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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Fair Value Measurements, Nonrecurring (Details) (USD $) In Millions, unless otherwise specified					1 Months Ended						1 Months Ended	3 Months Ended	1 Months Ended	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Fair Value, Measurements, Nonrecurring [Member]	Mar. 31, 2012 Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2012 Aruba Refinery [Member]	Mar. 31, 2012 Aruba Refinery [Member]	Mar. 31, 2012 Aruba Refinery [Member] Fair Value, Measurements, Nonrecurring [Member]	Mar. 31, 2012 Aruba Refinery [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]	Mar. 31, 2012 Aruba Refinery [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]	Mar. 31, 2012 Aruba Refinery [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]	Sep. 30, 2012 Refining Assets [Member]	Mar. 31, 2012 Refining Assets [Member]	Mar. 31, 2012 Construction in Progress [Member]	Mar. 31, 2012 Construction in Progress [Member]	Mar. 31, 2012 Construction in Progress [Member] Fair Value, Measurements, Nonrecurring [Member]	Mar. 31, 2012 Construction in Progress [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]	Mar. 31, 2012 Construction in Progress [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]	Mar. 31, 2012 Construction in Progress [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]
Assets:
Long-lived assets, fair value						$ 350	$ 350	$ 0	$ 0	$ 350					$ 2	$ 0	$ 0	$ 2
Asset impairment loss					333	595					308	595	16	16
Fair Value Measurements (Textual)
Long-lived assets, carrying value	26,398	26,300				945
Assets, nonrecurring			0
Liabilities, nonrecurring			$ 0	$ 0