits will decrease by up to $180 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 United States and Canada. The oldest tax years that remain subject to examination for those jurisdictions are 2012 and 2011, respectively.

Employee Benefits and Compensat

Employee Benefits and Compensation Plans	12 Months Ended
	Dec. 31, 2015
Compensation Related Costs [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) 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 and service providers (other than our non-employee directors). 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 determined by the Board prior to the IPO, assisted by an independent advisor, 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, both existing and future grants, will be settled in stock and, as a result, 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. Certain awards will continue to require liability treatment and receive the same treatment as previously noted. 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 $18.64 as of December 31, 2015 . We had 35,838,068 shares authorized and available for future grants of incentive-based equity awards at December 31, 2015 . During 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 . For further information on our derivative instruments, refer to Note 22 . RSU Awards RSU awards are incentive awards that have been granted to employees as phantom shares of Ally. 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, which resulted in the recording of an increase to additional paid-in capital of $62 million , with a corresponding decrease in the liability. The remaining RSU cost for these awards, based on the modification date value, will be ratably charged to expense over the applicable service periods with an offset to additional paid-in capital. RSU awards granted in 2012 can vest in one of two different methods. The first method allows vesting ratably over a three-year period starting on the date the award was issued, with awards fully vesting in February 2015. The second method allows vesting ratably over a two-year period, starting on the date the award was issued, with awards fully vesting in February 2014. RSU awards granted in 2015, 2014, and 2013 vest using a single method where vesting is ratable over a two-year period starting on the date the award was issued, with the majority of the awards fully vesting in January 2017, 2016, and 2015. 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 . At December 31, 2014 , there were a total of 4,293,216 RSU award shares outstanding, composed of 17,571 shares awarded during 2009 , 17,219 shares awarded during 2010 , 0 shares awarded during 2011 , 453,735 shares awarded during 2012 , 2,053,271 shares awarded during 2013 , and 1,751,420 shares awarded during 2014 . We recognized expense related to RSU awards of $49 million , $46 million , and $64 million for the years ended December 31, 2015 , 2014 , and 2013 , respectively. These costs were recorded as compensation and benefits expense in our Consolidated Statement of Income . DSU Awards 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 2013, 2014, and 2015 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, 2015 , and December 31, 2014 , there were a total of 1,395,105 and 3,009,942 DSU awards outstanding, respectively. We recognized expense related to DSU awards, before economic hedge, of $3 million , $42 million , and $65 million for the years ended December 31, 2015 , 2014 , and 2013 , 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 . IRSU Awards 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. IRSU awards from 2009, 2010, and 2011 have fully vested. There were no IRSU awards granted to senior executives in 2012. IRSU awards from 2013 vest two-thirds after two years from grant date and in full three years from grant date. IRSU awards from 2014 vest in 2016. As of December 31, 2014, Ally had repaid 100% of its TARP obligations, allowing complete payment of the fully vested awards. The vested IRSU awards that were being deferred until repayment of TARP obligations were paid out in January 2015. The remaining unvested IRSU awards are paid in cash after the vesting requirement is met. Payouts are based on fair value of Ally shares at the time of the payout. The awards require liability treatment and are remeasured monthly at fair value based on market price until they are paid. The compensation costs related to these awards are ratably charged to expense over the requisite service period. Changes in value relating to the portion of the awards that have vested and have not been paid are recognized in earnings in the period in which the changes occur. At December 31, 2015 , and December 31, 2014 , there were a total of 51,103 and 690,355 IRSU award shares outstanding, respectively. We recognized an expense related to IRSU awards, before economic hedge, of $1 million and $8 million for the years ended December 31, 2015 , and 2013 , 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 .

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2014
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. Fair value is based on the assumptions 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, 2015 . 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). • Mortgage loans held-for-sale, net — Certain of our mortgage loans held-for-sale are accounted for at fair value because of fair value option elections. Mortgage loans held-for-sale are typically pooled together and sold into certain exit markets depending on underlying attributes of the loan, such as eligibility with the Federal National Mortgage Association (Fannie Mae), the Federal Home Loan Mortgage Corporation (Freddie Mac), or the Government National Mortgage Association (Ginnie Mae) (collectively, the Government-sponsored Enterprises, or GSEs), product type, interest rate, and credit quality. Mortgage loans previously classified as Level 2 were mainly GSE-eligible mortgage loans carried at fair value due to fair value option election, which were valued predominantly using published forward agency prices. It also included any domestic loans where recently negotiated market prices for the loan pool exist with a counterparty (which approximates fair value) or quoted market prices for similar loans are available. These mortgage loans were transferred into Level 3 as of December 31, 2014, based on decreased observability of significant inputs resulting from no longer being an active seller of mortgage loans to GSEs. As a result, at December 31, 2014, they were valued based on a discounted cash flow basis utilizing cash flow projections from internally developed models that utilized prepayment, default, and discount rate assumptions. Refer to the section within this note titled Fair Value Option for Financial Assets for further information about the fair value elections. • Interests retained in financial asset sales — The interests retained are in securitization trusts and deferred purchase prices on the sale of whole-loans. 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, 2015, or December 31, 2014. 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, 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. State and political subdivisions — 716 — 716 Foreign government 10 167 — 177 Mortgage-backed residential — 10,366 — 10,366 Mortgage-backed commercial — 481 — 481 Asset-backed — 1,755 — 1,755 Corporate debt securities — 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 . Recurring fair value measurements December 31, 2014 ( $ in millions ) Level 1 Level 2 Level 3 Total Assets Investment securities Available-for-sale securities Debt securities U.S. Treasury and federal agencies $ 217 $ 961 $ — $ 1,178 U.S. State and political subdivisions — 406 — 406 Foreign government 14 218 — 232 Mortgage-backed residential — 10,425 — 10,425 Mortgage-backed commercial — 253 — 253 Asset-backed — 1,991 — 1,991 Corporate debt securities — 746 — 746 Total debt securities 231 15,000 — 15,231 Equity securities (a) 906 — — 906 Total available-for-sale securities 1,137 15,000 — 16,137 Mortgage loans held-for-sale, net (b) — — 3 3 Other assets Interests retained in financial asset sales — — 47 47 Derivative contracts in a receivable position (c) Interest rate 4 252 — 256 Foreign currency — 5 — 5 Other 2 — — 2 Total derivative contracts in a receivable position 6 257 — 263 Collateral placed with counterparties (d) — 15 — 15 Total assets $ 1,143 $ 15,272 $ 50 $ 16,465 Liabilities Accrued expenses and other liabilities Derivative contracts in a payable position (c) Interest rate $ (2 ) $ (166 ) $ — $ (168 ) Foreign currency — (78 ) — (78 ) Other (2 ) (4 ) — (6 ) Total derivative contracts in a payable position (4 ) (248 ) — (252 ) Total liabilities $ (4 ) $ (248 ) $ — $ (252 ) (a) Our investment in any one industry did not exceed 16% . (b) Carried at fair value due to fair value option elections. (c) For additional information on derivative instruments and hedging activities, refer to Note 22 . (d) Represents collateral in the form of investment securities. Cash collateral was excluded. 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 gains Fair value at December 31, 2015 Net unrealized gains included in earnings still held at December 31, 2015 ( $ in millions ) Fair value at January 1, 2015 included in earnings included in OCI Purchases Sales Issuances Settlements Transfers into level 3 Transfers out of level 3 Assets Loans held-for-sale $ 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 . Level 3 recurring fair value measurements Net realized/unrealized gains Fair value at December 31, 2014 Net unrealized gains included in earnings still held at December 31, 2014 ( $ in millions ) Fair value at January 1, 2014 included in earnings included in OCI Purchases Sales Issuances Settlements Transfers into level 3 Transfers out of level 3 Assets Loans held-for-sale $ — $ — $ — $ — $ — $ — $ — $ 3 $ — $ 3 $ 1 Other assets Interests retained in financial asset sales 100 13 (a) — — — — (66 ) — — 47 — Interest rate derivative contracts, net (1 ) — — — — — (2 ) — 3 — — Total assets $ 99 $ 13 $ — $ — $ — $ — $ (68 ) $ 3 $ 3 $ 50 $ 1 (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 fair value measurements Lower-of-cost or fair value or valuation reserve allowance 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 $ — $ — $ 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. Nonrecurring fair value measurements Lower-of-cost or fair value or valuation reserve allowance Total loss included in earnings for the year ended December 31, 2014 ( $ in millions ) Level 1 Level 2 Level 3 Total Assets Loans held-for-sale $ — $ — $ 36 $ 36 $ — n/m (a) Commercial finance receivables and loans, net (b) Automotive — — 24 24 (6 ) n/m (a) Other — — 32 32 (15 ) n/m (a) Total commercial finance receivables and loans, net — — 56 56 (21 ) n/m (a) Other assets Repossessed and foreclosed assets (c) — — 8 8 (2 ) n/m (a) Other — — 2 2 — n/m (a) Total assets $ — $ — $ 102 $ 102 $ (23 ) 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 2014 . 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 government-insured 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 market data to develop estimates of fair value, so the estimates are not necessarily indicative of the amounts that could be realized or would be paid in a current market exchange. The effect of using different market assumptions or estimation methodologies could be material to the estimated fair values. Fair value information presented herein was based on information available at December 31, 2015 , and 2014 . Estimated fair value December 31, ( $ in millions ) Carrying value Level 1 Level 2 Level 3 Total 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 2014 Financial assets Loans held-for-sale, net $ 2,003 $ — $ 485 $ 1,554 $ 2,039 Finance receivables and loans, net 98,971 — — 99,430 99,430 Nonmarketable equity investments 271 — 246 33 279 Financial liabilities Deposit liabilities $ 58,203 $ — $ — $ 58,777 $ 58,777 Short-term borrowings 7,062 — — 7,063 7,063 Long-term debt 66,380 — 25,224 44,084 69,308 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. As such, 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. As such, the carrying value approximates the fair value of these instruments. • Loans held-for-sale, net — Loans held-for-sale classified as Level 3 include all loans valued using internally developed valuation models because observable market prices were not available. We based our valuation of automotive loans held-for-sale on internally developed discounted cash flow models (an income approach). These valuation models estimate the exit price we expect to receive in the loan’s principal market, which, depending on characteristics of the loans, may be the whole-loan market or the securitization market. Although we utilize and give priority to market observable inputs, such as interest rates and market spreads within these models, we are typically required to utilize internal inputs, such as prepayment speeds (absolute prepayment model, or ABS), gross loss range by loan segment (percentage of receivable balance lost in the event of default), and credit spreads (the risk premium component added to observed benchmark rate to determine the discount rate used in the discounted cash flow model). While numerous controls exist to calibrate, corroborate, and validate these internal inputs, these internal inputs require the use of judgment and can have a significant impact on the determination of the loan’s value. Accordingly, we classified all automotive loans held-for-sale as Level 3 as of December 31, 2014. Loans held-for-sale classified as Level 2 as of December 31, 2014, represent mortgage TDR loans valued using quoted prices in active markets for similar assets. • 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. For consumer mortgage loans, we used valuation methods and assumptions similar to those used for mortgage loans held-for-sale. These valuations consider unique attributes of the loans such as geography, delinquency status, product type, and other factors. Refer to the section above titled Mortgage loans held-for-sale, net , for a description of methodologies and assumptions used to determine the fair value of mortgage loans held-for-sale. • 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 were 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	12 Months Ended
	Dec. 31, 2015
Offsetting [Abstract]
Assets and Liabilities Subject to Enforceable Master Netting Arrangements [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, 2015 , 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) Presented in the Consolidated Balance Sheet Gross Amounts Not Offset in the Consolidated Balance Sheet December 31, 2015 ( $ in millions ) Financial Instruments Collateral (a) (b) (c) 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 . (e) For additional information on securities sold under agreements to repurchase, refer to Note 15 . Gross Amounts of Recognized Assets/(Liabilities) Gross Amounts Offset in the Consolidated Balance Sheet Net Amounts of Assets/(Liabilities) Presented in the Consolidated Balance Sheet Gross Amounts Not Offset in the Consolidated Balance Sheet December 31, 2014 ( $ in millions ) Financial Instruments Collateral (a) Net Amount Assets Derivative assets in net asset positions $ 216 $ — $ 216 $ (60 ) $ (68 ) $ 88 Derivative assets in net liability positions 47 — 47 (47 ) — — Total assets (b) $ 263 $ — $ 263 $ (107 ) $ (68 ) $ 88 Liabilities Derivative liabilities in net liability positions $ (188 ) $ — $ (188 ) $ 47 $ 54 $ (87 ) Derivative liabilities in net asset positions (60 ) — (60 ) 60 — — Derivative liabilities with no offsetting arrangements (4 ) — (4 ) — — (4 ) Total derivative liabilities (b) (252 ) — (252 ) 107 54 (91 ) Securities sold under agreements to repurchase (c) (774 ) — (774 ) — 774 — Total liabilities $ (1,026 ) $ — $ (1,026 ) $ 107 $ 828 $ (91 ) (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) For additional information on derivative instruments and hedging activities, refer to Note 22 . (c) For additional information on securities sold under agreements to repurchase, refer to Note 15 .

Segment And Geographic Informat

Segment And Geographic Information	12 Months Ended
	Dec. 31, 2015
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. Change in Reportable Segments As a result of a change in how management views and operates our business, during the first quarter of 2016, we made changes in the composition of our operating segments. Financial information related to our Corporate Finance business is now presented as a separate reportable segment. Previously, all such activity was included in Corporate and Other. Additionally, only the activity of our ongoing bulk acquisitions of mortgage loans and other originations and refinancing is now presented in Mortgage Finance operations. The activity related to the management of our legacy mortgage portfolio is now included in Corporate and Other. Our other operating segments, Automotive Finance operations and Insurance operations, remained unchanged. We continue to allocate costs to our reportable segments in a manner consistent with the methodology updated during the fourth quarter of 2015. Amounts for 2014 and 2013 have been adjusted to conform to the current management view. 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 automotive financing services to consumers and automotive dealers. Our automotive financing services include providing retail installment sales financing, loans, and leases; offering term loans to dealers, financing dealer floorplans and other lines of credit to dealers; fleet financing, and vehicle remarketing services. Insurance operations — Offers both consumer financial and insurance products sold primarily through the automotive dealer channel, and commercial insurance products sold to dealers. As part of our focus on offering dealers a broad range of consumer financial and insurance products, we provide vehicle service contracts, maintenance coverage, and guaranteed asset protection products. We also underwrite selected commercial insurance coverages, which primarily insure dealers' vehicle inventories. Mortgage Finance operations — Includes the management of a held-for-investment consumer mortgage finance loan portfolio and includes the execution of bulk purchases of high-quality jumbo and LMI mortgage loans originated by third parties. Corporate Finance operations — Provides senior secured leveraged cash flow and asset-based loans primarily to U.S.-based middle market companies. The loans are used to support 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, the management of our legacy mortgage portfolio, and reclassifications and eliminations between the reportable operating segments. 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. Change in Allocation of Costs to Reportable Segments During the fourth quarter of 2015, we began to allocate additional overhead expenses related to centralized support functions to our Automotive Finance, Insurance, and Mortgage operations as a result of a change in management's view of our operations. These expenses were previously included within our Corporate and Other activities. Amounts for 2014 and 2013 have been reclassified to conform to the current management view. 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) 2015 Net financing revenue $ 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 (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 2013 Net financing revenue (loss) $ 3,159 $ 57 $ 38 $ 44 $ (519 ) $ 2,779 Other revenue (loss) 268 1,196 (1 ) 33 (12 ) 1,484 Total net revenue (loss) 3,427 1,253 37 77 (531 ) 4,263 Provision for loan losses 494 — (11 ) (6 ) 24 501 Total noninterest expense 1,755 999 30 39 582 3,405 Income (loss) from continuing operations before income tax expense $ 1,178 $ 254 $ 18 $ 44 $ (1,137 ) $ 357 Total assets $ 109,312 $ 7,124 $ 3,294 $ 1,633 $ 29,545 $ 150,908 (a) Net financing revenue after the provision for loan losses totaled $3.0 billion , $2.9 billion , and $2.3 billion for the years ended December 31, 2015 , 2014 , and 2013 , respectively. Information concerning principal geographic areas were as follows. Year ended December 31, ( $ in millions ) Revenue (a) Income (loss) from continuing operations before income tax expense (b) Net income (loss) (b) (c) Identifiable assets (d) Long-lived assets (e) 2015 Canada $ 98 $ 47 $ 35 $ 514 $ — Europe 1 4 27 325 — Latin America — — (2 ) 28 — Asia-Pacific — — 452 2 — Total foreign (f) 99 51 512 869 — Total domestic (g) 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 (f) 126 54 186 2,891 — Total domestic (g) 4,525 1,192 964 148,713 19,735 Total $ 4,651 $ 1,246 $ 1,150 $ 151,604 $ 19,735 2013 Canada $ 171 $ 64 $ 1,266 $ 704 $ — Europe (h) (8 ) (18 ) (88 ) 1,972 — Latin America — 7 300 29 — Asia-Pacific 1 (2 ) 117 520 — Total foreign 164 51 1,595 3,225 — Total domestic (g) 4,099 306 (1,234 ) 147,656 17,916 Total $ 4,263 $ 357 $ 361 $ 150,881 $ 17,916 (a) Revenue consists of net financing revenue and total other revenue as presented in our Consolidated Statement of Income . (b) The domestic amounts include original discount amortization of $62 million , $189 million , and $262 million for the years ended December 31, 2015 , 2014 , and 2013 , respectively. (c) Gain (loss) realized on sale of discontinued operations are allocated to the geographic area in which the business operated. (d) Identifiable assets consist of total assets excluding goodwill. (e) Long-lived assets consist of investment in operating leases, net, and net property and equipment. (f) Our foreign operations as of December 31, 2015 , and December 31, 2014 , consist of our ongoing Insurance operations in Canada, and our remaining international entities in wind-down. (g) Amounts include eliminations between our domestic and foreign operations. (h) Amounts include eliminations between our foreign operations.

Parent And Guarantor Consolidat

Parent And Guarantor Consolidating Financial Statements	12 Months Ended
	Dec. 31, 2015
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, 2015 , 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, 2015 ( $ in millions ) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing 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 available-for-sale investment securities — — 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 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 Depreciation expense on operating lease assets 7 — 2,242 — 2,249 Net financing (loss) 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 Servicing fees 1,137 — 834 (1,926 ) 45 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 236 — 539 (461 ) 314 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 available-for-sale investment securities — — 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 Depreciation expense on operating lease assets 161 — 2,072 — 2,233 Net financing (loss) 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 Servicing fees 1,071 — 792 (1,832 ) 31 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 208 — 507 (435 ) 280 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 Year ended December 31, 2013 ( $ in millions ) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing revenue and other interest income Interest and fees on finance receivables and loans $ 771 $ — $ 3,758 $ — $ 4,529 Interest and fees on finance receivables and loans — intercompany 59 — 68 (127 ) — Interest on loans held-for-sale — — 20 — 20 Interest and dividends on available-for-sale investment securities — — 325 — 325 Interest on cash and cash equivalents 3 — 7 — 10 Interest-bearing cash — intercompany — — 7 (7 ) — Operating leases 500 — 2,709 — 3,209 Total financing revenue and other interest income 1,333 — 6,894 (134 ) 8,093 Interest expense Interest on deposits 25 — 629 — 654 Interest on short-term borrowings 46 — 17 — 63 Interest on long-term debt 2,039 — 568 (5 ) 2,602 Interest on intercompany debt 66 — 62 (128 ) — Total interest expense 2,176 — 1,276 (133 ) 3,319 Depreciation expense on operating lease assets 369 — 1,626 — 1,995 Net financing (loss) revenue (1,212 ) — 3,992 (1 ) 2,779 Cash dividends from subsidiaries Nonbank subsidiaries 5,732 3,659 — (9,391 ) — Other revenue Servicing fees 152 — (26 ) — 126 Servicing asset valuation and hedge activities, net — — (213 ) — (213 ) Total servicing income (loss), net 152 — (239 ) — (87 ) Insurance premiums and service revenue earned — — 1,012 — 1,012 Gain on mortgage and automotive loans, net — — 55 — 55 (Loss) gain on extinguishment of debt (61 ) — 2 — (59 ) Other gain on investments, net — — 180 — 180 Other income, net of losses 157 — 1,438 (1,212 ) 383 Total other revenue 248 — 2,448 (1,212 ) 1,484 Total net revenue 4,768 3,659 6,440 (10,604 ) 4,263 Provision for loan losses 196 — 305 — 501 Noninterest expense Compensation and benefits expense 640 — 821 (442 ) 1,019 Insurance losses and loss adjustment expenses — — 405 — 405 Other operating expenses 501 — 2,250 (770 ) 1,981 Total noninterest expense 1,141 — 3,476 (1,212 ) 3,405 Income from continuing operations before income tax (benefit) expense and undistributed income (loss) of subsidiaries 3,431 3,659 2,659 (9,392 ) 357 Income tax (benefit) expense from continuing operations (969 ) — 910 — (59 ) Net income from continuing operations 4,400 3,659 1,749 (9,392 ) 416 (Loss) income from discontinued operations, net of tax (1,321 ) (19 ) 1,284 1 (55 ) Undistributed income (loss) of subsidiaries Bank subsidiary 883 883 — (1,766 ) — Nonbank subsidiaries (3,601 ) (2,393 ) — 5,994 — Net income 361 2,130 3,033 (5,163 ) 361 Other comprehensive loss, net of tax (587 ) (812 ) (873 ) 1,685 (587 ) Comprehensive (loss) income $ (226 ) $ 1,318 $ 2,160 $ (3,478 ) $ (226 ) Condensed Consolidating Balance Sheet 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 Investment 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. December 31, 2014 ( $ in millions ) Parent (a) Guarantors Nonguarantors (a) Consolidating adjustments Ally consolidated Assets Cash and cash equivalents Noninterest-bearing $ 986 $ — $ 362 $ — $ 1,348 Interest-bearing 1,300 — 2,928 — 4,228 Interest-bearing — intercompany — — 615 (615 ) — Total cash and cash equivalents 2,286 — 3,905 (615 ) 5,576 Investment securities — — 16,137 — 16,137 Loans held-for-sale, net 3 — 2,000 — 2,003 Finance receivables and loans, net Finance receivables and loans, net 4,225 — 95,723 — 99,948 Intercompany loans to Bank subsidiary 625 — — (625 ) — Nonbank subsidiaries 3,500 — 1,770 (5,270 ) — Allowance for loan losses (102 ) — (875 ) — (977 ) Total finance receivables and loans, net 8,248 — 96,618 (5,895 ) 98,971 Investment in operating leases, net — — 19,510 — 19,510 Intercompany receivables from Bank subsidiary 219 — — (219 ) — Nonbank subsidiaries 267 — 393 (660 ) — Investment in subsidiaries Bank subsidiary 15,967 15,967 — (31,934 ) — Nonbank subsidiaries 11,559 12 — (11,571 ) — Premiums receivable and other insurance assets — — 1,717 (22 ) 1,695 Other assets 4,757 — 4,814 (2,466 ) 7,105 Assets of operations held-for-sale 634 — — — 634 Total assets $ 43,940 $ 15,979 $ 145,094 $ (53,382 ) $ 151,631 Liabilities Deposit liabilities Noninterest-bearing $ — $ — $ 64 $ — $ 64 Interest-bearing 319 — 57,820 — 58,139 Total deposit liabilities 319 — 57,884 — 58,203 Short-term borrowings 3,338 — 3,724 — 7,062 Long-term debt 21,067 — 45,313 — 66,380 Intercompany debt to Nonbank subsidiaries 2,385 — 4,125 (6,510 ) — Intercompany payables to Bank subsidiary 94 — — (94 ) — Nonbank subsidiaries 454 — 354 (808 ) — Interest payable 316 — 161 — 477 Unearned insurance premiums and service revenue — — 2,375 — 2,375 Accrued expenses and other liabilities 568 82 3,551 (2,466 ) 1,735 Total liabilities 28,541 82 117,487 (9,878 ) 136,232 Total equity 15,399 15,897 27,607 (43,504 ) 15,399 Total liabilities and equity $ 43,940 $ 15,979 $ 145,094 $ (53,382 ) $ 151,631 (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, 2015 ( $ in millions ) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 354 $ 525 $ 6,390 $ (2,174 ) $ 5,095 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 Net decrease (increase) in finance receivables and loans 1,785 — (15,630 ) — (13,845 ) Proceeds from sales of finance receivables and loans originated as held-for investment — — 3,197 — 3,197 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 Other, net (47 ) — (105 ) — (152 ) 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 ) 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 (4,586 ) (524 ) 6,533 4,037 5,460 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 Net decrease (increase) in finance receivables and loans 1,900 — (6,941 ) 17 (5,024 ) Proceeds from sales of finance receivables and loans originated as held-for-investment — — 2,592 — 2,592 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 Other, net (29 ) — 101 — 72 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 Year ended December 31, 2013 ( $ in millions ) Parent Guarantors Nonguarantors Consolidating Ally Operating activities Net cash provided by operating activities $ 3,015 $ 3,572 $ 5,305 $ (9,391 ) $ 2,501 Investing activities Purchases of available-for-sale securities — — (12,304 ) — (12,304 ) Proceeds from sales of available-for-sale securities — — 3,627 — 3,627 Proceeds from maturities and repayments of available-for-sale securities — — 5,509 — 5,509 Net decrease (increase) in finance receivables and loans 4,898 79 (7,456 ) — (2,479 ) Net change in loans — intercompany 301 251 (1,503 ) 951 — Purchases of operating lease assets (1,450 ) — (7,746 ) — (9,196 ) Disposals of operating lease assets 130 — 2,834 — 2,964 Capital contributions to subsidiaries (477 ) — — 477 — Returns of contributed capital 1,002 150 — (1,152 ) — Sales of mortgage servicing rights — — 911 — 911 Proceeds from sale of business unit, net 1,799 554 5,091 — 7,444 Net change in restricted cash — (26 ) (44 ) — (70 ) Other, net 41 — 10 — 51 Net cash provided by (used in) investing activities 6,244 1,008 (11,071 ) 276 (3,543 ) Financing activities Net change in short-term borrowings — third party 131 36 1,424 — 1,591 Net (decrease) increase in deposits (543 ) — 5,861 39 5,357 Proceeds from issuance of long-term debt — third party 3,236 — 24,094 — 27,330 Repayments of long-term debt — third party (9,468 ) (70 ) (22,354 ) — (31,892 ) Net change in debt — intercompany 1,803 (271 ) (624 ) (908 ) — Proceeds from issuance of common stock 1,270 — — — 1,270 Repurchase of mandatorily convertible preferred stock held by U.S. Department of Treasury and elimination of share adjustment right (5,925 ) — — — (5,925 ) Dividends paid — third party (810 ) — — — (810 ) Dividends paid and returns of contributed capital — intercompany — (4,267 ) (6,275 ) 10,542 — Capital contributions from parent — 29 448 (477 ) — Net cash (used in) provided by financing activities (10,306 ) (4,543 ) 2,574 9,196 (3,079 ) Effect of exchange-rate changes on cash and cash equivalents — — 45 — 45 Net (decrease) increase in cash and cash equivalents (1,047 ) 37 (3,147 ) 81 (4,076 ) Adjustment for change in cash and cash equivalents of operations held-for-sale — — 2,094 — 2,094 Cash and cash equivalents at beginning of year 3,977 — 4,027 (491 ) 7,513 Cash and cash equivalents at end of year $ 2,930 $ 37 $ 2,974 $ (410 ) $ 5,531

Guarantees and Commitments

Guarantees and Commitments	12 Months Ended
	Dec. 31, 2015
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. 2015 2014 December 31, ( $ in millions ) Maximum liability Carrying value of liability Maximum liability Carrying value of liability Standby letters of credit and other guarantees $ 208 $ 13 $ 268 $ 19 Standby Letters of Credit Corporate Finance has exposure to standby letters of credit that represent irrevocable guarantees of payment of specified financial obligations. Third-party beneficiaries primarily utilize standby letters of credit as insurance in the event of nonperformance by our customers. Assets of the customers (e.g., trade receivables, inventory, and cash deposits) generally collateralize the letters of credit. Expiration dates on letters of credit range from certain ongoing commitments that will expire during the upcoming year to terms of several years for certain letters of credit. If nonperformance by a customer occurs for letters of credit, we can be liable for payment of the letter of credit to the beneficiary with our likely recourse being a charge back to the customer or liquidation of the collateral. Commitments Financing Commitments The contractual commitments were as follows. December 31, ( $ in millions ) 2015 2014 Commitments to provide capital to investees (a) $ 132 $ 66 Construction-lending commitments (b) 197 110 Home equity lines of credit (c) 358 371 Unused revolving credit line commitments and other (d) 1,445 1,284 (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, 2015 , are as follows. Year ended December 31, ( $ in millions ) 2016 $ 39 2017 34 2018 31 2019 31 2020 29 2021 and thereafter 99 Total minimum payment required $ 263 Certain of the leases contain escalation clauses and renewal or purchase options. Rental expenses under operating leases were $51 million , $50 million , and $47 million in 2015 , 2014 , and 2013 , 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 ) 2016 $ 47 2017 and 2018 51 2019 and thereafter 3 Total future payment obligations $ 101

Contingencies And Other Risks

Contingencies And Other Risks	12 Months Ended
	Dec. 31, 2015
Loss Contingency [Abstract]
Contingencies Disclosure and Other Risks [Text Block]	Contingencies and Other Risks In the normal course of business, we enter into transactions that expose us to varying degrees of risk. Concentration with GM and Chrysler While we are continuing to diversify our business, General Motors Company (GM) and Fiat Chrysler Automobiles US LLC (Chrysler) dealers and their retail customers continue to compose a significant portion of our customer base. It is possible that GM or Chrysler could take actions that negatively impact the amount of business 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, 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 vehicle recalls, 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 profitability and financial condition. We were previously party to agreements with each of GM and Chrysler that provided for certain exclusivity privileges related to subvention programs that they offered. Our agreement with Chrysler expired in April 2013. In addition, our agreement with GM expired effective February 28, 2014. These agreements provided Ally with certain preferred provider benefits, including limiting the use of other financing providers by GM and Chrysler for their incentive programs. During 2015, GM determined to provide subvention programs exclusively through a wholly-owned subsidiary. Legal Proceedings We are or may be subject to potential liability under various governmental proceedings, claims, and legal actions that are pending or otherwise asserted against us. We are named as defendants in a number of legal actions, and we are involved in governmental proceedings arising in connection with our respective businesses. Some of the pending actions purport to be class actions, and certain legal actions include claims for substantial compensatory and/or punitive damages or claims for indeterminate amounts of damages. We establish reserves for legal claims when payments associated with the claims become probable and the payments can be reasonably estimated. Given the inherent difficulty of predicting the outcome of litigation and regulatory matters, it is generally very difficult to predict what the eventual outcome will be, and when the matter will be resolved. The actual costs of resolving legal claims may be higher or lower than any amounts reserved for the claims. On the basis of information currently available, advice of counsel, available insurance coverage, and established reserves, it is the opinion of management that the eventual outcome of the current actions against us will not have a material adverse effect on our consolidated financial condition, results of operations, or cash flows. However, it is possible that the ultimate resolution of legal matters, if unfavorable, may be material to our consolidated financial condition, results of operations, or cash flows in a particular period. Regulatory Matters Ally and its subsidiaries, including Ally Bank, are or may become involved from time to time in formal and informal reviews, investigations, examinations, proceedings, and information-gathering requests by federal and state government and self-regulatory agencies, including, among others, the DOJ, Securities and Exchange Commission (SEC), CFPB, the FRB, the FDIC, the Utah Department of Financial Institutions, and the Federal Trade Commission regarding their respective operations. Mortgage Matters We have received subpoenas from the DOJ that include a broad request for documentation and other information relating to residential mortgage-backed securities issued by our former mortgage subsidiary, Residential Capital, LLC and its subsidiaries (ResCap RMBS). In connection with these requests, the DOJ is investigating potential fraud and other potential legal claims related to ResCap RMBS, including its investigation of potential claims under the Financial Institutions Reform, Recovery, and Enforcement Act of 1989. The DOJ is also investigating potential claims under the False Claims Act (FCA) related to representations made by us in connection with investments in Ally made by the United States 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. We continue to engage in discussions with the DOJ with respect to legal and factual aspects of their investigations and potential claims. As previously disclosed, at the request of the DOJ, we entered into an agreement to voluntarily extend the statutes of limitations related to potential FCA claims. This agreement expired at the end of January 2016. We have separately received subpoenas and document requests from the SEC that include information covering a wide range of mortgage-related matters. These matters could result in material adverse consequences including, without limitation, adverse judgments, significant settlements, fines, penalties, injunctions, or other 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, we received an information request from the New York Department of Financial Services requesting similar information. We have cooperated with each of these agencies with respect to these matters. These matters could result in material adverse consequences including, without limitation, adverse judgments, significant settlements, fines, penalties, injunctions, or other actions. CFPB In December 2013, Ally Financial Inc. and Ally Bank entered into Consent Orders issued by the CFPB and the DOJ pertaining to the allegation of disparate impact in 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 compliance to dealers, 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 dealers. Ally formed a compliance committee consisting of certain Ally 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. These matters could result in material adverse consequences including, without limitation, adverse judgments, significant settlements, fines, penalties, injunctions, or other actions. Other Contingencies We are subject to potential liability under various other exposures including tax, nonrecourse loans, self-insurance, and other miscellaneous contingencies. We establish reserves for these contingencies when the loss becomes probable and the amount can be reasonably estimated. The actual costs of resolving these items may be substantially higher or lower than the amounts reserved for any one item. Based on information currently available, it is the opinion of management that the eventual outcome of these items will not have a material adverse impact on our results of operations, financial position, or cash flows.

