Summary of Goodwill Activity (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010
Goodwill [Line Items]
Beginning balance	$ 1,349		$ 1,234
New acquisitions	615		111
Other adjustments	(9)	[1]	4	[1]
Ending balance	1,955		1,349
North America
Goodwill [Line Items]
Beginning balance	1,116		1,055
New acquisitions	417		60
Other adjustments			1	[1]
Ending balance	1,533		1,116
International
Goodwill [Line Items]
Beginning balance	233		179
New acquisitions	198		51
Other adjustments	(9)	[1]	3	[1]
Ending balance	$ 422		$ 233

[1] Primarily includes changes in foreign exchange for goodwill in our International segment.