Share-Based Compensation - Liability-Classified Compensation Table (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	May 05, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 18
Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense		$ 0	$ 0	$ (4)	$ 12
Performance Share Units | General and administrative expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense		0	(1)	(3)	7
Performance Share Units | Oil and natural gas properties
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense		0	1	0	2
Performance Share Units | Oil, natural gas and NGL production expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense		0	0	(1)	3
Performance Share Units | Exploration expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense		$ 0	$ 0	$ 0	$ 0