Price Risk Management Activities (Details) (USD $) In Millions, unless otherwise specified							3 Months Ended																																																		3 Months Ended
	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2012 Refining Industry [Member]	Dec. 31, 2011 Refining Industry [Member]	Mar. 31, 2012 Financial Services Industry [Member]	Dec. 31, 2011 Financial Services Industry [Member]	Mar. 31, 2012 Interest Rate Swap [Member]	Mar. 31, 2011 Interest Rate Swap [Member]	Mar. 31, 2012 Forward Contracts [Member]	Mar. 31, 2012 Fair Value Hedging [Member] Future [Member] Purchases (Long) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Fair Value Hedging [Member] Future [Member] Sales (Short) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Fair Value Hedging [Member] Forward Contracts [Member] Purchases (Long) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Cash Flow Hedging [Member] Swap [Member] Sales (Short) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Cash Flow Hedging [Member] Future [Member] Purchases (Long) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Cash Flow Hedging [Member] Future [Member] Sales (Short) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Cash Flow Hedging [Member] Forward Contracts [Member] Sales (Short) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Economic Hedging [Member] Swap [Member] Purchases (Long) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Economic Hedging [Member] Swap [Member] Purchases (Long) [Member] Maturity Year Two [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Economic Hedging [Member] Swap [Member] Sales (Short) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Economic Hedging [Member] Swap [Member] Sales (Short) [Member] Maturity Year Two [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Economic Hedging [Member] Future [Member] Purchases (Long) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Economic Hedging [Member] Future [Member] Purchases (Long) [Member] Maturity Current Year [Member] Grain In Bushels [Member] Mbushel	Mar. 31, 2012 Economic Hedging [Member] Future [Member] Purchases (Long) [Member] Maturity Year Two [Member] Emission Allowances [Member] Mg	Mar. 31, 2012 Economic Hedging [Member] Future [Member] Purchases (Long) [Member] Maturity Year Two [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Economic Hedging [Member] Future [Member] Purchases (Long) [Member] Maturity Year Two [Member] Grain In Bushels [Member] Mbushel	Mar. 31, 2012 Economic Hedging [Member] Future [Member] Sales (Short) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Economic Hedging [Member] Future [Member] Sales (Short) [Member] Maturity Current Year [Member] Grain In Bushels [Member] Mbushel	Mar. 31, 2012 Economic Hedging [Member] Future [Member] Sales (Short) [Member] Maturity Year Two [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Economic Hedging [Member] Future [Member] Sales (Short) [Member] Maturity Year Two [Member] Grain In Bushels [Member] Mbushel	Mar. 31, 2012 Economic Hedging [Member] Options Held [Member] Purchases (Long) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Economic Hedging [Member] Options Held [Member] Purchases (Long) [Member] Maturity Year Two [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Economic Hedging [Member] Forward Contracts [Member] Purchases (Long) [Member] Maturity Current Year [Member] Grain In Bushels [Member] Mbushel	Mar. 31, 2012 Economic Hedging [Member] Forward Contracts [Member] Purchases (Long) [Member] Maturity Year Two [Member] Grain In Bushels [Member] Mbushel	Mar. 31, 2012 Trading Derivatives [Member] Swap [Member] Purchases (Long) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Trading Derivatives [Member] Swap [Member] Purchases (Long) [Member] Maturity Current Year [Member] Grain In Bushels [Member] Mbushel	Mar. 31, 2012 Trading Derivatives [Member] Swap [Member] Purchases (Long) [Member] Maturity Year Two [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Trading Derivatives [Member] Swap [Member] Purchases (Long) [Member] Maturity Year Two [Member] Grain In Bushels [Member] Mbushel	Mar. 31, 2012 Trading Derivatives [Member] Swap [Member] Sales (Short) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Trading Derivatives [Member] Swap [Member] Sales (Short) [Member] Maturity Current Year [Member] Grain In Bushels [Member] Mbushel	Mar. 31, 2012 Trading Derivatives [Member] Swap [Member] Sales (Short) [Member] Maturity Year Two [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Trading Derivatives [Member] Swap [Member] Sales (Short) [Member] Maturity Year Two [Member] Grain In Bushels [Member] Mbushel	Mar. 31, 2012 Trading Derivatives [Member] Future [Member] Purchases (Long) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Trading Derivatives [Member] Future [Member] Purchases (Long) [Member] Maturity Current Year [Member] Grain In Bushels [Member] Mbushel	Mar. 31, 2012 Trading Derivatives [Member] Future [Member] Purchases (Long) [Member] Maturity Year Two [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Trading Derivatives [Member] Future [Member] Purchases (Long) [Member] Maturity Year Two [Member] Grain In Bushels [Member] Mbushel	Mar. 31, 2012 Trading Derivatives [Member] Future [Member] Sales (Short) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Trading Derivatives [Member] Future [Member] Sales (Short) [Member] Maturity Current Year [Member] Natural Gas In Btus [Member] BBTU	Mar. 31, 2012 Trading Derivatives [Member] Future [Member] Sales (Short) [Member] Maturity Current Year [Member] Grain In Bushels [Member] Mbushel	Mar. 31, 2012 Trading Derivatives [Member] Future [Member] Sales (Short) [Member] Maturity Year Two [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Trading Derivatives [Member] Future [Member] Sales (Short) [Member] Maturity Year Two [Member] Natural Gas In Btus [Member] BBTU	Mar. 31, 2012 Trading Derivatives [Member] Future [Member] Sales (Short) [Member] Maturity Year Two [Member] Grain In Bushels [Member] Mbushel	Mar. 31, 2012 Trading Derivatives [Member] Options Held [Member] Purchases (Long) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Trading Derivatives [Member] Options Held [Member] Purchases (Long) [Member] Maturity Year Two [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Trading Derivatives [Member] Options Held [Member] Sales (Short) [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Trading Derivatives [Member] Options Held [Member] Sales (Short) [Member] Maturity Year Two [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Purchases (Long) [Member] Cash Flow Hedging [Member] Swap [Member] Maturity Current Year [Member] Crude Oil In Barrels [Member] MBbls	Mar. 31, 2012 Biofuels Blending [Member]	Mar. 31, 2011 Biofuels Blending [Member]	Mar. 31, 2012 Minimum Inventory [Member]	Mar. 31, 2012 Emissions Allowance [Member]
Volume of outstanding contracts
Nonmonetary notional amount of price risk derivatives										10,670,000	33,088,000	22,418,000	5,961,000	34,601,000	32,112,000	2,489,000	51,124,000	0	48,424,000	0	55,939,000	14,670,000	55,000	0	50,000	56,511,000	40,330,000	0	2,180,000	2,000	0	16,759,000	2,121,000	14,799,000	8,795,000	13,070,000	0	14,659,000	9,085,000	13,190,000	0	72,215,000	7,720,000	8,050,000	0	74,651,000	650,000	7,720,000	5,550,000	0	0	2,615,000	0	2,500,000	0	5,961,000
Price Risk Management Activities (Textual)
Compliance program costs																																																									$ 67	$ 56	$ 2	$ 1
Notional amount of interest rate derivatives	0	0
Interest rate derivatives activity							0	0
Notional amount of foreign currency derivative purchase contracts									565
Foreign currency commitments maturity date									April 30, 2012
Net receivables related to derivative instruments from counterparties			$ 1	$ 2	$ 0	$ 0