Goodwill and Other Intangible Assets (Other intangible assets) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended			12 Months Ended	9 Months Ended		12 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Non-Compete Agreements [Member]	Dec. 31, 2011 Non-Compete Agreements [Member]	Sep. 30, 2012 Non-Compete Agreements [Member] RSC [Member]	Sep. 30, 2012 Customer Relationships [Member]	Dec. 31, 2011 Customer Relationships [Member]	Sep. 30, 2012 Customer Relationships [Member] RSC [Member]	Sep. 30, 2012 Trade Names, Associated Trademarks and Other [Member]	Sep. 30, 2012 Trade Names, Associated Trademarks and Other [Member] RSC [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-average remaining amortization period					54 months	46 months		14 years	9 years		55 months
Gross carrying amount					$ 79	$ 30		$ 1,250	$ 121		$ 84
Accumulated amortization					29	25		107	43		13
Net amount	1,264		1,264		50	5	44	1,143	78	1,052	71	70
Weighted-average initial amortization period (in years or months)							60 months			15 years		60 months
Amortization expense	47	3	82	6
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2012	48		48
2013	180		180
2014	164		164
2015	148		148
2016	133		133
Thereafter	$ 591		$ 591