Derivatives and Hedging (Details 2) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Derivatives, Fair Value
Derivative Assets	$ 188	$ 157
Derivative Liabilities	206	189
Notional Amount	2,157	2,245
Derivatives accounted for as hedges:
Derivatives, Fair Value
Derivative Assets	187	156
Derivative Liabilities	205	188
Notional Amount	1,929	1,999
Interest rate contracts | Derivatives accounted for as hedges:
Derivatives, Fair Value
Derivative Assets	18	16
Notional Amount	552	702
Foreign exchange contracts | Derivatives accounted for as hedges:
Derivatives, Fair Value
Derivative Assets	169	140
Derivative Liabilities	205	188
Notional Amount	1,377	1,297
Foreign exchange contracts | Derivatives not accounted for as hedges:
Derivatives, Fair Value
Derivative Assets	1	1
Derivative Liabilities	1	1
Notional Amount	$ 228	$ 246