Supplemental Disclosures (Schedule of Supplemental Cash Flow Disclosures) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplemental Cash Flow Information [Abstract]
Assets acquired, excluding cash	$ 1,327	$ 815	$ 217
Liabilities assumed	(199)	(64)	(53)
Contingent/deferred purchase consideration	(176)	(197)	(39)
Net cash outflow for current year acquisitions	952	554	125
Purchase of other intangibles	0	0	2
Net cash outflow for acquisitions	952	554	127
Interest paid	146	172	170
Income taxes paid, net of refunds	$ 433	$ 426	$ 360