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, 2016	Jun. 30, 2015
Supplemental Cash Flow Information [Abstract]
Assets acquired, excluding cash	$ 107	$ 338
Liabilities assumed	(4)	(12)
Contingent/deferred purchase consideration	(26)	(95)
Net cash outflow for current year acquisitions	77	231
Cash paid into escrow for future acquisition	0	29
Net cash outflow for acquisitions	77	260
Interest paid	86	69
Income taxes paid, net of refunds	$ 303	$ 223