Price Risk Management Activities, Hedging Instruments by Consolidated Balance Sheet Location (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Fair Values of Derivative Instruments
Total derivative assets, net	$ 2,945	$ 1,980
Total derivative liabilities, net	2,770	1,970
Designated as Hedging Instrument [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	132	300
Derivative liability, fair value, gross liability	130	286
Designated as Hedging Instrument [Member] | Future [Member] | Accrued Expenses [Member]
Fair Values of Derivative Instruments
Derivative liability, fair value, gross asset	2
Derivative liability, fair value, gross liability	1
Designated as Hedging Instrument [Member] | Future [Member] | Trade Accounts Receivable [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	95	264
Derivative asset, fair value, gross liability	95	240
Designated as Hedging Instrument [Member] | Swap [Member] | Accrued Expenses [Member]
Fair Values of Derivative Instruments
Derivative liability, fair value, gross asset	31	36
Derivative liability, fair value, gross liability	32	46
Designated as Hedging Instrument [Member] | Swap [Member] | Trade Accounts Receivable [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	4
Derivative asset, fair value, gross liability	2
Not Designated as Hedging Instrument [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	2,813	1,680
Derivative liability, fair value, gross liability	2,640	1,684
Not Designated as Hedging Instrument [Member] | Future [Member] | Accrued Expenses [Member]
Fair Values of Derivative Instruments
Derivative liability, fair value, gross asset	1,217
Derivative liability, fair value, gross liability	1,141
Not Designated as Hedging Instrument [Member] | Future [Member] | Trade Accounts Receivable [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	1,470	1,636
Derivative asset, fair value, gross liability	1,385	1,624
Not Designated as Hedging Instrument [Member] | Swap [Member] | Accrued Expenses [Member]
Fair Values of Derivative Instruments
Derivative liability, fair value, gross asset	13	38
Derivative liability, fair value, gross liability	20	51
Not Designated as Hedging Instrument [Member] | Swap [Member] | Trade Accounts Receivable [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	45
Derivative asset, fair value, gross liability	46
Not Designated as Hedging Instrument [Member] | Swap [Member] | Prepaid Expenses and Other Current Assets [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	49	4
Derivative asset, fair value, gross liability	42	2
Not Designated as Hedging Instrument [Member] | Commodity Option [Member] | Accrued Expenses [Member]
Fair Values of Derivative Instruments
Derivative liability, fair value, gross asset		0
Derivative liability, fair value, gross liability		2
Not Designated as Hedging Instrument [Member] | Commodity Option [Member] | Trade Accounts Receivable [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	1	2
Derivative asset, fair value, gross liability	1	0
Not Designated as Hedging Instrument [Member] | Forward Contracts [Member] | Inventories [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	18	0
Derivative asset, fair value, gross liability	0	2
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Accrued Expenses [Member]
Fair Values of Derivative Instruments
Derivative liability, fair value, gross asset	0	0
Derivative liability, fair value, gross liability	$ 5	$ 3