Derivative Financial Instruments (Schedule of Outstanding Hedges: (Notional Amount)) (Details) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Notional Amount of Derivatives	$ 4,648	$ 1,886
Swap Agreements and Forwards [Member] | Interest-Rate Contracts [Member] | Derivatives not Designated as Hedging Instruments [Member]
Notional Amount of Derivatives	192,346	52,383
Swap Agreements and Forwards [Member] | Designated as Hedging Instrument [Member]
Notional Amount of Derivatives	2,265	1,886
Options and Caps Purchased [Member] | Interest-Rate Contracts [Member] | Derivatives not Designated as Hedging Instruments [Member]
Notional Amount of Derivatives	1,156	140
Options and Caps Written [Member] | Interest-Rate Contracts [Member] | Derivatives not Designated as Hedging Instruments [Member]
Notional Amount of Derivatives	1,344	130
Futures [Member] | Interest-Rate Contracts [Member] | Derivatives not Designated as Hedging Instruments [Member]
Notional Amount of Derivatives	126,792	25,253
Futures [Member] | Designated as Hedging Instrument [Member]
Notional Amount of Derivatives	2,383
Forward, Swap and Spot [Member] | Foreign Exchange Contracts [Member] | Derivatives not Designated as Hedging Instruments [Member]
Notional Amount of Derivatives	1,000,892	637,847
Options Purchased [Member] | Foreign Exchange Contracts [Member] | Derivatives not Designated as Hedging Instruments [Member]
Notional Amount of Derivatives	13,228	14,299
Options Written [Member] | Foreign Exchange Contracts [Member] | Derivatives not Designated as Hedging Instruments [Member]
Notional Amount of Derivatives	12,943	14,587
Credit Default Swap Agreements [Member] | Credit Derivative Contracts [Member] | Derivatives not Designated as Hedging Instruments [Member]
Notional Amount of Derivatives	155	155
Stable Value Contracts [Member] | Other Contracts [Member] | Derivatives not Designated as Hedging Instruments [Member]
Notional Amount of Derivatives	$ 43,150	$ 46,758