Accounting For Suspended Exploratory Well Costs (Narrative) (Details) $ in Millions |
12 Months Ended | |||
|---|---|---|---|---|
|
Dec. 31, 2015
USD ($)
|
Dec. 31, 2014
USD ($)
|
Dec. 31, 2013
USD ($)
|
Dec. 31, 2012
USD ($)
|
|
| Exploratory Wells Drilled [Line Items] | ||||
| Number of projects that have exploratory well costs capitalized for a period greater than twelve months as of December 31, 2015 | 55 | 53 | 50 | |
| Number of projects that have drilling in the preceding twelve months or exploratory activity either planned in the next two years or subject to sanctions as of December 31, 2015 | 18 | |||
| Number of projects with completed exploratory activity progressing toward development as of December 31, 2015 | 37 | |||
| Capitalized exploratory well costs | $ 4,372 | $ 3,587 | $ 2,707 | $ 2,679 |
| Total 37 Projects [Member] | ||||
| Exploratory Wells Drilled [Line Items] | ||||
| Capitalized exploratory well costs | $ 1,154 | |||