Quarterly Financial Statments (

Quarterly Financial Statments (unaudited)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Statements [Abstract]
Quarterly Financial Information [Text Block]	Quarterly Financial Statements (unaudited) ( $ in millions ) First quarter Second quarter Third quarter Fourth quarter 2015 Net financing revenue $ 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 ) 2014 Net financing revenue $ 821 $ 866 $ 889 $ 799 Other revenue 321 365 375 215 Total net revenue 1,142 1,231 1,264 1,014 Provision for loan losses 137 63 102 155 Total noninterest expense 713 821 742 672 Income from continuing operations before income tax expense 292 347 420 187 Income tax expense from continuing operations 94 64 127 36 Net income from continuing operations 198 283 293 151 Income from discontinued operations, net of tax 29 40 130 26 Net income $ 227 $ 323 $ 423 $ 177 Basic earnings per common share Net income from continuing operations $ 0.27 $ 0.45 $ 0.47 $ 0.17 Net income 0.33 0.54 0.74 0.23 Diluted earnings per common share Net income from continuing operations $ 0.27 $ 0.45 $ 0.47 $ 0.17 Net income 0.33 0.54 0.74 0.23

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2015
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events Declaration of Quarterly Dividend Payments On January 11, 2016 , the Ally Board of Directors declared a quarterly dividend payment on certain outstanding preferred stock. This included a cash dividend of $0.53 per share, or a total of $15 million , on Fixed Rate/Floating Rate Perpetual Preferred Stock, Series A. The dividend was paid on February 16, 2016 . Realignment of Operating Segments As a result of a change in how management views and operates our business, during the first quarter of 2016, we made changes in the composition of our operating segments. Financial information related to our Corporate Finance business will be presented as a separate reportable segment. Currently, all such activity is disclosed in Corporate and Other. Additionally, only the activity of our ongoing bulk acquisitions of mortgage loans and other originations and refinancing will be presented in Mortgage operations. The activity related to the management of our legacy mortgage portfolio will be disclosed in Corporate and Other. Our other operating segments, Automotive Finance operations and Insurance operations, remain unchanged. Our segment results will be reported under this new structure beginning in the first quarter of 2016, and results from prior periods will be reported in a manner consistent with the new structure.

Description Of Business, Basi40

Description Of Business, Basis of Presentation, And Changes in Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
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 10 for further details on our VIEs.
Basis of Accounting [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]	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.
Cash and Cash Equivalents, Policy [Policy Text Block]	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.
Marketable Securities, Policy [Policy Text Block]	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. 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 currently includes securities classified as available-for-sale, which are carried at fair value with unrealized gains and losses included in accumulated other comprehensive income or loss. 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. 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 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. Noncredit component losses of a debt security are 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. 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 l ong 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 6 . In addition to our investment securities, we hold nonmarketable equity investments. Our nonmarketable equity investments are carried at cost less any previously recognized impairment, reported in other assets, and include Federal Home Loan Bank (FHLB) stock held to meet regulatory requirements, certain equity investments in low income housing tax credits, and other equity investments that are not publicly traded and therefore do not have a readily determinable fair value. As conditions warrant, we review our investments carried at cost for impairment and will adjust the carrying value of the investment if it is deemed to be impaired. No impairment was recognized in 2015 or 2014. For more information on our nonmarketable equity investments, refer to Note 25
Finance, Loans and Leases Receivable, Policy [Policy Text Block]	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 8 . 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. • 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 or 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 are reported as nonperforming loans in Note 8 . 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 a reduction to provision 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 and noncollateral dependent loans are fully written-off.
Loans and Leases Receivable, Allowance for Loan Losses Policy [Policy Text Block]	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 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 2015, 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 8 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, anticipated repossessions or foreclosures based on portfolio trends, and 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 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 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 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]	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 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 10 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 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 customary market representation and warranty repurchase provisions.
Finance, Loan and Lease Receivables, Held for Investments, Foreclosed Assets Policy [Policy Text Block]	Repossessed and Foreclosed Assets 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 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 and analysis. 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 2015 , 2014 , or 2013 . 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.
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]	Impairment of Long-lived Assets 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 2015 , 2014 , or 2013 . An impairment test on an asset group to be sold or otherwise disposed of is performed upon occurrence of a triggering event or when certain criteria are met (e.g., the asset is planned to be disposed of within twelve months, appropriate levels of authority have approved the sale, there is an active program to locate a buyer, etc.), which cause the disposal group to be classified as held-for-sale. Long-lived assets held-for-sale are recorded at the lower of their carrying amount or estimated fair value less cost to sell. If the net carrying value of the assets held-for-sale exceeds the fair value less cost to sell, we recognize an impairment loss based on the excess of the net carrying amount over the fair value of the assets less cost to sell. Refer to Note 2 for a discussion of discontinued and held-for-sale operations.
Property, Plant and Equipment, Policy [Policy Text Block]	Property and Equipment 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, and capitalized software costs. 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.
Revenue Recognition, Deferred Revenue [Policy Text Block]	Unearned Insurance Premiums and Service Revenue 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 3 .
Deferred Charges, Policy [Policy Text Block]	Deferred Policy Acquisition Costs Certain commissions, that are primarily related to and vary with the production of business, are deferred and recorded in other assets. 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 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 claims adjustment expenses relating to direct insurance and assumed reinsurance agreements. 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]	Legal and Regulatory Reserves 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 .
Earnings Per Share, Policy [Policy Text Block]	Earnings per Common Share 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 the dilutive potential common shares had been issued (assuming it does not have the effect of antidilution), if applicable.
Derivatives, Policy [Policy Text Block]	Derivative Instruments and Hedging Activities We primarily use derivative instruments for risk management 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 . 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 the 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]	Income Taxes 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 .
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	Share-based Compensation 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 remeasured quarterly at fair value until they are paid, with changes in fair value charged to compensation expense in the period in which the change occurs. Refer to Note 24 for a discussion of our share-based compensation plans.
Foreign Currency Transactions and Translations Policy [Policy Text Block]	Foreign Exchange 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. 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.

Discontinued and Held-for-sal41

Discontinued and Held-for-sale Operations Discontinued and Held-for-sale Operations (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Discontinued Operations, Policy [Policy Text Block]	Discontinued Operations Prior to the adoption of ASU 2014-08, which was prospectively applied only to newly identified disposals that qualified as discontinued operations beginning after January 1, 2015, we 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.

Discontinued and Held-for-sal42

Discontinued and Held-for-sale Operations Discontinued Operations and Disposal Groups (Tables)	12 Months Ended
	Dec. 31, 2015
Discontinued Operations and Disposal Groups [Abstract]
Select Income Statement Information for Discontinued Operations [Table Text Block]	Select financial information of discontinued operations is summarized below. The pretax income or loss, including direct costs to transact a sale, includes any impairment recognized to present the operations at the lower-of-cost or fair value. Fair value was based on the estimated sales price, which could differ from the ultimate sales price due to price volatility, changing interest rates, changing foreign-currency rates, and future economic conditions. Year ended December 31, ($ in millions) 2015 2014 2013 Select Insurance operations Total net revenue $ — $ — $ 190 Pretax income including direct costs to transact a sale (a) 3 6 319 (b) Tax expense (benefit) (c) 1 6 (14 ) Select Automotive Finance operations Total net revenue $ — $ 123 $ 572 Pretax income including direct costs to transact a sale (a) 452 129 660 (d) Tax expense (benefit) (c) 80 7 (101 ) Select Corporate Finance operations Total net revenue $ — $ — $ — Pretax income including direct costs to transact a sale (a) 22 23 — Tax expense (c) — 3 — Select Corporate and Other operations Total net revenue $ — $ — $ — Pretax loss (e) (9 ) (4 ) (1,741 ) Tax (benefit) (5 ) (87 ) (592 ) (a) Includes certain treasury and other corporate activity recognized by Corporate and Other. (b) Includes recognized pretax gain of $274 million in connection with the sale of our Mexican insurance business, ABA Seguros. (c) Includes certain income tax activity recognized by Corporate and Other. (d) Includes recognized pretax loss of $488 million in connection with the sale of our European and Latin American automotive finance operations and pretax gain of $888 million in connection with the sale of our Canadian automotive finance operations, Ally Credit Canada Limited and ResMor Trust. (e) Includes amounts related to our former ResCap subsidiary.

Insurance Premiums and Servic43

Insurance Premiums and Service Revenue Earned (Tables)	12 Months Ended
	Dec. 31, 2015
Premiums Written and 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. 2015 2014 2013 Year ended December 31, ($ in millions) Written Earned Written Earned Written Earned Insurance premiums Direct $ 313 $ 296 $ 294 $ 282 $ 270 $ 305 Assumed 2 16 43 54 61 58 Gross insurance premiums 315 312 337 336 331 363 Ceded (184 ) (125 ) (156 ) (117 ) (172 ) (120 ) Net insurance premiums 131 187 181 219 159 243 Service revenue 846 753 842 760 838 769 Insurance premiums and service revenue written and earned $ 977 $ 940 $ 1,023 $ 979 $ 997 $ 1,012

Other Income, Net Of Losses (Ta

Other Income, Net Of Losses (Tables)	12 Months Ended
	Dec. 31, 2015
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) 2015 2014 2013 Remarketing fees $ 101 $ 112 $ 82 Late charges and other administrative fees 90 88 94 Income from equity-method investments 52 18 15 Mortgage processing fees and other mortgage income — — 81 Fair value adjustment on derivatives (a) (8 ) (31 ) 24 Other, net 79 93 87 Total other income, net of losses $ 314 $ 280 $ 383 (a) Refer to Note 22 for a description of derivative instruments and hedging activities.

Other Operating Expenses (Table

Other Operating Expenses (Tables)	12 Months Ended
	Dec. 31, 2015
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) 2015 2014 2013 Insurance commissions $ 378 $ 374 $ 370 Technology and communications 267 334 346 Lease and loan administration 126 122 173 Advertising and marketing 107 111 136 Professional services 93 100 176 Premises and equipment depreciation 82 81 81 Regulatory and licensing fees 79 87 116 Vehicle remarketing and repossession 78 83 60 Occupancy 50 47 44 Provision for legal and regulatory settlements (a) 45 4 105 Non-income taxes 29 40 35 Mortgage representation and warranty obligation, net (13 ) (10 ) 104 Other 184 218 235 Total other operating expenses $ 1,505 $ 1,591 $ 1,981 (a) Results for the year ended December 31, 2013, include a $98 million settlement charge related to Consent Orders issued by the Consumer Financial Protection Bureau (CFPB) and the U.S. Department of Justice (DOJ) pertaining to the allegation of disparate impact in the automotive finance business. Refer to Note 30 for additional details.

Investment Securities (Tables)

Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2015
Available-for-sale Securities [Abstract]
Schedule of Available-for-sale Securities Reconciliation [Table Text Block]	Our portfolio of securities includes bonds, equity securities, asset- and mortgage-backed securities, and other investments. The cost, fair value, and gross unrealized gains and losses on available-for-sale securities were as follows. 2015 2014 Amortized cost Gross unrealized Fair 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 $ 1,760 $ — $ (19 ) $ 1,741 $ 1,195 $ 1 $ (18 ) $ 1,178 U.S. States and political subdivisions 693 24 (1 ) 716 389 17 — 406 Foreign government 169 8 — 177 224 8 — 232 Mortgage-backed residential (a) 10,459 52 (145 ) 10,366 10,431 119 (125 ) 10,425 Mortgage-backed commercial 486 — (5 ) 481 254 — (1 ) 253 Asset-backed 1,762 1 (8 ) 1,755 1,989 5 (3 ) 1,991 Corporate debt 1,213 8 (17 ) 1,204 734 14 (2 ) 746 Total debt securities (b) (c) 16,542 93 (195 ) 16,440 15,216 164 (149 ) 15,231 Equity securities 808 3 (94 ) 717 891 49 (34 ) 906 Total available-for-sale securities $ 17,350 $ 96 $ (289 ) $ 17,157 $ 16,107 $ 213 $ (183 ) $ 16,137 (a) Residential mortgage-backed securities include agency-backed bonds totaling $7,544 million and $7,557 million at December 31, 2015 , and December 31, 2014 , respectively. (b) Certain entities related to our Insurance operations are required to deposit securities with state regulatory authorities. These deposited securities totaled $14 million and $15 million at December 31, 2015 , and December 31, 2014 , respectively. (c) Investment securities with a fair value of $2,506 million and $801 million at December 31, 2015 , and December 31, 2014 , 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 $745 million of the underlying investment securities.
Investments Classified by Contractual Maturity Date [Table Text Block]	The maturity distribution of available-for-sale debt securities outstanding is summarized in the following tables. Call or prepayment options may cause actual maturities to differ from contractual maturities. Total Due in one year or less Due after one year through five years Due after five years through ten years Due after ten years ($ in millions) Amount Yield Amount Yield Amount Yield Amount Yield Amount Yield December 31, 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 — — Mortgage-backed residential 10,366 2.9 — — 33 2.1 36 2.5 10,297 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 December 31, 2014 Fair value of available-for-sale debt securities (a) U.S. Treasury and federal agencies $ 1,178 1.5 % $ 7 3.0 % $ 677 1.2 % $ 494 1.9 % $ — — % U.S. States and political subdivisions 406 3.7 34 1.9 12 2.1 106 3.0 254 4.3 Foreign government 232 2.7 — — 128 2.5 104 2.9 — — Mortgage-backed residential 10,425 2.6 34 3.1 58 2.1 — — 10,333 2.6 Mortgage-backed commercial 253 1.5 — — 30 1.8 — — 223 1.4 Asset-backed 1,991 1.9 — — 1,311 1.9 463 2.0 217 2.2 Corporate debt 746 3.2 33 3.1 460 2.7 216 3.8 37 5.6 Total available-for-sale debt securities $ 15,231 2.5 $ 108 2.7 $ 2,676 1.9 $ 1,383 2.4 $ 11,064 2.6 Amortized cost of available-for-sale debt securities $ 15,216 $ 108 $ 2,674 $ 1,374 $ 11,060 (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 available-for-sale securities. Year ended December 31, ($ in millions) 2015 2014 2013 Taxable interest $ 340 $ 336 $ 297 Taxable dividends 23 20 25 Interest and dividends exempt from U.S. federal income tax 18 11 3 Interest and dividends on available-for-sale securities $ 381 $ 367 $ 325
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) 2015 2014 2013 Gross realized gains $ 184 $ 209 $ 221 Gross realized losses (a) (15 ) (14 ) (21 ) Other-than-temporary impairment (14 ) (14 ) (20 ) Other gain on investments, net $ 155 $ 181 $ 180 (a) Certain available-for-sale securities were sold at a loss in 2015 , 2014 , and 2013 as a result of market conditions within these respective periods (e.g., a downgrade in the rating of a debt security), in accordance with our risk management policies and practices.
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 loses 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, 2015 , 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, 2015 , 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, 2015 . Refer to Note 1 for additional information related to investment securities and our methodology for evaluating potential other-than-temporary impairments. 2015 2014 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 $ 1,553 $ (17 ) $ 173 $ (2 ) $ 297 $ (3 ) $ 859 $ (15 ) U.S. States and political subdivisions 179 (1 ) — — 50 — — — Foreign government 2 — — — — — — — Mortgage-backed 4,096 (43 ) 2,453 (107 ) 1,172 (10 ) 3,098 (116 ) Asset-backed 1,402 (8 ) 64 — 819 (3 ) 8 — Corporate debt 745 (16 ) 12 (1 ) 132 (2 ) 11 — Total temporarily impaired debt securities 7,977 (85 ) 2,702 (110 ) 2,470 (18 ) 3,976 (131 ) Temporarily impaired equity securities 534 (54 ) 96 (40 ) 231 (24 ) 40 (10 ) Total temporarily impaired available-for-sale securities $ 8,511 $ (139 ) $ 2,798 $ (150 ) $ 2,701 $ (42 ) $ 4,016 $ (141 )

Loans Held-for-Sale, Net Loan47

Loans Held-for-Sale, Net Loans Held-for-Sale, Net (Tables)	12 Months Ended
	Dec. 31, 2015
Loans Held-for-Sale, Net [Abstract]
Loans Held-for-Sale, Net [Table Text Block]	Loans held-for-sale represent loans that we intend to sell. The composition of loans held-for-sale, net, was as follows. December 31, ( $ in millions ) 2015 2014 Consumer automotive $ — $ 1,515 Consumer mortgage Mortgage Finance — — Mortgage — Legacy — 452 Total consumer mortgage — 452 Total consumer — 1,967 Commercial and industrial — Other 105 36 Total loans held-for-sale, net $ 105 $ 2,003

Finance Receivables And Loans48

Finance Receivables And Loans, Net (Tables)	12 Months Ended
	Dec. 31, 2015
Loans and Leases Receivable, Net Reported Amount, by Category Alternative [Abstract]
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]	The composition of finance receivables and loans, net, reported at gross carrying value was as follows. December 31, ( $ in millions ) 2015 2014 Consumer automotive (a) $ 64,292 $ 56,570 Consumer mortgage Mortgage Finance (b) 6,413 3,504 Mortgage — Legacy (c) (d) 3,360 3,970 Total consumer mortgage 9,773 7,474 Total consumer 74,065 64,044 Commercial Commercial and industrial Automotive 31,469 30,871 Other 2,640 1,882 Commercial real estate — Automotive 3,426 3,151 Total commercial 37,535 35,904 Total finance receivables and loans (e) $ 111,600 $ 99,948 (a) Includes $66 million and $35 million of fair value adjustment for loans in hedge accounting relationships at December 31, 2015 , and December 31, 2014 , respectively. Refer to Note 22 for additional information. (b) Includes loans originated as interest-only mortgage loans of $44 million and $55 million at December 31, 2015 , and December 31, 2014 , respectively, 7% of which are expected to start principal amortization in 2016, 3% in 2017, none in 2018, 39% in 2019, and 38% thereafter. (c) Includes loans originated as interest-only mortgage loans of $941 million and $1.1 billion at December 31, 2015, and December 31, 2014, respectively, 35% of which are expected to start principal amortization in 2016, 22% in 2017, 2% in 2018, none in 2019, and 1% thereafter. (d) Includes consumer mortgages at a fair value of $1 million at December 31, 2014 , as a result of fair value option election. (e) Totals include a net increase of $110 million at December 31, 2015 , compared to a net reduction of $266 million at December 31, 2014 , 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, 2015 $ 685 $ 152 $ 140 $ 977 Charge-offs (840 ) (48 ) (4 ) (892 ) Recoveries 262 17 4 283 Net charge-offs (578 ) (31 ) — (609 ) Provision for loan losses 739 1 (33 ) 707 Other (a) (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) 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, 2014 $ 673 $ 389 $ 146 $ 1,208 Charge-offs (720 ) (51 ) (5 ) (776 ) Recoveries 219 8 12 239 Net charge-offs (501 ) (43 ) 7 (537 ) Provision for loan losses 540 (69 ) (14 ) 457 Other (a) (27 ) (125 ) 1 (151 ) Allowance at December 31, 2014 $ 685 $ 152 $ 140 $ 977 Allowance for loan losses Individually evaluated for impairment $ 23 $ 62 $ 21 $ 106 Collectively evaluated for impairment 662 90 119 871 Loans acquired with deteriorated credit quality — — — — Finance receivables and loans at gross carrying value Ending balance 56,570 7,473 35,904 99,947 Individually evaluated for impairment 282 336 82 700 Collectively evaluated for impairment 56,287 7,137 35,822 99,246 Loans acquired with deteriorated credit quality 1 — — 1 (a) 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 recorded at gross carrying value and transfers of finance receivables and loans from held-for-investment to held-for-sale. December 31, ( $ in millions ) 2015 2014 Consumer automotive $ 1,237 $ 4,106 Consumer mortgage 78 489 Commercial 2 36 Total sales and transfers $ 1,317 $ 4,631
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 ) 2015 2014 Consumer automotive $ 272 $ — Consumer mortgage 4,125 857 Total purchases $ 4,397 $ 857
Past Due Financing Receivables [Table Text Block]	The following table presents an analysis of our past due finance receivables and loans, net, 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 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 2014 Consumer automotive $ 1,340 $ 293 $ 164 $ 1,797 $ 54,773 $ 56,570 Consumer mortgage Mortgage Finance 11 2 11 24 3,480 3,504 Mortgage — Legacy 65 23 113 201 3,768 3,969 Total consumer mortgage 76 25 124 225 7,248 7,473 Total consumer 1,416 318 288 2,022 62,021 64,043 Commercial Commercial and industrial Automotive — 9 — 9 30,862 30,871 Other — — — — 1,882 1,882 Commercial real estate — Automotive — — — — 3,151 3,151 Total commercial — 9 — 9 35,895 35,904 Total consumer and commercial $ 1,416 $ 327 $ 288 $ 2,031 $ 97,916 $ 99,947
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 ) 2015 2014 Consumer automotive $ 475 $ 386 Consumer mortgage Mortgage Finance 15 19 Mortgage — Legacy 113 158 Total consumer mortgage 128 177 Total consumer 603 563 Commercial Commercial and industrial Automotive 25 32 Other 44 46 Commercial real estate — Automotive 8 4 Total commercial 77 82 Total consumer and commercial finance receivables and loans $ 680 $ 645
Financing Receivable Credit Quality Indicators [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 for additional information. 2015 2014 December 31, ( $ in millions ) Performing Nonperforming Total Performing Nonperforming Total Consumer automotive $ 63,817 $ 475 $ 64,292 $ 56,184 $ 386 $ 56,570 Consumer mortgage Mortgage Finance 6,398 15 6,413 3,485 19 3,504 Mortgage — Legacy 3,247 113 3,360 3,811 158 3,969 Total consumer mortgage 9,645 128 9,773 7,296 177 7,473 Total consumer $ 73,462 $ 603 $ 74,065 $ 63,480 $ 563 $ 64,043 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. 2015 2014 December 31, ( $ in millions ) Pass Criticized (a) Total Pass Criticized (a) Total Commercial and industrial Automotive $ 29,613 $ 1,856 $ 31,469 $ 29,150 $ 1,721 $ 30,871 Other 2,122 518 2,640 1,509 373 1,882 Commercial real estate — Automotive 3,265 161 3,426 3,015 136 3,151 Total commercial $ 35,000 $ 2,535 $ 37,535 $ 33,674 $ 2,230 $ 35,904 (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 recorded at gross carrying value. December 31, ( $ in millions ) Unpaid principal balance Gross carrying value Impaired with no allowance Impaired with an allowance Allowance for impaired loans 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 2014 Consumer automotive $ 282 $ 282 $ — $ 282 $ 23 Consumer mortgage Mortgage Finance 8 7 4 3 — Mortgage — Legacy 332 329 82 247 62 Total consumer mortgage 340 336 86 250 62 Total consumer 622 618 86 532 85 Commercial Commercial and industrial Automotive 32 32 4 28 5 Other 46 46 — 46 15 Commercial real estate — Automotive 4 4 1 3 1 Total commercial 82 82 5 77 21 Total consumer and commercial finance receivables and loans $ 704 $ 700 $ 91 $ 609 $ 106 The following table presents average balance and interest income for our impaired finance receivables and loans. 2015 2014 2013 Year ended December 31, ( $ in millions ) Average balance Interest income Average balance Interest income Average balance Interest income Consumer automotive $ 295 $ 16 $ 317 $ 20 $ 278 $ 18 Consumer mortgage Mortgage Finance 8 — 12 — 11 — Mortgage — Legacy 272 9 861 12 897 29 Total consumer mortgage 280 9 873 12 908 29 Total consumer 575 25 1,190 32 1,186 47 Commercial Commercial and industrial Automotive 33 1 61 2 152 6 Other 41 3 59 3 72 2 Commercial real estate — Automotive 5 — 6 — 29 1 Total commercial 79 4 126 5 253 9 Total consumer and commercial finance receivables and loans $ 654 $ 29 $ 1,316 $ 37 $ 1,439 $ 56
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. 2015 2014 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 17,222 $ 278 $ 237 17,511 $ 211 $ 187 Consumer mortgage Mortgage Finance 7 4 4 2 1 1 Mortgage — Legacy 197 42 40 394 79 73 Total consumer mortgage 204 46 44 396 80 74 Total consumer 17,426 324 281 17,907 291 261 Commercial Commercial and industrial Automotive — — — 3 23 23 Other 1 21 21 3 48 48 Commercial real estate — Automotive 1 3 3 — — — Total commercial 2 24 24 6 71 71 Total consumer and commercial finance receivables and loans 17,428 $ 348 $ 305 17,913 $ 362 $ 332
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 for additional information) except for commercial finance receivables and loans, where redefault is defined as 90 days past due. 2015 2014 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 6,836 $ 82 $ 47 7,117 $ 90 $ 47 Consumer mortgage Mortgage Finance — — — — — — Mortgage — Legacy 10 1 — 27 2 1 Total consumer finance receivables and loans 6,846 $ 83 $ 47 7,144 $ 92 $ 48
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. 2015 (a) 2014 December 31, Consumer automotive Consumer mortgage Consumer automotive Consumer mortgage Texas 13.7 % 6.2 % 13.6 % 6.0 % California 7.3 33.6 6.2 30.8 Florida 7.7 4.1 7.3 3.7 Pennsylvania 5.0 1.5 5.3 1.6 Illinois 4.4 4.1 4.4 4.2 Georgia 4.4 2.2 4.2 2.1 North Carolina 3.6 1.8 3.5 1.9 Ohio 3.7 0.6 3.9 0.6 New York 3.5 1.9 4.0 1.9 Michigan 3.1 2.4 3.8 3.1 Other United States 43.6 41.6 43.8 44.1 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, 2015 .
Commercial Concentration Risk [Table Text Block]	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, 2015 2014 Texas 17.7 % 13.8 % Florida 10.0 12.3 Michigan 8.9 9.9 California 8.7 9.0 North Carolina 3.8 3.9 Virginia 3.8 4.1 Georgia 3.6 3.7 Pennsylvania 3.4 3.8 New York 3.1 3.9 Illinois 2.9 2.7 Other United States 34.1 32.9 Total commercial real estate finance receivables and loans 100.0 % 100.0 %
Commercial Criticized Exposure [Table Text Block]	Finance receivables and loans classified as special mention, substandard, or doubtful are deemed 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. The following table presents the percentage of total commercial criticized finance receivables and loans reported at gross carrying value by industry concentrations. December 31, 2015 2014 Automotive 80.5 % 87.3 % Manufacturing 7.8 0.9 Services 5.3 2.0 Other 6.4 9.8 Total commercial criticized finance receivables and loans 100.0 % 100.0 %

