Capitalized Exploratory Well Costs and Undeveloped Leasehold Costs - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Undeveloped leasehold costs, net	$ 2,152	$ 2,373	$ 2,922
Domestic
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Undeveloped leasehold costs, net	79
International
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Undeveloped leasehold costs, net	58
Delaware Basin
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Undeveloped leasehold costs, net	1,900
Eagle Ford
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Undeveloped leasehold costs, net	$ 100