Supplemental Disclosures (Schedule of Supplemental Cash Flow Disclosures) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental Cash Flow Information [Abstract]
Assets acquired, excluding cash	$ 815	$ 217	$ 380
Released from escrow in 2012	0	0	(62)
Liabilities assumed	(64)	(53)	(42)
Contingent/deferred purchase consideration	(197)	(39)	(46)
Net cash outflow for current year acquisitions	554	125	230
Purchase of other intangibles	0	2	3
Net cash outflow for acquisitions	554	127	233
Interest paid	172us-gaap_InterestPaid	170us-gaap_InterestPaid	183us-gaap_InterestPaid
Income taxes paid, net of refunds	$ 426us-gaap_IncomeTaxesPaidNet	$ 360us-gaap_IncomeTaxesPaidNet	$ 350us-gaap_IncomeTaxesPaidNet

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Payments to Acquire Businesses, Net of Cash Acquired, Before Payments for Previous Acquisition

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Amount of liabilities incurred by the acquirer as part of consideration transferred in a business combination.

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