Accounting For Suspended Exploratory Well Costs (Schedule Of Number Of Projects With Suspended Exploratory Well Costs) (Details) - Projects |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|---|
| Accounting For Suspended Exploratory Well Costs [Abstract] | |||
| Number of projects that only have exploratory well costs capitalized for a period of one year or less | 4 | 6 | 11 |
| Number of projects that have exploratory well costs capitalized for a period of greater than one year | 46 | 52 | 46 |
| Total | 50 | 58 | 57 |