Investment In Operating Lease49

Investment In Operating Leases, Net (Tables)	12 Months Ended
	Dec. 31, 2015
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 ) 2015 2014 Vehicles $ 20,211 $ 23,144 Accumulated depreciation (3,940 ) (3,634 ) Investment in operating leases, net $ 16,271 $ 19,510
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 ) 2015 2014 2013 Depreciation expense on operating lease assets (excluding remarketing gains) $ 2,600 $ 2,666 $ 2,327 Remarketing gains (351 ) (433 ) (332 ) Net depreciation expense on operating lease assets $ 2,249 $ 2,233 $ 1,995
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 ) 2016 $ 2,687 2017 1,445 2018 406 2019 57 2020 and thereafter 1 Total $ 4,596

Securitizations And Variable 50

Securitizations And Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2015
Securitizations And Variable Interest Entities [Abstract]
Schedule of Variable Interest Entities [Table Text Block]	Our involvement with consolidated and nonconsolidated VIEs in which we hold variable interests is presented below. December 31, ( $ in millions ) Consolidated involvement with VIEs Assets of nonconsolidated VIEs (a) Maximum exposure to loss in nonconsolidated VIEs 2015 On-balance sheet variable interest entities Consumer automotive $ 27,967 (b) Commercial automotive 16,763 Off-balance sheet variable interest entities Consumer automotive — $ 3,034 $ 3,034 (c) Commercial other 210 (d) — (e) 493 (f) Total $ 44,940 $ 3,034 $ 3,527 2014 On-balance sheet variable interest entities Consumer automotive $ 31,966 (b) Commercial automotive 18,153 Off-balance sheet variable interest entities Consumer automotive — $ 2,801 $ 2,801 (c) Commercial other 146 (d) — (e) 362 (f) Total $ 50,265 $ 2,801 $ 3,163 (a) Asset values represent the current unpaid principal balance of outstanding consumer finance receivables and loans within the VIEs. (b) Includes $10.6 billion and $12.7 billion of assets which are not encumbered by VIE beneficial interests held by third parties at December 31, 2015 , and December 31, 2014 , respectively. Ally or consolidated affiliates hold the interests in these assets which eliminate in consolidation. (c) Maximum exposure to loss represents the current unpaid principal balance of outstanding loans based on our customary representation and warranty provisions. 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. (d) Includes $222 million and $164 million classified as other assets, offset by $12 million and $18 million classified as accrued expenses and other liabilities at December 31, 2015 , and December 31, 2014 , respectively. (e) Includes a VIE for which we have no management oversight and therefore we are not able to provide the total assets of the VIEs. (f) For certain nonconsolidated affordable housing entities, maximum exposure to loss represents the yield we guaranteed investors through long term guarantee contracts. The amount disclosed is based on the unlikely event that the underlying properties cease generating yield to investors and the yield delivered to investors in the form of low income tax housing credits is recaptured. For nonconsolidated equity investments, maximum exposure to loss represents our outstanding investment, additional committed capital, and low income housing tax credits subject to recapture. The amount disclosed is based on the unlikely event that our committed capital is funded, our investments become worthless, and the tax credits previously delivered to us are recaptured. This required disclosure is not an indication of our expected loss.
Schedule of 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 ) 2015 2014 Assets Finance receivables and loans, net Consumer $ 11,682 $ 12,594 Commercial 16,247 17,487 Allowance for loan losses (196 ) (179 ) Total finance receivables and loans, net 27,733 29,902 Investment in operating leases, net 4,791 5,595 Other assets 1,624 1,964 Total assets $ 34,148 $ 37,461 Liabilities Long-term debt 20,267 24,297 Accrued expenses and other liabilities 22 173 Total liabilities $ 20,289 $ 24,470
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, asset-backed financings, or other similar transfers of financial assets 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 in 2015 , 2014 , and 2013 . 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 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 ) 2013 Cash proceeds from transfers completed during the period $ — $ 8,676 Servicing fees 13 70 Representations and warranties obligations — (66 ) Other cash flows — 70
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 past due Net credit losses December 31, ( $ in millions ) 2015 2014 2015 2014 2015 2014 On-balance sheet loans Consumer automotive $ 64,292 $ 58,085 $ 591 $ 457 $ 578 $ 501 Consumer mortgage 9,773 7,926 108 151 31 43 Commercial automotive 34,895 34,022 — 9 3 1 Commercial other 2,745 1,918 — — (3 ) (8 ) Total on-balance sheet loans 111,705 101,951 699 617 609 537 Off-balance sheet securitization entities Consumer automotive 2,529 2,801 9 5 5 1 Total off-balance sheet securitization entities 2,529 2,801 9 5 5 1 Whole-loan transactions (a) 2,252 929 13 33 — 6 Total $ 116,486 $ 105,681 $ 721 $ 655 $ 614 $ 544 (a) Whole-loan transactions 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, 2015
Servicing Activities [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 ) 2015 2014 On-balance sheet automotive finance loans and leases Consumer automotive $ 64,067 $ 58,085 Commercial automotive 34,895 34,022 Operating leases 15,965 19,510 Other 72 55 Off-balance sheet automotive finance loans Loans sold to third-party investors Securitizations 2,550 2,832 Whole-loan 2,259 887 Total serviced automotive finance loans and leases $ 119,808 $ 115,391

Premiums Receivable and Other52

Premiums Receivable and Other Insurance Assets (Tables)	12 Months Ended
	Dec. 31, 2015
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 ) 2015 2014 Prepaid reinsurance premiums $ 382 $ 326 Reinsurance recoverable on unpaid losses 120 143 Reinsurance recoverable on paid losses 18 12 Premiums receivable 82 90 Deferred policy acquisition costs 1,199 1,124 Total premiums receivable and other insurance assets $ 1,801 $ 1,695

Other Assets (Tables)

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2015
Other Assets [Abstract]
Schedule of Other Assets [Table Text Block]	The components of other assets were as follows. December 31, ( $ in millions ) 2015 2014 Property and equipment at cost $ 691 $ 775 Accumulated depreciation (456 ) (550 ) Net property and equipment 235 225 Restricted cash collections for securitization trusts (a) 2,010 2,221 Net deferred tax assets 1,369 1,812 Nonmarketable equity investments 418 271 Cash reserve deposits held-for-securitization trusts (b) 252 303 Fair value of derivative contracts in receivable position (c) 233 263 Other accounts receivable 158 298 Collateral placed with counterparties 125 236 Restricted cash and cash equivalents 120 122 Other assets 1,401 1,354 Total other assets $ 6,321 $ 7,105 (a) Represents cash collection from customer payments on securitized receivables. These funds are distributed to investors as payments on the related secured debt. (b) Represents credit enhancement in the form of cash reserves for various securitization transactions. (c) For additional information on derivative instruments and hedging activities, refer to Note 22 .

Deposit Liabilities (Tables)

Deposit Liabilities (Tables)	12 Months Ended
	Dec. 31, 2015
Deposits [Abstract]
Schedule of Deposit Liabilities [Table Text Block]	Deposit liabilities consisted of the following. December 31, ( $ in millions ) 2015 2014 Noninterest-bearing deposits $ 89 $ 64 Interest-bearing deposits Savings and money market checking accounts 36,386 26,769 Certificates of deposit 29,774 31,051 Dealer deposits 229 319 Total deposit liabilities $ 66,478 $ 58,203
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 2016 $ 16,313 Due in 2017 8,800 Due in 2018 3,068 Due in 2019 695 Due in 2020 898 Total certificates of deposit $ 29,774

Short-Term Borrowings (Tables)

Short-Term Borrowings (Tables)	12 Months Ended
	Dec. 31, 2015
Short-term Debt [Abstract]
Schedule of Short-term Debt [Table Text Block]	The following table presents the composition of our short-term borrowings portfolio. 2015 2014 December 31, ( $ in millions ) Unsecured Secured (a) Total Unsecured Secured (a) Total Demand notes $ 3,369 $ — $ 3,369 $ 3,338 $ — $ 3,338 Federal Home Loan Bank — 4,000 4,000 — 2,950 2,950 Securities sold under agreements to repurchase — 648 648 — 774 774 Other 84 — 84 — — — Total short-term borrowings $ 3,453 $ 4,648 $ 8,101 $ 3,338 $ 3,724 $ 7,062 Weighted average interest rate (b) 0.8 % 0.8 % (a) Refer to Note 16 for further details on assets restricted as collateral for payment of the related debt. (b) Based on the debt outstanding and the interest rate at December 31 of each year.

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2015
Long-term Debt, Unclassified [Abstract]
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 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 2014 Unsecured debt Fixed rate (b) $ 18,858 Variable rate 374 Trust preferred securities 2,598 Fair value adjustment (c) 452 Total unsecured debt 22,282 0.33 - 8.30% 5.90 % 2015 - 2049 Secured debt Fixed rate 19,793 Variable rate 24,305 Total secured debt (d) (e) (f) 44,098 0.21 - 4.59% 0.94 % 2015 - 2023 Total long-term debt $ 66,380 (a) Based on the debt outstanding and the interest rate at December 31 of each year. (b) Includes subordinated debt of $1.1 billion and $296 million at December 31, 2015 , and 2014 , 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 for additional information. (d) Includes $20.3 billion and $ 24.3 billion of VIE secured debt outstanding at December 31, 2015 , and 2014 , respectively. (e) Includes $19.9 billion and $17.0 billion of debt outstanding from the Automotive secured revolving credit facilities at December 31, 2015 , and 2014 , respectively. (f) Includes advances from the FHLB of $5.4 billion and $2.8 billion at December 31, 2015 , and 2014 , respectively.
Schedule of Debt [Table Text Block]	2015 2014 December 31, ( $ in millions ) Unsecured Secured Total Unsecured Secured Total Long-term debt Due within one year $ 1,829 $ 9,427 $ 11,256 $ 4,780 $ 12,603 $ 17,383 Due after one year 18,803 35,844 54,647 17,050 31,495 48,545 Fair value adjustment 334 (3 ) 331 452 — 452 Total long-term debt $ 20,966 $ 45,268 $ 66,234 $ 22,282 $ 44,098 $ 66,380
Scheduled Remaining Maturity of Long-term Debt [Table Text Block]	The following table presents the scheduled remaining maturity of long-term debt, assuming no early redemptions will occur. The actual payment of secured debt may vary based on the payment activity of the related pledged assets. Year ended December 31, ( $ in millions ) 2016 2017 2018 2019 2020 2021 and thereafter Fair value adjustment Total Unsecured Long-term debt $ 1,904 $ 4,371 $ 3,702 $ 1,615 $ 2,228 $ 8,203 $ 334 $ 22,357 Original issue discount (75 ) (87 ) (98 ) (35 ) (35 ) (1,061 ) — (1,391 ) Total unsecured 1,829 4,284 3,604 1,580 2,193 7,142 334 20,966 Secured Long-term debt 9,427 15,217 9,109 5,823 3,414 2,281 (3 ) 45,268 Total long-term debt $ 11,256 $ 19,501 $ 12,713 $ 7,403 $ 5,607 $ 9,423 $ 331 $ 66,234
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. 2015 2014 December 31, ( $ in millions ) Total Ally Bank (a) Total Ally Bank (a) Investment securities (b) $ 2,420 $ 1,761 $ 786 $ 786 Mortgage assets held-for-investment and lending receivables 9,743 9,743 7,541 7,541 Consumer automotive finance receivables 34,324 9,167 33,438 11,263 Commercial automotive finance receivables 19,623 19,177 20,605 20,083 Investment in operating leases, net 5,539 3,205 6,820 4,672 Total assets restricted as collateral (c) (d) $ 71,649 $ 43,053 $ 69,190 $ 44,345 Secured debt $ 49,916 (e) $ 24,787 $ 47,822 (e) $ 27,103 (a) Ally Bank is a component of the total column. (b) Certain investment securities are restricted under repurchase agreements. Refer to Note 15 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 $14.9 billion and $10.7 billion at December 31, 2015 , and 2014 , 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 $2.9 billion and $3.2 billion at December 31, 2015 , and 2014 , 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 13 for additional information. (e) Includes $4.6 billion and $3.7 billion of short-term borrowings at December 31, 2015 , and 2014 , respectively
Schedule Of Committed Funding Facilities [Table Text Block]	Outstanding Unused capacity (a) Total capacity December 31, ( $ in millions ) 2015 2014 2015 2014 2015 2014 Bank funding Secured (b) $ 3,250 $ 3,250 $ — $ 250 $ 3,250 $ 3,500 Parent funding Secured 16,914 15,030 251 3,425 17,165 18,455 Total committed facilities $ 20,164 $ 18,280 $ 251 $ 3,675 $ 20,415 $ 21,955 (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.

Accrued Expenses and Other Li57

Accrued Expenses and Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2015
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 ) 2015 2014 Accounts payable $ 391 $ 298 Employee compensation and benefits 242 298 Reserves for insurance losses and loss adjustment expenses 169 208 Fair value of derivative contracts in payable position (a) 145 252 Deferred revenue 108 151 Collateral received from counterparties 82 71 Other liabilities 408 457 Total accrued expenses and other liabilities $ 1,545 $ 1,735 (a) For additional information on derivative instruments and hedging activities, refer to Note 22 .

Equity (Tables)

Equity (Tables)	12 Months Ended
	Dec. 31, 2015
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, ( in shares ) 2015 2014 2013 Common stock Total issued, January 1, 480,136,039 479,767,470 412,600,700 New issuances Employee benefits and compensation plans 2,654,657 368,569 — Private placement (a) — — 67,166,770 Total issued, December 31, 482,790,696 480,136,039 479,767,470 Total treasury stock, December 31, (810,585 ) (41,148 ) — Total outstanding, December 31, 481,980,111 480,094,891 479,767,470 (a) On November 20, 2013, Ally completed its private placement of its common stock for an aggregate price of $1.3 billion .
Schedule of Stock by Class [Table Text Block]	The following table summarizes information about our Series A and Series G preferred stock. December 31, 2015 December 31, 2014 Series A preferred stock (a) Carrying value ( $ in millions ) $ 696 $ 1,021 Par value ( per share ) 0.01 0.01 Liquidation preference ( per share ) 25 25 Number of shares authorized 40,870,560 40,870,560 Number of shares issued and outstanding 27,870,560 40,870,560 Dividend/coupon Prior to May 15, 2016 8.5 % 8.5 % On and after May 15, 2016 Three month Three month Series G preferred stock Carrying value ( $ in millions ) $ — $ 234 Par value ( per share ) — 0.01 Liquidation preference ( per share ) — 1,000 Number of shares authorized — 2,576,601 Number of shares issued and outstanding — 2,576,601 Dividend/coupon — % 7 % (a) Nonredeemable prior to May 15, 2016.

Accumulated Other Comprehensi59

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2015
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) income. ( $ in millions ) Unrealized gains (losses) on investment securities (a) Translation adjustments and net investment hedges (b) Cash flow hedges (b) Defined benefit pension plans Accumulated other comprehensive income (loss) Balance at January 1, 2013 $ 76 $ 368 $ 2 $ (135 ) $ 311 2013 net change (345 ) (303 ) 3 58 (587 ) Balance at December 31, 2013 (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 ) (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 .
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]	The following table presents the before- and after-tax changes in each component of accumulated other comprehensive (loss) income. Year ended December 31, 2015 ( $ in millions ) Before Tax Tax Effect After Tax Unrealized losses on 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 (benefit) from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 22 . (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 Unrealized gains on 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 (benefit) expense from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 22 . (d) Includes losses reclassified to compensation and benefits expense in our Consolidated Statement of Income . Year ended December 31, 2013 ( $ in millions ) Before Tax Tax Effect After Tax Unrealized losses on investment securities Net unrealized losses arising during the period $ (333 ) $ 174 $ (159 ) Less: Net realized gains reclassified to income from continuing operations 180 (a) (2 ) (b) 178 Less: Net realized gains reclassified to income from discontinued operations, net of tax 10 (2 ) 8 Net change (523 ) 178 (345 ) Translation adjustments Net unrealized losses arising during the period (104 ) 24 (80 ) Less: Net realized gains reclassified to income from discontinued operations, net of tax 337 92 429 Net change (441 ) (68 ) (509 ) Net investment hedges (c) Net unrealized gains arising during the period 59 (22 ) 37 Less: Net realized losses reclassified to income from discontinued operations, net of tax (250 ) 81 (169 ) Net change 309 (103 ) 206 Cash flow hedges (c) Net unrealized losses arising during the period (1 ) — (1 ) Less: Net realized losses reclassified to income from continuing operations (7 ) (d) 3 (b) (4 ) Net change 6 (3 ) 3 Defined benefit pension plans Net unrealized gains arising during the period 26 (8 ) 18 Less: Net realized losses reclassified to income from continuing operations (2 ) (e) — (b) (2 ) Less: Net realized losses reclassified to income from discontinued operations, net of tax (49 ) 11 (38 ) Net change 77 (19 ) 58 Other comprehensive loss $ (572 ) $ (15 ) $ (587 ) (a) Includes gains reclassified to other gain on investments, net in our Consolidated Statement of Income . (b) Includes amounts reclassified to income tax expense (benefit) from continuing operations in our Consolidated Statement of Income . (c) For additional information on derivative instruments and hedging activities, refer to Note 22 . (d) Includes losses reclassified to long-term debt in our Consolidated Statement of Income . (e) 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, 2015
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 ) (a) 2015 2014 2013 Net income from continuing operations $ 897 $ 925 $ 416 Preferred stock dividends — U.S. Department of the Treasury — — (543 ) Impact of repurchase of mandatorily convertible preferred stock held by U.S. Department of the Treasury and elimination of share adjustment right — — (240 ) Preferred stock dividends (b) (2,571 ) (268 ) (267 ) Net (loss) income from continuing operations attributable to common shareholders (1,674 ) 657 (634 ) Income (loss) from discontinued operations, net of tax 392 225 (55 ) Net (loss) income attributable to common shareholders $ (1,282 ) $ 882 $ (689 ) Basic weighted-average common shares outstanding (c) 482,873,120 481,154,609 420,166,188 Diluted weighted-average common shares outstanding (c) (d) 482,873,120 481,933,811 420,166,188 Basic earnings per common share Net (loss) income from continuing operations $ (3.47 ) $ 1.36 $ (1.51 ) Income (loss) from discontinued operations, net of tax 0.81 0.47 (0.13 ) Net (loss) income $ (2.66 ) $ 1.83 $ (1.64 ) Diluted earnings per common share Net (loss) income from continuing operations $ (3.47 ) $ 1.36 $ (1.51 ) Income (loss) from discontinued operations, net of tax 0.81 0.47 (0.13 ) Net (loss) income $ (2.66 ) $ 1.83 $ (1.64 ) (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 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. Refer to Note 18 for additional preferred stock information. (c) Includes shares related to share-based compensation that vested but were not yet issued for the years ended December 31, 2015 , and 2014 , respectively. (d) Due to antidilutive effect of the net loss from continuing operations attributable to common shareholders for the years ended December 31, 2015 , and 2013, respectively, basic weighted-average common shares outstanding were used to calculate basic and diluted earnings per share.

Regulatory Capital (Tables)

Regulatory Capital (Tables)	12 Months Ended
	Dec. 31, 2015
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. Under Basel III Under Basel I December 31, 2015 (a) December 31, 2014 (b) Required minimum Well-capitalized minimum ( $ in millions ) Amount Ratio Amount Ratio Risk-based capital Common Equity Tier 1 (to risk-weighted assets) (c) Ally Financial Inc. $ 12,507 9.21 % $ 12,588 9.64 % 4.50 % (d) Ally Bank 16,594 17.05 16,022 16.89 4.50 6.50 % Tier 1 (to risk-weighted assets) Ally Financial Inc. $ 15,077 11.10 % $ 16,389 12.55 % 6.00 % 6.00 % Ally Bank 16,594 17.05 16,022 16.89 6.00 8.00 Total (to risk-weighted assets) Ally Financial Inc. $ 17,005 12.52 % $ 17,294 13.24 % 8.00 % 10.00 % Ally Bank 17,043 17.51 16,468 17.36 8.00 10.00 Tier 1 leverage (to adjusted quarterly average assets) (e) Ally Financial Inc. $ 15,077 9.73 % $ 16,389 10.94 % 4.00 % (d) Ally Bank 16,594 15.38 16,022 15.44 15.00 (f) 5.00 % (a) U.S. Basel III became effective for us on January 1, 2015, subject to transitional provisions primarily related to deductions and adjustments impacting Common Equity Tier 1 capital and Tier 1 capital. (b) Capital ratios as of December 31, 2014, are presented under the U.S. Basel I capital framework. (c) Previously referred to as Tier 1 Common Equity under the U.S. Basel I capital framework. (d) Currently, there is no ratio component for determining whether a BHC is "well-capitalized." (e) Federal regulatory reporting guidelines require the calculation of adjusted quarterly average assets using a daily average methodology. (f) Ally Bank, in accordance with the CLMA, is required 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, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value Amounts Of Derivative Instruments Reported On Our 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. 2015 2014 Derivative contracts in a Notional amount Derivative contracts in a Notional amount December 31, ( $ in millions ) receivable position (a) payable position (b) receivable position (a) payable position (b) Derivatives qualifying for hedge accounting Interest rate contracts Swaps (c) (d) (e) $ 126 $ 9 $ 14,151 $ 118 $ 7 $ 18,554 Foreign exchange contracts Forwards — 1 189 — — 210 Total derivatives qualifying for hedge accounting 126 10 14,340 118 7 18,764 Economic hedges Interest rate contracts Swaps 30 51 6,101 40 65 11,979 Futures and forwards 2 2 1,905 4 2 18,886 Written options — 72 18,220 — 94 14,823 Purchased options 73 — 18,240 94 — 15,159 Total interest rate risk 105 125 44,466 138 161 60,847 Foreign exchange contracts Swaps — — — — 74 1,210 Futures and forwards — — 278 5 4 304 Total foreign exchange risk — — 278 5 78 1,514 Equity contracts Forwards — 9 32 — 3 74 Written options — 1 — — 3 1 Purchased options 2 — — 2 — — Total equity risk 2 10 32 2 6 75 Total economic hedges 107 135 44,776 145 245 62,436 Total derivatives $ 233 $ 145 $ 59,116 $ 263 $ 252 $ 81,200 (a) Derivative contracts in a receivable position are classified as other assets on the Consolidated Balance Sheet, and includes accrued interest of $46 million and $50 million at December 31, 2015 , and 2014 , respectively. (b) Derivative contracts in a liability position are classified as accrued expenses and other liabilities on the Consolidated Balance Sheet, and includes accrued interest of $12 million and $17 million at December 31, 2015 , and 2014 , respectively. (c) Includes fair value hedges consisting of receive-fixed swaps on fixed-rate debt obligations with $112 million and $97 million in a receivable position, $3 million and $1 million in a payable position, and a $6.8 billion and $4.7 billion notional amount at December 31, 2015 , and December 31, 2014 , respectively. Of the hedge notional amount at December 31, 2015 , $2.6 billion is associated with debt maturing in five or more years. (d) Other fair value hedges include pay-fixed swaps on portfolios of held-for-investment automotive loan assets with $13 million and $21 million in a receivable position, $3 million and $6 million in a payable position, and a $6.8 billion and $13.9 billion notional amount at December 31, 2015 , and December 31, 2014 , respectively. (e) Fair value hedges were executed during the fourth quarter consisting of receive-fixed swaps on fixed-rate secured debt obligations (FHLB Advances) with $1 million in a receivable position, $2 million in a payable position, and a $500 million notional amount at December 31, 2015 .
Gains and Losses on Derivative Instruments Reported in our Consolidated Statement of 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 ) 2015 2014 2013 Derivatives qualifying for hedge accounting (Loss) gain recognized in earnings on derivatives Interest rate contracts Interest and fees on finance receivables and loans (a) $ (9 ) $ 15 $ 7 Interest on long-term debt (b) (c) 35 199 (389 ) Gain (loss) recognized in earnings on hedged items Interest rate contracts Interest and fees on finance receivables and loans (d) 39 34 2 Interest on long-term debt (e) (30 ) (185 ) 402 Total derivatives qualifying for hedge accounting 35 63 22 Economic derivatives (Loss) gain recognized in earnings on derivatives Interest rate contracts Servicing asset valuation and hedge activities, net — — (112 ) Loss on mortgage and automotive loans, net (2 ) — (37 ) Other income, net of losses (17 ) (37 ) 14 Total interest rate contracts (19 ) (37 ) (135 ) Foreign exchange contracts (f) Interest on long-term debt (139 ) (172 ) 94 Other income, net of losses 12 12 24 Total foreign exchange contracts (127 ) (160 ) 118 Equity contracts Compensation and benefits expense (10 ) (5 ) — Total equity contracts (10 ) (5 ) — (Loss) gain recognized in earnings on derivatives $ (121 ) $ (139 ) $ 5 (a) Amounts exclude losses related to interest for qualifying accounting hedges of portfolios of retail automotive loans held-for-investment, which are primarily offset by the fixed coupon payments of the loans. The losses were $64 million , $61 million , and $9 million for the years ended December 31, 2015 , and 2014 , and 2013 , respectively. (b) Amounts exclude gains related to interest for qualifying accounting hedges of debt, which are primarily offset by the fixed coupon payment on the long-term debt. The gains were $97 million , $112 million , and $131 million for the years ended December 31, 2015 , 2014 , and 2013 , 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 $1 million for the year ended December 31, 2015. (d) Amounts exclude losses related to amortization of deferred loan basis adjustments on the de-designated hedged item of $8 million for the year ended December 31, 2015 . (e) Amounts exclude gains related to amortization of deferred basis adjustments on the de-designated hedged item of $73 million , $155 million , and $247 million for the years ended December 31, 2015 , 2014 , and 2013 , respectively. (f) Amounts exclude gains and losses related to the revaluation of the related foreign-denominated debt or receivable. Gains of $132 million , and $165 million , and losses of $117 million , were recognized for the years ended December 31, 2015 , 2014 , and 2013 , 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 ) 2015 2014 2013 Cash flow hedges Interest rate contracts Loss reclassified from accumulated other comprehensive income to interest on long-term debt $ — $ (2 ) $ (7 ) Total interest on long-term debt $ — $ (2 ) $ (7 ) Gain recognized in other comprehensive income $ 2 $ 2 $ 6 Net investment hedges Foreign exchange contracts Loss reclassified from accumulated other comprehensive income to income (loss) from discontinued operations, net $ (4 ) $ — $ (250 ) Total loss from discontinued operations, net $ (4 ) $ — $ (250 ) Gain recognized in other comprehensive income (a) $ 33 $ 13 $ 309 (a) The amounts represent the effective portion of net investment hedges. There are offsetting amounts recognized in accumulated other comprehensive income 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 . There were losses of $59 million , $41 million , and $582 million for the years ended December 31, 2015 , 2014 , and 2013 , respectively.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	The significant components of income tax expense (benefit) from continuing operations were as follows. Year ended December 31, ( $ in millions ) 2015 2014 2013 Current income tax expense (benefit) U.S. federal $ — $ (3 ) $ — Foreign 6 8 4 State and local 3 5 — Total current expense 9 10 4 Deferred income tax expense (benefit) U.S. federal 454 270 (67 ) Foreign 1 2 (1 ) State and local 32 39 5 Total deferred expense (benefit) 487 311 (63 ) Total income tax expense (benefit) from continuing operations $ 496 $ 321 $ (59 )
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	A reconciliation of income tax expense (benefit) 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 ) 2015 2014 2013 Statutory U.S. federal tax expense $ 488 $ 436 $ 125 Change in tax resulting from State and local income taxes, net of federal income tax benefit 38 48 16 Effect of valuation allowance change (26 ) (64 ) (154 ) Nondeductible expenses 14 31 26 Tax credits (12 ) (10 ) (45 ) Changes in unrecognized tax benefits (5 ) (63 ) (10 ) Tax law enactment — (39 ) (44 ) Other, net (1 ) (18 ) 27 Total income tax expense (benefit) from continuing operations $ 496 $ 321 $ (59 )
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 ) 2015 2014 Deferred tax assets Tax credit carryforwards $ 1,941 $ 1,911 Tax loss carryforwards 950 1,158 Adjustments to loan value 311 520 State and local taxes 194 227 Unearned insurance premiums 141 141 Hedging transactions 99 139 Other 212 210 Gross deferred tax assets 3,848 4,306 Valuation allowance (582 ) (734 ) Deferred tax assets, net of valuation allowance 3,266 3,572 Deferred tax liabilities Lease transactions 1,273 1,148 Deferred acquisition costs 403 378 Debt transactions 162 161 Other 69 78 Gross deferred tax liabilities 1,907 1,765 Net deferred tax assets (a) $ 1,359 $ 1,807 (a) Total net deferred tax assets includes $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 $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, 2015 .
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, 2015 . ( $ in millions ) Deferred Tax Asset/(Liability) Valuation Allowance Net Deferred Tax Asset/(Liability) Years of Expiration Tax credit carryforwards Foreign tax credits $ 1,748 $ (472 ) $ 1,276 2016 - 2025 General business credits 173 — 173 2032 - 2035 AMT credits 20 — 20 n/a Total tax credit carryforwards 1,941 (472 ) 1,469 Tax loss carryforwards Net operating losses — federal 950 — 950 2031 - 2033 Net operating losses — state 208 (a) (77 ) 131 2016 - 2035 Capital losses — state 28 (a) (28 ) — 2016 - 2017 Total tax loss carryforwards 1,186 (105 ) 1,081 Other deferred tax assets 721 (5 ) 716 n/a Deferred tax assets 3,848 (582 ) 3,266 Deferred tax liabilities (1,907 ) — (1,907 ) n/a Net deferred tax assets $ 1,941 $ (582 ) $ 1,359 (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 ) 2015 2014 2013 Balance at January 1, $ 191 $ 262 $ 102 Additions based on tax positions related to the current year — — 174 Additions for tax positions of prior years 7 9 1 Settlements (10 ) (79 ) (14 ) Expiration of statute of limitations (3 ) (1 ) (1 ) Balance at December 31, $ 185 $ 191 $ 262

