Supplemental Disclosures to the Consolidated Statements of Cash Flows (Additional Information Concerning Acquisitions, Interest And Income Taxes Paid) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Supplemental Cash Flow Information [Abstract]
Assets acquired, excluding cash	$ 576	$ 107
Liabilities assumed	(74)	(4)
Contingent/deferred purchase consideration	(90)	(26)
Net cash outflow for acquisitions	412	77
Interest paid	92	86
Income taxes paid, net of refunds	$ 297	$ 303