Acquisitions (Details) (Oakleaf [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Jul. 28, 2011
Adjustments to preliminary purchase price allocation
Accounts and other receivables	$ 71	$ 70
Other current assets	28	28
Property and equipment	72	72
Goodwill	327	327
Other intangible assets	87	87
Accounts payable	(82)	(82)
Accrued liabilities	(48)	(48)
Deferred income taxes, net	(10)	(10)
Other liabilities	(13)	(12)
Total purchase price	432	432	432
Adjustments [Member]
Adjustments to preliminary purchase price allocation
Accounts and other receivables	1
Other current assets
Property and equipment
Goodwill
Other intangible assets
Accounts payable
Accrued liabilities
Deferred income taxes, net
Other liabilities	(1)
Total purchase price