Supplemental Disclosures To The Consolidated Statements Of Cash Flows (Additional Information Concerning Acquisitions, Interest And Income Taxes Paid) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Supplemental Cash Flow Information [Abstract]
Assets acquired, excluding cash	$ 93	$ 124
Liabilities Assumed	27
Liabilities assumed	(38)	(21)
Contingent/deferred purchase consideration	13	13
Net cash outflow for current year acquisitions	53	90
Deferred purchase consideration from prior year acquisitions	7	14
Net cash outflow for acquisitions	60	104
Interest paid	65	72
Income taxes (refunded)/paid	$ 79	$ 85