Inventories (Details) (USD $)	12 Months Ended
	Dec. 31, 2009	Dec. 31, 2011	Dec. 31, 2010
Domestic crude oil and refined products		$ 1,273,000,000	$ 954,000,000
Foreign subsidiary crude oil		346,000,000	177,000,000
Materials and supplies		87,000,000	82,000,000
Oxygenates and by-products		43,000,000	30,000,000
Merchandise		14,000,000	14,000,000
Total Inventories		1,763,000,000	1,257,000,000
Excess of replacement or current costs over stated LIFO value		1,700,000,000	1,400,000,000
Effect of LIFO Inventory Liquidation on Income	$ 69,000,000