Derivative Financial Instruments (Schedule Of Outstanding Hedges: (Notional Amount)) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of Derivatives	$ 3,832	$ 3,872
Swap Agreements And Forwards [Member] | Interest-Rate Contracts [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of Derivatives	45,491	238,008
Options And Caps Purchased [Member] | Interest-Rate Contracts [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of Derivatives	95	1,431
Options And Caps Written [Member] | Interest-Rate Contracts [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of Derivatives	95	1,324
Futures [Member] | Interest-Rate Contracts [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of Derivatives	52,158	66,620
Forward, Swap And Spot [Member] | Foreign Exchange Contracts [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of Derivatives	828,436	1,033,045
Options Purchased [Member] | Foreign Exchange Contracts [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of Derivatives	13,610	11,215
Options Written [Member] | Foreign Exchange Contracts [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of Derivatives	12,976	12,342
Credit Default Swap Agreements [Member] | Credit Derivative Contracts [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of Derivatives	95	105
Stable Value Contracts [Member] | Other Contracts [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of Derivatives	38,734	40,963
Swap Agreements [Member] | Interest-Rate Contracts [Member] | Designated As Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of Derivatives	3,832	3,872
Forwards [Member] | Foreign Exchange Contracts [Member] | Designated As Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of Derivatives	$ 2,379	$ 2,613