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
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, 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. State and political subdivisions — 716 — 716 Foreign government 10 167 — 177 Mortgage-backed residential — 10,366 — 10,366 Mortgage-backed commercial — 481 — 481 Asset-backed — 1,755 — 1,755 Corporate debt securities — 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 . Recurring fair value measurements December 31, 2014 ( $ in millions ) Level 1 Level 2 Level 3 Total Assets Investment securities Available-for-sale securities Debt securities U.S. Treasury and federal agencies $ 217 $ 961 $ — $ 1,178 U.S. State and political subdivisions — 406 — 406 Foreign government 14 218 — 232 Mortgage-backed residential — 10,425 — 10,425 Mortgage-backed commercial — 253 — 253 Asset-backed — 1,991 — 1,991 Corporate debt securities — 746 — 746 Total debt securities 231 15,000 — 15,231 Equity securities (a) 906 — — 906 Total available-for-sale securities 1,137 15,000 — 16,137 Mortgage loans held-for-sale, net (b) — — 3 3 Other assets Interests retained in financial asset sales — — 47 47 Derivative contracts in a receivable position (c) Interest rate 4 252 — 256 Foreign currency — 5 — 5 Other 2 — — 2 Total derivative contracts in a receivable position 6 257 — 263 Collateral placed with counterparties (d) — 15 — 15 Total assets $ 1,143 $ 15,272 $ 50 $ 16,465 Liabilities Accrued expenses and other liabilities Derivative contracts in a payable position (c) Interest rate $ (2 ) $ (166 ) $ — $ (168 ) Foreign currency — (78 ) — (78 ) Other (2 ) (4 ) — (6 ) Total derivative contracts in a payable position (4 ) (248 ) — (252 ) Total liabilities $ (4 ) $ (248 ) $ — $ (252 ) (a) Our investment in any one industry did not exceed 16% . (b) Carried at fair value due to fair value option elections. (c) For additional information on derivative instruments and hedging activities, refer to Note 22 . (d) Represents collateral in the form of investment securities. Cash collateral was excluded.
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 gains Fair value at December 31, 2015 Net unrealized gains included in earnings still held at December 31, 2015 ( $ in millions ) Fair value at January 1, 2015 included in earnings included in OCI Purchases Sales Issuances Settlements Transfers into level 3 Transfers out of level 3 Assets Loans held-for-sale $ 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 . Level 3 recurring fair value measurements Net realized/unrealized gains Fair value at December 31, 2014 Net unrealized gains included in earnings still held at December 31, 2014 ( $ in millions ) Fair value at January 1, 2014 included in earnings included in OCI Purchases Sales Issuances Settlements Transfers into level 3 Transfers out of level 3 Assets Loans held-for-sale $ — $ — $ — $ — $ — $ — $ — $ 3 $ — $ 3 $ 1 Other assets Interests retained in financial asset sales 100 13 (a) — — — — (66 ) — — 47 — Interest rate derivative contracts, net (1 ) — — — — — (2 ) — 3 — — Total assets $ 99 $ 13 $ — $ — $ — $ — $ (68 ) $ 3 $ 3 $ 50 $ 1 (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 fair value measurements Lower-of-cost or fair value or valuation reserve allowance 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 $ — $ — $ 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. Nonrecurring fair value measurements Lower-of-cost or fair value or valuation reserve allowance Total loss included in earnings for the year ended December 31, 2014 ( $ in millions ) Level 1 Level 2 Level 3 Total Assets Loans held-for-sale $ — $ — $ 36 $ 36 $ — n/m (a) Commercial finance receivables and loans, net (b) Automotive — — 24 24 (6 ) n/m (a) Other — — 32 32 (15 ) n/m (a) Total commercial finance receivables and loans, net — — 56 56 (21 ) n/m (a) Other assets Repossessed and foreclosed assets (c) — — 8 8 (2 ) n/m (a) Other — — 2 2 — n/m (a) Total assets $ — $ — $ 102 $ 102 $ (23 ) 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 2014 . 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 Instruments [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 market data to develop estimates of fair value, so the estimates are not necessarily indicative of the amounts that could be realized or would be paid in a current market exchange. The effect of using different market assumptions or estimation methodologies could be material to the estimated fair values. Fair value information presented herein was based on information available at December 31, 2015 , and 2014 . Estimated fair value December 31, ( $ in millions ) Carrying value Level 1 Level 2 Level 3 Total 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 2014 Financial assets Loans held-for-sale, net $ 2,003 $ — $ 485 $ 1,554 $ 2,039 Finance receivables and loans, net 98,971 — — 99,430 99,430 Nonmarketable equity investments 271 — 246 33 279 Financial liabilities Deposit liabilities $ 58,203 $ — $ — $ 58,777 $ 58,777 Short-term borrowings 7,062 — — 7,063 7,063 Long-term debt 66,380 — 25,224 44,084 69,308

Offsetting Assets and Liabili65

Offsetting Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2015
Offsetting [Abstract]
Offsetting Assets and 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) Presented in the Consolidated Balance Sheet Gross Amounts Not Offset in the Consolidated Balance Sheet December 31, 2015 ( $ in millions ) Financial Instruments Collateral (a) (b) (c) 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 . (e) For additional information on securities sold under agreements to repurchase, refer to Note 15 . Gross Amounts of Recognized Assets/(Liabilities) Gross Amounts Offset in the Consolidated Balance Sheet Net Amounts of Assets/(Liabilities) Presented in the Consolidated Balance Sheet Gross Amounts Not Offset in the Consolidated Balance Sheet December 31, 2014 ( $ in millions ) Financial Instruments Collateral (a) Net Amount Assets Derivative assets in net asset positions $ 216 $ — $ 216 $ (60 ) $ (68 ) $ 88 Derivative assets in net liability positions 47 — 47 (47 ) — — Total assets (b) $ 263 $ — $ 263 $ (107 ) $ (68 ) $ 88 Liabilities Derivative liabilities in net liability positions $ (188 ) $ — $ (188 ) $ 47 $ 54 $ (87 ) Derivative liabilities in net asset positions (60 ) — (60 ) 60 — — Derivative liabilities with no offsetting arrangements (4 ) — (4 ) — — (4 ) Total derivative liabilities (b) (252 ) — (252 ) 107 54 (91 ) Securities sold under agreements to repurchase (c) (774 ) — (774 ) — 774 — Total liabilities $ (1,026 ) $ — $ (1,026 ) $ 107 $ 828 $ (91 ) (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) For additional information on derivative instruments and hedging activities, refer to Note 22 . (c) For additional information on securities sold under agreements to repurchase, refer to Note 15 .

Segment And Geographic Inform66

Segment And Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2015
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) 2015 Net financing revenue $ 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 (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 2013 Net financing revenue (loss) $ 3,159 $ 57 $ 38 $ 44 $ (519 ) $ 2,779 Other revenue (loss) 268 1,196 (1 ) 33 (12 ) 1,484 Total net revenue (loss) 3,427 1,253 37 77 (531 ) 4,263 Provision for loan losses 494 — (11 ) (6 ) 24 501 Total noninterest expense 1,755 999 30 39 582 3,405 Income (loss) from continuing operations before income tax expense $ 1,178 $ 254 $ 18 $ 44 $ (1,137 ) $ 357 Total assets $ 109,312 $ 7,124 $ 3,294 $ 1,633 $ 29,545 $ 150,908 (a) Net financing revenue after the provision for loan losses totaled $3.0 billion , $2.9 billion , and $2.3 billion for the years ended December 31, 2015 , 2014 , and 2013 , respectively.
Information Concerning Principal Geographic Areas [Table Text Block]	Information concerning principal geographic areas were as follows. Year ended December 31, ( $ in millions ) Revenue (a) Income (loss) from continuing operations before income tax expense (b) Net income (loss) (b) (c) Identifiable assets (d) Long-lived assets (e) 2015 Canada $ 98 $ 47 $ 35 $ 514 $ — Europe 1 4 27 325 — Latin America — — (2 ) 28 — Asia-Pacific — — 452 2 — Total foreign (f) 99 51 512 869 — Total domestic (g) 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 (f) 126 54 186 2,891 — Total domestic (g) 4,525 1,192 964 148,713 19,735 Total $ 4,651 $ 1,246 $ 1,150 $ 151,604 $ 19,735 2013 Canada $ 171 $ 64 $ 1,266 $ 704 $ — Europe (h) (8 ) (18 ) (88 ) 1,972 — Latin America — 7 300 29 — Asia-Pacific 1 (2 ) 117 520 — Total foreign 164 51 1,595 3,225 — Total domestic (g) 4,099 306 (1,234 ) 147,656 17,916 Total $ 4,263 $ 357 $ 361 $ 150,881 $ 17,916 (a) Revenue consists of net financing revenue and total other revenue as presented in our Consolidated Statement of Income . (b) The domestic amounts include original discount amortization of $62 million , $189 million , and $262 million for the years ended December 31, 2015 , 2014 , and 2013 , respectively. (c) Gain (loss) realized on sale of discontinued operations are allocated to the geographic area in which the business operated. (d) Identifiable assets consist of total assets excluding goodwill. (e) Long-lived assets consist of investment in operating leases, net, and net property and equipment. (f) Our foreign operations as of December 31, 2015 , and December 31, 2014 , consist of our ongoing Insurance operations in Canada, and our remaining international entities in wind-down. (g) Amounts include eliminations between our domestic and foreign operations. (h) Amounts include eliminations between our foreign operations.

Parent And Guarantor Consolid67

Parent And Guarantor Consolidating Financial Statements (Tables)	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Income Statement [Table Text Block]	Condensed Consolidating Statements of Comprehensive Income Year ended December 31, 2015 ( $ in millions ) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing 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 available-for-sale investment securities — — 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 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 Depreciation expense on operating lease assets 7 — 2,242 — 2,249 Net financing (loss) 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 Servicing fees 1,137 — 834 (1,926 ) 45 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 236 — 539 (461 ) 314 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 available-for-sale investment securities — — 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 Depreciation expense on operating lease assets 161 — 2,072 — 2,233 Net financing (loss) 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 Servicing fees 1,071 — 792 (1,832 ) 31 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 208 — 507 (435 ) 280 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 Year ended December 31, 2013 ( $ in millions ) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Financing revenue and other interest income Interest and fees on finance receivables and loans $ 771 $ — $ 3,758 $ — $ 4,529 Interest and fees on finance receivables and loans — intercompany 59 — 68 (127 ) — Interest on loans held-for-sale — — 20 — 20 Interest and dividends on available-for-sale investment securities — — 325 — 325 Interest on cash and cash equivalents 3 — 7 — 10 Interest-bearing cash — intercompany — — 7 (7 ) — Operating leases 500 — 2,709 — 3,209 Total financing revenue and other interest income 1,333 — 6,894 (134 ) 8,093 Interest expense Interest on deposits 25 — 629 — 654 Interest on short-term borrowings 46 — 17 — 63 Interest on long-term debt 2,039 — 568 (5 ) 2,602 Interest on intercompany debt 66 — 62 (128 ) — Total interest expense 2,176 — 1,276 (133 ) 3,319 Depreciation expense on operating lease assets 369 — 1,626 — 1,995 Net financing (loss) revenue (1,212 ) — 3,992 (1 ) 2,779 Cash dividends from subsidiaries Nonbank subsidiaries 5,732 3,659 — (9,391 ) — Other revenue Servicing fees 152 — (26 ) — 126 Servicing asset valuation and hedge activities, net — — (213 ) — (213 ) Total servicing income (loss), net 152 — (239 ) — (87 ) Insurance premiums and service revenue earned — — 1,012 — 1,012 Gain on mortgage and automotive loans, net — — 55 — 55 (Loss) gain on extinguishment of debt (61 ) — 2 — (59 ) Other gain on investments, net — — 180 — 180 Other income, net of losses 157 — 1,438 (1,212 ) 383 Total other revenue 248 — 2,448 (1,212 ) 1,484 Total net revenue 4,768 3,659 6,440 (10,604 ) 4,263 Provision for loan losses 196 — 305 — 501 Noninterest expense Compensation and benefits expense 640 — 821 (442 ) 1,019 Insurance losses and loss adjustment expenses — — 405 — 405 Other operating expenses 501 — 2,250 (770 ) 1,981 Total noninterest expense 1,141 — 3,476 (1,212 ) 3,405 Income from continuing operations before income tax (benefit) expense and undistributed income (loss) of subsidiaries 3,431 3,659 2,659 (9,392 ) 357 Income tax (benefit) expense from continuing operations (969 ) — 910 — (59 ) Net income from continuing operations 4,400 3,659 1,749 (9,392 ) 416 (Loss) income from discontinued operations, net of tax (1,321 ) (19 ) 1,284 1 (55 ) Undistributed income (loss) of subsidiaries Bank subsidiary 883 883 — (1,766 ) — Nonbank subsidiaries (3,601 ) (2,393 ) — 5,994 — Net income 361 2,130 3,033 (5,163 ) 361 Other comprehensive loss, net of tax (587 ) (812 ) (873 ) 1,685 (587 ) Comprehensive (loss) income $ (226 ) $ 1,318 $ 2,160 $ (3,478 ) $ (226 )
Condensed Balance Sheet [Table Text Block]	Condensed Consolidating Balance Sheet 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 Investment 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. December 31, 2014 ( $ in millions ) Parent (a) Guarantors Nonguarantors (a) Consolidating adjustments Ally consolidated Assets Cash and cash equivalents Noninterest-bearing $ 986 $ — $ 362 $ — $ 1,348 Interest-bearing 1,300 — 2,928 — 4,228 Interest-bearing — intercompany — — 615 (615 ) — Total cash and cash equivalents 2,286 — 3,905 (615 ) 5,576 Investment securities — — 16,137 — 16,137 Loans held-for-sale, net 3 — 2,000 — 2,003 Finance receivables and loans, net Finance receivables and loans, net 4,225 — 95,723 — 99,948 Intercompany loans to Bank subsidiary 625 — — (625 ) — Nonbank subsidiaries 3,500 — 1,770 (5,270 ) — Allowance for loan losses (102 ) — (875 ) — (977 ) Total finance receivables and loans, net 8,248 — 96,618 (5,895 ) 98,971 Investment in operating leases, net — — 19,510 — 19,510 Intercompany receivables from Bank subsidiary 219 — — (219 ) — Nonbank subsidiaries 267 — 393 (660 ) — Investment in subsidiaries Bank subsidiary 15,967 15,967 — (31,934 ) — Nonbank subsidiaries 11,559 12 — (11,571 ) — Premiums receivable and other insurance assets — — 1,717 (22 ) 1,695 Other assets 4,757 — 4,814 (2,466 ) 7,105 Assets of operations held-for-sale 634 — — — 634 Total assets $ 43,940 $ 15,979 $ 145,094 $ (53,382 ) $ 151,631 Liabilities Deposit liabilities Noninterest-bearing $ — $ — $ 64 $ — $ 64 Interest-bearing 319 — 57,820 — 58,139 Total deposit liabilities 319 — 57,884 — 58,203 Short-term borrowings 3,338 — 3,724 — 7,062 Long-term debt 21,067 — 45,313 — 66,380 Intercompany debt to Nonbank subsidiaries 2,385 — 4,125 (6,510 ) — Intercompany payables to Bank subsidiary 94 — — (94 ) — Nonbank subsidiaries 454 — 354 (808 ) — Interest payable 316 — 161 — 477 Unearned insurance premiums and service revenue — — 2,375 — 2,375 Accrued expenses and other liabilities 568 82 3,551 (2,466 ) 1,735 Total liabilities 28,541 82 117,487 (9,878 ) 136,232 Total equity 15,399 15,897 27,607 (43,504 ) 15,399 Total liabilities and equity $ 43,940 $ 15,979 $ 145,094 $ (53,382 ) $ 151,631 (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, 2015 ( $ in millions ) Parent Guarantors Nonguarantors Consolidating adjustments Ally consolidated Operating activities Net cash provided by operating activities $ 354 $ 525 $ 6,390 $ (2,174 ) $ 5,095 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 Net decrease (increase) in finance receivables and loans 1,785 — (15,630 ) — (13,845 ) Proceeds from sales of finance receivables and loans originated as held-for investment — — 3,197 — 3,197 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 Other, net (47 ) — (105 ) — (152 ) 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 ) 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 (4,586 ) (524 ) 6,533 4,037 5,460 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 Net decrease (increase) in finance receivables and loans 1,900 — (6,941 ) 17 (5,024 ) Proceeds from sales of finance receivables and loans originated as held-for-investment — — 2,592 — 2,592 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 Other, net (29 ) — 101 — 72 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 Year ended December 31, 2013 ( $ in millions ) Parent Guarantors Nonguarantors Consolidating Ally Operating activities Net cash provided by operating activities $ 3,015 $ 3,572 $ 5,305 $ (9,391 ) $ 2,501 Investing activities Purchases of available-for-sale securities — — (12,304 ) — (12,304 ) Proceeds from sales of available-for-sale securities — — 3,627 — 3,627 Proceeds from maturities and repayments of available-for-sale securities — — 5,509 — 5,509 Net decrease (increase) in finance receivables and loans 4,898 79 (7,456 ) — (2,479 ) Net change in loans — intercompany 301 251 (1,503 ) 951 — Purchases of operating lease assets (1,450 ) — (7,746 ) — (9,196 ) Disposals of operating lease assets 130 — 2,834 — 2,964 Capital contributions to subsidiaries (477 ) — — 477 — Returns of contributed capital 1,002 150 — (1,152 ) — Sales of mortgage servicing rights — — 911 — 911 Proceeds from sale of business unit, net 1,799 554 5,091 — 7,444 Net change in restricted cash — (26 ) (44 ) — (70 ) Other, net 41 — 10 — 51 Net cash provided by (used in) investing activities 6,244 1,008 (11,071 ) 276 (3,543 ) Financing activities Net change in short-term borrowings — third party 131 36 1,424 — 1,591 Net (decrease) increase in deposits (543 ) — 5,861 39 5,357 Proceeds from issuance of long-term debt — third party 3,236 — 24,094 — 27,330 Repayments of long-term debt — third party (9,468 ) (70 ) (22,354 ) — (31,892 ) Net change in debt — intercompany 1,803 (271 ) (624 ) (908 ) — Proceeds from issuance of common stock 1,270 — — — 1,270 Repurchase of mandatorily convertible preferred stock held by U.S. Department of Treasury and elimination of share adjustment right (5,925 ) — — — (5,925 ) Dividends paid — third party (810 ) — — — (810 ) Dividends paid and returns of contributed capital — intercompany — (4,267 ) (6,275 ) 10,542 — Capital contributions from parent — 29 448 (477 ) — Net cash (used in) provided by financing activities (10,306 ) (4,543 ) 2,574 9,196 (3,079 ) Effect of exchange-rate changes on cash and cash equivalents — — 45 — 45 Net (decrease) increase in cash and cash equivalents (1,047 ) 37 (3,147 ) 81 (4,076 ) Adjustment for change in cash and cash equivalents of operations held-for-sale — — 2,094 — 2,094 Cash and cash equivalents at beginning of year 3,977 — 4,027 (491 ) 7,513 Cash and cash equivalents at end of year $ 2,930 $ 37 $ 2,974 $ (410 ) $ 5,531

Guarantees and Commitments (Tab

Guarantees and Commitments (Tables)	12 Months Ended
	Dec. 31, 2015
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. 2015 2014 December 31, ( $ in millions ) Maximum liability Carrying value of liability Maximum liability Carrying value of liability Standby letters of credit and other guarantees $ 208 $ 13 $ 268 $ 19
Financing Commitments [Table Text Block]	The contractual commitments were as follows. December 31, ( $ in millions ) 2015 2014 Commitments to provide capital to investees (a) $ 132 $ 66 Construction-lending commitments (b) 197 110 Home equity lines of credit (c) 358 371 Unused revolving credit line commitments and other (d) 1,445 1,284 (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, 2015 , are as follows. Year ended December 31, ( $ in millions ) 2016 $ 39 2017 34 2018 31 2019 31 2020 29 2021 and thereafter 99 Total minimum payment required $ 263
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 ) 2016 $ 47 2017 and 2018 51 2019 and thereafter 3 Total future payment obligations $ 101

Quarterly Financial Statements

Quarterly Financial Statements (Tables)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Statements [Abstract]
Schedule of Quarterly Financial Information [Table Text Block]	( $ in millions ) First quarter Second quarter Third quarter Fourth quarter 2015 Net financing revenue $ 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 ) 2014 Net financing revenue $ 821 $ 866 $ 889 $ 799 Other revenue 321 365 375 215 Total net revenue 1,142 1,231 1,264 1,014 Provision for loan losses 137 63 102 155 Total noninterest expense 713 821 742 672 Income from continuing operations before income tax expense 292 347 420 187 Income tax expense from continuing operations 94 64 127 36 Net income from continuing operations 198 283 293 151 Income from discontinued operations, net of tax 29 40 130 26 Net income $ 227 $ 323 $ 423 $ 177 Basic earnings per common share Net income from continuing operations $ 0.27 $ 0.45 $ 0.47 $ 0.17 Net income 0.33 0.54 0.74 0.23 Diluted earnings per common share Net income from continuing operations $ 0.27 $ 0.45 $ 0.47 $ 0.17 Net income 0.33 0.54 0.74 0.23

Description Of Business, Basi70

Description Of Business, Basis Of Presentation, And Changes In Significant Accounting Policies Accounting Standard Adoption (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other Assets	$ 6,321	$ 7,105
Long-term debt	66,234	66,380
Interest-bearing deposit liabilities	66,389	58,139
New Accounting Pronouncement, Early Adoption, Effect [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other Assets	(190)	(197)
Long-term debt	(168)	(178)
Interest-bearing deposit liabilities	$ (22)	$ (19)

Discontinued and Held-for-sal71

Discontinued and Held-for-sale Operations (Selected Income Statement Information for Discontinued Operations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	$ 452	$ (7)	$ 666
Insurance Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total net (loss) revenue - Discontinued Operations	0	0	190
Pretax income (loss) including direct costs to transact a sale	3	6	319
Tax (benefit) expense - Discontinued Operations	1	6	(14)
Automotive finance operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total net (loss) revenue - Discontinued Operations	0	123	572
Pretax income (loss) including direct costs to transact a sale	452	129	660
Tax (benefit) expense - Discontinued Operations	80	7	(101)
Corporate Finance Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total net (loss) revenue - Discontinued Operations	0	0	0
Pretax income (loss) including direct costs to transact a sale	22	23	0
Tax (benefit) expense - Discontinued Operations	0	3	0
Corporate and Other operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total net (loss) revenue - Discontinued Operations	0	0	0
Pretax income (loss) including direct costs to transact a sale	(9)	(4)	(1,741)
Tax (benefit) expense - Discontinued Operations	$ (5)	(87)	$ (592)
MEXICO
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax		274
Europe and Latin America [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax		(488)
CANADA
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax		$ 888

Discontinued and Held-for-sal72

Discontinued and Held-for-sale Operations (Select Balance Sheet Information for Held-for-sale Operations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other Assets	$ 6,321	$ 7,105
Assets of operations held-for-sale	$ 0	634
Automotive finance operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Interest in Joint Venture	40.00%
Equity Method Investment, Realized Gain (Loss) on Disposal	$ 400
Other Assets		$ 634

Insurance Premiums and Servic73

Insurance Premiums and Service Revenue Earned (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Premiums Written and Earned [Abstract]
Direct Premiums Written, Property and Casualty	$ 313	$ 294	$ 270
Direct Premiums Earned, Property and Casualty	296	282	305
Assumed Premiums Written, Property and Casualty	2	43	61
Assumed Premiums Earned, Property and Casualty	16	54	58
Premiums Written, Gross	315	337	331
Gross Insurance Premiums Earned	312	336	363
Ceded Premiums Written, Property and Casualty	(184)	(156)	(172)
Ceded Premiums Earned, Property and Casualty	(125)	(117)	(120)
Premiums Written, Net, Property and Casualty	131	181	159
Premiums Earned, Net, Property and Casualty	187	219	243
Insurance Commissions and Fees Written	846	842	838
Insurance Commissions and Fees	753	760	769
Insurance Services Revenue Written	977	1,023	997
Insurance premiums and service revenue earned	$ 940	$ 979	$ 1,012

Other Income, Net Of Losses (Ot

Other Income, Net Of Losses (Other Income, Net Of Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other Nonoperating Income (Expense) [Abstract]
Remarketing Fees	$ 101	$ 112	$ 82
Fees and Commissions, Other	90	88	94
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions	52	18	15
Fees and Commissions, Mortgage Banking and Servicing	0	0	81
Unrealized Gain (Loss) on Derivatives	(8)	(31)	24
Other Income	79	93	87
Other income, net of losses	$ 314	$ 280	$ 383

Other Operating Expenses (Detai

Other Operating Expenses (Details Of Other Operating Expenses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Expenses [Abstract]
Insurance Commissions	$ 378	$ 374	$ 370
Communications and Information Technology	267	334	346
Lease and loan administration	126	122	173
Marketing and Advertising Expense	107	111	136
Professional Fees	93	100	176
Depreciation, Nonproduction	82	81	81
Regulatory and licensing fees	79	87	116
Vehicle remarketing and repossession	78	83	60
Occupancy, Net	50	47	44
Legal Fees	45	4	105
State And Local Non-Income Taxes Amount	29	40	35
Mortgage Representation And Warranty, Net	(13)	(10)	104
Other Cost and Expense, Operating	184	218	235
Total other operating expenses	$ 1,505	$ 1,591	1,981
CFPB Settlement			$ 98

Investment Securities (Schedule

Investment Securities (Schedule of Available-for-sale Securities Reconciliation) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 17,350	$ 16,107
Available-for-sale Securities, Gross Unrealized Gains	96	213
Available-for-sale Securities, Gross Unrealized Losses	(289)	(183)
Available-for-sale Securities	17,157	16,137
Total agency backed bonds	7,544	7,557
Deposit Assets	14	15
Cash Equivalents, at Carrying Value	1,000	2,000
Pledged Assets Separately Reported, Securities Pledged for Federal Home Loan Bank, at Fair Value	2,506	801
Pledged Assets Separately Reported, Other Assets Pledged as Collateral, at Fair Value	745
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	16,542	15,216
Available-for-sale Debt Securities Gross Unrealized Gain	93	164
Available-for-sale Debt Securities, Gross Unrealized Loss	(195)	(149)
Available-for-sale Securities, Debt Securities	16,440	15,231
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	1,760	1,195
Available-for-sale Debt Securities Gross Unrealized Gain	0	1
Available-for-sale Debt Securities, Gross Unrealized Loss	(19)	(18)
Available-for-sale Securities, Debt Securities	1,741	1,178
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	693	389
Available-for-sale Debt Securities Gross Unrealized Gain	24	17
Available-for-sale Debt Securities, Gross Unrealized Loss	(1)	0
Available-for-sale Securities, Debt Securities	716	406
Foreign Government Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	169	224
Available-for-sale Debt Securities Gross Unrealized Gain	8	8
Available-for-sale Debt Securities, Gross Unrealized Loss	0	0
Available-for-sale Securities, Debt Securities	177	232
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	10,459	10,431
Available-for-sale Debt Securities Gross Unrealized Gain	52	119
Available-for-sale Debt Securities, Gross Unrealized Loss	(145)	(125)
Available-for-sale Securities, Debt Securities	10,366	10,425
Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	486	254
Available-for-sale Debt Securities Gross Unrealized Gain	0	0
Available-for-sale Debt Securities, Gross Unrealized Loss	(5)	(1)
Available-for-sale Securities, Debt Securities	481	253
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	1,762	1,989
Available-for-sale Debt Securities Gross Unrealized Gain	1	5
Available-for-sale Debt Securities, Gross Unrealized Loss	(8)	(3)
Available-for-sale Securities, Debt Securities	1,755	1,991
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	1,213	734
Available-for-sale Debt Securities Gross Unrealized Gain	8	14
Available-for-sale Debt Securities, Gross Unrealized Loss	(17)	(2)
Available-for-sale Securities, Debt Securities	1,204	746
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Equity Securities, Amortized Cost Basis	808	891
Available-for-sale Equity Securities, Gross Unrealized Gain	3	49
Available-for-sale Equity Securities, Gross Unrealized Loss	(94)	(34)
Available-for-sale Securities, Equity Securities	$ 717	$ 906

