Segment Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 30, 2015
Segment Reporting Information [Line Items]
Oil, NGL and Gas Sales from Third Parties	$ 4,060	$ 3,389	$ 3,093
Income from Equity Method Investees and Other	196	102	90
Intersegment Revenues	0	0	0
Total Revenues	4,256	3,491	3,183
Lease Operating Expense	571	542	563
Production and Ad Valorem Taxes	138	78	127
Gathering, Transportation and Processing Expense	432	480	306
Total	1,141	1,100	996
DD&A	2,053	2,454	2,131
Clayton Williams Acquisition Expenses	100	0	0
Loss (Gain) on Debt Extinguishment	98	(80)	0
Loss on Marcellus Shale Upstream Divestiture	2,379	0	0
Asset Impairments	70	92	533
(Gain) Loss on Commodity Derivative Instruments	(63)	139	(501)
(Loss) Income Before Income Taxes	(2,191)	(1,772)	(2,219)
Equity Method Investments	305	400	453
Additions to Long-Lived Assets	2,851	1,526	3,062
Goodwill	1,310	0		$ 779
Assets	21,476	21,011	24,196
Noble Midstream
Segment Reporting Information [Line Items]
Revenues from third parties	19
Intersegment Eliminations
Segment Reporting Information [Line Items]
Oil, NGL and Gas Sales from Third Parties	0	0	0
Income from Equity Method Investees and Other	0	0	0
Intersegment Revenues	(277)	(200)	(119)
Total Revenues	(277)	(200)	(119)
Lease Operating Expense	(14)	(18)	(12)
Production and Ad Valorem Taxes	0	0	0
Gathering, Transportation and Processing Expense	(188)	(128)	(85)
Total	(202)	(146)	(97)
DD&A	(5)	0	0
Clayton Williams Acquisition Expenses	0
Loss (Gain) on Debt Extinguishment	0
Loss on Marcellus Shale Upstream Divestiture	0
Asset Impairments	0	0	0
(Gain) Loss on Commodity Derivative Instruments	0	0	0
(Loss) Income Before Income Taxes	(62)	(51)	(21)
Equity Method Investments	0	0	0
Additions to Long-Lived Assets	(79)	(53)	(21)
Goodwill	0
Assets	(163)	(98)	(46)
Corporate
Segment Reporting Information [Line Items]
Oil, NGL and Gas Sales from Third Parties	0	0	0
Income from Equity Method Investees and Other	0	0	0
Intersegment Revenues	0	0	0
Total Revenues	0	0	0
Lease Operating Expense	0	0	0
Production and Ad Valorem Taxes	0	0	0
Gathering, Transportation and Processing Expense	0	0	0
Total	0	0	0
DD&A	63	40	44
Clayton Williams Acquisition Expenses	0
Loss (Gain) on Debt Extinguishment	98
Loss on Marcellus Shale Upstream Divestiture	0
Asset Impairments	0	0	0
(Gain) Loss on Commodity Derivative Instruments	0		0
(Loss) Income Before Income Taxes	(559)	(626)	(622)
Equity Method Investments	0	0	0
Additions to Long-Lived Assets	102	32	80
Goodwill	0
Assets	247	304	220
United States | Operating Segments
Segment Reporting Information [Line Items]
Oil, NGL and Gas Sales from Third Parties	3,156	2,416	2,011
Income from Equity Method Investees and Other	0	0	0
Intersegment Revenues	0	0	0
Total Revenues	3,156	2,416	2,011
Lease Operating Expense	466	418	398
Production and Ad Valorem Taxes	135	76	126
Gathering, Transportation and Processing Expense	550	564	366
Total	1,151	1,058	890
DD&A	1,739	2,103	1,677
Clayton Williams Acquisition Expenses	100
Loss (Gain) on Debt Extinguishment	0
Loss on Marcellus Shale Upstream Divestiture	2,379
Asset Impairments	63	0	158
(Gain) Loss on Commodity Derivative Instruments	(92)	126	(347)
(Loss) Income Before Income Taxes	(2,365)	(1,277)	(1,693)
Equity Method Investments	0	0	0
