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Accounting For Suspended Exploratory Well Costs (Narrative) (Details) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | |||
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Dec. 31, 2011
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Dec. 31, 2010
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Dec. 31, 2009
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Dec. 31, 2008
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| Exploratory Wells Drilled [Line Items] | ||||
| Number of projects that have exploratory well costs capitalized for a period greater than twelve months as of December 31, 2011 | 58 | 59 | 57 | |
| Number of projects that have drilling in the preceding twelve months or exploratory activity planned in the next two years as of December 31, 2011 | 26 | |||
| Number of projects with completed exploratory activity progressing toward development as of December 31, 2011 | 32 | |||
| Capitalized exploratory well costs | $ 2,881 | $ 2,893 | $ 2,005 | $ 1,585 |
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Total 32 Projects [Member]
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| Exploratory Wells Drilled [Line Items] | ||||
| Capitalized exploratory well costs | $ 1,133 | |||