Capitalized Exploratory Well Costs and Undeveloped Leasehold Costs - Aging of Exploratory Well Costs for Greater than One Year (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]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	$ 258	$ 348	$ 510
Dalit (Offshore Israel)
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	23
Cyprus (Offshore Cyprus)
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	100
Felicita (Block O, Offshore Equatorial Guinea)
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	49
YoYo (YoYo Block, Offshore Cameroon) and Yolanda (Block I, Offshore Equatorial Guinea)
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	80
Projects less than $20 million
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	6
Suspended Since 2017 and 2018
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	(3)
Suspended Since 2017 and 2018 | Dalit (Offshore Israel)
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	(9)
Suspended Since 2017 and 2018 | Cyprus (Offshore Cyprus)
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	3
Suspended Since 2017 and 2018 | Felicita (Block O, Offshore Equatorial Guinea)
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	2
Suspended Since 2017 and 2018 | YoYo (YoYo Block, Offshore Cameroon) and Yolanda (Block I, Offshore Equatorial Guinea)
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	2
Suspended Since 2017 and 2018 | Projects less than $20 million
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	(1)
Suspended Since 2015 and 2016
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	17
Suspended Since 2015 and 2016 | Dalit (Offshore Israel)
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	3
Suspended Since 2015 and 2016 | Cyprus (Offshore Cyprus)
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	15
Suspended Since 2015 and 2016 | Felicita (Block O, Offshore Equatorial Guinea)
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	4
Suspended Since 2015 and 2016 | YoYo (YoYo Block, Offshore Cameroon) and Yolanda (Block I, Offshore Equatorial Guinea)
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	5
Suspended Since 2015 and 2016 | Projects less than $20 million
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	(10)
Suspended Since 2014 and Prior
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	244
Suspended Since 2014 and Prior | Dalit (Offshore Israel)
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	29
Suspended Since 2014 and Prior | Cyprus (Offshore Cyprus)
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	82
Suspended Since 2014 and Prior | Felicita (Block O, Offshore Equatorial Guinea)
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	43
Suspended Since 2014 and Prior | YoYo (YoYo Block, Offshore Cameroon) and Yolanda (Block I, Offshore Equatorial Guinea)
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	73
Suspended Since 2014 and Prior | Projects less than $20 million
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling	$ 17