Price Risk Management Activities, Hedging Instruments by Consolidated Balance Sheet Location (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Fair Values of Derivative Instruments
Total derivatives assets, net	$ 537	$ 1,215
Total derivative liabilities, net	529	1,209
Designated as Hedging Instrument [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset		94
Derivative liability, fair value, gross liability		79
Designated as Hedging Instrument [Member] | Future [Member] | Commodity Contract [Member] | Trade Accounts Receivable [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	25	77
Derivative asset, fair value, gross liability	36	64
Designated as Hedging Instrument [Member] | Swap [Member] | Commodity Contract [Member] | Trade Accounts Receivable [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset		15
Derivative asset, fair value, gross liability		13
Designated as Hedging Instrument [Member] | Swap [Member] | Commodity Contract [Member] | Prepaid Expenses And Other [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset		2
Derivative asset, fair value, gross liability		2
Not Designated as Hedging Instrument [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	512	1,121
Derivative liability, fair value, gross liability	493	1,130
Not Designated as Hedging Instrument [Member] | Future [Member] | Commodity Contract [Member] | Trade Accounts Receivable [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	474	1,066
Derivative asset, fair value, gross liability	455	1,073
Not Designated as Hedging Instrument [Member] | Swap [Member] | Commodity Contract [Member] | Trade Accounts Receivable [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	33	9
Derivative asset, fair value, gross liability	18	6
Not Designated as Hedging Instrument [Member] | Swap [Member] | Commodity Contract [Member] | Prepaid Expenses And Other [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	3
Derivative asset, fair value, gross liability	0
Not Designated as Hedging Instrument [Member] | Swap [Member] | Commodity Contract [Member] | Accrued Expenses [Member]
Fair Values of Derivative Instruments
Derivative liability, fair value, gross asset	0	32
Derivative liability, fair value, gross liability	5	46
Not Designated as Hedging Instrument [Member] | Options Held [Member] | Commodity Contract [Member] | Trade Accounts Receivable [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	2	1
Derivative asset, fair value, gross liability	2	4
Not Designated as Hedging Instrument [Member] | Options Held [Member] | Commodity Contract [Member] | Accrued Expenses [Member]
Fair Values of Derivative Instruments
Derivative liability, fair value, gross asset		1
Derivative liability, fair value, gross liability		0
Not Designated as Hedging Instrument [Member] | Forward Contracts [Member] | Physical Purchase Contracts [Member] | Inventories [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	0	11
Derivative asset, fair value, gross liability	5	0
Not Designated as Hedging Instrument [Member] | Forward Contracts [Member] | Foreign Currency Contract [Member] | Trade Accounts Receivable [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset		1
Derivative asset, fair value, gross liability		0
Not Designated as Hedging Instrument [Member] | Forward Contracts [Member] | Foreign Currency Contract [Member] | Accrued Expenses [Member]
Fair Values of Derivative Instruments
Derivative liability, fair value, gross asset	0	0
Derivative liability, fair value, gross liability	$ 8	$ 1