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Assets and Liabilities with Recurring Fair Value Measurements Fair Value Hierarchy (Details) (USD $)
In Millions, unless otherwise specified |
Sep. 30, 2014
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Dec. 31, 2013
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|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||||||||||||
| Cash equivalents | $ 1,753 | [1] | $ 1,134 | [1] | ||||||||
| Margin deposits | 177 | [2] | 261 | [2] | ||||||||
| Commodity futures contracts | 649 | 434 | ||||||||||
| Commodity forward contracts | 190 | [3] | 107 | [3] | ||||||||
| Interest Rate Swap Assets, Fair Value Disclosure | 5 | 9 | ||||||||||
| Total assets | 2,774 | 1,945 | ||||||||||
| Margin deposits held by us posted by our counterparties | 67 | [2],[4] | 5 | [2],[4] | ||||||||
| Commodity futures contracts | 575 | 495 | ||||||||||
| Commodity forward contracts | 141 | [3] | 70 | [3] | ||||||||
| Interest rate swaps | 113 | 129 | ||||||||||
| Liabilities, Fair Value Disclosure | 896 | 699 | ||||||||||
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Fair Value, Inputs, Level 1 [Member]
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| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||||||||||||
| Cash equivalents | 1,753 | [1] | 1,134 | [1] | ||||||||
| Margin deposits | 177 | 261 | ||||||||||
| Commodity futures contracts | 649 | 434 | ||||||||||
| Commodity forward contracts | 0 | [3] | 0 | [3] | ||||||||
| Interest Rate Swap Assets, Fair Value Disclosure | 0 | 0 | ||||||||||
| Total assets | 2,579 | 1,829 | ||||||||||
| Margin deposits held by us posted by our counterparties | 67 | 5 | ||||||||||
| Commodity futures contracts | 575 | 495 | ||||||||||
| Commodity forward contracts | 0 | [3] | 0 | [3] | ||||||||
| Interest rate swaps | 0 | 0 | ||||||||||
| Liabilities, Fair Value Disclosure | 642 | 500 | ||||||||||
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Fair Value, Inputs, Level 2 [Member]
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| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||||||||||||
| Cash equivalents | 0 | [1] | 0 | [1] | ||||||||
| Margin deposits | 0 | 0 | ||||||||||
| Commodity futures contracts | 0 | 0 | ||||||||||
| Commodity forward contracts | 132 | [3] | 75 | [3] | ||||||||
| Interest Rate Swap Assets, Fair Value Disclosure | 5 | 9 | ||||||||||
| Total assets | 137 | 84 | ||||||||||
| Margin deposits held by us posted by our counterparties | 0 | 0 | ||||||||||
| Commodity futures contracts | 0 | 0 | ||||||||||
| Commodity forward contracts | 94 | [3] | 52 | [3] | ||||||||
| Interest rate swaps | 113 | 129 | ||||||||||
| Liabilities, Fair Value Disclosure | 207 | 181 | ||||||||||
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Fair Value, Inputs, Level 3 [Member]
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| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||||||||||||
| Cash equivalents | 0 | [1] | 0 | [1] | ||||||||
| Margin deposits | 0 | 0 | ||||||||||
| Commodity futures contracts | 0 | 0 | ||||||||||
| Commodity forward contracts | 58 | [3] | 32 | [3] | ||||||||
| Interest Rate Swap Assets, Fair Value Disclosure | 0 | 0 | ||||||||||
| Total assets | 58 | 32 | ||||||||||
| Margin deposits held by us posted by our counterparties | 0 | 0 | ||||||||||
| Commodity futures contracts | 0 | 0 | ||||||||||
| Commodity forward contracts | 47 | [3] | 18 | [3] | ||||||||
| Interest rate swaps | 0 | 0 | ||||||||||
| Liabilities, Fair Value Disclosure | $ 47 | $ 18 | ||||||||||
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