Price Risk Management Activities, Gain (Loss) by Income Statement Location (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Price Risk Management Activities (Textual)
Accumulated other comprehensive income, cumulative after-tax gains on cash flow hedges	$ 0		$ 0
Fair Value Hedging [Member] \| Commodity Contract [Member] \| Cost of Sales [Member]
Effect of Derivative Instruments on Income and OCI
Gain (loss) recognized in income on derivatives	(16)	(17)	(42)	(38)
Gain recognized in income on hedged item	17	19	42	41
Gain recognized in income on derivatives (ineffective portion)	1	2	0	3
Cash Flow Hedging [Member] \| Commodity Contract [Member]
Effect of Derivative Instruments on Income and OCI
Gain (loss) recognized in OCI on derivatives (effective portion)	(5)	3	(1)	(6)
Cash Flow Hedging [Member] \| Commodity Contract [Member] \| Cost of Sales [Member]
Effect of Derivative Instruments on Income and OCI
Gain (loss) reclassified from accumulated OCI into income (effective portion)	(5)	6	(2)	1
Gain (loss) recognized in income on derivatives (ineffective portion)	0	16	(1)	13
Economic Hedging [Member]
Effect of Derivative Instruments on Income and OCI
Gain (loss) recognized in income on derivatives	397	(98)	242	219
Economic Hedging [Member] \| Commodity Contract [Member] \| Cost of Sales [Member]
Effect of Derivative Instruments on Income and OCI
Gain (loss) recognized in income on derivatives	354	(76)	222	205
Economic Hedging [Member] \| Foreign Currency Contract [Member] \| Cost of Sales [Member]
Effect of Derivative Instruments on Income and OCI
Gain (loss) recognized in income on derivatives	43	(22)	20	14
Trading Derivatives [Member]
Effect of Derivative Instruments on Income and OCI
Gain (loss) recognized in income on derivatives	11	11	14	(4)
Trading Derivatives [Member] \| Commodity Contract [Member] \| Cost of Sales [Member]
Effect of Derivative Instruments on Income and OCI
Gain (loss) recognized in income on derivatives	11	11	14	16
Trading Derivatives [Member] \| RINs Fixed-Price Contracts [Member] \| Cost of Sales [Member]
Effect of Derivative Instruments on Income and OCI
Gain (loss) recognized in income on derivatives	$ 0	$ 0	$ 0	$ (20)

Accumulated change, net of tax, in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges. Includes an entity's share of an equity investee's Increase or Decrease in deferred hedging gains or losses.

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Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

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