Investment Securities (Investme

Investment Securities (Investments Classified by Contractual Maturity Date) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Due in one year or less, Amount	$ 157	$ 108
Available-for-sale debt securities, Due after one year through five years, Amount	2,397	2,676
Available-for-sale debt securities, Due after five years through ten years, Amount	2,424	1,383
Available-for-sale debt securities, Due after ten years, Amount	11,462	11,064
Amortized cost of available-for-sale debt securities, Due in one year or less, Amount	156	108
Amortized cost of available-for-sale debt securities, Due after one year through five years, Amount	2,404	2,674
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Amortized Cost Basis	2,436	1,374
Amortized cost of available-for-sale debt securities, Due after ten years, Amount	$ 11,546	$ 11,060
Available-for-sale debt securities, Yield	2.70%	2.50%
Available-for-sale debt securities, Due in one year or less, Yield	2.00%	2.70%
Available-for-sale debt securities, Due after one year through five years, Yield	2.10%	1.90%
Available-for-sale debt securities, Due after five years through ten years, Yield	2.50%	2.40%
Available-for-sale debt securities, Due after ten years, Yield	2.90%	2.60%
Available-for-sale Securities, Debt Securities	$ 16,440	$ 15,231
Available-for-sale Debt Securities, Amortized Cost Basis	16,542	15,216
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Due in one year or less, Amount	6	7
Available-for-sale debt securities, Due after one year through five years, Amount	510	677
Available-for-sale debt securities, Due after five years through ten years, Amount	1,225	494
Available-for-sale debt securities, Due after ten years, Amount	$ 0	$ 0
Available-for-sale debt securities, Yield	1.80%	1.50%
Available-for-sale debt securities, Due in one year or less, Yield	5.10%	3.00%
Available-for-sale debt securities, Due after one year through five years, Yield	1.20%	1.20%
Available-for-sale debt securities, Due after five years through ten years, Yield	2.10%	1.90%
Available-for-sale debt securities, Due after ten years, Yield	0.00%	0.00%
Available-for-sale Securities, Debt Securities	$ 1,741	$ 1,178
Available-for-sale Debt Securities, Amortized Cost Basis	1,760	1,195
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Due in one year or less, Amount	86	34
Available-for-sale debt securities, Due after one year through five years, Amount	37	12
Available-for-sale debt securities, Due after five years through ten years, Amount	141	106
Available-for-sale debt securities, Due after ten years, Amount	$ 452	$ 254
Available-for-sale debt securities, Yield	3.20%	3.70%
Available-for-sale debt securities, Due in one year or less, Yield	1.30%	1.90%
Available-for-sale debt securities, Due after one year through five years, Yield	2.20%	2.10%
Available-for-sale debt securities, Due after five years through ten years, Yield	2.80%	3.00%
Available-for-sale debt securities, Due after ten years, Yield	3.70%	4.30%
Available-for-sale Securities, Debt Securities	$ 716	$ 406
Available-for-sale Debt Securities, Amortized Cost Basis	693	389
Foreign Government Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Due in one year or less, Amount	9	0
Available-for-sale debt securities, Due after one year through five years, Amount	77	128
Available-for-sale debt securities, Due after five years through ten years, Amount	91	104
Available-for-sale debt securities, Due after ten years, Amount	$ 0	$ 0
Available-for-sale debt securities, Yield	2.60%	2.70%
Available-for-sale debt securities, Due in one year or less, Yield	1.90%	0.00%
Available-for-sale debt securities, Due after one year through five years, Yield	2.80%	2.50%
Available-for-sale debt securities, Due after five years through ten years, Yield	2.60%	2.90%
Available-for-sale debt securities, Due after ten years, Yield	0.00%	0.00%
Available-for-sale Securities, Debt Securities	$ 177	$ 232
Available-for-sale Debt Securities, Amortized Cost Basis	169	224
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Due in one year or less, Amount	0	34
Available-for-sale debt securities, Due after one year through five years, Amount	33	58
Available-for-sale debt securities, Due after five years through ten years, Amount	36	0
Available-for-sale debt securities, Due after ten years, Amount	$ 10,297	$ 10,333
Available-for-sale debt securities, Yield	2.90%	2.60%
Available-for-sale debt securities, Due in one year or less, Yield	0.00%	3.10%
Available-for-sale debt securities, Due after one year through five years, Yield	2.10%	2.10%
Available-for-sale debt securities, Due after five years through ten years, Yield	2.50%	0.00%
Available-for-sale debt securities, Due after ten years, Yield	2.90%	2.60%
Available-for-sale Securities, Debt Securities	$ 10,366	$ 10,425
Available-for-sale Debt Securities, Amortized Cost Basis	10,459	10,431
Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Due in one year or less, Amount	0	0
Available-for-sale debt securities, Due after one year through five years, Amount	0	30
Available-for-sale debt securities, Due after five years through ten years, Amount	3	0
Available-for-sale debt securities, Due after ten years, Amount	$ 478	$ 223
Available-for-sale debt securities, Yield	2.00%	1.50%
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, Yield	0.00%	1.80%
Available-for-sale debt securities, Due after five years through ten years, Yield	2.70%	0.00%
Available-for-sale debt securities, Due after ten years, Yield	2.00%	1.40%
Available-for-sale Securities, Debt Securities	$ 481	$ 253
Available-for-sale Debt Securities, Amortized Cost Basis	486	254
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Due in one year or less, Amount	6	0
Available-for-sale debt securities, Due after one year through five years, Amount	1,027	1,311
Available-for-sale debt securities, Due after five years through ten years, Amount	518	463
Available-for-sale debt securities, Due after ten years, Amount	$ 204	$ 217
Available-for-sale debt securities, Yield	2.30%	1.90%
Available-for-sale debt securities, Due in one year or less, Yield	1.40%	0.00%
Available-for-sale debt securities, Due after one year through five years, Yield	2.10%	1.90%
Available-for-sale debt securities, Due after five years through ten years, Yield	2.60%	2.00%
Available-for-sale debt securities, Due after ten years, Yield	2.20%	2.20%
Available-for-sale Securities, Debt Securities	$ 1,755	$ 1,991
Available-for-sale Debt Securities, Amortized Cost Basis	1,762	1,989
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Due in one year or less, Amount	50	33
Available-for-sale debt securities, Due after one year through five years, Amount	713	460
Available-for-sale debt securities, Due after five years through ten years, Amount	410	216
Available-for-sale debt securities, Due after ten years, Amount	$ 31	$ 37
Available-for-sale debt securities, Yield	2.90%	3.20%
Available-for-sale debt securities, Due in one year or less, Yield	3.00%	3.10%
Available-for-sale debt securities, Due after one year through five years, Yield	2.50%	2.70%
Available-for-sale debt securities, Due after five years through ten years, Yield	3.40%	3.80%
Available-for-sale debt securities, Due after ten years, Yield	5.40%	5.60%
Available-for-sale Securities, Debt Securities	$ 1,204	$ 746
Available-for-sale Debt Securities, Amortized Cost Basis	$ 1,213	$ 734

Investment Securities (Invest78

Investment Securities (Investment Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Available-for-sale Securities [Abstract]
Taxable interest	$ 340	$ 336	$ 297
Taxable dividends	23	20	25
Interest and dividends exempt from U.S. federal income tax	18	11	3
Interest and dividends on available-for-sale investment securities	$ 381	$ 367	$ 325

Investment Securities (Schedu79

Investment Securities (Schedule Of Realized Gain (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Available-for-sale Securities [Abstract]
Available-for-sale Securities, Gross Realized Gains	$ 184	$ 209	$ 221
Available-for-sale Securities, Gross Realized Losses	(15)	(14)	(21)
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	(14)	(14)	(20)
Other gain (loss) on investments, net	$ 155	$ 181	$ 180

Investment Securities (Schedu80

Investment Securities (Schedule of Unrealized Loss on Investments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	$ 8,511	$ 2,701
Available-for-sale Securities, Unrealized Loss Less than 12 months	(139)	(42)
Available-for-sale Securities, Fair value 12 months or longer	2,798	4,016
Available-for-sale Securities, Unrealized Loss 12 months or longer	(150)	(141)
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	7,977	2,470
Available-for-sale Securities, Unrealized Loss Less than 12 months	(85)	(18)
Available-for-sale Securities, Fair value 12 months or longer	2,702	3,976
Available-for-sale Securities, Unrealized Loss 12 months or longer	(110)	(131)
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	1,553	297
Available-for-sale Securities, Unrealized Loss Less than 12 months	(17)	(3)
Available-for-sale Securities, Fair value 12 months or longer	173	859
Available-for-sale Securities, Unrealized Loss 12 months or longer	(2)	(15)
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	179	50
Available-for-sale Securities, Unrealized Loss Less than 12 months	(1)	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
Foreign Government Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	2	0
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
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	4,096	1,172
Available-for-sale Securities, Unrealized Loss Less than 12 months	(43)	(10)
Available-for-sale Securities, Fair value 12 months or longer	2,453	3,098
Available-for-sale Securities, Unrealized Loss 12 months or longer	(107)	(116)
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	1,402	819
Available-for-sale Securities, Unrealized Loss Less than 12 months	(8)	(3)
Available-for-sale Securities, Fair value 12 months or longer	64	8
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	745	132
Available-for-sale Securities, Unrealized Loss Less than 12 months	(16)	(2)
Available-for-sale Securities, Fair value 12 months or longer	12	11
Available-for-sale Securities, Unrealized Loss 12 months or longer	(1)	0
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	534	231
Available-for-sale Securities, Unrealized Loss Less than 12 months	(54)	(24)
Available-for-sale Securities, Fair value 12 months or longer	96	40
Available-for-sale Securities, Unrealized Loss 12 months or longer	$ (40)	$ (10)

Loans Held-for-Sale, Net Loan81

Loans Held-for-Sale, Net Loans Held-for-Sale, Net (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-for-sale, net	$ 105	$ 2,003
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-for-sale, net	0	1,967
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-for-sale, net	0	1,515
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-for-sale, net	0	452
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-for-sale, net	0	0
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-for-sale, net	0	452
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-for-sale, net	$ 105	$ 36

Finance Receivables And Loans82

Finance Receivables And Loans, Net (Schedule of Accounts, Notes, Loans and Financing Receivables) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 111,600	$ 99,948
Interest and Fee Income, Loans and Leases	4,570	4,457	$ 4,529
Loans and Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	(110)	266
Fair Value Option Election, Fair Value [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	111,600	99,948
Designated as Hedging Instrument [Member] | Gain (Loss) Recognized in Earnings on Hedged Item [Member] | Interest Rate Contract [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest and Fee Income, Loans and Leases	(39)	(34)	$ (2)
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	74,065	64,044
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	64,292	56,570
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Designated as Hedging Instrument [Member] | Gain (Loss) Recognized in Earnings on Hedged Item [Member] | Fair Value Option Election, Fair Value [Member] | Interest Rate Contract [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest and Fee Income, Loans and Leases	66	35
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	9,773	7,474
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	6,413	3,504
Held For Investment Mortgage Finance Receivables Interest Only Mortgage Loans	$ 44	55
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	7.00%
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	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	0.00%
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] | Five years or greater [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	38.00%
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 3,360	3,970
Held For Investment Mortgage Finance Receivables Interest Only Mortgage Loans	$ 941	1,100
Loans Receivable, Fair Value Disclosure		1
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	35.00%
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	22.00%
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member] | Three 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] | 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] | 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]
Finance receivables and loans, net	$ 37,535	35,904
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	31,469	30,871
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	2,640	1,882
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 3,426	$ 3,151

Finance Receivables And Loans83

Finance Receivables And Loans, Net (Allowance For Credit Losses On Financing Receivables) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance, Beginning Balance	$ 977	$ 1,208
Allowance for Loan and Lease Losses, Write-offs	(892)	(776)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	283	239
Allowance for Loan and Lease Losses Write-offs, Net	(609)	(537)
Provision for Loan and Lease Losses	707	457
Allowance for Loan and Lease Losses, Adjustments, Net	(21)	(151)
Loans and Leases Receivable, Allowance, Ending Balance	1,054	977
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses, Individually evaluated for impairment	86	106
Allowance for loan losses, Collectively evaluated for impairment	968	871
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	111,600	99,947
Finance receivables and loans, net	111,600	99,948
Financing Receivable, Individually Evaluated for Impairment	658	700
Financing receivable, Collectively evaluated for impairment	110,942	99,246
Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Allowance for Credit Losses	0	0
Finance receivables and loans, net	0	1
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance, Beginning Balance	685	673
Allowance for Loan and Lease Losses, Write-offs	(840)	(720)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	262	219
Allowance for Loan and Lease Losses Write-offs, Net	(578)	(501)
Provision for Loan and Lease Losses	739	540
Allowance for Loan and Lease Losses, Adjustments, Net	(12)	(27)
Loans and Leases Receivable, Allowance, Ending Balance	834	685
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses, Individually evaluated for impairment	22	23
Allowance for loan losses, Collectively evaluated for impairment	812	662
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	64,292	56,570
Finance receivables and loans, net	64,292	56,570
Financing Receivable, Individually Evaluated for Impairment	315	282
Financing receivable, Collectively evaluated for impairment	63,977	56,287
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
Finance receivables and loans, net	0	1
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	6,413	3,504
Finance receivables and loans, net	6,413	3,504
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	3,360	3,969
Finance receivables and loans, net	3,360	3,970
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance, Beginning Balance	152	389
Allowance for Loan and Lease Losses, Write-offs	(48)	(51)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	17	8
Allowance for Loan and Lease Losses Write-offs, Net	(31)	(43)
Provision for Loan and Lease Losses	1	(69)
Allowance for Loan and Lease Losses, Adjustments, Net	(8)	(125)
Loans and Leases Receivable, Allowance, Ending Balance	114	152
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses, Individually evaluated for impairment	44	62
Allowance for loan losses, Collectively evaluated for impairment	70	90
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	9,773	7,473
Finance receivables and loans, net	9,773	7,474
Financing Receivable, Individually Evaluated for Impairment	266	336
Financing receivable, Collectively evaluated for impairment	9,507	7,137
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
Finance receivables and loans, net	0	0
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance, Beginning Balance	140	146
Allowance for Loan and Lease Losses, Write-offs	(4)	(5)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	4	12
Allowance for Loan and Lease Losses Write-offs, Net	0	7
Provision for Loan and Lease Losses	(33)	(14)
Allowance for Loan and Lease Losses, Adjustments, Net	(1)	1
Loans and Leases Receivable, Allowance, Ending Balance	106	140
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses, Individually evaluated for impairment	20	21
Allowance for loan losses, Collectively evaluated for impairment	86	119
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	37,535	35,904
Finance receivables and loans, net	37,535	35,904
Financing Receivable, Individually Evaluated for Impairment	77	82
Financing receivable, Collectively evaluated for impairment	37,458	35,822
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
Finance receivables and loans, net	$ 0	$ 0

Finance Receivables And Loans84

Finance Receivables And Loans, Net (Schedule Of Sales Of Financing Receivables And Loans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Significant Sales and Transfers	$ 1,317	$ 4,631
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Significant Sales and Transfers	1,237	4,106
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Significant Sales and Transfers	78	489
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Significant Sales and Transfers	$ 2	$ 36

Finance Receivables And Loans85

Finance Receivables And Loans, Net Finance Receivables and Loans, Net (Schedule of Purchases of Finance Receivables and Loans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Significant Purchases	$ 4,397	$ 857
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Significant Purchases	272	0
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Significant Purchases	$ 4,125	$ 857

Finance Receivables And Loans86

Finance Receivables And Loans, Net (Past Due Financing Receivables And Loans) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	$ 2,414	$ 2,031
Current	109,186	97,916
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	111,600	99,947
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	2,414	2,022
Current	71,651	62,021
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	74,065	64,043
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	2,209	1,797
Current	62,083	54,773
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	64,292	56,570
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	205	225
Current	9,568	7,248
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	9,773	7,473
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	59	24
Current	6,354	3,480
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	6,413	3,504
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	146	201
Current	3,214	3,768
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	3,360	3,969
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	9
Current	37,535	35,895
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	37,535	35,904
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	9
Current	31,469	30,862
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	31,469	30,871
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Current	2,640	1,882
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	2,640	1,882
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Current	3,426	3,151
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	3,426	3,151
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,715	1,416
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	1,715	1,416
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	1,618	1,340
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	97	76
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	44	11
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	53	65
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	0	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	0	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	394	327
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	394	318
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	369	293
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	25	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	5	2
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	20	23
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	9
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	9
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	305	288
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	305	288
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	222	164
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	83	124
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	10	11
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	73	113
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	0	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	0	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 Loans87

Finance Receivables And Loans, Net (Schedule of Financing Receivables, Non Accrual Status) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	$ 680	$ 645
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	603	563
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	475	386
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	128	177
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	15	19
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	113	158
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	77	82
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	25	32
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	44	46
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans on nonaccrual status	$ 8	$ 4

Finance Receivables And Loans88

Finance Receivables And Loans, Net (Financing Receivable Credit Quality Indicators) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 111,600	$ 99,948
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	111,600	99,947
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	74,065	64,044
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	74,065	64,043
Consumer Portfolio Segment [Member] | Consumer Loan [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	73,462	63,480
Consumer Portfolio Segment [Member] | Consumer Loan [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	603	563
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	64,292	56,570
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	64,292	56,570
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	63,817	56,184
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	475	386
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	9,773	7,474
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	9,773	7,473
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	9,645	7,296
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	128	177
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	6,413	3,504
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	6,413	3,504
Consumer Portfolio Segment [Member] | Mortgage Finance [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	6,398	3,485
Consumer Portfolio Segment [Member] | Mortgage Finance [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	15	19
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	3,360	3,970
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	3,360	3,969
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	3,247	3,811
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 113	$ 158

Finance Receivables And Loans89

Finance Receivables And Loans, Net (Schedule Of Pass And Criticized Credit Quality Indicators Of Finance Receivables) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 111,600	$ 99,948
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	37,535	35,904
Commercial Portfolio Segment [Member] | Commercial Loan [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	35,000	33,674
Commercial Portfolio Segment [Member] | Commercial Loan [Member] | Criticized Member
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	2,535	2,230
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	31,469	30,871
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	29,613	29,150
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member] | Criticized Member
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	1,856	1,721
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	2,640	1,882
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	2,122	1,509
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member] | Criticized Member
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	518	373
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	3,426	3,151
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	3,265	3,015
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member] | Criticized Member
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 161	$ 136

Finance Receivables And Loans90

Finance Receivables And Loans, Net (Impaired Financing Receivables) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	$ 661	$ 704
Carrying value before allowance	658	700
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	69	91
Impaired Financing Receivable, with Related Allowance, Recorded Investment	589	609
Impaired Financing Receivable, Related Allowance	86	106
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	584	622
Carrying value before allowance	581	618
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	64	86
Impaired Financing Receivable, with Related Allowance, Recorded Investment	517	532
Impaired Financing Receivable, Related Allowance	66	85
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	315	282
Carrying value before allowance	315	282
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	0	0
Impaired Financing Receivable, with Related Allowance, Recorded Investment	315	282
Impaired Financing Receivable, Related Allowance	22	23
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	269	340
Carrying value before allowance	266	336
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	64	86
Impaired Financing Receivable, with Related Allowance, Recorded Investment	202	250
Impaired Financing Receivable, Related Allowance	44	62
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	9	8
Carrying value before allowance	9	7
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	5	4
Impaired Financing Receivable, with Related Allowance, Recorded Investment	4	3
Impaired Financing Receivable, Related Allowance	1	0
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	260	332
Carrying value before allowance	257	329
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	59	82
Impaired Financing Receivable, with Related Allowance, Recorded Investment	198	247
Impaired Financing Receivable, Related Allowance	43	62
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	77	82
Carrying value before allowance	77	82
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	5	5
Impaired Financing Receivable, with Related Allowance, Recorded Investment	72	77
Impaired Financing Receivable, Related Allowance	20	21
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	25	32
Carrying value before allowance	25	32
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	4	4
Impaired Financing Receivable, with Related Allowance, Recorded Investment	21	28
Impaired Financing Receivable, Related Allowance	3	5
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	44	46
Carrying value before allowance	44	46
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	0	0
Impaired Financing Receivable, with Related Allowance, Recorded Investment	44	46
Impaired Financing Receivable, Related Allowance	15	15
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	8	4
Carrying value before allowance	8	4
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	1	1
Impaired Financing Receivable, with Related Allowance, Recorded Investment	7	3
Impaired Financing Receivable, Related Allowance	$ 2	$ 1

Finance Receivables And Loans91

Finance Receivables And Loans, Net (Average Balance And Interest Income Of Impaired Finance Receivables) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	$ 654	$ 1,316	$ 1,439
Impaired Financing Receivable, Interest Income, Accrual Method	29	37	56
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	575	1,190	1,186
Impaired Financing Receivable, Interest Income, Accrual Method	25	32	47
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	295	317	278
Impaired Financing Receivable, Interest Income, Accrual Method	16	20	18
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	280	873	908
Impaired Financing Receivable, Interest Income, Accrual Method	9	12	29
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	8	12	11
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	272	861	897
Impaired Financing Receivable, Interest Income, Accrual Method	9	12	29
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	79	126	253
Impaired Financing Receivable, Interest Income, Accrual Method	4	5	9
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	33	61	152
Impaired Financing Receivable, Interest Income, Accrual Method	1	2	6
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	41	59	72
Impaired Financing Receivable, Interest Income, Accrual Method	3	3	2
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	5	6	29
Impaired Financing Receivable, Interest Income, Accrual Method	$ 0	$ 0	$ 1

Finance Receivables And Loans92

Finance Receivables And Loans, Net Finance Receivables and Loans, Net (Troubled Debt Restructurings) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	17,428	17,913
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 348	$ 362
Financing Receivable, Modifications, Post-Modification Recorded Investment	305	$ 332
Financing Receivable, Modifications, Recorded Investment	625
Total TDR movement during the period	$ (56)
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	17,426	17,907
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 324	$ 291
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 281	$ 261
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	17,222	17,511
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 278	$ 211
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 237	$ 187
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	204	396
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 46	$ 80
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 44	$ 74
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	7	2
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 4	$ 1
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 4	$ 1
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	197	394
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 42	$ 79
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 40	$ 73
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	2	6
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 24	$ 71
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 24	$ 71
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	0	3
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 0	$ 23
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 0	$ 23
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	1	3
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 21	$ 48
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 21	$ 48
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	1	0
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 3	$ 0
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 3	$ 0

Finance Receivables And Loans93

Finance Receivables And Loans, Net (Redefaults) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts	6,846	7,144
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 83	$ 92
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	47	48
Loans and Leases Receivable, Impaired, Commitment to Lend	$ 2	$ 4
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts	6,836	7,117
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 82	$ 90
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	$ 47	$ 47
Consumer Portfolio Segment [Member] | 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
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts	10	27
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 1	$ 2
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	$ 0	$ 1

Finance Receivables And Loans94

Finance Receivables And Loans, Net (Consumer Concentration Risk by State and Foreign Geographic Region) (Details)	Dec. 31, 2015	Dec. 31, 2014
Texas and California [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	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	13.70%	13.60%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | CALIFORNIA
Concentration Risk [Line Items]
Consumer Concentration Risk	7.30%	6.20%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | FLORIDA
Concentration Risk [Line Items]
Consumer Concentration Risk	7.70%	7.30%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | PENNSYLVANIA
Concentration Risk [Line Items]
Consumer Concentration Risk	5.00%	5.30%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | ILLINOIS
Concentration Risk [Line Items]
Consumer Concentration Risk	4.40%	4.40%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | GEORGIA
Concentration Risk [Line Items]
Consumer Concentration Risk	4.40%	4.20%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | NORTH CAROLINA
Concentration Risk [Line Items]
Consumer Concentration Risk	3.60%	3.50%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | OHIO
Concentration Risk [Line Items]
Consumer Concentration Risk	3.70%	3.90%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | NEW YORK
Concentration Risk [Line Items]
Consumer Concentration Risk	3.50%	4.00%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | MICHIGAN
Concentration Risk [Line Items]
Consumer Concentration Risk	3.10%	3.80%
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Other United States [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	43.60%	43.80%
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	6.20%	6.00%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | CALIFORNIA
Concentration Risk [Line Items]
Consumer Concentration Risk	33.60%	30.80%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | FLORIDA
Concentration Risk [Line Items]
Consumer Concentration Risk	4.10%	3.70%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | PENNSYLVANIA
Concentration Risk [Line Items]
Consumer Concentration Risk	1.50%	1.60%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | ILLINOIS
Concentration Risk [Line Items]
Consumer Concentration Risk	4.10%	4.20%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | GEORGIA
Concentration Risk [Line Items]
Consumer Concentration Risk	2.20%	2.10%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | NORTH CAROLINA
Concentration Risk [Line Items]
Consumer Concentration Risk	1.80%	1.90%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | OHIO
Concentration Risk [Line Items]
Consumer Concentration Risk	0.60%	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	2.40%	3.10%
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | Other United States [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	41.60%	44.10%

Finance Receivables and Loans95

Finance Receivables and Loans, Net (Commercial Concentration Risk) (Details)	Dec. 31, 2015	Dec. 31, 2014
Concentration Risk [Line Items]
Commercial Concentration Risk	100.00%	100.00%
TEXAS
Concentration Risk [Line Items]
Commercial Concentration Risk	17.70%	13.80%
FLORIDA
Concentration Risk [Line Items]
Commercial Concentration Risk	10.00%	12.30%
MICHIGAN
Concentration Risk [Line Items]
Commercial Concentration Risk	8.90%	9.90%
CALIFORNIA
Concentration Risk [Line Items]
Commercial Concentration Risk	8.70%	9.00%
NORTH CAROLINA
Concentration Risk [Line Items]
Commercial Concentration Risk	3.80%	3.90%
VIRGINIA
Concentration Risk [Line Items]
Commercial Concentration Risk	3.80%	4.10%
GEORGIA
Concentration Risk [Line Items]
Commercial Concentration Risk	3.60%	3.70%
PENNSYLVANIA
Concentration Risk [Line Items]
Commercial Concentration Risk	3.40%	3.80%
NEW YORK
Concentration Risk [Line Items]
Commercial Concentration Risk	3.10%	3.90%
ILLINOIS
Concentration Risk [Line Items]
Commercial Concentration Risk	2.90%	2.70%
Other United States [Member]
Concentration Risk [Line Items]
Commercial Concentration Risk	34.10%	32.90%

Finance Receivables and Loans96

Finance Receivables and Loans, Net (Commercial Criticized Exposure) (Details)	Dec. 31, 2015	Dec. 31, 2014
Concentration Risk [Line Items]
Commercial Criticized Finance Receivables and Loans	100.00%	100.00%
5500 Retail, Auto Dealers and Gasoline Stations [Member]
Concentration Risk [Line Items]
Commercial Criticized Finance Receivables and Loans	80.50%	87.30%
310000 to 330000 Manufacturing [Member]
Concentration Risk [Line Items]
Commercial Criticized Finance Receivables and Loans	7.80%	0.90%
540000 to 549999 Professional, Scientific, and Technical Services [Member]
Concentration Risk [Line Items]
Commercial Criticized Finance Receivables and Loans	5.30%	2.00%
810000 to 819999 Other Services (except Public Administration) [Member]
Concentration Risk [Line Items]
Commercial Criticized Finance Receivables and Loans	6.40%	9.80%

Investment In Operating Lease97

Investment In Operating Leases, Net (Investments In Operating Leases) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Leases, Operating [Abstract]
Property Subject to or Available for Operating Lease, Gross	$ 20,211	$ 23,144
Property Subject to or Available for Operating Lease, Accumulated Depreciation	(3,940)	(3,634)
Property Subject to or Available for Operating Lease, Net	$ 16,271	$ 19,510

Investment In Operating Lease98

Investment In Operating Leases, Net (Schedule Of Depreciation Expense On Operating Lease Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Leases, Operating [Abstract]
Depreciation Expense On Operating Lease Assets	$ 2,600	$ 2,666	$ 2,327
Gross Remarketing (Gains) Losses	(351)	(433)	(332)
Depreciation expense on operating lease assets	$ 2,249	$ 2,233	$ 1,995

Investment in Operating Lease99

Investment in Operating Leases, Net (Schedule of Operating Leases of Lessor) (Details) $ in Millions	Dec. 31, 2015USD ($)
Leases, Operating [Abstract]
Operating Leases, Future Minimum Payments Receivable, Current	$ 2,687
Operating Leases, Future Minimum Payments Receivable, in Two Years	1,445
Operating Leases, Future Minimum Payments Receivable, in Three Years	406
Operating Leases, Future Minimum Payments Receivable, in Four Years	57
Operating Leases, Future Minimum Payments Receivable, Thereafter	1
Operating Leases, Future Minimum Payments Receivable	$ 4,596

Securitizations And Variable100

Securitizations And Variable Interest Entities (Schedule Of Variable Interest Entities) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Assets of nonconsolidated variable interest entities	$ 3,034	$ 2,801
Maximum exposure to loss in nonconsolidated VIEs	3,527	3,163
Total consoldiated involvement with VIEs	44,940	50,265
Other Assets	6,321	7,105
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	27,967	31,966
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	0	0
Assets of nonconsolidated variable interest entities	3,034	2,801
Maximum exposure to loss in nonconsolidated VIEs	3,034	2,801
Continuing Involvement with Continued to be Recognized Transferred Financial Assets, Amount Outstanding	10,600	12,700
Commercial Portfolio Segment [Member] | Automobile Loan [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	16,763	18,153
Commercial Portfolio Segment [Member] | Unallocated Financing Receivables [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	210	146
Assets of nonconsolidated variable interest entities	0	0
Maximum exposure to loss in nonconsolidated VIEs	493	362
Other Assets	222	164
Accrued Liabilities	$ 12	$ 18

Securitizations and Variable101

Securitizations and Variable Interest Entities (Schedule of On-balance Sheet Variable Interest Entities) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
On-balance Sheet Variable Interest Entities [Line Items]
Finance receivables and loans, net	$ 111,600	$ 99,948
Loans and Leases Receivable, Allowance	(1,054)	(977)	$ (1,208)
Total finance receivables and loans, net	110,546	98,971
Investment in operating leases, net	16,271	19,510
Other Assets	6,321	7,105
Assets	158,581	151,631	$ 150,908
Long-term debt	66,234	66,380
Accrued expenses and other liabilities	1,545	1,735
Liabilities	145,142	136,232
Variable Interest Entity, Primary Beneficiary [Member]
On-balance Sheet Variable Interest Entities [Line Items]
Finance receivables and loans, net	27,929	30,081
Loans and Leases Receivable, Allowance	(196)	(179)
Total finance receivables and loans, net	27,733	29,902
Investment in operating leases, net	4,791	5,595
Other Assets	1,624	1,964
Assets	34,148	37,461
Long-term debt	20,267	24,297
Accrued expenses and other liabilities	22	173
Liabilities	20,289	24,470
Consumer Portfolio Segment [Member] | Variable Interest Entity, Primary Beneficiary [Member]
On-balance Sheet Variable Interest Entities [Line Items]
Finance receivables and loans, net	11,682	12,594
Commercial Portfolio Segment [Member] | Variable Interest Entity, Primary Beneficiary [Member]
On-balance Sheet Variable Interest Entities [Line Items]
Finance receivables and loans, net	$ 16,247	$ 17,487

