Other Expense (Schedule of Components of Other Expense) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended			9 Months Ended
	May 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Cost and Reserve [Line Items]
South Texas deficiency fee obligation		$ 0	$ 0		$ 69	$ 0
Idle drilling and well service equipment expense		16	5		69	18
Loss on early extinguishment of debt	$ 23	0	0		27	0
Transportation commitment charges		4	5		12	70
Legal and environmental charges		2	4		7	12
Restructuring charges		74	1		75	159
Asset impairment		0	4		1	34
Accelerated depreciation		0	0		0	23
Vertical integration services (income) loss, net		(2)	1		(1)	19
Asset divestiture-related charges (Note 3)		0	4		0	28
Other		4	8		14	27
Other expense		98	32		273	390
Gross revenues		11	25		36	89
Gross costs and expenses		$ 9	$ 26		35	108
Employee severance
Restructuring Cost and Reserve [Line Items]
Restructuring charges					72	$ 133
Sand mine
Restructuring Cost and Reserve [Line Items]
Accelerated depreciation				$ 12	$ 23