Segment Information - Operating Results by Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenue from Sales	$ 1,020	$ 1,052
Lease Operating Expense	138	151
Production and Ad Valorem Taxes	39	49
Gathering, Transportation and Processing Expense	95	102
Total	276	305
Exploration Expense	1,504	24
Depreciation, Depletion and Amortization	492	508
Asset Impairments	2,703
Goodwill, Impairment Loss	110	0
(Gain) Loss on Commodity Derivative Instruments	(389)	212
(Loss) Income Before Income Taxes	(4,018)	(373)
Additions to Long-Lived Assets, Excluding Acquisitions	442	712
Additions to Equity Method Investments	153
Additions to Equity Method Investments	226	271
Property, Plant and Equipment, Net	13,221		$ 17,451
Intersegment Eliminations and Other
Segment Reporting Information [Line Items]
Revenue from Sales	(115)	(106)
Lease Operating Expense	(14)	(9)
Production and Ad Valorem Taxes	0	0
Gathering, Transportation and Processing Expense	(75)	(69)
Total	(89)	(78)
Depreciation, Depletion and Amortization	(9)	(7)
Asset Impairments	0
Goodwill, Impairment Loss	0
(Gain) Loss on Commodity Derivative Instruments	0	0
(Loss) Income Before Income Taxes	(11)	(14)
Additions to Long-Lived Assets, Excluding Acquisitions	(24)	(23)
Additions to Equity Method Investments	0
Additions to Equity Method Investments		0
Property, Plant and Equipment, Net	(225)		(223)
Corporate
Segment Reporting Information [Line Items]
Revenue from Sales	17	27
Lease Operating Expense	0	0
Production and Ad Valorem Taxes	0	0
Gathering, Transportation and Processing Expense	0	0
Total	0	0
Depreciation, Depletion and Amortization	13	15
Asset Impairments	0
Goodwill, Impairment Loss	0
(Gain) Loss on Commodity Derivative Instruments	0	0
(Loss) Income Before Income Taxes	(208)	(264)
Additions to Long-Lived Assets, Excluding Acquisitions	7	11
Additions to Equity Method Investments	0
Additions to Equity Method Investments		0
Property, Plant and Equipment, Net	171		216
United States | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	639	763
Lease Operating Expense	108	125
Production and Ad Valorem Taxes	37	47
Gathering, Transportation and Processing Expense	146	142
Total	295	317
Depreciation, Depletion and Amortization	419	439
Asset Impairments	2,703
Goodwill, Impairment Loss	0
(Gain) Loss on Commodity Derivative Instruments	(389)	188
(Loss) Income Before Income Taxes	(3,917)	(247)
Additions to Long-Lived Assets, Excluding Acquisitions	357	511
Additions to Equity Method Investments	0
Additions to Equity Method Investments		0
Property, Plant and Equipment, Net	7,641		11,859
United States | Noble Midstream
Segment Reporting Information [Line Items]
Revenue from Sales	218	165
Lease Operating Expense	1	1
Production and Ad Valorem Taxes	2	2
Gathering, Transportation and Processing Expense	21	29
Total	24	32
Depreciation, Depletion and Amortization	26	25
Asset Impairments	0
Goodwill, Impairment Loss	110
(Gain) Loss on Commodity Derivative Instruments	0	0
(Loss) Income Before Income Taxes	(31)	73
Additions to Long-Lived Assets, Excluding Acquisitions	43	66
Additions to Equity Method Investments	153
Additions to Equity Method Investments		271
Property, Plant and Equipment, Net	1,734		1,721
United States | Intersegment Eliminations and Other
Segment Reporting Information [Line Items]
Revenue from Sales	115	106
Eastern Mediterranean | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	189	118
Lease Operating Expense	13	10
Production and Ad Valorem Taxes	0	0
Gathering, Transportation and Processing Expense	3	0
Total	16	10
Depreciation, Depletion and Amortization	19	16
Asset Impairments	0
Goodwill, Impairment Loss	0
(Gain) Loss on Commodity Derivative Instruments	0	0
(Loss) Income Before Income Taxes	145	84
Additions to Long-Lived Assets, Excluding Acquisitions	31	132
Additions to Equity Method Investments	0
Additions to Equity Method Investments		0
Property, Plant and Equipment, Net	3,055		3,041
West Africa | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	72	85
Lease Operating Expense	30	24
Production and Ad Valorem Taxes	0	0
Gathering, Transportation and Processing Expense	0	0
Total	30	24
Depreciation, Depletion and Amortization	24	20
Asset Impairments	0
Goodwill, Impairment Loss	0
(Gain) Loss on Commodity Derivative Instruments	0	24
