Derivative Instruments and Hedging Activities (Fair Value Amounts of Derivative Instruments Reported on our Condensed Consolidated Balance Sheet) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 141	$ 233
Derivative Liability, Fair Value, Gross Liability	46	145
Derivative, Notional Amount	38,379	59,116
Interest Receivable	408	402
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	114	126
Derivative Liability, Fair Value, Gross Liability	7	10
Derivative, Notional Amount	6,975	14,340
Interest Rate Swap [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	114	126
Derivative Liability, Fair Value, Gross Liability	7	9
Derivative, Notional Amount	6,754	14,151
Hedge notional amount associated with debt maturing in five or more years	2,300
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	0	1
Derivative, Notional Amount	221	189
Fair Value Hedging [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Receive-fixed Swaps, Fair Value, Gross Asset	104	112
Receive-fixed Swaps, Fair Value, Gross Liability	0	3
Receive-fixed Swaps, Notional Amount	2,300	6,800
Pay-fixed Swaps, Fair Value, Gross Asset	0	13
Pay-fixed Swaps, Fair Value, Gross Liability	7	3
Pay-fixed Swaps, Notional Amount	3,500	6,800
Interest Rate Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	26	105
Derivative Liability, Fair Value, Gross Liability	35	125
Derivative, Notional Amount	31,276	44,466
Foreign Exchange Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1	0
Derivative Liability, Fair Value, Gross Liability	0	0
Derivative, Notional Amount	111	278
Equity Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	2
Derivative Liability, Fair Value, Gross Liability	4	10
Derivative, Notional Amount	17	32
Interest Rate Swap [Member] \| Interest Rate Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	5	30
Derivative Liability, Fair Value, Gross Liability	15	51
Derivative, Notional Amount	864	6,101
Foreign Exchange Forward [Member] \| Foreign Exchange Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1	0
Derivative Liability, Fair Value, Gross Liability	0	0
Derivative, Notional Amount	111	278
Futures and Forwards [Member] \| Interest Rate Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	2
Derivative Liability, Fair Value, Gross Liability	0	2
Derivative, Notional Amount	0	1,905
Written Options [Member] \| Interest Rate Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	20	72
Derivative, Notional Amount	15,206	18,220
Written Options [Member] \| Equity Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	0	1
Derivative, Notional Amount	0	0
Purchased Options [Member] \| Interest Rate Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	21	73
Derivative Liability, Fair Value, Gross Liability	0	0
Derivative, Notional Amount	15,206	18,240
Purchased Options [Member] \| Equity Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	2
Derivative Liability, Fair Value, Gross Liability	0	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	4	9
Derivative, Notional Amount	17	32
Other Trading [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	27	107
Derivative Liability, Fair Value, Gross Liability	39	135
Derivative, Notional Amount	31,404	44,776
Secured Debt [Member] \| Fair Value Hedging [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Receive-fixed Swaps, Fair Value, Gross Asset	10	1
Receive-fixed Swaps, Fair Value, Gross Liability	0	2
Receive-fixed Swaps, Notional Amount	898	500
Derivative assets in net asset position [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	140	224
Interest Receivable	7	46
Derivative assets in net liability positions [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1	9
Interest Receivable	$ 1	$ 12

Hedge notional amount associated with debt maturing in five or more years

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- Definition

Pay-fixed Swaps on portfolios of held-for-investment automotive loan assets, Fair Value, Gross Asset

+ References

No definition available.

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- Definition

Pay-fixed Swaps on portfolios of held-for-investment automotive loan assets, Fair Value, Gross Liability

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Pay-fixed Swaps on portfolios of held-for-investment automotive loan assets, Fair Value, Notional Amount

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Receive-fixed Swaps on Fixed-rate Debt Obligations, Fair Value, Gross Asset

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Receive-fixed Swaps on Fixed-rate Debt Obligations, Fair Value, Gross Liability

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Receive-fixed Swaps on Fixed-rate Debt Obligations, Notional Amount

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No definition available.

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- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
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- Definition

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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