Suspended Wells - Aging of suspended well balances (Details) |
Dec. 31, 2019
USD ($)
|
Dec. 31, 2018
USD ($)
|
Dec. 31, 2017
USD ($)
|
Dec. 31, 2016
USD ($)
|
|---|---|---|---|---|
| Aging of suspended well cost | ||||
| Exploratory well costs capitalized for a period of one year or less | $ 206,000,000 | $ 145,000,000 | $ 67,000,000 | |
| Exploratory well costs capitalized for a period greater than one year | 814,000,000 | 711,000,000 | 786,000,000 | |
| Ending balance | $ 1,020,000,000 | $ 856,000,000 | $ 853,000,000 | $ 1,063,000,000 |
| Number of projects that have exploratory well costs that have been capitalized for a period greater than one year | 23 | 24 | 23 |