Basis of Presentation - Balance Sheet Information (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Accounts Receivable, Net
Commodity Sales	$ 384	$ 383
Joint Interest Billings	124	137
Other	80	111
Allowance for Doubtful Accounts	(15)	(15)
Total	573	616
Other Current Assets
Commodity Derivative Assets	9	180
Inventories, Materials and Supplies	70	55
Assets Held for Sale	0	133
Prepaid Expenses and Other Current Assets	63	50
Total	142	418
Other Noncurrent Assets
Equity Method Investments	559	286
Operating Lease Right of Use Assets	273	0
Customer-Related Intangible Assets, Net	302	310
Goodwill	110	110
Other Assets, Noncurrent	132	135
Total	1,376	841
Other Current Liabilities
Production and Ad Valorem Taxes	106	103
Asset Retirement Obligations	118	118
Interest Payable	85	66
Other Liabilities, Current	350	232
Total	659	519
Other Noncurrent Liabilities
Deferred Compensation Liabilities	149	147
Asset Retirement Obligations	749	762
Operating Lease Liabilities	194	0
Firm Transportation Exit Cost Accrual	156	67
Production and Ad Valorem Taxes	88	83
Other Liabilities, Noncurrent	102	106
Total	1,438	1,165
Accumulated amortization	38	$ 30
EPIC Y-Grade, LP | Noble Midstream
Other Noncurrent Assets
Equity Method Investments	227
Delaware Crossing JV | Noble Midstream
Other Noncurrent Assets
Equity Method Investments	$ 38