Acquisitions (Pro-Forma Information) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2010	Sep. 30, 2012	Sep. 30, 2011
Acquisitions [Abstract]
Revenue	$ 2,848	$ 2,850	$ 8,946	$ 8,762
Income from continuing operations	247	133	943	738
Net income attributable to the Company	$ 242	$ 130	$ 921	$ 737
Basic net income per share - Continuing operations (in dollars per share)	$ 0.44	$ 0.24	$ 1.69	$ 1.32
Basic net income per share - Net income attributable to the Company (in dollars per share)	$ 0.44	$ 0.24	$ 1.69	$ 1.35
Diluted net income per share - Continuing operations (in dollars per share)	$ 0.44	$ 0.23	$ 1.67	$ 1.30
Diluted net income per share - Net income attributable to the Company (in dollars per share)	$ 0.44	$ 0.24	$ 1.66	$ 1.33

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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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