Inventories (Details) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Inventory Disclosure [Abstract]
Domestic crude oil and refined products	$ 1,362,000,000	$ 1,273,000,000
Foreign subsidiary crude oil	277,000,000	346,000,000
Materials and supplies	90,000,000	87,000,000
Oxygenates and by-products	36,000,000	43,000,000
Merchandise	16,000,000	14,000,000
Total Inventories	1,781,000,000	1,763,000,000
Excess of replacement or current costs over stated LIFO value	$ 1,500,000,000	$ 1,700,000,000