Derivatives (Details 2) (USD $) In Millions	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Commodity Contracts - cash-flow hedges
Unrealized gains (losses) recognized in AOCI	$ 37	$ 10	$ 31	$ 105
Losses reclassified into income	39	28	115	91
(Losses) recognized in income - ineffective portion	(1)	(1)	(1)
Net After-tax Derivative Activity recorded in AOCI
Beginning balance-AOCI	(66)	(127)	(111)	(227)
Unrealized gains (losses) recognized in AOCI	24	7	20	67
Losses reclassified into income	25	18	74	58
Ending balance - AOCI	(17)	(102)	(17)	(102)
Reclassification of net after-tax derivative losses to income during next 12 months			$ 4

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- Definition

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 (decrease) in deferred hedging gains or losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 130

-Paragraph 26

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- Definition

The estimated net amount of existing gains (losses) on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

+ References

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 45

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- Definition

The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

+ References

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

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- Definition

Net of tax effect of the reclassification adjustment for accumulated gains and losses from derivative instrument designated and qualifying as the effective portion of cash flow hedges included in accumulated comprehensive income that was realized in net income during the period.

+ References

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 130

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-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 51

-Paragraph 38

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- Definition

Change in accumulated gains and losses from derivative instrument designated and qualifying as the effective portion of cash flow hedges, net of tax effect. The after tax effect change includes an entity's share of an equity investee's increase (decrease) in deferred hedging gains or losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Name Statement of Financial Accounting Standard (FAS)

-Number 130

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- Definition

The amount of net gains (losses) on price risk cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income.

+ References

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-Name Statement of Financial Accounting Standard (FAS)

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- Definition

Amount of unrealized gain from the increase in fair value of price risk derivatives designated as cash flow hedging instruments recorded in accumulated other comprehensive income in the period, before taxes, to the extent that the cash flow hedge is determined to be effective.

+ References

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