Acquisitions and Dispositions (Pro-Forma Information) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Business Combinations [Abstract]
Revenue	$ 4,346	$ 4,339	$ 8,863	$ 8,902
Net income attributable to the Company	$ 463	$ 513	$ 1,134	$ 626
Basic net income per share:
Basic net income per share attributable to the Company (in dollars per share)	$ 0.91	$ 1.01	$ 2.24	$ 1.23
Diluted net income per share:
Diluted net income per share attributable to the Company (in dollars per share)	$ 0.90	$ 1.00	$ 2.22	$ 1.22