(Loss) Income Before Income Taxes	10	11
Additions to Long-Lived Assets, Excluding Acquisitions	19	5
Additions to Equity Method Investments	0
Additions to Equity Method Investments		0
Property, Plant and Equipment, Net	792		793
Other Int'l | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Lease Operating Expense	0	0
Production and Ad Valorem Taxes	0	0
Gathering, Transportation and Processing Expense	0	0
Total	0	0
Depreciation, Depletion and Amortization	0	0
Asset Impairments	0
Goodwill, Impairment Loss	0
(Gain) Loss on Commodity Derivative Instruments	0	0
(Loss) Income Before Income Taxes	(6)	(16)
Additions to Long-Lived Assets, Excluding Acquisitions	9	10
Additions to Equity Method Investments	0
Additions to Equity Method Investments		0
Property, Plant and Equipment, Net	53		$ 44
Oil, NGL and Gas Sales
Segment Reporting Information [Line Items]
Revenue from Sales	894	937
Oil, NGL and Gas Sales | Intersegment Eliminations and Other
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Oil, NGL and Gas Sales | Corporate
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Oil, NGL and Gas Sales | United States | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	614	749
Oil, NGL and Gas Sales | United States | Noble Midstream
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Oil, NGL and Gas Sales | Eastern Mediterranean | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	191	118
Oil, NGL and Gas Sales | West Africa | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	89	70
Oil, NGL and Gas Sales | Other Int'l | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Crude Oil Sales
Segment Reporting Information [Line Items]
Revenue from Sales	578	612
Crude Oil Sales | Intersegment Eliminations and Other
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Crude Oil Sales | Corporate
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Crude Oil Sales | United States | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	492	545
Crude Oil Sales | United States | Noble Midstream
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Crude Oil Sales | Eastern Mediterranean | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	1	1
Crude Oil Sales | West Africa | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	85	66
Crude Oil Sales | Other Int'l | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
NGL Sales
Segment Reporting Information [Line Items]
Revenue from Sales	62	96
NGL Sales | Intersegment Eliminations and Other
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
NGL Sales | Corporate
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
NGL Sales | United States | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	62	96
NGL Sales | United States | Noble Midstream
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
NGL Sales | Eastern Mediterranean | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
NGL Sales | West Africa | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
NGL Sales | Other Int'l | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Natural Gas Sales
Segment Reporting Information [Line Items]
Revenue from Sales	254	229
Natural Gas Sales | Intersegment Eliminations and Other
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Natural Gas Sales | Corporate
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Natural Gas Sales | United States | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	60	108
Natural Gas Sales | United States | Noble Midstream
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Natural Gas Sales | Eastern Mediterranean | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	190	117
Natural Gas Sales | West Africa | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	4	4
Natural Gas Sales | Other Int'l | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Cost of Purchased of Gas
Segment Reporting Information [Line Items]
Revenue from Sales	125	74
Cost of Purchased Oil and Gas	139	87
Firm Transportation Exit Cost		92
Cost of Purchased of Gas | Intersegment Eliminations and Other
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Cost of Purchased Oil and Gas	0	0
Firm Transportation Exit Cost		0
Cost of Purchased of Gas | Corporate
Segment Reporting Information [Line Items]
Revenue from Sales	17	27
