| **Derivative Instruments and Hedging Activities (Details 3) (USD $)In Millions, unless otherwise specified**                                                                                                                                                                    | 12 Months Ended |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|
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| **Derivative Instruments, Gain (Loss) [Line Items]**                                                                                                                                                                                                                            |            |   |   |  |
| Amount of (Gain) Loss on Derivative Instruments Recognized in Other Comprehensive (Income) Loss                                                                                                                                                                                 | $ 0             | $ (23) | $ 63 |  |
| Amount of (Gain) Loss on Derivative Instruments Reclassified from Accumulated Other Comprehensive (Income) Loss                                                                                                                                                                 | 1               | 1 | 21 |  |
| Crude Oil                                                                                                                                                                                                                                                                       |            |   |   |  |
| **Derivative Instruments, Gain (Loss) [Line Items]**                                                                                                                                                                                                                            |            |   |   |  |
| Amount of (Gain) Loss on Derivative Instruments Recognized in Other Comprehensive (Income) Loss                                                                                                                                                                                 | 0               | 0 | 0 |  |
| Amount of (Gain) Loss on Derivative Instruments Reclassified from Accumulated Other Comprehensive (Income) Loss                                                                                                                                                                 | 0               | 0 | 19 | [1] |
| Natural Gas                                                                                                                                                                                                                                                                     |            |   |   |  |
| **Derivative Instruments, Gain (Loss) [Line Items]**                                                                                                                                                                                                                            |            |   |   |  |
| Amount of (Gain) Loss on Derivative Instruments Recognized in Other Comprehensive (Income) Loss                                                                                                                                                                                 | 0               | 0 | 0 |  |
| Amount of (Gain) Loss on Derivative Instruments Reclassified from Accumulated Other Comprehensive (Income) Loss                                                                                                                                                                 | 0               | 0 | 1 | [1] |
| Interest Rate Derivative Instruments in Cash Flow Hedging Relationships                                                                                                                                                                                                         |            |   |   |  |
| **Derivative Instruments, Gain (Loss) [Line Items]**                                                                                                                                                                                                                            |            |   |   |  |
| Amount of (Gain) Loss on Derivative Instruments Recognized in Other Comprehensive (Income) Loss                                                                                                                                                                                 | 0               | (23) | 63 |  |
| Amount of (Gain) Loss on Derivative Instruments Reclassified from Accumulated Other Comprehensive (Income) Loss                                                                                                                                                                 | $ 1             | $ 1 | $ 1 |  |
|                                                                                                                                                                                                                                                                                 |
| [1]Includes effect of commodity derivative instruments previously accounted for as cash flow hedges. All net derivative gains and losses that were deferred in AOCL as a result of previous cash flow hedge accounting, had been reclassified to earnings by December 31, 2010. |

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| - Definition
The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44C -Subparagraph b -Clause 4 -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 133 -Paragraph 205G -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 -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624171-113959Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4D -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624177-113959
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| - Definition
The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 205G -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 Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624171-113959Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44C -Subparagraph b -Clause 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.
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