Securitizations And Variable102

Securitizations And Variable Interest Entities (Schedule Of Cash Flow Received and Paid To Nonconsolidated Securitization Entities) (Details) - Consumer Portfolio Segment [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Automobile Loan [Member]
Cash Flow Received and Paid to Nonconsolidated Securitization Entities [Line Items]
Cash Flows Between Transferor and Transferee, Proceeds from New Transfers	$ 1,551	$ 2,594	$ 0
Cash Flows Between Transferor and Transferee, Servicing Fees	28	11	13
Representations and warranties obligations		0	0
Cash Flows Between Transferor and Transferee, Receipts on Transferor's Interest in Transferred Financial Assets, Other			0
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale, Gain (Loss) on Sale	(3)	1	0
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	8,676
Cash Flows Between Transferor and Transferee, Servicing Fees	0	0	70
Representations and warranties obligations		(31)	(66)
Cash Flows Between Transferor and Transferee, Receipts on Transferor's Interest in Transferred Financial Assets, Other			70
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale, Gain (Loss) on Sale	$ 0	$ 0	$ 112

Securitizations And Variable103

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, 2015	Dec. 31, 2014
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	$ 116,486	$ 105,681
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	721	655
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	614	544
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	111,705	101,951
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	699	617
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	609	537
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	64,292	58,085
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	591	457
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	578	501
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	9,773	7,926
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	108	151
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	31	43
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	34,895	34,022
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	0	9
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	3	1
On-Balance Sheet Loans [Member] | Commercial Portfolio Segment [Member] | Unallocated 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	2,745	1,918
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	(3)	(8)
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	2,529	2,801
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	9	5
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	5	1
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	2,529	2,801
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	9	5
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	5	1
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	2,252	929
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	13	33
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	$ 0	$ 6

Servicing Activities (Schedule

Servicing Activities (Schedule Of Total Serviced Automobile Loans Outstanding) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Automobile Serviced Assets [Line Items]
Servicing fees	$ 45	$ 31	$ 126
Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Servicing fees	45	31	$ 58
Total Primary Serviced Assets	119,808	115,391
Consumer Loan [Member] | On-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	64,067	58,085
Commercial Loan [Member] | On-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	34,895	34,022
Operating Leases Member | On-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	15,965	19,510
Other Assets [Member] | On-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	72	55
Securitizations [Member] | Off-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	2,550	2,832
Whole-Loan Transactions [Member] | Off-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	$ 2,259	$ 887

Premiums Receivable and Othe105

Premiums Receivable and Other Insurance Assets (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Premiums Receivable and Other Insurance Assets [Abstract]
Prepaid Reinsurance Premiums	$ 382	$ 326
Reinsurance Receivables, Incurred but Not Reported Claims	120	143
Reinsurance Recoverables	18	12
Premiums Receivable, at Carrying Value	82	90
Deferred Policy Acquisition Costs	1,199	1,124
Premiums receivable and other insurance assets	$ 1,801	$ 1,695

Other Assets (Schedule Of Other

Other Assets (Schedule Of Other Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Other Assets [Abstract]
Property, Plant and Equipment, Gross	$ 691	$ 775
Accumulated depreciation	(456)	(550)
Property, Plant and Equipment, Net	235	225
Restricted cash collections for securitization trusts	2,010	2,221
Deferred Tax Assets, State Taxes	1,369	1,812
Nonmarketable equity securities	418	271
Cash reserve deposits held for securitization trusts	252	303
Derivative Asset, Fair Value, Gross Asset	233	263
Other accounts receivable	158	298
Cash and securities collateral placed with counterparties	125	236
Restricted cash and cash equivalents	120	122
Other Assets, Miscellaneous	1,401	1,354
Other Assets	$ 6,321	$ 7,105

Deposit Liabilities (Schedule O

Deposit Liabilities (Schedule Of Deposit Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Deposits [Abstract]
Noninterest-bearing deposit liabilities	$ 89	$ 64
Interest-bearing Deposit Liabilities, by Component [Abstract]
Deposits, Savings Deposits	36,386	26,769
Time Deposits	29,774	31,051
Deposits, Retail	229	319
Total deposit liabilities	66,478	58,203
Time Deposits, $100,000 or More, Domestic	11,500	13,000
Time Deposits, $250,000 or More, Domestic	$ 3,200	$ 3,700

Deposit Liabilities (Schedul108

Deposit Liabilities (Schedule of Maturities For Total Time Deposits) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Schedule of Maturities For Total Time Deposits [Line Items]
Time Deposits	$ 29,774	$ 31,051
One year or less [Member]
Schedule of Maturities For Total Time Deposits [Line Items]
Time Deposits	16,313
Two years or less [Member]
Schedule of Maturities For Total Time Deposits [Line Items]
Time Deposits	8,800
Three years or less [Member]
Schedule of Maturities For Total Time Deposits [Line Items]
Time Deposits	3,068
Four years or less [Member]
Schedule of Maturities For Total Time Deposits [Line Items]
Time Deposits	695
Five years or less [Member]
Schedule of Maturities For Total Time Deposits [Line Items]
Time Deposits	$ 898

Short-Term Borrowings (Schedule

Short-Term Borrowings (Schedule of Short-term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Short-term Debt [Line Items]
Demand Notes	$ 3,369	$ 3,338
Federal Home Loan Bank, Advances, Short-term	4,000	2,950
Securities Sold under Agreements to Repurchase, Gross	648	774
Other Short-term Borrowings	84	0
Short-term borrowings	$ 8,101	$ 7,062
Short-term Debt, Weighted Average Interest Rate	0.80%	0.80%
Non-derivative Cash Collateral Received from Counterparties Associated with the Repurchase Agreements.	$ 21
Unsecured Debt [Member]
Short-term Debt [Line Items]
Demand Notes	3,369	$ 3,338
Federal Home Loan Bank, Advances, Short-term	0	0
Securities Sold under Agreements to Repurchase, Gross	0	0
Other Short-term Borrowings	84	0
Short-term borrowings	3,453	3,338
Secured Debt [Member]
Short-term Debt [Line Items]
Demand Notes	0	0
Federal Home Loan Bank, Advances, Short-term	4,000	2,950
Securities Sold under Agreements to Repurchase, Gross	648	774
Other Short-term Borrowings	0	0
Short-term borrowings	4,648	$ 3,724
Secured Debt [Member] | Maturity Less than 30 Days [Member]
Short-term Debt [Line Items]
Mortgage-backed Residential Securities Sold under Agreements to Repurchase, Maturity Period	403
Secured Debt [Member] | Maturity 31 to 60 Days [Member]
Short-term Debt [Line Items]
Mortgage-backed Residential Securities Sold under Agreements to Repurchase, Maturity Period	$ 245

Long-Term Debt (Schedule of Lon

Long-Term Debt (Schedule of Long-term Debt Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Derivative, Amount of Hedged Item	$ 331	$ 452
Long-term debt	66,234	66,380
Secured Debt	49,916	47,822
Fixed Income Interest Rate [Member]
Debt Instrument [Line Items]
Unsecured Debt	17,657	18,858
Trust preferred securities	2,600	2,598
Secured Debt	20,511	19,793
Variable Income Interest Rate [Member]
Debt Instrument [Line Items]
Unsecured Debt	375	374
Secured Debt	24,760	24,305
Unsecured Debt [Member]
Debt Instrument [Line Items]
Derivative, Amount of Hedged Item	334	452
Long-term debt	$ 20,966	$ 22,282
Long-term Debt, Weighted Average Interest Rate	5.40%	5.90%
Secured Debt [Member]
Debt Instrument [Line Items]
Derivative, Amount of Hedged Item	$ (3)	$ 0
Long-term debt	$ 45,268	$ 44,098
Long-term Debt, Weighted Average Interest Rate	1.18%	0.94%
Variable Interest Entity Debt	$ 20,300	$ 24,300
Subordinated Debt [Member]
Debt Instrument [Line Items]
Unsecured Debt	1,100	296
Revolving secured funding facilities [Member]
Debt Instrument [Line Items]
Secured Debt	19,900	17,000
Federal Home Loan Bank Advances [Member]
Debt Instrument [Line Items]
Secured Debt	$ 5,400	$ 2,800
Minimum [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-Term Debt Interest Rate	0.37%	0.33%
Minimum [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Long-Term Debt Interest Rate	0.48%	0.21%
Maximum [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-Term Debt Interest Rate	8.13%	8.30%
Maximum [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Long-Term Debt Interest Rate	4.06%	4.59%

Long-Term Debt (Schedule of Deb

Long-Term Debt (Schedule of Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Due within one year	$ 11,256	$ 17,383
Due after one year	54,647	48,545
Derivative, Amount of Hedged Item	331	452
Long-term debt	66,234	66,380
Unsecured Debt [Member]
Debt Instrument [Line Items]
Due within one year	1,829	4,780
Due after one year	18,803	17,050
Derivative, Amount of Hedged Item	334	452
Long-term debt	20,966	22,282
Secured Debt [Member]
Debt Instrument [Line Items]
Due within one year	9,427	12,603
Due after one year	35,844	31,495
Derivative, Amount of Hedged Item	(3)	0
Long-term debt	$ 45,268	$ 44,098

Long-Term Debt (Scheduled Remai

Long-Term Debt (Scheduled Remaining Maturity Of Long-Term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
2,016	$ 11,256
2,017	19,501
2,018	12,713
2,019	7,403
2,020	5,607
2021 and thereafter	9,423
Derivative, Amount of Hedged Item	331	$ 452
Long-term debt	66,234	66,380
Derivative Instrument Converting Fixed-rate Debt into Variable-rate Obligations	8,300
Derivative Instrument Converting Variable-rate Debt into Fixed-rate Obligations	900
Unsecured Debt [Member]
Debt Instrument [Line Items]
2,016	1,829
2,017	4,284
2,018	3,604
2,019	1,580
2,020	2,193
2021 and thereafter	7,142
Derivative, Amount of Hedged Item	334	452
Long-term debt	20,966	22,282
Secured Debt [Member]
Debt Instrument [Line Items]
Derivative, Amount of Hedged Item	(3)	0
Long-term debt	45,268	$ 44,098
Long-term Debt [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
2,016	1,904
2,017	4,371
2,018	3,702
2,019	1,615
2,020	2,228
2021 and thereafter	8,203
Derivative, Amount of Hedged Item	334
Long-term debt	22,357
Long-term Debt [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
2,016	9,427
2,017	15,217
2,018	9,109
2,019	5,823
2,020	3,414
2021 and thereafter	2,281
Derivative, Amount of Hedged Item	(3)
Long-term debt	45,268
Original Issue Discount [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
2,016	(75)
2,017	(87)
2,018	(98)
2,019	(35)
2,020	(35)
2021 and thereafter	(1,061)
Derivative, Amount of Hedged Item	0
Long-term debt	$ (1,391)

Long-Term Debt (Pledged Assets

Long-Term Debt (Pledged Assets Related to Secured Borrowings And Repurchase Agreement) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Pledged Assets related to secured borrowings [Line Items]
Pledged Financial Instruments, Not Separately Reported, Other Debt Securities Available-for-sale or Held-for-investment	$ 2,420	$ 786
Pledged Assets, Mortgage assets held for investment	9,743	7,541
Pledged Assets, Investment in operating leases	5,539	6,820
Pledged Assets, Other, Not Separately Reported on Statement of Financial Position	71,649	69,190
Secured Debt	49,916	47,822
Short-term borrowings	8,101	7,062
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	1,761	786
Pledged Assets, Mortgage assets held for investment	9,743	7,541
Pledged Assets, Investment in operating leases	3,205	4,672
Pledged Assets, Other, Not Separately Reported on Statement of Financial Position	43,053	44,345
Secured Debt	24,787	27,103
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	14,900	10,700
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	2,900	3,200
Secured Debt [Member]
Pledged Assets related to secured borrowings [Line Items]
Short-term borrowings	4,648	3,724
Automobile Loan [Member] | Consumer Portfolio Segment [Member]
Pledged Assets related to secured borrowings [Line Items]
Pledged Assets, Not Separately Reported, Finance Receivables	34,324	33,438
Automobile Loan [Member] | Consumer Portfolio Segment [Member] | Ally Bank [Member]
Pledged Assets related to secured borrowings [Line Items]
Pledged Assets, Not Separately Reported, Finance Receivables	9,167	11,263
Automobile Loan [Member] | Commercial Portfolio Segment [Member]
Pledged Assets related to secured borrowings [Line Items]
Pledged Assets, Not Separately Reported, Finance Receivables	19,623	20,605
Automobile Loan [Member] | Commercial Portfolio Segment [Member] | Ally Bank [Member]
Pledged Assets related to secured borrowings [Line Items]
Pledged Assets, Not Separately Reported, Finance Receivables	$ 19,177	$ 20,083

Long-Term Debt Long-Term Debt (

Long-Term Debt Long-Term Debt (Narrative - Trust Preferred Securities) (Details) $ / shares in Units, $ in Millions	Dec. 31, 2015USD ($)$ / shares	Dec. 31, 2014USD ($)
Narrative - Trust Preferred Securities [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	8.125%
Liquidation preference (per share) | $ / shares	$ 25
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%
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 | $	$ 2,600	$ 2,598

Long-Term Debt (Schedule of Com

Long-Term Debt (Schedule of Committed Funding Facilities) (Details) - Committed Funding Facilities [Member] - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Outstanding	$ 20,164	$ 18,280
Unused capacity	251	3,675
Total capacity	20,415	21,955
Bank Funding Member | Secured Debt [Member]
Debt Instrument [Line Items]
Outstanding	3,250	3,250
Unused capacity	0	250
Total capacity	3,250	3,500
Nonbank Funding Member | Secured Debt [Member]
Debt Instrument [Line Items]
Outstanding	16,914	15,030
Unused capacity	251	3,425
Total capacity	17,165	$ 18,455
Revolving secured funding facilities [Member]
Debt Instrument [Line Items]
Total capacity	20,100
Revolving secured funding facilities 1 year or greater [Member]
Debt Instrument [Line Items]
Total capacity	$ 12,500

Accrued Expenses and Other L116

Accrued Expenses and Other Liabilities (Schedule of Accrued Expenses and Other Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Accounts Payable and Accrued Liabilities [Abstract]
Accounts Payable	$ 391	$ 298
Accrued Employee Benefits	242	298
Liability for Claims and Claims Adjustment Expense	169	208
Derivative Liability, Fair Value, Gross Liability	145	252
Deferred Revenue	108	151
Cash collateral received from counterparties	82	71
Other Accrued Liabilities	408	457
Accrued expenses and other liabilities	$ 1,545	$ 1,735

Equity (Schedule of Stockholder

Equity (Schedule of Stockholders Equity) (Details) $ / shares in Units, $ in Billions	12 Months Ended
	Dec. 31, 2015$ / sharesshares	Dec. 31, 2014$ / sharesshares	Dec. 31, 2013USD ($)shares
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
Common Stock, Shares, Issued, Beginning Balance	480,136,039	479,767,470	412,600,700
Stock Issued During Period, Shares, New Issues	2,654,657	368,569	0
Stock Issued During Period, Shares, Conversion of Convertible Securities	0	0	67,166,770
Common Stock, Shares, Issued, Ending Balance	482,790,696	480,136,039	479,767,470
Treasury Stock, Shares	(810,585)	(41,148)	0
Common Stock, Shares, Outstanding	481,980,111	480,094,891	479,767,470
Common Stock, Value, Issued | $			$ 1.3

Equity (Narrative - Preferred S

Equity (Narrative - Preferred Stock) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 14, 2015	Apr. 23, 2015	Apr. 10, 2015
Class of Stock [Line Items]
Stock Repurchased During Period, Value			$ 325		$ 5,925
Stock Repurchase and Redemption Premium			$ 2,364
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage			8.50%	8.50%
Preferred stock dividend rate at August 15, 2016			6.243%
Preferred Stock, Shares Authorized	40,870,560		40,870,560	40,870,560
Stock Repurchase Program, Number of Shares Authorized to be Repurchased							13,000,000
Stock Repurchase Program, Repurchase Price per Share							$ 26.65
Stock Repurchased During Period, Shares			13,000,000
Preferred Stock Repurchase, Aggregate Liquidation Preference			$ 325
Payments for Repurchase of Preferred Stock and Preference Stock			347
Stock Repurchased During Period, Value			325
Stock Repurchase and Redemption Premium			$ 22
Preferred Stock, Shares Issued and Outstanding	27,870,560		27,870,560	40,870,560
Series G Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Redemption Date	1,288,301	1,288,300
Preferred Stock, Dividend Rate, Percentage			0.00%	7.00%
Preferred Stock, Shares Authorized	0		0	2,576,601
Stock Repurchase and Redemption Premium	$ 1,171	$ 1,171
Preferred Stock, Shares Issued and Outstanding	0		0	2,576,601
Preferred Stock, Redemption Price Per Share						$ 1,000		$ 1,000
Dividends Payable, Amount Per Share						$ 5.64		$ 10.50
Preferred Stock Redemption, Aggregate Liquidation Preference	$ 1,288	1,288
Preferred Stock, Redemption Amount	1,295	1,302	$ 1,295					$ 1,300
Preferred stock dividends paid for Series G redemption	7	14
Stock Redeemed or Called During Period, Value	$ 117	$ 117

Equity (Schedule Of Preferred S

Equity (Schedule Of Preferred Stock) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Schedule of Capitalization, Equity [Line Items]
Preferred stock	$ 696	$ 1,255
Liquidation preference (per share)	$ 25
Series A Preferred Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Preferred stock	$ 696	$ 1,021
Preferred stock par value (per share)	$ 0.01	$ 0.01
Liquidation preference (per share)	$ 25	$ 25
Preferred Stock, Shares Authorized	40,870,560	40,870,560
Preferred Stock, Shares Issued and Outstanding	27,870,560	40,870,560
Preferred Stock, Dividend Rate, Percentage	8.50%	8.50%
Preferred Stock, Dividend Payment Rate, Variable	Three month LIBOR + 6.243%	Three month LIBOR + 6.243%
Series G Preferred Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Preferred stock	$ 0	$ 234
Preferred stock par value (per share)	$ 0	$ 0.01
Liquidation preference (per share)	$ 0	$ 1,000
Preferred Stock, Shares Authorized	0	2,576,601
Preferred Stock, Shares Issued and Outstanding	0	2,576,601
Preferred Stock, Dividend Rate, Percentage	0.00%	7.00%

Accumulated Other Comprehens120

Accumulated Other Comprehensive Income (Loss) Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
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	$ (21)	$ (269)	$ 76
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent	(138)	248	(345)
Ending Balance Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(159)	(21)	(269)
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	36	65	368
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustments and Net Investment Hedges, Net of Tax, Portion Attributable to Parent	(27)	(29)	(303)
Ending Balance Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	9	36	65
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	7	5	2
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent	1	2	3
Ending 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), 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	(88)	(77)	(135)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent	(1)	(11)	58
Ending Balance Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax	(89)	(88)	(77)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Beginning Balance Accumulated Other Comprehensive Income (Loss), Net of Tax	(66)	(276)	311
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(165)	210	(587)
Ending Balance Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (231)	$ (66)	$ (276)

Accumulated Other Comprehens121

Accumulated Other Comprehensive Income (Loss) Before and After Tax (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
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	$ (65)	$ 557	$ (333)
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, before Tax	155	181	180
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Discontinued Operations, before Tax			10
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent	(220)	376	(523)
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax [Abstract]
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	26	(142)	174
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Tax	(56)	(14)	(2)
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Discontinued Operations, Tax			(2)
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax, Portion Attributable to Parent	82	(128)	178
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	(39)	415	(159)
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	99	167	178
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Discontinued Operations, Net of Tax			8
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent	(138)	248	(345)
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	(39)	(27)	(104)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax	42	23	337
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax, Portion Attributable to Parent	(81)	(50)	(441)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax [Abstract]
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	13	10	24
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Tax	(20)	(3)	92
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax, Portion Attributable to Parent	33	13	(68)
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	(26)	(17)	(80)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	22	20	429
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent	(48)	(37)	(509)
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	29	13	59
Other Comprehensive Income (Loss), Reclassification Adjustment for Net Investment Hedges Included in Net Income, Discontinued Operation, before Tax	(4)		(250)
Other Comprehensive Income (Loss), Net Investment Hedges Attributable to Parent, before Tax	33		309
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	2	2	(1)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax			(7)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax, Portion Attributable to Parent			6
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	(11)	(5)	(22)
Other Comprehensive Income (Loss), Reclassification Adjustment for Net Investment Hedges Included in Net Income, Discontinued Operation, Tax	1		81
Other Comprehensive Income (Loss), Net Investment Hedges Attributable to Parent, Tax	(12)		(103)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(1)	0	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax			3
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax, Portion Attributable to Parent			(3)
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	18	8	37
Other Comprehensive Income (Loss), Reclassification Adjustment for Net Investment Hedges Included in Net Income, Discontinued Operation, Net of Tax	(3)	0	(169)
Other Comprehensive Income (Loss), Net Investment Hedges Attributable to Parent, Net of Tax	21	8	206
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	1	2	(1)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	0	0	(4)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent	1	2	3
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	0	(24)	26
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax	1	(7)	(2)
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans Included in Net Income, Discontinued Operations, before Tax			(49)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax, Portion Attributable to Parent	(1)	(17)	77
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	0	9	(8)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net (Gain) Loss, Tax	0	3	0
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans Included in Net Income, Discontinued Operations, Tax			11
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax, Portion Attributable to Parent	0	6	(19)
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	0	(15)	18
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net (Gain) Loss, Net of Tax	1	(4)	(2)
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans Included in Net Income, Discontinued Operations, Net of Tax			(38)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent	(1)	(11)	58
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	(267)	324	(572)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	102	(114)	(15)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ (165)	$ 210	$ (587)

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, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Net income (loss) from continuing operations	$ 276	$ 273	$ 169	$ 179	$ 151	$ 293	$ 283	$ 198	$ 897	$ 925	$ 416
Preferred stock dividends - U.S. Department of Treasury									0	0	(543)
Impact of repurchase of MCP held by U.S. Department of Treasury									0	0	(240)
Preferred stock dividends									(2,571)	(268)	(267)
Net income (loss) from continuing operations attributable to common shareholders									(1,674)	657	(634)
Income (loss) from discontinued operations, net of tax	$ (13)	$ (5)	$ 13	$ 397	$ 26	$ 130	$ 40	$ 29	392	225	(55)
Net income (loss) attributable to common shareholders									$ (1,282)	$ 882	$ (689)
Basic weighted-average common shares outstanding									482,873,120	481,154,609	420,166,188
Diluted weighted-average common shares outstanding									482,873,120	481,933,811	420,166,188
Earnings Per Share, Basic [Abstract]
Net income (loss) from continuing operations, Per Basic Share	$ (1.94)	$ 0.49	$ (2.24)	$ 0.23	$ 0.17	$ 0.47	$ 0.45	$ 0.27	$ (3.47)	$ 1.36	$ (1.51)
Income (Loss) from Discontinued Operations, Net of Tax, Per Basic Share									0.81	0.47	(0.13)
Net (loss) income, Basic	(1.97)	0.48	(2.22)	1.06	0.23	0.74	0.54	0.33	(2.66)	1.83	(1.64)
Earnings Per Share, Diluted [Abstract]
Net income (loss) from continuing operations, Per Diluted Share	(1.94)	0.49	(2.24)	0.23	0.17	0.47	0.45	0.27	(3.47)	1.36	(1.51)
Income (loss) from discontinued operations, net of tax, Diluted									0.81	0.47	(0.13)
Net (loss) income, Diluted	$ (1.97)	$ 0.47	$ (2.22)	$ 1.06	$ 0.23	$ 0.74	$ 0.54	$ 0.33	$ (2.66)	$ 1.83	$ (1.64)
Stock Repurchase and Redemption Premium									$ 2,364
Potential common shares excluded from diluted earnings per share calculation											89,000,000

Regulatory Capital (Schedule Of

Regulatory Capital (Schedule Of Regulatory Capital Amount And Ratios) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Leverage To Average Assets For Ally Bank	15.00%
Parent Company [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 (to risk-weighted assets), Amount	$ 15,077	$ 16,389
Tier 1 (to risk-weighted assets), Ratio	11.10%	12.55%
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	6.00%
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	6.00%
Total (to risk-weighted assets), Amount	$ 17,005	$ 17,294
Total (to risk-weighted assets), Ratio	12.52%	13.24%
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%
Capital Required to be Well Capitalized to Risk Weighted Assets	10.00%
Tier 1 leverage (to adjusted average assets), Amount	$ 15,077	$ 16,389
Tier One Leverage Capital to Average Assets	9.73%	10.94%
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	4.00%
Tier 1 common (to risk-weighted assets), Amount	$ 12,507	$ 12,588
Tier 1 common (to risk-weighted assets), Ratio	9.21%	9.64%
Common Equity Tier 1 Capital Required for Capital Adequacy to Risk-weighted Assets	4.50%
Parent Company [Member] | Minimum [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier One Leverage Capital Required for Capital Adequacy to Average Assets		3.00%
Parent Company [Member] | Maximum [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier One Leverage Capital Required for Capital Adequacy to Average Assets		4.00%
Ally Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 (to risk-weighted assets), Amount	$ 16,594	$ 16,022
Tier 1 (to risk-weighted assets), Ratio	17.05%	16.89%
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	6.00%
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	8.00%
Total (to risk-weighted assets), Amount	$ 17,043	$ 16,468
Total (to risk-weighted assets), Ratio	17.51%	17.36%
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%
Capital Required to be Well Capitalized to Risk Weighted Assets	10.00%
Tier 1 leverage (to adjusted average assets), Amount	$ 16,594	$ 16,022
Tier One Leverage Capital to Average Assets	15.38%	15.44%
Tier 1 Leverage To Average Assets For Ally Bank	15.00%
Tier One Leverage Capital Required to be Well Capitalized to Average Assets	5.00%
Tier 1 common (to risk-weighted assets), Amount	$ 16,594	$ 16,022
Tier 1 common (to risk-weighted assets), Ratio	17.05%	16.89%
Common Equity Tier 1 Capital Required for Capital Adequacy to Risk-weighted Assets	4.50%
Common Equity Tier 1 Capital Required to be Well Capitalized to Risk-weighted Assets	6.50%

Regulatory Capital (Regulatory

Regulatory Capital (Regulatory Matters) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Nov. 12, 2015	Sep. 30, 2015	Apr. 10, 2015
Regulatory Matters [Line Items]
Common equity Tier 1 capital conservation buffer	2.50%
Tier 1 Leverage To Average Assets For Ally Bank	15.00%
assets greater than $50 billion	$ 50,000
Stock Repurchased During Period, Value	325		$ 5,925
Assets	158,581	$ 151,631	150,908
Insurance Operations [Member]
Regulatory Matters [Line Items]
Assets	7,053	7,190	$ 7,124
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval	$ 93
Ally Bank [Member]
Regulatory Matters [Line Items]
Common Equity Tier 1 Capital Required for Capital Adequacy to Risk-weighted Assets	4.50%
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	6.00%
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%
Tier 1 Leverage To Average Assets For Ally Bank	15.00%
Assets	$ 111,300	104,400
Cash Dividends Paid to Parent Company	525	1,800
FRB required reserve balance	$ 216	$ 313
Parent Company [Member]
Regulatory Matters [Line Items]
Common Equity Tier 1 Capital Required for Capital Adequacy to Risk-weighted Assets	4.50%
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	6.00%
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	4.00%
Minimum [Member] | Parent Company [Member]
Regulatory Matters [Line Items]
Tier One Leverage Capital Required for Capital Adequacy to Average Assets		3.00%
Maximum [Member] | Parent Company [Member]
Regulatory Matters [Line Items]
Tier One Leverage Capital Required for Capital Adequacy to Average Assets		4.00%
Series G Preferred Stock [Member]
Regulatory Matters [Line Items]
Preferred Stock, Redemption Amount	$ 1,295				$ 1,302	$ 1,300
Preferred Stock, Notice of Redemption				1,288,301
Series A Preferred Stock [Member]
Regulatory Matters [Line Items]
Stock Repurchased During Period, Value	$ 325

Derivative Instruments And H125

Derivative Instruments And Hedging Activities (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Forward Contract Indexed to Issuer's Equity [Line Items]
Derivative, Notional Amount	$ 59,116	$ 81,200
Cash Collateral Placed with Counterparties	103	221
Cash and securities collateral placed with counterparties	86	15
Non-derivative Cash Collateral Received from Counterparties Associated with the Repurchase Agreements.	21
Non-derivative collateral placed with counterparties			$ 18
Cash collateral received from counterparties	82	71
noncash collateral received	$ 7	$ 15

