Derivative Instruments and Hedging Activities (Details Textuals) (USD $)	9 Months Ended
Sep. 30, 2011 bbl Counterparty Country
Derivative Instruments and Hedging Activities (Textuals)
Number of counterparties	20
Number of barrels to be delivered as per contract	20,000
Floor price of oil, Dated Brent	$ 70
Average ceiling price	98.56
Realization of gains and losses on hedges in future earnings	mid 2014
Net gain included in accumulated other comprehensive income (loss), before tax applied to next twelve months	213,000,000
Net gain included in accumulated other comprehensive income (loss), after tax applied to next twelve months	$ 146,000,000

Derivative instruments and hedging activities.

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Net loss included in accumulated other comprehensive income (loss) after tax.

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Net loss included in accumulated other comprehensive income (loss) before tax.

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Number of barrels to be delivered as per contract.

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Number of counterparties.

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- Definition

Realization of gains and losses on hedges in future earnings.

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- Definition

The average cap rate on a group of price risk derivatives such as caps or collars. A payment or receipt is triggered if the market rate exceeds the cap rate on the contract.

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- Definition

Floor rate on a price risk derivative such as a floor or a collar. A payment or receipt is triggered if the market rate falls below the floor rate on the contract.

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