Additions to Long-Lived Assets	1,994	1,353	2,409
Goodwill	1,310
Assets	15,767	16,153	18,043
United States | Noble Midstream
Segment Reporting Information [Line Items]
Oil, NGL and Gas Sales from Third Parties	0	0	0
Income from Equity Method Investees and Other	76	52	51
Intersegment Revenues	277	200	119
Total Revenues	353	252	170
Lease Operating Expense	0	0	0
Production and Ad Valorem Taxes	3	2	1
Gathering, Transportation and Processing Expense	70	44	25
Total	73	46	26
DD&A	30	19	14
Clayton Williams Acquisition Expenses	0
Loss (Gain) on Debt Extinguishment	0
Loss on Marcellus Shale Upstream Divestiture	0
Asset Impairments	0	0	0
(Gain) Loss on Commodity Derivative Instruments	0	0	0
(Loss) Income Before Income Taxes	233	176	123
Equity Method Investments	80	183	226
Additions to Long-Lived Assets	423	58	146
Goodwill	0
Assets	1,357	851	799
Eastern Mediterranean | Operating Segments
Segment Reporting Information [Line Items]
Oil, NGL and Gas Sales from Third Parties	534	540	497
Income from Equity Method Investees and Other	0	0	0
Intersegment Revenues	0	0	0
Total Revenues	534	540	497
Lease Operating Expense	29	37	42
Production and Ad Valorem Taxes	0	0	0
Gathering, Transportation and Processing Expense	0	0	0
Total	29	37	42
DD&A	76	81	70
Clayton Williams Acquisition Expenses	0
Loss (Gain) on Debt Extinguishment	0
Loss on Marcellus Shale Upstream Divestiture	0
Asset Impairments	0	88	36
(Gain) Loss on Commodity Derivative Instruments	0	0	0
(Loss) Income Before Income Taxes	413	543	313
Equity Method Investments	0	0	0
Additions to Long-Lived Assets	411	88	147
Goodwill	0
Assets	2,846	2,233	2,676
West Africa | Operating Segments
Segment Reporting Information [Line Items]
Oil, NGL and Gas Sales from Third Parties	370	433	580
Income from Equity Method Investees and Other	120	50	39
Intersegment Revenues	0	0	0
Total Revenues	490	483	619
Lease Operating Expense	90	105	131
Production and Ad Valorem Taxes	0	0	0
Gathering, Transportation and Processing Expense	0	0	0
Total	90	105	131
DD&A	146	205	326
Clayton Williams Acquisition Expenses	0
Loss (Gain) on Debt Extinguishment	0
Loss on Marcellus Shale Upstream Divestiture	0
Asset Impairments	0	0	339
(Gain) Loss on Commodity Derivative Instruments	29	13	(154)
(Loss) Income Before Income Taxes	203	(338)	(90)
Equity Method Investments	225	217	227
Additions to Long-Lived Assets	34	54	124
Goodwill	0
Assets	1,308	1,479	2,299
Other International | Operating Segments
Segment Reporting Information [Line Items]
Oil, NGL and Gas Sales from Third Parties	0	0	5
Income from Equity Method Investees and Other	0	0	0
Intersegment Revenues	0	0	0
Total Revenues	0	0	5
Lease Operating Expense	0	0	4
Production and Ad Valorem Taxes	0	0	0
Gathering, Transportation and Processing Expense	0	0	0
Total	0	0	4
DD&A	4	6	0
Clayton Williams Acquisition Expenses	0
Loss (Gain) on Debt Extinguishment	0
Loss on Marcellus Shale Upstream Divestiture	0
Asset Impairments	7	4	0
(Gain) Loss on Commodity Derivative Instruments	0	0	0
(Loss) Income Before Income Taxes	(54)	(199)	(229)
Equity Method Investments	0	0	0
Additions to Long-Lived Assets	(34)	(6)	177
Goodwill	0
Assets	114	89	205
Foreign Countries
Segment Reporting Information [Line Items]
Revenues from third parties	904	973	1,100
Long-lived assets	$ 2,800	$ 3,000	$ 3,900