Derivative Instruments And H126

Derivative Instruments And Hedging Activities (Fair Value Amounts Of Derivative Instruments Reported On Our Condensed Consolidated Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 233	$ 263
Derivative Liability, Fair Value, Gross Liability	145	252
Derivative, Notional Amount	59,116	81,200
Accrued Interest [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	46	50
Derivative Liability, Fair Value, Gross Liability	12	17
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	126	118
Derivative Liability, Fair Value, Gross Liability	10	7
Derivative, Notional Amount	14,340	18,764
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	126	118
Derivative Liability, Fair Value, Gross Liability	9	7
Derivative, Notional Amount	14,151	18,554
Hedge notional amount associated with debt maturing in five or more years	2,600
Foreign Exchange Forward [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	0
Derivative, Notional Amount	189	210
Fair Value Hedging [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Pay-fixed Swaps, Fair Value, Gross Asset	13	21
Pay-fixed Swaps, Fair Value, Gross Liability	3	6
Pay-fixed Swaps, Notional Amount	6,800	13,900
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	105	138
Derivative Liability, Fair Value, Gross Liability	125	161
Derivative, Notional Amount	44,466	60,847
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	5
Derivative Liability, Fair Value, Gross Liability	0	78
Derivative, Notional Amount	278	1,514
Equity Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	2	2
Derivative Liability, Fair Value, Gross Liability	10	6
Derivative, Notional Amount	32	75
Interest Rate Swap [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	30	40
Derivative Liability, Fair Value, Gross Liability	51	65
Derivative, Notional Amount	6,101	11,979
Futures and Forwards [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	2	4
Derivative Liability, Fair Value, Gross Liability	2	2
Derivative, Notional Amount	1,905	18,886
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	72	94
Derivative, Notional Amount	18,220	14,823
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	3
Derivative, Notional Amount	0	1
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	94
Derivative Liability, Fair Value, Gross Liability	0	0
Derivative, Notional Amount	18,240	15,159
Purchased Options [Member] | Equity Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	2	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	9	3
Derivative, Notional Amount	32	74
Swap [Member] | Foreign Exchange 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	74
Derivative, Notional Amount	0	1,210
Foreign Exchange Forward [Member] | Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	5
Derivative Liability, Fair Value, Gross Liability	0	4
Derivative, Notional Amount	278	304
Other Trading [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	107	145
Derivative Liability, Fair Value, Gross Liability	135	245
Derivative, Notional Amount	44,776	62,436
Unsecured Debt [Member] | Fair Value Hedging [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Receive-fixed Swaps, Fair Value, Gross Asset	112	97
Receive-fixed Swaps, Fair Value, Gross Liability	3	1
Receive-fixed Swaps, Notional Amount	6,800	$ 4,700
Secured Debt [Member] | Fair Value Hedging [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Receive-fixed Swaps, Fair Value, Gross Asset	1
Receive-fixed Swaps, Fair Value, Gross Liability	2
Receive-fixed Swaps, Notional Amount	$ 500

Derivative Instruments And H127

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, 2015	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Interest and Fee Income, Loans and Leases	$ (4,570)	$ (4,457)	$ (4,529)
Interest on long-term debt	(1,662)	(2,067)	(2,602)
Servicing asset valuation and hedge activities, net	0	0	(213)
Gain (loss) on mortgage and automotive loans, net	45	7	55
Other income, net of losses	314	280	383
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	(19)	(37)	(135)
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	(127)	(160)	118
Gain (Loss) on Equity Forward Contract Not Designated as Hedging Instruments	(10)	(5)	0
Gain (Loss) on Derivative Instruments, Net, Pretax	(121)	(139)	5
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(8)
Gains on amortization of deferred basis adjustments on the hedged items	73	155	247
Gain (Loss) from Revaulation of Foreign-Denominated Debt or Receivable	132	165	(117)
Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	35	63	22
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Gain (Loss) Recognized in Earnings on Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest and Fee Income, Loans and Leases	(9)	15	7
Interest on long-term debt	35	199	(389)
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Gain (Loss) Recognized in Earnings on Hedged Item [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest and Fee Income, Loans and Leases	39	34	2
Interest on long-term debt	(30)	(185)	402
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Gain (loss) Excluded from Earnings on Derivatives [Domain]
Derivative Instruments, Gain (Loss) [Line Items]
Interest and Fee Income, Loans and Leases	(64)	(61)	(9)
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Servicing asset valuation and hedge activities, net	0	0	(112)
Gain (loss) on mortgage and automotive loans, net	(2)	0	(37)
Other income, net of losses	(17)	(37)	14
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest on long-term debt	(139)	(172)	94
Other income, net of losses	12	12	24
Forward Contracts [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other income, net of losses	(10)	(5)	0
Unsecured Debt [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest Gain For Qualifying Accounting Hedges Of Debt	97	$ 112	$ 131
Secured Debt [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest Gain For Qualifying Accounting Hedges Of Debt	$ 1

Derivative Instruments And H128

Derivative Instruments And Hedging Activities (Derivative Instruments Used In Net Investment Hedge Accounting Relationships) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Cumulative Translation Adjustment, Net of Tax, Period Increase (Decrease)	$ (59)	$ (41)	$ (582)
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	(2)	(7)
Cash flow hedges, total interest on long-term debt	0	(2)	(7)
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	2	2	6
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	(4)	0	(250)
Net Investment Hedges - Total Other Income, Net of Losses	(4)	0	(250)
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	$ 33	$ 13	$ 309

Income Taxes (Schedule of Signi

Income Taxes (Schedule of Significant Components of Income Tax Expense) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Current Federal Tax Expense (Benefit)									$ 0	$ (3)	$ 0
Current Foreign Tax Expense (Benefit)									6	8	4
Current State and Local Tax Expense (Benefit)									3	5	0
Current Income Tax Expense (Benefit)									9	10	4
Deferred Federal Income Tax Expense (Benefit)									454	270	(67)
Deferred Foreign Income Tax Expense (Benefit)									1	2	(1)
Deferred State and Local Income Tax Expense (Benefit)									32	39	5
Deferred Income Tax Expense (Benefit)									487	311	(63)
Income tax expense (benefit) from continuing operations	$ 155	$ 144	$ 94	$ 103	$ 36	$ 127	$ 64	$ 94	$ 496	$ 321	$ (59)

Income Taxes (Schedule of Effec

Income Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Income Tax Reconciliation, Income Tax Expense (Benefit), at Federal Statutory Income Tax Rate									$ 488	$ 436	$ 125
Income Tax Reconciliation, State and Local Income Taxes									38	48	16
Income Tax Reconciliation, Change in Deferred Tax Assets Valuation Allowance									(26)	(64)	(154)
Income Tax Reconciliation, Equity in Earnings (Losses) of Unconsolidated Subsidiary									14	31	26
Income Tax Reconciliation, Foreign Capital Loss									(12)	(10)	(45)
Effective Income Tax Rate Reconciliation, Change in Unrecognized Tax Benefits									(5)	(63)	(10)
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount									0	(39)	(44)
Income Tax Reconciliation, Other Adjustments									(1)	(18)	27
Income tax expense (benefit) from continuing operations	$ 155	$ 144	$ 94	$ 103	$ 36	$ 127	$ 64	$ 94	$ 496	$ 321	$ (59)

Income Taxes (Schedule of Defer

Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets and Liabilities [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards	$ 1,941	$ 1,911
Deferred Tax Assets, Tax Loss Carryforward	950	1,158
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities	311	520
Deferred Tax Assets, State and local taxes	194	227
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Unearned Premiums Reserve	141	141
Deferred Tax Assets, Hedging Transactions	99	139
Deferred Tax Assets, Other	212	210
Deferred Tax Assets, Gross	3,848	4,306
Deferred Tax Assets, Valuation Allowance	(582)	(734)
Deferred Tax Assets, Net of Valuation Allowance	3,266	3,572
Deferred Tax Liabilities, Leasing Arrangements	1,273	1,148
Deferred tax liabilities, deferred expense, deferred acqusition cost	403	378
Deferred Tax Liabilities, Financing Arrangements	162	161
Deferred Tax Liabilities, Other	69	78
Deferred Tax Liabilities, Gross	1,907	1,765
Deferred Tax Assets, Net	1,359	1,807
Other Assets	6,321	7,105
Accrued expenses and other liabilities	1,545	$ 1,735
Deferred Tax Asset [Member]
Deferred Tax Assets and Liabilities [Line Items]
Other Assets	1,369
Deferred Tax Liability [Member]
Deferred Tax Assets and Liabilities [Line Items]
Accrued expenses and other liabilities	$ 10

Income Taxes (Schedule of De132

Income Taxes (Schedule of Deferred tax assets and related valuation allowances recognized for net operating and other loss carryforwards and tax credit carryforwards) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards	$ 1,941	$ 1,911
Tax Credit Carryforward, Valuation Allowance	(472)
Net Deferred Tax Assets, Tax Credit Carryforwards	1,469
Deferred Tax Assets, Tax Loss Carryforward	950	1,158
Deferred Tax Assets, State and Local Tax Carryforwards	1,186
State and Local Tax Carryforwards, Valuation Allowance	(105)
Net Deferred Tax Assets, State and Local Tax Carryforwards	1,081
Deferred Tax Assets, Other Non-Attribute	721
Other Non-Attribute, Valuation Allowance	(5)
Net Deferred Tax Assets, Other Non-Attribute	716
Deferred Tax Assets, Gross	3,848	4,306
Deferred Tax Assets, Gross, Valuation Allowance	(582)
Deferred Tax Assets, Net of Valuation Allowance	3,266	3,572
Deferred Tax Liabilities, Gross	(1,907)	(1,765)
Deferred Tax Liabilities, Gross, Valuation Allowance	0
Deferred Tax Liabilities, Net	(1,907)
Deferred Tax Assets, Gross, Net of Deferred Tax Liabilities	1,941
Deferred Tax Assets, Valuation Allowance	(582)	(734)
Deferred Tax Assets, Net	1,359	$ 1,807
Foreign Tax Credits [Domain]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards	1,748
Tax Credit Carryforward, Valuation Allowance	(472)
Net Deferred Tax Assets, Tax Credit Carryforwards	1,276
General Business Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards	173
Tax Credit Carryforward, Valuation Allowance	0
Net Deferred Tax Assets, Tax Credit Carryforwards	173
AMT credits [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards	20
Tax Credit Carryforward, Valuation Allowance	0
Net Deferred Tax Assets, Tax Credit Carryforwards	20
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	950
Operating Loss Carryforwards, Valuation Allowance	0
Net Deferred Tax Assets, Operating Loss Carryforwards	950
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	208
Operating Loss Carryforwards, Valuation Allowance	(77)
Net Deferred Tax Assets, Operating Loss Carryforwards	131
Deferred Tax Assets, Capital Loss Carryforwards	28
Capital Loss Carryforwards, Valuation Allowance	(28)
Net Deferred Tax Assets, Capital Loss Carryforwards	$ 0

Income Tax (Schedule of Unrecog

Income Tax (Schedule of Unrecognized Tax Benefits Roll Forward) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits Beginning Balance	$ 191	$ 262	$ 102
Unrecognized Tax Benefits, Increases Resulting from Current Period Tax Positions	0	0	174
Unrecognized Tax Benefits, Increases Resulting from Prior Period Tax Positions	7	9	1
Unrecognized Tax Benefits, Decreases Resulting from Settlements with Taxing Authorities	(10)	(79)	(14)
Unrecognized Tax Benefits, Reductions Resulting from Lapse of Applicable Statute of Limitations	(3)	(1)	(1)
Unrecognized Tax Benefits Ending Balance	$ 185	$ 191	$ 262

Income Tax (Narrative - Unrecog

Income Tax (Narrative - Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 177	$ 182	$ 240
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	1	1	2
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	2	$ 5	$ 7
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	$ 180

Employee Benefits and Compen135

Employee Benefits and Compensation Plans (Share-based compensation) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Apr. 10, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Price	$ 18.64			$ 23.98
Adjustments to Additional Paid in Capital, Share-based Compensation, Restricted Stock Unit or Restricted Stock Award, Requisite Service Period Recognition		$ 62
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	35,838,068
TARP Repayment		100.00%
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	6,476,427	4,293,216
Share-based Compensation	$ 49	$ 46	$ 64
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	1,395,105	3,009,942
Share-based Compensation	$ 3	$ 42	65
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	690,355
Share-based Compensation	$ 1	$ (2)	$ 8
Shares Awarded 2009 [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		17,571
Shares Awarded 2010 [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		17,219
Shares Awarded 2011 [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		0
Shares Awarded 2012 [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		453,735
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	2,053,271
Shares Awarded 2014 [Member] [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	1,691,509	1,751,420
Shares Awarded 2015 [Member] [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	4,530,768

Fair Value (Fair Value Measurme

Fair Value (Fair Value Measurment - Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	$ 17,157	$ 16,137
Available-for-sale, Equity Investment in Any One Industry Did Not Exceed Percentage	14.00%	16.00%
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	$ 17,157	$ 16,137
Mortgage loans held-for-sale, net		3
Retained Interest, Fair Value Disclosure	40	47
Derivative Assets	233	263
Securities Held as Collateral, at Fair Value		15
Total assets	17,430	16,465
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	(145)	(252)
Liabilities, Fair Value Disclosure	(145)	(252)
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	(135)	(168)
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)	(78)
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	(9)	(6)
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	16,440	15,231
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	1,741	1,178
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	716	406
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	177	232
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	10,366	10,425
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	481	253
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	1,755	1,991
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	1,204	746
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	717	906
Fair Value, Measurements, Recurring [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	231	256
Fair Value, Measurements, Recurring [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets		5
Fair Value, Measurements, Recurring [Member] | Other Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	2	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	2,196	1,137
Mortgage loans held-for-sale, net		0
Retained Interest, Fair Value Disclosure	0	0
Derivative Assets	4	6
Securities Held as Collateral, at Fair Value		0
Total assets	2,200	1,143
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	(3)	(4)
Liabilities, Fair Value Disclosure	(3)	(4)
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	(2)	(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	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)	(2)
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	1,479	231
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	1,469	217
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	10	14
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Collateralized 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	717	906
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	2	4
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	2	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	14,961	15,000
Mortgage loans held-for-sale, net		0
Retained Interest, Fair Value Disclosure	0	0
Derivative Assets	229	257
Securities Held as Collateral, at Fair Value		15
Total assets	15,190	15,272
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	(142)	(248)
Liabilities, Fair Value Disclosure	(142)	(248)
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	(133)	(166)
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)	(78)
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	(8)	(4)
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	14,961	15,000
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	272	961
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	716	406
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	167	218
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Collateralized Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	10,366	10,425
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	481	253
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	1,755	1,991
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	1,204	746
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	229	252
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		5
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
Mortgage loans held-for-sale, net		3
Retained Interest, Fair Value Disclosure	40	47
Derivative Assets	0	0
Securities Held as Collateral, at Fair Value		0
Total assets	40	50
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	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] | Collateralized 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, 2015	Dec. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Assets, Beginning balance	$ 50	$ 99
Net realized/unrealized gains (losses) included in earnings, Assets	10	13
Net realized/unrealized gains (losses) included in other comprehensive income, Assets	0	0
Purchases, Assets	0	0
Sales, Assets	(4)	0
Issuances, Assets	26	0
Settlements, Assets	(42)	(68)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0	3
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0	3
Fair Value, Assets, Ending balance	40	50
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	1
Loans Held-for-Sale [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Assets, Beginning balance	3	0
Net realized/unrealized gains (losses) included in earnings, Assets	1	0
Net realized/unrealized gains (losses) included in other comprehensive income, Assets	0	0
Purchases, Assets	0	0
Sales, Assets	(4)	0
Issuances, Assets	0	0
Settlements, Assets	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0	3
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0	0
Fair Value, Assets, Ending balance	0	3
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	1
Retained Interest [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Assets, Beginning balance	47	100
Net realized/unrealized gains (losses) included in earnings, Assets	9	13
Net realized/unrealized gains (losses) included in other comprehensive income, Assets	0	0
Purchases, Assets	0	0
Sales, Assets	0	0
Issuances, Assets	26	0
Settlements, Assets	(42)	(66)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0	0
Fair Value, Assets, Ending balance	40	47
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0
Interest Rate Contract [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Net Derivative Asset (Liability), Beginning balance	$ 0	(1)
Gain (Loss) Included in Earnings, Net Derivative Asset (Liability)		0
Gain (Loss) Included in Other Comprehensive Income (Loss), Net Derivative Asset (Liability)		0
Purchases, Net Derivative Asset (Liability)		0
Sales, Net Derivative Asset (Liability)		0
Issuances, Net Derivative Asset (Liability)		0
Settlements, Net Derivative Asset (Liability)		(2)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers into Level 3		0
Transfers out of Level 3, Net Derivative Asset (Liability)		3
Fair Value, Net Derivative Asset (Liability), Ending balance		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		$ 0

Fair Value (Fair Value Measu138

Fair Value (Fair Value Measurement - Nonrecurring Basis) (Details) - Fair Value, Measurements, Nonrecurring [Member] - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Loans Held-for-Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Disposal Group, Including Discontinued Operation, Other Loans	$ 105	$ 36
Lower of cost or fair value or valuation reserve allowance	0	0
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	19	24
Lower of cost or fair value or valuation reserve allowance	(2)	(6)
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	29	32
Lower of cost or fair value or valuation reserve allowance	(15)	(15)
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)
Commercial Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial Finance Receivables and Loans, Net, Fair Value	52	56
Lower of cost or fair value or valuation reserve allowance	(20)	(21)
Repossessed And Foreclosed Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	9	8
Lower of cost or fair value or valuation reserve allowance	(3)	(2)
Other Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	6	2
Lower of cost or fair value or valuation reserve allowance	(2)	0
Assets, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	172	102
Lower of cost or fair value or valuation reserve allowance	(25)	(23)
Fair Value, Inputs, Level 1 [Member] | Loans Held-for-Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Disposal Group, Including Discontinued Operation, Other Loans	0	0
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, 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, 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, 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, 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, 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, Inputs, Level 1 [Member] | Assets, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0	0
Fair Value, Inputs, Level 2 [Member] | Loans Held-for-Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Disposal Group, Including Discontinued Operation, Other Loans	0	0
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, 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, 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, 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, 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, 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, Inputs, Level 2 [Member] | Assets, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0	0
Fair Value, Inputs, Level 3 [Member] | Loans Held-for-Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Disposal Group, Including Discontinued Operation, Other Loans	105	36
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	19	24
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	29	32
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, 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	52	56
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	9	8
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	6	2
Fair Value, Inputs, Level 3 [Member] | Assets, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	$ 172	$ 102

Fair Value (Fair Value of Finan

Fair Value (Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held-for-sale, net	$ 105	$ 2,003
Total finance receivables and loans, net	110,546	98,971
Nonmarketable equity securities	418	271
Deposit liabilities	66,478	58,203
Short-term borrowings	8,101	7,062
Long-term debt	66,234	66,380
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held-for-sale, net	105	2,003
Total finance receivables and loans, net	110,546	98,971
Nonmarketable equity securities	418	271
Deposit liabilities	66,478	58,203
Short-term borrowings	8,101	7,062
Long-term debt	66,234	66,380
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held-for-sale, net	0	0
Total finance receivables and loans, net	0	0
Nonmarketable equity securities	0	0
Deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held-for-sale, net	0	485
Total finance receivables and loans, net	0	0
Nonmarketable equity securities	391	246
Deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	23,018	25,224
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held-for-sale, net	105	1,554
Total finance receivables and loans, net	110,737	99,430
Nonmarketable equity securities	42	33
Deposit liabilities	66,889	58,777
Short-term borrowings	8,102	7,063
Long-term debt	45,157	44,084
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held-for-sale, net	105	2,039
Total finance receivables and loans, net	110,737	99,430
Nonmarketable equity securities	433	279
Deposit liabilities	66,889	58,777
Short-term borrowings	8,102	7,063
Long-term debt	$ 68,175	$ 69,308

Offsetting Assets and Liabil140

Offsetting Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Offsetting Assets and Liabilities [Line Items]
Non-cash derivative collateral pledged to us is not recorded on our Condensed Consolidated Balance Sheet unless certain conditions are met.	$ 7
Derivative Asset, Fair Value, Gross Asset	233	$ 263
Derivative Asset, Fair Value, Amount Offset Against Collateral	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	(78)	(107)
Derivative, Collateral, Right to Reclaim Cash	(67)	(68)
Derivative Liability, Fair Value, Gross Liability	(145)	(252)
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	78	107
Derivative, Collateral, Obligation to Return Cash	2	54
Securities Sold under Agreements to Repurchase, Gross	(648)	(774)
Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral	0	0
Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral, Net	(648)	(774)
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	0	0
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Cash	648	774
Securities Sold under Agreements to Repurchase	0	0
Net Asset [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	224	216
Derivative Asset, Fair Value, Amount Offset Against Collateral	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	(69)	(60)
Derivative, Collateral, Right to Reclaim Cash	(67)	(68)
Derivative assets in net liability positions [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	9	47
Derivative Asset, Fair Value, Amount Offset Against Collateral	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	(9)	(47)
Derivative, Collateral, Right to Reclaim Cash	0	0
Net liability [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability	(68)	(188)
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	9	47
Derivative, Collateral, Obligation to Return Cash	2	54
Derivative liabilities in net asset positions [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability	(69)	(60)
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	69	60
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative liabilities with no offsetting arrangements [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability	(8)	(4)
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	0	0
Derivative, Collateral, Obligation to Return Cash	0	0
Assets [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative, Fair Value, Amount Offset Against Collateral, Net	233	263
Derivative Assets	88	88
Assets [Member] | Net Asset [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative, Fair Value, Amount Offset Against Collateral, Net	224	216
Derivative Assets	88	88
Assets [Member] | Derivative assets in net liability positions [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative, Fair Value, Amount Offset Against Collateral, Net	9	47
Derivative Assets	0	0
Liabilities, Total [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative, Fair Value, Amount Offset Against Collateral, Net	(145)	(252)
Derivative Liability	(65)	(91)
Gross Amounts of Recognized Liabilities	(793)	(1,026)
Gross Amounts Offset in the Condensed Consolidated Balance Sheet	0	0
Net Amounts of Liabilities Presented in the Condensed Consolidated Balance Sheet	(793)	(1,026)
Gross Amounts Not Offset Against Collateral	78	107
Obligation to Return Cash	650	828
Net Amount	(65)	(91)
Liabilities, Total [Member] | Net liability [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative, Fair Value, Amount Offset Against Collateral, Net	(68)	(188)
Derivative Liability	(57)	(87)
Liabilities, Total [Member] | Derivative liabilities in net asset positions [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative, Fair Value, Amount Offset Against Collateral, Net	(69)	(60)
Derivative Liability	0	0
Liabilities, Total [Member] | Derivative liabilities with no offsetting arrangements [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative, Fair Value, Amount Offset Against Collateral, Net	(8)	(4)
Derivative Liability	$ (8)	$ (4)

Segment And Geographic Infor141

Segment And Geographic Information (Financial Information Operating Segments) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Net financing revenue (loss)	$ 983	$ 970	$ 916	$ 850	$ 799	$ 889	$ 866	$ 821	$ 3,719	$ 3,375	$ 2,779
Other revenue	356	332	211	243	215	375	365	321	1,142	1,276	1,484
Total net revenue (loss)	1,339	1,302	1,127	1,093	1,014	1,264	1,231	1,142	4,861	4,651	4,263
Provision for loan losses	240	211	140	116	155	102	63	137	707	457	501
Total noninterest expense	668	674	724	695	672	742	821	713	2,761	2,948	3,405
Income (loss) from continuing operations before income tax expense	431	$ 417	$ 263	$ 282	187	$ 420	$ 347	$ 292	1,393	1,246	357
Assets	158,581				151,631				158,581	151,631	150,908
Net Interest Income (Loss) after Provision for Loan Losses									3,000	2,900	2,300
Automotive finance operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)									3,429	3,321	3,159
Other revenue									235	264	268
Total net revenue (loss)									3,664	3,585	3,427
Provision for loan losses									696	542	494
Total noninterest expense									1,633	1,614	1,755
Income (loss) from continuing operations before income tax expense									1,335	1,429	1,178
Assets	115,636				113,188				115,636	113,188	109,312
Insurance Operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)									57	56	57
Other revenue									1,033	1,129	1,196
Total net revenue (loss)									1,090	1,185	1,253
Provision for loan losses									0	0	0
Total noninterest expense									879	988	999
Income (loss) from continuing operations before income tax expense									211	197	254
Assets	7,053				7,190				7,053	7,190	7,124
Mortgage Finance Operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)									57	36	38
Other revenue									0	0	(1)
Total net revenue (loss)									57	36	37
Provision for loan losses									7	3	(11)
Total noninterest expense									39	21	30
Income (loss) from continuing operations before income tax expense									11	12	18
Assets	6,461				3,542				6,461	3,542	3,294
Corporate Finance Operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)									89	59	44
Other revenue									25	32	33
Total net revenue (loss)									114	91	77
Provision for loan losses									9	(16)	(6)
Total noninterest expense									55	43	39
Income (loss) from continuing operations before income tax expense									50	64	44
Assets	2,677				1,870				2,677	1,870	1,633
Corporate And Other [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)									87	(97)	(519)
Other revenue									(151)	(149)	(12)
Total net revenue (loss)									(64)	(246)	(531)
Provision for loan losses									(5)	(72)	24
Total noninterest expense									155	282	582
Income (loss) from continuing operations before income tax expense									(214)	(456)	(1,137)
Assets	$ 26,754				$ 25,841				$ 26,754	$ 25,841	$ 29,545

Segment And Geographic Infor142

Segment And Geographic Information (Information Concerning Principal Geographic Areas) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net revenue (loss)	$ 1,339	$ 1,302	$ 1,127	$ 1,093	$ 1,014	$ 1,264	$ 1,231	$ 1,142	$ 4,861	$ 4,651	$ 4,263
Income (loss) from continuing operations before income tax expense	431	417	263	282	187	420	347	292	1,393	1,246	357
Net income (loss)	263	$ 268	$ 182	$ 576	177	$ 423	$ 323	$ 227	1,289	1,150	361
Identifiable Assets	158,554				151,604				158,554	151,604	150,881
Long-Lived Assets	16,506				19,735				16,506	19,735	17,916
Foreign [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net revenue (loss)									99	126	164
Income (loss) from continuing operations before income tax expense									51	54	51
Net income (loss)									512	186	1,595
Identifiable Assets	869				2,891				869	2,891	3,225
Long-Lived Assets	0				0				0	0	0
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net revenue (loss)									98	124	171
Income (loss) from continuing operations before income tax expense									47	54	64
Net income (loss)									35	68	1,266
Identifiable Assets	514				590				514	590	704
Long-Lived Assets	0				0				0	0	0
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net revenue (loss)									1	2	(8)
Income (loss) from continuing operations before income tax expense									4	0	(18)
Net income (loss)									27	4	(88)
Identifiable Assets	325				1,636				325	1,636	1,972
Long-Lived Assets	0				0				0	0	0
Latin America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net revenue (loss)									0	0	0
Income (loss) from continuing operations before income tax expense									0	0	7
Net income (loss)									(2)	(8)	300
Identifiable Assets	28				29				28	29	29
Long-Lived Assets	0				0				0	0	0
Asia-Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net revenue (loss)									0	0	1
Income (loss) from continuing operations before income tax expense									0	0	(2)
Net income (loss)									452	122	117
Identifiable Assets	2				636				2	636	520
Long-Lived Assets	0				0				0	0	0
Domestic [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net revenue (loss)									4,762	4,525	4,099
Income (loss) from continuing operations before income tax expense									1,342	1,192	306
Net income (loss)									777	964	(1,234)
Identifiable Assets	157,685				148,713				157,685	148,713	147,656
Long-Lived Assets	$ 16,506				$ 19,735				16,506	19,735	17,916
Amortization of Debt Discount (Premium)									$ 62	$ 189	$ 262

