Price Risk Management Activities, Gain (Loss) by Income Statement Location (Details) (USD $)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Price Risk Management Activities (Textual)
Accumulated other comprehensive income, cumulative after-tax gains on cash flow hedges	$ 0
Fair Value Hedging [Member] \| Commodity Contracts [Member] \| Cost of Sales [Member]
Effect of Derivative Instruments on Income and OCI
Gain (loss) recognized in income on derivatives	0	(31,000,000)
Gain recognized in income on hedged item	0	30,000,000
Loss recognized in income on derivatives (ineffective portion)	0	(1,000,000)
Cash Flow Hedging [Member] \| Commodity Contracts [Member]
Effect of Derivative Instruments on Income and OCI
Gain recognized in OCI on derivatives (effective portion)	0	7,000,000
Cash Flow Hedging [Member] \| Commodity Contracts [Member] \| Cost of Sales [Member]
Effect of Derivative Instruments on Income and OCI
Gain reclassified from accumulated OCI into income (effective portion)	0	3,000,000
Loss recognized in income on derivatives (ineffective portion)	0	(4,000,000)
Economic Hedging [Member] \| Commodity Contracts [Member] \| Cost of Sales [Member]
Effect of Derivative Instruments on Income and OCI
Gain (loss) recognized in income on derivatives	64,000,000	4,000,000
Economic Hedging [Member] \| Foreign Currency Contracts [Member] \| Cost of Sales [Member]
Effect of Derivative Instruments on Income and OCI
Gain (loss) recognized in income on derivatives	22,000,000	9,000,000
Trading Derivatives [Member] \| Commodity Contracts [Member] \| Cost of Sales [Member]
Effect of Derivative Instruments on Income and OCI
Gain (loss) recognized in income on derivatives	$ 20,000,000	$ (1,000,000)

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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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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