Inventories (Details) (USD $)	Mar. 31, 2012	Dec. 31, 2011
Schedule of Inventories
Refinery feedstocks	$ 2,730,000,000	$ 2,474,000,000
Refined products and blendstocks	2,862,000,000	2,633,000,000
Ethanol feedstocks and products	236,000,000	195,000,000
Convenience store merchandise	98,000,000	103,000,000
Materials and supplies	219,000,000	218,000,000
Inventories	6,145,000,000	5,623,000,000
Inventories (Textual)
Excess of market value over carrying amount of LIFO inventories	$ 8,700,000,000	$ 6,800,000,000