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Financial Instruments (Realized And Unrealized Gains (Losses) On Financial Instruments) (Details) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | ||
|---|---|---|---|
|
Dec. 31, 2011
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Dec. 31, 2010
|
Dec. 31, 2009
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| Realized and unrealized gains on financial instruments, net (note 8) | $ 84 | $ 62 | $ (589) |