Derivative Financial Instruments (Schedule Of Outstanding Hedges: (Notional Amount)) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	$ 2,614	$ 3,153
Swap agreements and forwards | Interest-rate contracts | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	1,426	1,578
Options and caps purchased | Interest-rate contracts | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	57	68
Options and caps written | Interest-rate contracts | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	57	68
Futures | Interest-rate contracts | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	5,239	1,910
Forward, swap and spot | Foreign exchange contracts | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	967,407	897,354
Options purchased | Foreign exchange contracts | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	7,584	9,454
Options written | Foreign exchange contracts | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	7,092	8,734
Credit swap agreements | Credit derivative contracts | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	42	27
Stable value contracts | Other contracts | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	32,171	33,512
Swap agreements | Interest-rate contracts | Derivatives designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	2,614	3,153
Forward and swap | Foreign exchange contracts | Derivatives designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	$ 3,276	$ 3,477