The charge against earnings resulting from the aggregate write down of all assets from their carrying value to their fair value.

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Carrying amount (lower of cost or market) as of the balance sheet date of inventories less all valuation and other allowances. Excludes noncurrent inventory balances (expected to remain on hand past one year or one operating cycle, if longer).

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Fair Value Measurements, Nonrecurring (Details) (USD $) In Millions, unless otherwise specified					1 Months Ended		12 Months Ended					1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended							12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2011 Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2012 Aruba Refinery [Member]	Mar. 31, 2012 Aruba Refinery [Member]	Dec. 31, 2012 Aruba Refinery [Member]	Dec. 31, 2012 Aruba Refinery [Member] Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2012 Aruba Refinery [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2012 Aruba Refinery [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2012 Aruba Refinery [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]	Sep. 30, 2012 Refining Assets [Member]	Dec. 31, 2012 Refining Assets [Member]	Sep. 30, 2012 Inventory Related Assets [Member]	Dec. 31, 2012 Inventory Related Assets [Member]	Dec. 31, 2012 Construction in Progress [Member]	Dec. 31, 2010 Construction in Progress [Member]	Dec. 31, 2012 Construction in Progress [Member] Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2012 Construction in Progress [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2012 Construction in Progress [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2012 Construction in Progress [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2012 Retail [Member]	Dec. 31, 2012 Retail [Member] Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2012 Retail [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2012 Retail [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2012 Retail [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Long-lived assets, fair value						$ 350		$ 0	$ 0	$ 0	$ 0							$ 2	$ 0	$ 0	$ 2		$ 8	$ 0	$ 0	$ 8
Materials and supplies inventories	5,973	5,623						0	0	0	0
Asset impairment loss					333	595	928					308	903	25	25	65	2					21
Fair Value Measurements (Textual)
Assets, nonrecurring				0
Liabilities, nonrecurring			$ 0	$ 0