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Assets and Liabilities with Recurring Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified | Dec. 31, 2012 | Dec. 31, 2011
--- | --- | ---
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Cash equivalents | $ 1,502 | [1] | $ 1,415 | [1]
Margin deposits | 196 | [2] | 140 | [2]
Commodity futures contracts | 385 |  | 1,043 |
Commodity forward contracts | 48 | [3] | 111 | [3]
Interest rate swaps | 4 |  | 10 |
Total assets | 2,135 |  | 2,719 |
Margin deposits held by us posted by our counterparties | 11 | [2],[4] | 34 | [2],[4]
Commodity futures contracts | 424 |  | 899 |
Commodity forward contracts | 26 | [3] | 204 | [3]
Interest rate swaps | 200 |  | 320 |
Total liabilities | 661 |  | 1,457 |
Fair Value, Inputs, Level 1 [Member] |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Cash equivalents | 1,502 | [1] | 1,415 | [1]
Margin deposits | 196 |  | 140 |
Commodity futures contracts | 385 |  | 1,043 |
Commodity forward contracts | 0 | [3] | 0 | [3]
Interest rate swaps | 0 |  | 0 |
Total assets | 2,083 |  | 2,598 |
Margin deposits held by us posted by our counterparties | 11 |  | 34 |
Commodity futures contracts | 424 |  | 899 |
Commodity forward contracts | 0 | [3] | 0 | [3]
Interest rate swaps | 0 |  | 0 |
Total liabilities | 435 |  | 933 |
Fair Value, Inputs, Level 2 [Member] |  |  |  |
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 | 24 | [3] | 74 | [3]
Interest rate swaps | 4 |  | 10 |
Total assets | 28 |  | 84 |
Margin deposits held by us posted by our counterparties | 0 |  | 0 |
Commodity futures contracts | 0 |  | 0 |
Commodity forward contracts | 18 | [3] | 184 | [3]
Interest rate swaps | 200 |  | 320 |
Total liabilities | 218 |  | 504 |
Fair Value, Inputs, Level 3 [Member] |  |  |  |
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 | 24 | [3] | 37 | [3]
Interest rate swaps | 0 |  | 0 |
Total assets | 24 |  | 37 |
Margin deposits held by us posted by our counterparties | 0 |  | 0 |
Commodity futures contracts | 0 |  | 0 |
Commodity forward contracts | 8 | [3] | 20 | [3]
Interest rate swaps | 0 |  | 0 |
Total liabilities | $ 8 |  | $ 20 |
[1] | As of December 31, 2012 and 2011, we had cash equivalents of $1,274 million and $1,249 million included in cash and cash equivalents and $228 million and $166 million included in restricted cash, respectively.
[2] | Balances are subject to master netting arrangements and presented on a gross basis on our Consolidated Balance Sheets. We do not offset fair value amounts recognized for derivative instruments executed with the same counterparty under a master netting arrangement for financial statement presentation.
[3] | Includes OTC swaps and options.
[4] | Included in other current liabilities on our Consolidated Balance Sheets.

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- Definition This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258 + Details
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- Definition This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Company may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 8 -Footnote 2 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 7, 8, 9, 10 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Cash -URI http://asc.fasb.org/extlink&oid=6506951 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Cash Equivalents -URI http://asc.fasb.org/extlink&oid=6507016 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 7 -Footnote 1 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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- Definition The amount of the obligation to return cash collateral under master netting arrangements that have not been offset against net derivative instrument positions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41678-113959 + Details
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