Basis of Presentation - Balance Sheet Information (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Accounts Receivable, Net
Commodity Sales	$ 346	$ 383
Joint Interest Billings	153	137
Other	91	111
Allowance for Doubtful Accounts	(15)	(15)
Total	575	616
Other Current Assets
Commodity Derivative Assets	30	180
Inventories, Materials and Supplies	68	55
Assets Held for Sale	0	133
Restricted Cash	132	3	$ 0	$ 38
Prepaid Expenses and Other Current Assets	83	47
Total	313	418
Other Noncurrent Assets
Equity Method Investments	699	286
Operating Lease Right of Use Assets	272	0
Customer-Related Intangible Assets, Net	294	310
Goodwill	110	110
Other Assets, Noncurrent	141	135
Total	1,516	841
Other Current Liabilities
Production and Ad Valorem Taxes	132	103
Asset Retirement Obligations	85	118
Interest Payable	64	66
Operating Lease Liabilities	88	0
Commercial Paper Borrowings	240	0
Partner Advances	132	0
Other Liabilities, Current	257	232
Total	998	519
Other Noncurrent Liabilities
Deferred Compensation Liabilities	147	147
Asset Retirement Obligations	707	762
Operating Lease Liabilities	190	0
Firm Transportation Exit Cost Accrual	144	67
Production and Ad Valorem Taxes	24	83
Other Liabilities, Noncurrent	95	106
Total	1,307	1,165
Accumulated amortization	46	$ 30
EPIC Investments | Noble Midstream
Other Noncurrent Assets
Equity Method Investments	369
Delaware Crossing JV | Noble Midstream
Other Noncurrent Assets
Equity Method Investments	$ 39