Impairments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Property, Plant and Equipment [Line Items]
Fair value of proved properties	$ 910
Fair value of unproved properties	530
Asset impairment charges	4,100
Pre-tax Impairment	2,703
Goodwill impairment	110	$ 0
Finance Lease Right-of-Use Asset Impairment	40	$ 0
Leasehold Impairment
Property, Plant and Equipment [Line Items]
Net Book Value	2,015
Pre-tax Impairment	1,485
Delaware Basin | Leasehold Impairment
Property, Plant and Equipment [Line Items]
Net Book Value	1,915
Pre-tax Impairment	1,385
Eagle Ford Shale | Leasehold Impairment
Property, Plant and Equipment [Line Items]
Net Book Value	100
Pre-tax Impairment	100
Goodwill
Property, Plant and Equipment [Line Items]
Net Book Value	110
Goodwill impairment	110
Finance Lease Right-of-Use Asset Impairment
Property, Plant and Equipment [Line Items]
Net Book Value	88
Finance Lease Right-of-Use Asset Impairment	40
Non-controlling Interests
Property, Plant and Equipment [Line Items]
Goodwill impairment	72
Non-controlling Interests | Goodwill
Property, Plant and Equipment [Line Items]
Pre-tax Impairment	72
Parent Company | Goodwill
Property, Plant and Equipment [Line Items]
Pre-tax Impairment	$ 38