Supplemental Disclosures to the Consolidated Statements of Cash Flows (Additional Information Concerning Acquisitions, Interest And Income Taxes Paid) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Supplemental Cash Flow Information [Abstract]
Assets acquired, excluding cash	$ 852	$ 121
Liabilities assumed	(129)	(4)
Contingent/deferred purchase consideration	(94)	(29)
Net cash outflow for current year acquisitions	629	88
Interest paid	174	148
Income taxes paid, net of refunds	$ 406	$ 417