Supplemental Disclosures to the Consolidated Statements of Cash Flows (Additional Information Concerning Acquisitions, Interest And Income Taxes Paid) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Supplemental Cash Flow Information [Abstract]
Assets acquired, excluding cash	$ 577	$ 105
Liabilities assumed	(76)	(4)
Contingent/deferred purchase consideration	(90)	(26)
Net cash outflow for acquisitions	411	75
Interest paid	62	58
Income taxes paid, net of refunds	$ 100	$ 187