Cost of Purchased Oil and Gas	31	42
Firm Transportation Exit Cost		92
Cost of Purchased of Gas | United States | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	25	14
Cost of Purchased Oil and Gas	28	14
Firm Transportation Exit Cost		0
Cost of Purchased of Gas | United States | Noble Midstream
Segment Reporting Information [Line Items]
Revenue from Sales	83	33
Cost of Purchased Oil and Gas	80	31
Firm Transportation Exit Cost		0
Cost of Purchased of Gas | Eastern Mediterranean | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Cost of Purchased Oil and Gas	0	0
Firm Transportation Exit Cost		0
Cost of Purchased of Gas | West Africa | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Cost of Purchased Oil and Gas	0	0
Firm Transportation Exit Cost		0
Cost of Purchased of Gas | Other Int'l | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Cost of Purchased Oil and Gas	0	0
Firm Transportation Exit Cost		0
Loss from Equity Method Investments and Other
Segment Reporting Information [Line Items]
Revenue from Sales	(24)	17
Loss from Equity Method Investments and Other | Intersegment Eliminations and Other
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Loss from Equity Method Investments and Other | Corporate
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Loss from Equity Method Investments and Other | United States | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Loss from Equity Method Investments and Other | United States | Noble Midstream
Segment Reporting Information [Line Items]
Revenue from Sales	(5)	2
Loss from Equity Method Investments and Other | Eastern Mediterranean | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	(2)	0
Loss from Equity Method Investments and Other | West Africa | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	(17)	15
Loss from Equity Method Investments and Other | Other Int'l | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Midstream Services Revenues – Third Party
Segment Reporting Information [Line Items]
Revenue from Sales	25	24
Midstream Services Revenues – Third Party | Intersegment Eliminations and Other
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Midstream Services Revenues – Third Party | Corporate
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Midstream Services Revenues – Third Party | United States | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Midstream Services Revenues – Third Party | United States | Noble Midstream
Segment Reporting Information [Line Items]
Revenue from Sales	25	24
Midstream Services Revenues – Third Party | United States | Intersegment Eliminations and Other
Segment Reporting Information [Line Items]
Revenue from Sales	0
Midstream Services Revenues – Third Party | Eastern Mediterranean | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Midstream Services Revenues – Third Party | West Africa | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Midstream Services Revenues – Third Party | Other Int'l | Operating Segments
Segment Reporting Information [Line Items]
Revenue from Sales	0	0
Other Royalty Expense
Segment Reporting Information [Line Items]
Cost of Purchased Oil and Gas	4	3
Exploration Expense	1,504
Other Royalty Expense | Intersegment Eliminations and Other
Segment Reporting Information [Line Items]
Cost of Purchased Oil and Gas	0	0
Exploration Expense	0
Other Royalty Expense | Corporate
Segment Reporting Information [Line Items]
Cost of Purchased Oil and Gas	0	0
Exploration Expense	0
Other Royalty Expense | United States | Operating Segments
Segment Reporting Information [Line Items]
Cost of Purchased Oil and Gas	4	3
Exploration Expense	1,494
Other Royalty Expense | United States | Noble Midstream
Segment Reporting Information [Line Items]
Cost of Purchased Oil and Gas	0	0
Exploration Expense	0
Other Royalty Expense | Eastern Mediterranean | Operating Segments
Segment Reporting Information [Line Items]
Cost of Purchased Oil and Gas	0	0
Exploration Expense	2
Other Royalty Expense | West Africa | Operating Segments
Segment Reporting Information [Line Items]
Cost of Purchased Oil and Gas	0	0
Exploration Expense	3
Other Royalty Expense | Other Int'l | Operating Segments
Segment Reporting Information [Line Items]
Cost of Purchased Oil and Gas	0	$ 0
Exploration Expense	$ 5