Goodwill and Other Intangible Assets (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Definite-lived intangible assets
Carrying amount of indefinite-lived intangible assets	$ 630	$ 630
Carrying amount of indefinite-lived intangible assets	67	67
Gross Carrying Amount	541	528
Accumulated Amortization	(300)	(246)
Net Carrying Amount	241	282
Definite-lived intangible assets acquired during the year, amount assigned	2
Definite-lived intangible assets acquired during the year, weighted-average amortization period	5 years
Increase (decrease) to net definite-lived intangible assets due to changes in foreign currency exchange rates	4		(5)
Aggregate amortization expense for definite-lived intangible assets	47	45	46
Estimated intangible amortization expense for next five years:
2013	44
2014	38
2015	31
2016	25
2017	21
Customer relationships
Definite-lived intangible assets
Gross Carrying Amount	152	145
Accumulated Amortization	(72)	(69)
Net Carrying Amount	80	76
Contracts
Definite-lived intangible assets
Gross Carrying Amount	238	233
Accumulated Amortization	(146)	(122)
Net Carrying Amount	92	111
Other
Definite-lived intangible assets
Gross Carrying Amount	151	150
Accumulated Amortization	(82)	(55)
Net Carrying Amount	$ 69	$ 95