Goodwill and Other Intangible Assets (Other intangible assets) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended						12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 Non-Compete Agreements [Member] RSC [Member] Months	Jun. 30, 2012 Customer Relationships [Member] RSC [Member] Years	Jun. 30, 2012 Trade Names, Associated Trademarks and Other [Member] RSC [Member] Months	Jun. 30, 2012 Non-Compete Agreements [Member]	Dec. 31, 2011 Non-Compete Agreements [Member]	Jun. 30, 2012 Customer Relationships [Member]	Dec. 31, 2011 Customer Relationships [Member]	Jun. 30, 2012 Trade Names, Associated Trademarks and Other [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-average remaining amortization period								57 months	46 months	14 years	9 years	58 months
Gross carrying amount								$ 77	$ 30	$ 1,229	$ 121	$ 82
Accumulated amortization								26	25	69	43	6
Net amount					45	1,087	77	51	5	1,160	78	76
Weighted-average initial amortization period (in years or months)					60	15	60
Amortization expense	27	1	30	3
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2012			94
2013			177
2014			161
2015			145
2016			130
Thereafter			580
Total			$ 1,287