Supplemental Disclosures (Schedule of Supplemental Cash Flow Disclosures) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplemental Cash Flow Information [Abstract]
Assets acquired, excluding cash	$ 8,655	$ 1,100	$ 898
Liabilities assumed	(2,804)	(83)	(134)
Non-controlling interests assumed	(280)	0	0
Contingent/deferred purchase consideration	(66)	(133)	(109)
Net cash outflow for acquisitions	5,505	884	655
Interest paid	427	264	199
Income taxes paid, net of refunds	$ 661	$ 632	$ 583