Derivative Financial Instruments and Risk Management (Details 2) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Derivatives, Fair Value
Asset Fair Value	$ 208	$ 238
Liability Fair Value	(29)	(15)
Designated derivatives
Derivatives, Fair Value
Asset (Liability) Fair Value	190	218
Designated derivatives | Interest rate contracts | Other assets
Derivatives, Fair Value
Asset Fair Value	198	226
Designated derivatives | Interest rate contracts | Accrued expenses
Derivatives, Fair Value
Liability Fair Value	(8)	(8)
Undesignated derivatives
Derivatives, Fair Value
Asset (Liability) Fair Value	(11)	5
Undesignated derivatives | Interest rate contracts | Other assets
Derivatives, Fair Value
Asset Fair Value	1	2
Undesignated derivatives | Interest rate contracts | Accrued expenses
Derivatives, Fair Value
Liability Fair Value	(1)	(1)
Undesignated derivatives | Foreign exchange contracts | Other assets
Derivatives, Fair Value
Asset Fair Value	9	10
Undesignated derivatives | Foreign exchange contracts | Accrued expenses
Derivatives, Fair Value
Liability Fair Value	(16)	(5)
Undesignated derivatives | Cross currency contracts | Accrued expenses
Derivatives, Fair Value
Liability Fair Value	$ (4)	$ (1)