|
Derivative and Financial Instruments - Commodity Balance Sheet (Details) (USD $)
In Millions, unless otherwise specified |
Mar. 31, 2013
|
Mar. 31, 2012
|
|---|---|---|
|
Prepaid expenses and other current assets [Member]
|
||
| Derivatives, Fair Value [Line Items] | ||
| Commodity derivative assets | $ 1,402 | $ 1,538 |
|
Other assets [Member]
|
||
| Derivatives, Fair Value [Line Items] | ||
| Commodity derivative assets | 98 | 105 |
|
Other accruals [Member]
|
||
| Derivatives, Fair Value [Line Items] | ||
| Commodity derivative liabilities | 1,461 | 1,509 |
|
Other liabilities and deferred credits [Member]
|
||
| Derivatives, Fair Value [Line Items] | ||
| Commodity derivative liabilities | $ 94 | $ 99 |