Acquisitions / Dispositions (Pro-Forma Information) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Combinations [Abstract]
Revenue	$ 13,185	$ 13,395	$ 12,550
Income from continuing operations	1,676	1,475	1,395
Net income attributable to the Company	$ 1,639	$ 1,469	$ 1,373
Basic net income per share:
Basic net income per share - Continuing operations (in dollars per share)	$ 3.09	$ 2.65	$ 2.49
Basic net income per share - Net income attributable to the Company (in dollars per share)	3.09	2.69	2.50
Diluted net income per share:
Diluted net income per share - Continuing operations (in dollars per share)	3.05	2.61	2.45
Diluted net income per share - Net income attributable to the Company (in dollars per share)	$ 3.05	$ 2.66	$ 2.46