Basis of Presentation - Statements of Operations Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Other Revenue
Revenue from sales	$ 571	$ 1,093	$ 1,591	$ 2,145
Production Expense
Lease Operating Expense	98	122	236	273
Production and Ad Valorem Taxes	24	41	63	90
Gathering, Transportation and Processing Expense	89	96	184	198
Total	214	260	490	565
Exploration Expense
Leasehold impairment	3	0	1,488	0
Seismic, Staffing Expense and Other	12	33	31	57
Total	15	33	1,519	57
Other Operating Expense, Net
Finance lease right-of use asset impairment	0	0	40	0
Marketing Expense	10	14	19	19
Firm Transportation Exit Cost	0	0	0	92
Corporate Restructuring	30	1	30	1
Other, Net	33	7	28	27
Total	73	22	117	139
Other Revenue
Other Revenue
Revenue from sales	29	36	30	77
Income (Loss) from Equity Method Investments and Other
Other Revenue
Revenue from sales	3	16	(21)	33
Midstream Services Revenues – Third Party
Other Revenue
Revenue from sales	26	20	51	44
Other Royalty Expense
Production Expense
Other Royalty Expense	$ 3	$ 1	$ 7	$ 4