Acquisitions (Pro-Forma Information) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Acquisitions [Abstract]
Revenue	$ 3,099	$ 3,061	$ 6,237	$ 6,153
Income from continuing operations	404	344	817	701
Net income attributable to the Company	$ 391	$ 334	$ 806	$ 684
Basic net income per share - Continuing operations (in dollars per share)	$ 0.72	$ 0.62	$ 1.45	$ 1.26
Basic net income per share - Net income attributable to the Company (in dollars per share)	$ 0.71	$ 0.61	$ 1.47	$ 1.25
Diluted net income per share - Continuing operations (in dollars per share)	$ 0.71	$ 0.61	$ 1.43	$ 1.24
Diluted net income per share - Net income attributable to the Company (in dollars per share)	$ 0.70	$ 0.60	$ 1.44	$ 1.24

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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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