Segment Information (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) Operating_Segment	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting [Abstract]
Number of operating segments | Operating_Segment			5
Segment Reporting Information [Line Items]
Oil, NGL and Gas Sales from Third Parties	$ 907	$ 882	$ 2,918	$ 2,411
Income from Equity Method Investees and Other	53	28	137	70
Intersegment Revenues	0	0	0	0
Total	960	910	3,055	2,481
Lease Operating Expense	151	131	414	412
Production and Ad Valorem Taxes	36	30	119	73
Gathering, Transportation and Processing Expense	93	121	333	354
Total	280	282	866	839
DD&A	523	621	1,554	1,859
Loss on Marcellus Shale Upstream Divestiture	4	0	2,326	0
Clayton Williams Energy Acquisition Expenses	4	0	98	0
Loss on Commodity Derivative Instruments	22	(55)	(145)	53
(Loss) Income Before Income Taxes	(208)	(280)	(2,483)	(1,231)
Goodwill	1,295		1,295		$ 0
Total Assets	21,649		21,649		21,011
Intersegment Eliminations
Segment Reporting Information [Line Items]
Oil, NGL and Gas Sales from Third Parties	0	0	0	0
Income from Equity Method Investees and Other	0	0	0	0
Intersegment Revenues	(72)	(57)	(198)	(143)
Total	(72)	(57)	(198)	(143)
Lease Operating Expense	(1)	(5)	(6)	(12)
Production and Ad Valorem Taxes	0	0	0	0
Gathering, Transportation and Processing Expense	(56)	(34)	(136)	(94)
Total	(57)	(39)	(142)	(106)
DD&A	(1)	0	(2)	0
Loss on Marcellus Shale Upstream Divestiture	0		0
Clayton Williams Energy Acquisition Expenses	0		0
Loss on Commodity Derivative Instruments	0	0	0	0
(Loss) Income Before Income Taxes	(12)	(18)	(47)	(37)
Goodwill	0		0
Total Assets	(142)		(142)		(98)
Corporate
Segment Reporting Information [Line Items]
Oil, NGL and Gas Sales from Third Parties	0	0	0	0
Income from Equity Method Investees and Other	0	0	0	0
Intersegment Revenues	0		0	0
Total	0	0	0	0
Lease Operating Expense	0	0	0	0
Production and Ad Valorem Taxes	0	0	0	0
Gathering, Transportation and Processing Expense	0	0	0	0
Total	0	0	0	0
DD&A	12	11	34	30
Loss on Marcellus Shale Upstream Divestiture	0		0
Clayton Williams Energy Acquisition Expenses	0		0
Loss on Commodity Derivative Instruments	0	0	0	0
(Loss) Income Before Income Taxes	(295)	(204)	(657)	(510)
Goodwill	0		0
Total Assets	292		292		304
United States | Operating Segments
Segment Reporting Information [Line Items]
Oil, NGL and Gas Sales from Third Parties	696	638	2,246	1,705
Income from Equity Method Investees and Other	0	0	0	0
Intersegment Revenues	0	0	0	0
Total	696	638	2,246	1,705
Lease Operating Expense	118	106	332	324
Production and Ad Valorem Taxes	35	29	117	70
Gathering, Transportation and Processing Expense	129	144	416	417
Total	282	279	865	811
DD&A	442	536	1,326	1,599
Loss on Marcellus Shale Upstream Divestiture	4		2,326
Clayton Williams Energy Acquisition Expenses	4		98
Loss on Commodity Derivative Instruments	16	(48)	(138)	45
(Loss) Income Before Income Taxes	(115)	(255)	(2,433)	(1,076)
Goodwill	1,295		1,295
Total Assets	16,287		16,287		16,153
United States | Noble Midstream
Segment Reporting Information [Line Items]
Oil, NGL and Gas Sales from Third Parties	0	0	0	0
Income from Equity Method Investees and Other	20	9	53	39
Intersegment Revenues	72	57	198	143
Total	92	66	251	182
Lease Operating Expense	0	0	0	0
Production and Ad Valorem Taxes	1	1	2	3
Gathering, Transportation and Processing Expense	20	11	53	31
Total	21	12	55	34
DD&A	10	5	20	14
Loss on Marcellus Shale Upstream Divestiture	0		0
Clayton Williams Energy Acquisition Expenses	0		0
Loss on Commodity Derivative Instruments	0	0	0	0
(Loss) Income Before Income Taxes	58	47	165	126
Goodwill	0		0
Total Assets	1,158		1,158		851
Eastern Mediter- ranean | Operating Segments
Segment Reporting Information [Line Items]
Oil, NGL and Gas Sales from Third Parties	141	150	406	407
Income from Equity Method Investees and Other	0	0	0	0
Intersegment Revenues	0	0	0	0
Total	141	150	406	407
Lease Operating Expense	9	8	23	25
Production and Ad Valorem Taxes	0	0	0	0
Gathering, Transportation and Processing Expense	0	0	0	0
Total	9	8	23	25
DD&A	18	22	58	62
Loss on Marcellus Shale Upstream Divestiture	0		0
Clayton Williams Energy Acquisition Expenses	0		0
Loss on Commodity Derivative Instruments	0	0	0	0
(Loss) Income Before Income Taxes	109	135	316	290
Goodwill	0		0
Total Assets	2,681		2,681		2,233
West Africa | Operating Segments
Segment Reporting Information [Line Items]
Oil, NGL and Gas Sales from Third Parties	70	94	266	299
Income from Equity Method Investees and Other	33	19	84	31
Intersegment Revenues	0	0	0	0
Total	103	113	350	330
Lease Operating Expense	25	22	65	75
Production and Ad Valorem Taxes	0	0	0	0
Gathering, Transportation and Processing Expense	0	0	0	0
Total	25	22	65	75
DD&A	41	46	114	150
Loss on Marcellus Shale Upstream Divestiture	0		0
Clayton Williams Energy Acquisition Expenses	0		0
Loss on Commodity Derivative Instruments	6	(7)	(7)	8
(Loss) Income Before Income Taxes	24	48	162	74
Goodwill	0		0
Total Assets	1,265		1,265		1,479
Other Int'l | Operating Segments
Segment Reporting Information [Line Items]
Oil, NGL and Gas Sales from Third Parties	0	0	0	0
Income from Equity Method Investees and Other	0	0	0	0
Intersegment Revenues	0	0	0	0
Total	0	0	0	0
Lease Operating Expense	0	0	0	0
Production and Ad Valorem Taxes	0	0	0	0
Gathering, Transportation and Processing Expense	0	0	0	0
Total	0	0	0	0
DD&A	1	1	4	4
Loss on Marcellus Shale Upstream Divestiture	0		0
Clayton Williams Energy Acquisition Expenses	0		0
Loss on Commodity Derivative Instruments	0	0	0	0
(Loss) Income Before Income Taxes	23	$ (33)	11	$ (98)
Goodwill	0		0
Total Assets	$ 108		$ 108		$ 89