Parent And Guarantor Consoli143

Parent And Guarantor Consolidating Financial Statements (Schedule of Consolidating Statement of Income) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									$ 4,570	$ 4,457	$ 4,529
Interest on loans held-for-sale									40	1	20
Interest and dividends on available-for-sale investment securities									381	367	325
Interest-bearing cash									8	8	10
Operating leases									3,398	3,558	3,209
Total financing revenue and other interest income									8,397	8,391	8,093
Interest on deposits									718	664	654
Interest on short-term borrowings									49	52	63
Interest on long-term debt									1,662	2,067	2,602
Interest Expense, Related Party									0	0	0
Total interest expense									2,429	2,783	3,319
Depreciation expense on operating lease assets									2,249	2,233	1,995
Net financing revenue (loss)	$ 983	$ 970	$ 916	$ 850	$ 799	$ 889	$ 866	$ 821	3,719	3,375	2,779
Dividends from Bank Subsidiary									0	0
Nonbank subsidiaries									0	0	0
Servicing fees									45	31	126
Servicing asset valuation and hedge activities, net									0	0	(213)
Total servicing income, net									45	31	(87)
Insurance premiums and service revenue earned									940	979	1,012
Gain (loss) on mortgage and automotive loans, net									45	7	55
Gain (loss) on extinguishment of debt									(357)	(202)	(59)
Other gain (loss) on investments, net									155	181	180
Other income, net of losses									314	280	383
Total other revenue	356	332	211	243	215	375	365	321	1,142	1,276	1,484
Total net revenue (loss)	1,339	1,302	1,127	1,093	1,014	1,264	1,231	1,142	4,861	4,651	4,263
Provision for loan losses	240	211	140	116	155	102	63	137	707	457	501
Compensation and benefits expense									963	947	1,019
Insurance losses and loss adjustment expenses									293	410	405
Other operating expenses									1,505	1,591	1,981
Total noninterest expense	668	674	724	695	672	742	821	713	2,761	2,948	3,405
(Loss) income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries	431	417	263	282	187	420	347	292	1,393	1,246	357
Income tax expense (benefit) from continuing operations	155	144	94	103	36	127	64	94	496	321	(59)
Net income (loss) from continuing operations	276	273	169	179	151	293	283	198	897	925	416
Income (loss) from discontinued operations, net of tax	(13)	(5)	13	397	26	130	40	29	392	225	(55)
Undistributed income of bank subsidiaries									0	0	0
Undistributed income of nonbank subsidiaries									0	0	0
Net income (loss)	$ 263	$ 268	$ 182	$ 576	$ 177	$ 423	$ 323	$ 227	1,289	1,150	361
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									(165)	210	(587)
Comprehensive income (loss)									1,124	1,360	(226)
Parent [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									(83)	(14)	771
Interest on loans held-for-sale									0	0	0
Interest and dividends on available-for-sale investment securities									0	0	0
Interest-bearing cash									1	1	3
Operating leases									9	269	500
Total financing revenue and other interest income									(56)	293	1,333
Interest on deposits									10	15	25
Interest on short-term borrowings									40	43	46
Interest on long-term debt									1,121	1,492	2,039
Interest Expense, Related Party									32	88	66
Total interest expense									1,203	1,638	2,176
Depreciation expense on operating lease assets									7	161	369
Net financing revenue (loss)									(1,266)	(1,506)	(1,212)
Dividends from Bank Subsidiary									525	1,800
Nonbank subsidiaries									1,123	651	5,732
Servicing fees									1,137	1,071	152
Servicing asset valuation and hedge activities, net											0
Total servicing income, net											152
Insurance premiums and service revenue earned									0	0	0
Gain (loss) on mortgage and automotive loans, net									(9)	(5)	0
Gain (loss) on extinguishment of debt									(355)	(202)	(61)
Other gain (loss) on investments, net									0	0	0
Other income, net of losses									236	208	157
Total other revenue									1,009	1,072	248
Total net revenue (loss)									1,391	2,017	4,768
Provision for loan losses									157	250	196
Compensation and benefits expense									571	586	640
Insurance losses and loss adjustment expenses									0	0	0
Other operating expenses									1,247	1,267	501
Total noninterest expense									1,818	1,853	1,141
(Loss) income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries									(584)	(86)	3,431
Income tax expense (benefit) from continuing operations									(267)	(457)	(969)
Net income (loss) from continuing operations									(317)	371	4,400
Income (loss) from discontinued operations, net of tax									356	193	(1,321)
Undistributed income of bank subsidiaries									581	(680)	883
Undistributed income of nonbank subsidiaries									669	1,266	(3,601)
Net income (loss)									1,289	1,150	361
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									(165)	210	(587)
Comprehensive income (loss)									1,124	1,360	(226)
Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									0	0	0
Interest on loans held-for-sale									0	0	0
Interest and dividends on available-for-sale investment securities									0	0	0
Interest-bearing cash									0	0	0
Operating leases									0	0	0
Total financing revenue and other interest income									0	0	0
Interest on deposits									0	0	0
Interest on short-term borrowings									0	0	0
Interest on long-term debt									0	0	0
Interest Expense, Related Party									0	0	0
Total interest expense									0	0	0
Depreciation expense on operating lease assets									0	0	0
Net financing revenue (loss)									0	0	0
Dividends from Bank Subsidiary									525	1,800
Nonbank subsidiaries									0	0	3,659
Servicing fees									0	0	0
Servicing asset valuation and hedge activities, net											0
Total servicing income, net											0
Insurance premiums and service revenue earned									0	0	0
Gain (loss) on mortgage and automotive loans, net									0	0	0
Gain (loss) on extinguishment of debt									0	0	0
Other gain (loss) on investments, net									0	0	0
Other income, net of losses									0	0	0
Total other revenue									0	0	0
Total net revenue (loss)									525	1,800	3,659
Provision for loan losses									0	0	0
Compensation and benefits expense									0	0	0
Insurance losses and loss adjustment expenses									0	0	0
Other operating expenses									0	0	0
Total noninterest expense									0	0	0
(Loss) income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries									525	1,800	3,659
Income tax expense (benefit) from continuing operations									0	0	0
Net income (loss) from continuing operations									525	1,800	3,659
Income (loss) from discontinued operations, net of tax									0	0	(19)
Undistributed income of bank subsidiaries									581	(680)	883
Undistributed income of nonbank subsidiaries									(1)	(1)	(2,393)
Net income (loss)									1,105	1,119	2,130
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									(43)	188	(812)
Comprehensive income (loss)									1,062	1,307	1,318
Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									4,653	4,471	3,758
Interest on loans held-for-sale									40	1	20
Interest and dividends on available-for-sale investment securities									381	367	325
Interest-bearing cash									7	7	7
Operating leases									3,389	3,289	2,709
Total financing revenue and other interest income									8,502	8,223	6,894
Interest on deposits									708	649	629
Interest on short-term borrowings									9	9	17
Interest on long-term debt									541	575	568
Interest Expense, Related Party									17	37	62
Total interest expense									1,275	1,270	1,276
Depreciation expense on operating lease assets									2,242	2,072	1,626
Net financing revenue (loss)									4,985	4,881	3,992
Dividends from Bank Subsidiary									0	0
Nonbank subsidiaries									0	0	0
Servicing fees									834	792	(26)
Servicing asset valuation and hedge activities, net											(213)
Total servicing income, net											(239)
Insurance premiums and service revenue earned									940	979	1,012
Gain (loss) on mortgage and automotive loans, net									54	12	55
Gain (loss) on extinguishment of debt									(2)	0	2
Other gain (loss) on investments, net									155	181	180
Other income, net of losses									539	507	1,438
Total other revenue									2,520	2,471	2,448
Total net revenue (loss)									7,505	7,352	6,440
Provision for loan losses									550	207	305
Compensation and benefits expense									842	793	821
Insurance losses and loss adjustment expenses									293	410	405
Other operating expenses									2,195	2,159	2,250
Total noninterest expense									3,330	3,362	3,476
(Loss) income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries									3,625	3,783	2,659
Income tax expense (benefit) from continuing operations									763	778	910
Net income (loss) from continuing operations									2,862	3,005	1,749
Income (loss) from discontinued operations, net of tax									36	32	1,284
Undistributed income of bank subsidiaries									0	0	0
Undistributed income of nonbank subsidiaries									0	0	0
Net income (loss)									2,898	3,037	3,033
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									(172)	212	(873)
Comprehensive income (loss)									2,726	3,249	2,160
Consolidation, Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									0	0	0
Interest on loans held-for-sale									0	0	0
Interest and dividends on available-for-sale investment securities									0	0	0
Interest-bearing cash									0	0	0
Operating leases									0	0	0
Total financing revenue and other interest income									(49)	(125)	(134)
Interest on deposits									0	0	0
Interest on short-term borrowings									0	0	0
Interest on long-term debt									0	0	(5)
Interest Expense, Related Party									(49)	(125)	(128)
Total interest expense									(49)	(125)	(133)
Depreciation expense on operating lease assets									0	0	0
Net financing revenue (loss)									0	0	(1)
Dividends from Bank Subsidiary									(1,050)	(3,600)
Nonbank subsidiaries									(1,123)	(651)	(9,391)
Servicing fees									(1,926)	(1,832)	0
Servicing asset valuation and hedge activities, net											0
Total servicing income, net											0
Insurance premiums and service revenue earned									0	0	0
Gain (loss) on mortgage and automotive loans, net									0	0	0
Gain (loss) on extinguishment of debt									0	0	0
Other gain (loss) on investments, net									0	0	0
Other income, net of losses									(461)	(435)	(1,212)
Total other revenue									(2,387)	(2,267)	(1,212)
Total net revenue (loss)									(4,560)	(6,518)	(10,604)
Provision for loan losses									0	0	0
Compensation and benefits expense									(450)	(432)	(442)
Insurance losses and loss adjustment expenses									0	0	0
Other operating expenses									(1,937)	(1,835)	(770)
Total noninterest expense									(2,387)	(2,267)	(1,212)
(Loss) income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries									(2,173)	(4,251)	(9,392)
Income tax expense (benefit) from continuing operations									0	0	0
Net income (loss) from continuing operations									(2,173)	(4,251)	(9,392)
Income (loss) from discontinued operations, net of tax									0	0	1
Undistributed income of bank subsidiaries									(1,162)	1,360	(1,766)
Undistributed income of nonbank subsidiaries									(668)	(1,265)	5,994
Net income (loss)									(4,003)	(4,156)	(5,163)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									215	(400)	1,685
Comprehensive income (loss)									(3,788)	(4,556)	(3,478)
Affiliated Entity [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									0	0	0
Interest-bearing cash									0	0	0
Affiliated Entity [Member] | Parent [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									17	37	59
Interest-bearing cash									0	0	0
Affiliated Entity [Member] | Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									0	0	0
Interest-bearing cash									0	0	0
Affiliated Entity [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									24	82	68
Interest-bearing cash									8	6	7
Affiliated Entity [Member] | Consolidation, Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									(41)	(119)	(127)
Interest-bearing cash									$ (8)	$ (6)	$ (7)

Parent And Guarantor Consoli144

Parent And Guarantor Consolidating Financial Statements (Schedule Of Condensed Consolidating Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and Due from Banks	$ 2,148	$ 1,348
Interest-bearing Deposits in Banks and Other Financial Institutions	4,232	4,228
Total cash and cash equivalents	6,380	5,576	$ 5,531	$ 7,513
Investment securities	17,157	16,137
Loans held-for-sale, net	105	2,003
Finance receivables and loans, net	111,600	99,948
Loans to bank subsidiary	0	0
Loans to nonbank subsidiary	0	0
Allowance for loan losses	(1,054)	(977)	(1,208)
Total finance receivables and loans, net	110,546	98,971
Investment in operating leases, net	16,271	19,510
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	1,801	1,695
Other Assets	6,321	7,105
Assets of operations held-for-sale	0	634
Total assets	158,581	151,631	150,908
Noninterest-bearing deposit liabilities	89	64
Interest-bearing deposit liabilities	66,389	58,139
Total deposit liabilities	66,478	58,203
Short-term borrowings	8,101	7,062
Long-term debt	66,234	66,380
Debt Payable To Nonbank Subsidiaries	0	0
Payables to Bank Subsidiaries	0	0
Payables to Nonbank Subsidiaries	0	0
Interest payable	350	477
Unearned insurance premiums and service revenue	2,434	2,375
Accrued expenses and other liabilities	1,545	1,735
Total liabilities	145,142	136,232
Total equity	13,439	15,399	14,208	19,898
Total liabilities and equity	158,581	151,631
Parent [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and Due from Banks	1,234	986
Interest-bearing Deposits in Banks and Other Financial Institutions	401	1,300
Total cash and cash equivalents	1,635	2,286	2,930	3,977
Investment securities	0	0
Loans held-for-sale, net	0	3
Finance receivables and loans, net	2,636	4,225
Loans to bank subsidiary	600	625
Loans to nonbank subsidiary	3,277	3,500
Allowance for loan losses	(72)	(102)
Total finance receivables and loans, net	6,441	8,248
Investment in operating leases, net	81	0
Receivables from bank subsidiary	186	219
Receivables from nonbank subsidiary	259	267
Investment in bank subsidiaries	16,496	15,967
Investment in nonbank subsidiaries	10,902	11,559
Premiums receivable and other insurance assets	0	0
Other Assets	4,785	4,757
Assets of operations held-for-sale		634
Total assets	40,785	43,940
Noninterest-bearing deposit liabilities	0	0
Interest-bearing deposit liabilities	229	319
Total deposit liabilities	229	319
Short-term borrowings	3,453	3,338
Long-term debt	21,048	21,067
Debt Payable To Nonbank Subsidiaries	1,409	2,385
Payables to Bank Subsidiaries	142	94
Payables to Nonbank Subsidiaries	420	454
Interest payable	258	316
Unearned insurance premiums and service revenue	0	0
Accrued expenses and other liabilities	387	568
Total liabilities	27,346	28,541
Total equity	13,439	15,399
Total liabilities and equity	40,785	43,940
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
Total cash and cash equivalents	0	0	37	0
Investment securities	0	0
Loans held-for-sale, net	0	0
Finance receivables and loans, net	0	0
Loans to bank subsidiary	0	0
Loans to nonbank subsidiary	0	0
Allowance for loan losses	0	0
Total finance receivables and loans, net	0	0
Investment in operating leases, net	0	0
Receivables from bank subsidiary	0	0
Receivables from nonbank subsidiary	0	0
Investment in bank subsidiaries	16,496	15,967
Investment in nonbank subsidiaries	11	12
Premiums receivable and other insurance assets	0	0
Other Assets	0	0
Assets of operations held-for-sale		0
Total assets	16,507	15,979
Noninterest-bearing deposit liabilities	0	0
Interest-bearing deposit liabilities	0	0
Total deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Debt Payable To Nonbank Subsidiaries	0	0
Payables to Bank Subsidiaries	0	0
Payables to Nonbank Subsidiaries	0	0
Interest payable	0	0
Unearned insurance premiums and service revenue	0	0
Accrued expenses and other liabilities	82	82
Total liabilities	82	82
Total equity	16,425	15,897
Total liabilities and equity	16,507	15,979
Non-Guarantor Subsidiaries [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and Due from Banks	914	362
Interest-bearing Deposits in Banks and Other Financial Institutions	3,831	2,928
Total cash and cash equivalents	5,595	3,905	2,974	4,027
Investment securities	17,157	16,137
Loans held-for-sale, net	105	2,000
Finance receivables and loans, net	108,964	95,723
Loans to bank subsidiary	0	0
Loans to nonbank subsidiary	559	1,770
Allowance for loan losses	(982)	(875)
Total finance receivables and loans, net	108,541	96,618
Investment in operating leases, net	16,190	19,510
Receivables from bank subsidiary	0	0
Receivables from nonbank subsidiary	282	393
Investment in bank subsidiaries	0	0
Investment in nonbank subsidiaries	0	0
Premiums receivable and other insurance assets	1,827	1,717
Other Assets	4,488	4,814
Assets of operations held-for-sale		0
Total assets	154,185	145,094
Noninterest-bearing deposit liabilities	89	64
Interest-bearing deposit liabilities	66,160	57,820
Total deposit liabilities	66,249	57,884
Short-term borrowings	4,648	3,724
Long-term debt	45,186	45,313
Debt Payable To Nonbank Subsidiaries	3,877	4,125
Payables to Bank Subsidiaries	0	0
Payables to Nonbank Subsidiaries	191	354
Interest payable	92	161
Unearned insurance premiums and service revenue	2,434	2,375
Accrued expenses and other liabilities	4,028	3,551
Total liabilities	126,705	117,487
Total equity	27,480	27,607
Total liabilities and equity	154,185	145,094
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
Total cash and cash equivalents	(850)	(615)	$ (410)	$ (491)
Investment securities	0	0
Loans held-for-sale, net	0	0
Finance receivables and loans, net	0	0
Loans to bank subsidiary	(600)	(625)
Loans to nonbank subsidiary	(3,836)	(5,270)
Allowance for loan losses	0	0
Total finance receivables and loans, net	(4,436)	(5,895)
Investment in operating leases, net	0	0
Receivables from bank subsidiary	(186)	(219)
Receivables from nonbank subsidiary	(541)	(660)
Investment in bank subsidiaries	(32,992)	(31,934)
Investment in nonbank subsidiaries	(10,913)	(11,571)
Premiums receivable and other insurance assets	(26)	(22)
Other Assets	(2,952)	(2,466)
Assets of operations held-for-sale		0
Total assets	(52,896)	(53,382)
Noninterest-bearing deposit liabilities	0	0
Interest-bearing deposit liabilities	0	0
Total deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Debt Payable To Nonbank Subsidiaries	(5,286)	(6,510)
Payables to Bank Subsidiaries	(142)	(94)
Payables to Nonbank Subsidiaries	(611)	(808)
Interest payable	0	0
Unearned insurance premiums and service revenue	0	0
Accrued expenses and other liabilities	(2,952)	(2,466)
Total liabilities	(8,991)	(9,878)
Total equity	(43,905)	(43,504)
Total liabilities and equity	(52,896)	(53,382)
Fair Value Option Election, Fair Value [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Finance receivables and loans, net	111,600	99,948
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 [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	850	615
Affiliated Entity [Member] | Consolidation, Eliminations [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Interest-bearing Deposits in Banks and Other Financial Institutions	$ (850)	$ (615)

Parent And Guarantor Consoli145

Parent And Guarantor Consolidating Financial Statements (Schedule Of Condensed Consolidating Statement of Cash Flow) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 5,095	$ 3,403	$ 2,501
Purchases of available-for-sale securities	(12,250)	(5,417)	(12,304)
Proceeds from sales of available-for-sale securities	6,874	4,260	3,627
Proceeds from maturities of available-for-sale securities	4,255	2,657	5,509
Net (increase) decrease in finance receivables and loans	(13,845)	(5,024)	(2,479)
Proceeds from Sale of Loans and Leases Held-for-investment	3,197	2,592
Purchases of operating lease assets	(4,685)	(9,884)	(9,196)
Disposals Of Operating Lease Assets	5,546	5,860	2,964
Capital contributions to subsidiaries	0	0	0
Returns of contributed capital	0	0	0
Payments for (Proceeds from) Mortgage Servicing Rights			911
Proceeds from sale of business units, net	1,049	47	7,444
Increase (Decrease) in Restricted Cash	264	1,625	(70)
Other, net	(152)	72	51
Net cash (used in) provided by investing activities	(9,747)	(3,212)	(3,543)
Net change in short-term borrowings	1,028	(1,494)	1,591
Net increase in bank deposits	8,247	4,851	5,357
Proceeds from issuance of long-term debt	30,665	27,192	27,330
Repayments of long-term debt	(31,350)	(30,426)	(31,892)
Net Change in Debt, Intercompany	0	0	0
Payments for Repurchase of Redeemable Preferred Stock	(559)	0	0
Proceeds from Issuance of Common Stock	0	0	1,270
Payments for Repurchase of Convertible Preferred Stock			(5,925)
Payments for Repurchase of Convertible Preferred Stock	0	0	(5,925)
Dividends paid	(2,571)	(268)	(810)
Dividends paid and returns of contributed capital	0	0	0
Capital contributions from parent	0	0	0
Net cash provided by (used in) financing activities	5,460	(145)	(3,079)
Effect of exchange-rate changes on cash and cash equivalents	(4)	(1)	45
Cash and Cash Equivalents, Period Increase (Decrease)	804	45	(4,076)
Net Cash Provided by (Used in) Discontinued Operations	0	0	2,094
Cash and cash equivalents at beginning of period	5,576	5,531	7,513
Cash and cash equivalents at end of period	6,380	5,576	5,531
Parent [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	354	330	3,015
Purchases of available-for-sale securities	0	0	0
Proceeds from sales of available-for-sale securities	0	0	0
Proceeds from maturities of available-for-sale securities	0	0	0
Net (increase) decrease in finance receivables and loans	1,785	1,900	4,898
Proceeds from Sale of Loans and Leases Held-for-investment	0	0
Purchases of operating lease assets	(94)	(2,337)	(1,450)
Disposals Of Operating Lease Assets	7	3,053	130
Capital contributions to subsidiaries	(796)	(1,179)	(477)
Returns of contributed capital	1,444	1,422	1,002
Payments for (Proceeds from) Mortgage Servicing Rights			0
Proceeds from sale of business units, net	1,049	46	1,799
Increase (Decrease) in Restricted Cash	(7)	0	0
Other, net	(47)	(29)	41
Net cash (used in) provided by investing activities	3,581	4,304	6,244
Net change in short-term borrowings	115	113	131
Net increase in bank deposits	(91)	(121)	(543)
Proceeds from issuance of long-term debt	5,428	3,132	3,236
Repayments of long-term debt	(5,931)	(8,186)	(9,468)
Net Change in Debt, Intercompany	(977)	52	1,803
Payments for Repurchase of Redeemable Preferred Stock	(559)
Proceeds from Issuance of Common Stock			1,270
Payments for Repurchase of Convertible Preferred Stock			(5,925)
Dividends paid	(2,571)	(268)	(810)
Dividends paid and returns of contributed capital	0	0	0
Capital contributions from parent	0	0	0
Net cash provided by (used in) financing activities	(4,586)	(5,278)	(10,306)
Effect of exchange-rate changes on cash and cash equivalents	0	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	(651)	(644)	(1,047)
Net Cash Provided by (Used in) Discontinued Operations			0
Cash and cash equivalents at beginning of period	2,286	2,930	3,977
Cash and cash equivalents at end of period	1,635	2,286	2,930
Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	525	1,789	3,572
Purchases of available-for-sale securities	0	0	0
Proceeds from sales of available-for-sale securities	0	0	0
Proceeds from maturities of available-for-sale securities	0	0	0
Net (increase) decrease in finance receivables and loans	0	0	79
Proceeds from Sale of Loans and Leases Held-for-investment	0	0
Purchases of operating lease assets	0	0	0
Disposals Of Operating Lease Assets	0	0	0
Capital contributions to subsidiaries	(1)	0	0
Returns of contributed capital	0	0	150
Payments for (Proceeds from) Mortgage Servicing Rights			0
Proceeds from sale of business units, net	0	0	554
Increase (Decrease) in Restricted Cash	0	0	(26)
Other, net	0	0	0
Net cash (used in) provided by investing activities	(1)	0	1,008
Net change in short-term borrowings	0	0	36
Net increase in bank deposits	0	0	0
Proceeds from issuance of long-term debt	0	0	0
Repayments of long-term debt	0	0	(70)
Net Change in Debt, Intercompany	0	0	(271)
Payments for Repurchase of Redeemable Preferred Stock	0
Proceeds from Issuance of Common Stock			0
Payments for Repurchase of Convertible Preferred Stock			0
Dividends paid	0	0	0
Dividends paid and returns of contributed capital	(525)	(1,826)	(4,267)
Capital contributions from parent	1	0	29
Net cash provided by (used in) financing activities	(524)	(1,826)	(4,543)
Effect of exchange-rate changes on cash and cash equivalents	0	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	0	(37)	37
Net Cash Provided by (Used in) Discontinued Operations			0
Cash and cash equivalents at beginning of period	0	37	0
Cash and cash equivalents at end of period	0	0	37
Non-Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	6,390	5,533	5,305
Purchases of available-for-sale securities	(12,250)	(5,417)	(12,304)
Proceeds from sales of available-for-sale securities	6,874	4,277	3,627
Proceeds from maturities of available-for-sale securities	4,255	2,657	5,509
Net (increase) decrease in finance receivables and loans	(15,630)	(6,941)	(7,456)
Proceeds from Sale of Loans and Leases Held-for-investment	3,197	2,592
Purchases of operating lease assets	(4,591)	(7,547)	(7,746)
Disposals Of Operating Lease Assets	5,539	2,807	2,834
Capital contributions to subsidiaries	0	0	0
Returns of contributed capital	0	0	0
Payments for (Proceeds from) Mortgage Servicing Rights			911
Proceeds from sale of business units, net	0	1	5,091
Increase (Decrease) in Restricted Cash	271	1,625	(44)
Other, net	(105)	101	10
Net cash (used in) provided by investing activities	(11,229)	(5,691)	(11,071)
Net change in short-term borrowings	913	(1,607)	1,424
Net increase in bank deposits	8,338	4,972	5,861
Proceeds from issuance of long-term debt	25,237	24,060	24,094
Repayments of long-term debt	(25,419)	(22,240)	(22,354)
Net Change in Debt, Intercompany	(240)	(1,428)	(624)
Payments for Repurchase of Redeemable Preferred Stock	0
Proceeds from Issuance of Common Stock			0
Payments for Repurchase of Convertible Preferred Stock			0
Dividends paid	0	0	0
Dividends paid and returns of contributed capital	(3,092)	(3,846)	(6,275)
Capital contributions from parent	796	1,179	448
Net cash provided by (used in) financing activities	6,533	1,090	2,574
Effect of exchange-rate changes on cash and cash equivalents	(4)	(1)	45
Cash and Cash Equivalents, Period Increase (Decrease)	1,690	931	(3,147)
Net Cash Provided by (Used in) Discontinued Operations			2,094
Cash and cash equivalents at beginning of period	3,905	2,974	4,027
Cash and cash equivalents at end of period	5,595	3,905	2,974
Consolidation, Eliminations [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(2,174)	(4,249)	(9,391)
Purchases of available-for-sale securities	0	0	0
Proceeds from sales of available-for-sale securities	0	(17)	0
Proceeds from maturities of available-for-sale securities	0	0	0
Net (increase) decrease in finance receivables and loans	0	17	0
Proceeds from Sale of Loans and Leases Held-for-investment	0	0
Purchases of operating lease assets	0	0	0
Disposals Of Operating Lease Assets	0	0	0
Capital contributions to subsidiaries	797	1,179	477
Returns of contributed capital	(1,444)	(1,422)	(1,152)
Payments for (Proceeds from) Mortgage Servicing Rights			0
Proceeds from sale of business units, net	0	0	0
Increase (Decrease) in Restricted Cash	0	0	0
Other, net	0	0	0
Net cash (used in) provided by investing activities	(2,098)	(1,825)	276
Net change in short-term borrowings	0	0	0
Net increase in bank deposits	0	0	39
Proceeds from issuance of long-term debt	0	0	0
Repayments of long-term debt	0	0	0
Net Change in Debt, Intercompany	1,217	1,376	(908)
Payments for Repurchase of Redeemable Preferred Stock	0
Proceeds from Issuance of Common Stock			0
Payments for Repurchase of Convertible Preferred Stock			0
Dividends paid	0	0	0
Dividends paid and returns of contributed capital	3,617	5,672	10,542
Capital contributions from parent	(797)	(1,179)	(477)
Net cash provided by (used in) financing activities	4,037	5,869	9,196
Effect of exchange-rate changes on cash and cash equivalents	0	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	(235)	(205)	81
Net Cash Provided by (Used in) Discontinued Operations			0
Cash and cash equivalents at beginning of period	(615)	(410)	(491)
Cash and cash equivalents at end of period	(850)	(615)	(410)
Affiliated Entity [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net (increase) decrease in finance receivables and loans	0	0	0
Affiliated Entity [Member] | Parent [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net (increase) decrease in finance receivables and loans	240	1,428	301
Affiliated Entity [Member] | Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net (increase) decrease in finance receivables and loans	0	0	251
Affiliated Entity [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net (increase) decrease in finance receivables and loans	1,211	154	(1,503)
Affiliated Entity [Member] | Consolidation, Eliminations [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net (increase) decrease in finance receivables and loans	$ (1,451)	$ (1,582)	$ 951

Guarantees and Commitments (Gua

Guarantees and Commitments (Guarantees to third parties) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Guarantor Obligations [Line Items]
Standby letters of credit and other guarantees	$ 13	$ 19
Maximum [Member]
Guarantor Obligations [Line Items]
Standby letters of credit and other guarantees	$ 208	$ 268

Guarantees and Commitments (Con

Guarantees and Commitments (Contractual financing commitments) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Guarantees [Abstract]
Commitment to provide capital to investees	$ 132	$ 66
Warehouse and construction lending commitments	197	110
Commitment to fund remaining unused balances on home equity lines of credit	358	371
Unused revolving credit line commitments and other	$ 1,445	$ 1,284

Guarantees and Commitments (Sch

Guarantees and Commitments (Schedule of Lease Commitments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Guarantees [Abstract]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$ 39
Operating Leases, Future Minimum Payments, Due in Two Years	34
Operating Leases, Future Minimum Payments, Due in Three Years	31
Operating Leases, Future Minimum Payments, Due in Four Years	31
Operating Leases, Future Minimum Payments, Due in Five Years	29
Operating Leases, Future Minimum Payments, Due Thereafter	99
Operating Leases, Future Minimum Payments Due	263
Operating Leases, Rent Expense	$ 51	$ 50	$ 47

Guarantees and Commitments (Oth

Guarantees and Commitments (Other Purchase Commitments) (Details) $ in Millions	Dec. 31, 2015USD ($)
Guarantees [Abstract]
Other Commitment, Due in Next Twelve Months	$ 47
Other Commitment, Due in Second and Third Year	51
Other Commitment, Due in Fourth Year	3
Other Commitment	$ 101

Quarterly Financial Statemen150

Quarterly Financial Statements (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Statements [Abstract]
Net financing revenue (loss)	$ 983	$ 970	$ 916	$ 850	$ 799	$ 889	$ 866	$ 821	$ 3,719	$ 3,375	$ 2,779
Other revenue	356	332	211	243	215	375	365	321	1,142	1,276	1,484
Total net revenue (loss)	1,339	1,302	1,127	1,093	1,014	1,264	1,231	1,142	4,861	4,651	4,263
Provision for loan losses	240	211	140	116	155	102	63	137	707	457	501
Total noninterest expense	668	674	724	695	672	742	821	713	2,761	2,948	3,405
Income (loss) from continuing operations before income tax expense	431	417	263	282	187	420	347	292	1,393	1,246	357
Income tax expense (benefit) from continuing operations	155	144	94	103	36	127	64	94	496	321	(59)
Net income (loss) from continuing operations	276	273	169	179	151	293	283	198	897	925	416
Income (loss) from discontinued operations, net of tax	(13)	(5)	13	397	26	130	40	29	392	225	(55)
Net income (loss)	$ 263	$ 268	$ 182	$ 576	$ 177	$ 423	$ 323	$ 227	$ 1,289	$ 1,150	$ 361
Net income (loss) from continuing operations, Per Basic Share	$ (1.94)	$ 0.49	$ (2.24)	$ 0.23	$ 0.17	$ 0.47	$ 0.45	$ 0.27	$ (3.47)	$ 1.36	$ (1.51)
Net (loss) income, Basic	(1.97)	0.48	(2.22)	1.06	0.23	0.74	0.54	0.33	(2.66)	1.83	(1.64)
Net income (loss) from continuing operations, Per Diluted Share	(1.94)	0.49	(2.24)	0.23	0.17	0.47	0.45	0.27	(3.47)	1.36	(1.51)
Net (loss) income, Diluted	$ (1.97)	$ 0.47	$ (2.22)	$ 1.06	$ 0.23	$ 0.74	$ 0.54	$ 0.33	$ (2.66)	$ 1.83	$ (1.64)

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event [Member] - Series A Preferred Stock [Member] $ / shares in Units, $ in Millions	Jan. 11, 2016USD ($)$ / shares
Subsequent Event [Line Items]
Dividends Payable, Amount Per Share | $ / shares	$ 0.53
Dividends, Preferred Stock | $	$ 15