|
Divestitures (Details) (USD $)
In Millions, unless otherwise specified |
3 Months Ended | |
|---|---|---|
|
Mar. 31, 2013
acre
|
Mar. 31, 2012
|
|
| Divestitures [Abstract] | ||
| Proceeds received on sale of Canadian shallow gas assets | $ 480 | |
| Estimated Acreage From Sales of Producing Properties And Acreage | 28,500 | |
| Proceeds from Sales of Producing Properties and Acreage | $ 450 | |