Acquisitions and Dispositions (Pro-Forma Information) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Business Combinations [Abstract]
Revenue	$ 3,968	$ 4,016	$ 12,859	$ 12,979
Net income attributable to the Company	$ 316	$ 307	$ 1,644	$ 1,453
Basic net income per share attributable to the Company (in dollars per share)	$ 0.62	$ 0.61	$ 3.25	$ 2.87
Diluted net income per share attributable to the Company (in dollars per share)	$ 0.62	$ 0.60	$ 3.22	$ 2.84