Price Risk Management Activities, Hedging Instruments by Consolidated Balance Sheet Location (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair Values of Derivative Instruments
Total derivative assets, net		$ 537
Total derivative liabilities, net		529
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
Derivative asset, fair value, gross liability		36
Not Designated as Hedging Instrument [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	1,384	512
Derivative liability, fair value, gross liability	1,253	493
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	1,334	474
Derivative asset, fair value, gross liability	1,185	455
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	41	33
Derivative asset, fair value, gross liability	49	18
Not Designated as Hedging Instrument [Member] \| Swap [Member] \| Commodity Contract [Member] \| Accrued Liabilities [Member]
Fair Values of Derivative Instruments
Derivative liability, fair value, gross asset	1	0
Derivative liability, fair value, gross liability	1	5
Not Designated as Hedging Instrument [Member] \| Swap [Member] \| Commodity Contract [Member] \| Prepaid Expenses and Other Current Assets [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] \| Options Held [Member] \| Commodity Contract [Member] \| Trade Accounts Receivable [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	0	2
Derivative asset, fair value, gross liability	1	2
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	0
Derivative asset, fair value, gross liability	17	5
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	8
Derivative asset, fair value, gross liability	0
Not Designated as Hedging Instrument [Member] \| Forward Contracts [Member] \| Foreign Currency Contract [Member] \| Accrued Liabilities [Member]
Fair Values of Derivative Instruments
Derivative liability, fair value, gross asset		0
Derivative liability, fair value, gross liability		$ 8

Fair value, after offset of derivative liability, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, after offset of derivative asset, of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, elected not to be and before offset against a right to receive collateral under a master netting arrangement. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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