|
Financial Instruments and Derivative Contracts - Assets and Liabilities Accounted for at Fair Value on Recurring Basis (Detail) (USD $)
In Millions, unless otherwise specified |
Dec. 31, 2011
|
Dec. 31, 2010
|
|---|---|---|
| Assets | ||
| Total assets | $ 4,870 | $ 3,298 |
| Liabilities | ||
| Total liabilities | 4,725 | 3,393 |
| Net assets (liabilities) | 145 | (95) |
|
Commodity Contract [Member]
|
||
| Assets | ||
| Total assets | 4,826 | 3,263 |
| Liabilities | ||
| Total liabilities | 4,702 | 3,384 |
|
Interest rate derivatives [Member]
|
||
| Assets | ||
| Total assets | 31 | 20 |
|
Foreign currency exchange derivatives [Member]
|
||
| Assets | ||
| Total assets | 13 | 15 |
| Liabilities | ||
| Total liabilities | 23 | 9 |
|
Level 1 [Member]
|
||
| Assets | ||
| Total assets | 2,807 | 1,456 |
| Liabilities | ||
| Total liabilities | 2,970 | 1,611 |
| Net assets (liabilities) | (163) | (155) |
|
Level 1 [Member] | Commodity Contract [Member]
|
||
| Assets | ||
| Total assets | 2,807 | 1,456 |
| Liabilities | ||
| Total liabilities | 2,970 | 1,611 |
|
Level 2 [Member]
|
||
| Assets | ||
| Total assets | 1,991 | 1,779 |
| Liabilities | ||
| Total liabilities | 1,745 | 1,746 |
| Net assets (liabilities) | 246 | 33 |
|
Level 2 [Member] | Commodity Contract [Member]
|
||
| Assets | ||
| Total assets | 1,947 | 1,744 |
| Liabilities | ||
| Total liabilities | 1,722 | 1,737 |
|
Level 2 [Member] | Interest rate derivatives [Member]
|
||
| Assets | ||
| Total assets | 31 | 20 |
|
Level 2 [Member] | Foreign currency exchange derivatives [Member]
|
||
| Assets | ||
| Total assets | 13 | 15 |
| Liabilities | ||
| Total liabilities | 23 | 9 |
|
Level 3 [Member]
|
||
| Assets | ||
| Total assets | 72 | 63 |
| Liabilities | ||
| Total liabilities | 10 | 36 |
| Net assets (liabilities) | 62 | 27 |
|
Level 3 [Member] | Commodity Contract [Member]
|
||
| Assets | ||
| Total assets | 72 | 63 |
| Liabilities | ||
| Total liabilities | $ 10 | $ 36 |