Accounting for Suspended Exploratory Wells (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($)
Accounting for Suspended Exploratory Wells [Abstract]
Capitalized cost of exploratory wells	$ 2,500
Decrease in capitalized cost of suspended wells from the prior year end	(574)
Capitalized exploratory well cost, charged to expense	$ 496