Derivative Financial Instruments and Risk Management (Details 2) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Derivatives, Fair Value
Asset Fair Value	$ 170	$ 238
Liability Fair Value	(9)	(15)
Designated derivatives
Derivatives, Fair Value
Asset (Liability) Fair Value	147	218
Designated derivatives | Interest rate contracts | Other assets
Derivatives, Fair Value
Asset Fair Value	153	226
Designated derivatives | Interest rate contracts | Accrued expenses
Derivatives, Fair Value
Liability Fair Value	(6)	(8)
Undesignated derivatives
Derivatives, Fair Value
Asset (Liability) Fair Value	14	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	0	(1)
Undesignated derivatives | Foreign exchange contracts | Other assets
Derivatives, Fair Value
Asset Fair Value	10	10
Undesignated derivatives | Foreign exchange contracts | Accrued expenses
Derivatives, Fair Value
Liability Fair Value	(3)	(5)
Undesignated derivatives | Cross currency contracts | Other assets
Derivatives, Fair Value
Asset Fair Value	6	0
Undesignated derivatives | Cross currency contracts | Accrued expenses
Derivatives, Fair Value
Liability Fair Value	$ 0	$ (1)