Derivative Instruments And Hedging Activities (Fair Value Amounts Of Derivative Instruments Reported On Our Condensed Consolidated Balance Sheet) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 315,000,000	$ 263,000,000
Derivative Liability, Fair Value, Gross Liability	268,000,000	252,000,000
Notional amount	84,240,000,000invest_DerivativeNotionalAmount	81,200,000,000invest_DerivativeNotionalAmount
Accrued Interest [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	49,000,000	50,000,000
Derivative Liability, Fair Value, Gross Liability	10,000,000	17,000,000
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	170,000,000	118,000,000
Derivative Liability, Fair Value, Gross Liability	13,000,000	7,000,000
Notional amount	19,403,000,000	18,764,000,000
Interest Rate Swap [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	170,000,000	118,000,000
Derivative Liability, Fair Value, Gross Liability	12,000,000	7,000,000
Notional amount	19,166,000,000	18,554,000,000
Hedge notional amount associated with debt maturing in five or more years	2,600,000,000
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	1,000,000	0
Notional amount	237,000,000	210,000,000
Fair Value Hedging [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Receive-fixed Swaps, Fair Value, Gross Asset	166,000,000	97,000,000
Receive-fixed Swaps, Fair Value, Gross Liability	0	1,000,000
Receive-fixed Swaps, Notional Amount	5,900,000,000	4,700,000,000
Pay-fixed Swaps, Fair Value, Gross Asset	4,000,000	21,000,000
Pay-fixed Swaps, Fair Value, Gross Liability	12,000,000	6,000,000
Pay-fixed Swaps, Notional Amount	13,200,000,000	13,900,000,000
Interest Rate Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	124,000,000	138,000,000
Derivative Liability, Fair Value, Gross Liability	150,000,000	161,000,000
Notional amount	63,243,000,000	60,847,000,000
Foreign Exchange Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	21,000,000	5,000,000
Derivative Liability, Fair Value, Gross Liability	94,000,000	78,000,000
Notional amount	1,531,000,000	1,514,000,000
Equity Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	2,000,000
Derivative Liability, Fair Value, Gross Liability	11,000,000	6,000,000
Notional amount	63,000,000	75,000,000
Interest Rate Swap [Member] \| Interest Rate Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	47,000,000	40,000,000
Derivative Liability, Fair Value, Gross Liability	72,000,000	65,000,000
Notional amount	12,721,000,000	11,979,000,000
Futures and Forwards [Member] \| Interest Rate Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	6,000,000	4,000,000
Derivative Liability, Fair Value, Gross Liability	7,000,000	2,000,000
Notional amount	18,955,000,000	18,886,000,000
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	71,000,000	94,000,000
Notional amount	15,665,000,000	14,823,000,000
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	2,000,000	3,000,000
Notional amount	1,000,000	1,000,000
Purchased Options [Member] \| Interest Rate Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	71,000,000	94,000,000
Derivative Liability, Fair Value, Gross Liability	0	0
Notional amount	15,902,000,000	15,159,000,000
Purchased Options [Member] \| Equity Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	2,000,000
Derivative Liability, Fair Value, Gross Liability	0	0
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	9,000,000	3,000,000
Notional amount	62,000,000	74,000,000
Swap [Member] \| Foreign Exchange Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	12,000,000	0
Derivative Liability, Fair Value, Gross Liability	88,000,000	74,000,000
Notional amount	1,073,000,000	1,210,000,000
Foreign Exchange Forward [Member] \| Foreign Exchange Contract [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	9,000,000	5,000,000
Derivative Liability, Fair Value, Gross Liability	6,000,000	4,000,000
Notional amount	458,000,000	304,000,000
Other Trading [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	145,000,000	145,000,000
Derivative Liability, Fair Value, Gross Liability	255,000,000	245,000,000
Notional amount	$ 64,837,000,000	$ 62,436,000,000

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- Definition

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

+ References

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- Definition

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

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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

-Sentence Column B

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (a),(c)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624163-113959

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

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-Section 55

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-URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226000-175313

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