Acquisitions and Divestitures (Details) bbl / d in Thousands, bbl in Thousands, $ in Millions						3 Months Ended				6 Months Ended
	Jun. 28, 2017 USD ($) $ / MMBTU payment	Jun. 26, 2017 USD ($) a shares	May 18, 2017 USD ($) shares	Apr. 24, 2017 USD ($) a shares	Apr. 03, 2017 USD ($) bbl / d mi bbl	Jun. 30, 2017 USD ($) MMcf / d MMBoe	Mar. 31, 2017 USD ($) well	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Jun. 30, 2017 USD ($) MMBoe	Jun. 30, 2016 USD ($) a	Apr. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds										$ 1,028.0	$ 0.0
Gain/loss						$ (2,322.0)		$ 0.0		(2,322.0)	0.0
Firm Transportation Liability						41.0		0.0		41.0	0.0
Income (loss) before income taxes						$ (2,334.0)		(498.0)		$ (2,275.0)	(951.0)
Proved undeveloped reserves (MMBOEs) | MMBoe						(551)				(551)
Consideration							$ 301.0
Allocated to undeveloped leasehold							$ 246.0
Number of wells | well							7
Number of wells operated by company | well							4
Cash consideration										$ 616.0	0.0
Borrowings										195.0	0.0
Gain/loss on sale						$ (2,270.0)		0.0		(2,270.0)	0.0
Proceeds receivable						0.0				0.0			$ 40.0
Percentage of divestiture farmed out													35.00%
Marcellus Shale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total transaction value	$ 1,200.0
Proceeds	1,000.0
Contingent adjustment	$ 100.0
Number of payments | payment	3
Individual payment	$ 33.3
Contingent consideration ($ per MMBtu) | $ / MMBTU	3.30
Gain, net of tax	$ 1,500.0
Assets												$ 3,400.0
Income (loss) before income taxes						$ 2,300.0		91.0		2,300.0	167.0
Natural gas production per day (MMcf per day) | MMcf / d						393
CONE Gathering LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total transaction value			$ 765.0
Assets						$ 173.0				$ 173.0
Ownership			50.00%
Ownership interest			33.50%
MONTANA
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds											43.0
Gain/loss on sale											(23.0)
Onshore US
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds											$ 20.0
Producing and Undeveloped Net Acres in the DJ Basin
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds								486.0
Purchase and sales agreement, area (acres) | a											33,100
Purchase and sales agreement, consideration								$ 505.0			$ 505.0
Wells Ranch Development Area
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Land exchanged (acres) | a											11,700
Bronco Development Area
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase and sales agreement, area (acres) | a											13,500
Cyprus Block 12
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds receivable							$ 40.0
Proceeds received from farm-out agreement							$ 131.0
Percentage of divestiture farmed out							35.00%
Alon A And Alon C
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total transaction value									$ 73.0
Contingent adjustment									6.0
Assets									$ 67.0
Percentage of divestiture farmed out									47.00%
Clayton Williams Energy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Decrease (MMBOEs) | MMBoe										(86)
Proved developed reserves (MMBOEs) | MMBoe						(17)				(17)
Proved undeveloped reserves (MMBOEs) | MMBoe						(69)				(69)
Consideration				$ 2,513.0
Area acquired (acres) | a				118,000
Cash consideration				$ 637.0
Shares exchange in acquisition (shares) | shares				56,000,000
Leaseholds and Leasehold Improvements | Marcellus Shale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets							$ 883.0
Noble Midstream Partners LP | Blanco River DevCo
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Additional voting interests acquired in limited partnership		15.00%
Equity interest in acquiree		40.00%
Noble Midstream Partners LP | Colorado River DevCo
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Additional voting interests acquired in limited partnership		20.00%
Noble Midstream Partners LP | Blanco River and Colorado River DevCos
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration		$ 270.0
Subsidiaries | Blanco River and Colorado River DevCos
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration		$ 270.0
Dedications area for oil, gas and water gathering services (in acres) | a		111,000
Cash consideration		$ 245.0
Shares exchange in acquisition (shares) | shares		562,430
Proceeds from equity		$ 138.0
Borrowings		$ 90.0
Corporate Joint Venture | Advantage Pipeline
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership					50.00%
Consideration					$ 133.0
Length of pipeline (miles) | mi					70
Shipping capacity (barrels per day) | bbl / d					150
Storage capacity (barrels per day) | bbl					490
Advantage Joint Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Payments to acquire joint venture					$ 66.5
Maximum | Corporate Joint Venture | Advantage Pipeline
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Shipping capacity (barrels per day) | bbl / d					200
Member Units | CONE Gathering LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Equity owned (units) | shares			21,700,000
Marcellus Shale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Decrease (MMBOEs) | MMBoe						241
Proved developed reserves (MMBOEs) | MMBoe						190				190
Proved undeveloped reserves (MMBOEs) | MMBoe						51				51
Onshore US
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets						$ 18.0				$ 18.0