Derivative Instruments and Hedging Activities (Details Textuals) (USD $)	6 Months Ended
Jun. 30, 2011
Derivative Instruments and Hedging Activities (Textuals)
Number of counterparties	19
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 loss included in accumulated other comprehensive income (loss), before tax applied to next twelve months	77,000,000
Net loss included in accumulated other comprehensive income (loss), after tax applied to next twelve months	$ 52,000,000

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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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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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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