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Accrued Expenses and Other Long-Term Liabilities, Asset Retirement Obligations (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Asset Retirement Obligations Rollforward Analysis
Balance as of beginning of year	$ 87	$ 101	$ 179
Additions to accrual	28	4	3
Reductions to accrual	(1)	0	(34)
Accretion expense	5	4	7
Settlements	(11)	(22)	(54)
Balance as of end of year	$ 108	$ 87	$ 101
Retail Location [Member]
Asset Retirement Obligations (Textual)
Property, plant and equipment, useful life	20 years

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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- Definition

Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.

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