Acquisitions/Dispositions (Pro-Forma Information) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Combinations [Abstract]
Revenue	$ 15,174	$ 14,440	$ 13,724
Income from continuing operations	1,680	1,516	1,787
Net income attributable to the Company	$ 1,660	$ 1,498	$ 1,759
Basic net income per share:
Basic net income per share - Continuing operations (in dollars per share)	$ 3.28	$ 2.92	$ 3.39
Basic net income per share - Net income attributable to the Company (in dollars per share)	3.28	2.92	3.39
Diluted net income per share:
Diluted net income per share - Continuing operations (in dollars per share)	3.25	2.88	3.36
Diluted net income per share - Net income attributable to the Company (in dollars per share)	$ 3.25	$ 2.89	$ 3.36
Business Acquisition [Line Items]
Revenue related to acquisitions		$ 156	$ 25
Net operating income related to acquisitions		19	$ 4
Acquisition related costs	$ 7	$ 3
Current Fiscal Period Acquisitions
Business Acquisition [Line Items]
Revenue related to acquisitions	120
Net operating income related to acquisitions	$ 2

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Business Acquisition, Pro Forma Earnings Per Share, Diluted [Abstract]

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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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