Acquisitions (Pro-Forma Information) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2012	Mar. 31, 2011
Acquisitions [Abstract]
Revenue	$ 3,058	$ 2,929
Income from continuing operations	355	315
Net income attributable to the Company	$ 348	$ 321
Basic net income per share - Continuing operations (in dollars per share)	$ 0.64	$ 0.56
Basic net income per share - Net income attributable to the Company (in dollars per share)	$ 0.64	$ 0.59
Diluted net income per share - Continuing operations (in dollars per share)	$ 0.63	$ 0.56
Diluted net income per share - Net income attributable to the Company (in dollars per share)	$ 0.63	$ 0.58

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The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

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