Intangible Assets (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 976	$ 976
Finite-Lived Intangible Assets, Accumulated Amortization	(670)	(600)
Marketing agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	730	730
Finite-Lived Intangible Assets, Accumulated Amortization	(545)	(486)
Contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	193	193
Finite-Lived Intangible Assets, Accumulated Amortization	(72)	(61)
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	53	53
Finite-Lived Intangible Assets, Accumulated Amortization	$ (53)	$ (53)