Acquisitions and Divestitures - Narrative (Details) $ in Millions								1 Months Ended	3 Months Ended			6 Months Ended
	Mar. 14, 2018 USD ($) shares	Feb. 15, 2018 USD ($) $ / bbl	Jan. 31, 2018 USD ($)	Jun. 28, 2017 USD ($) $ / MMBTU	Jun. 26, 2017 USD ($) a shares	Apr. 24, 2017 USD ($) shares	Apr. 03, 2017 USD ($)	Jan. 31, 2018 USD ($)	Jun. 30, 2018 USD ($) shares	Mar. 31, 2018 USD ($)	Jun. 30, 2017 USD ($) MMcf / d MMBoe well	Jun. 30, 2018 USD ($) shares	Jun. 30, 2017 USD ($) MMBoe well	Apr. 11, 2018 MMBoe	Feb. 01, 2018 shares	Jan. 29, 2018	Jan. 28, 2018	Dec. 31, 2017 USD ($) MMBoe shares
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Long-Term Debt						$ 595.0
Gain (loss) on divestiture									$ 78.0		$ 0.0	$ 666.0	$ 0.0
Asset Impairments									$ 0.0		0.0	$ 168.0	0.0
Undeveloped Leasehold Costs						1,571.0
Equity owned (units) | shares									14,217,198			14,217,198						21,692,198
Proceeds from divestiture												$ 72.0	101.0
Consideration						2,488.0
Cash consideration						637.0						0.0	616.0
Fair value of common stock issued						1,851.0
Proceeds from sale												443.0	0.0
Proceeds from Sale of 7.5% Interest in Tamar Field												(484.0)	0.0
Intangible assets									$ 326.0			326.0						$ 0.0
Goodwill						1,291.0			1,402.0			1,402.0						$ 1,310.0
Gain (loss) on disposition									0.0		$ (2,322.0)	0.0	(2,322.0)
Natural gas production per day | MMcf / d											393
Proceeds from Noble Midstream Services Revolving Credit Facility												$ 610.0	195.0
CONE Gathering LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on divestiture								$ 196.0	$ 109.0
Ownership			50.00%					50.00%	22.30%			22.30%			34.10%
Shares sold (in shares) | shares									7,500,000
Proceeds from divestiture								$ 308.0	$ 135.0
Marcellus Shale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total transaction value				$ 1,200.0
Assets				3,400.0
Proceeds from Sale of Oil and Gas Property and Equipment				1,000.0								$ 0.0	$ 1,028.0
Adjustment to consideration				100.0
Adjustment to consideration, individual payment amounts				$ 33.3
Minimum index price for contingent payments to be required (in usd per unit) | $ / MMBTU				3.30
Gain (loss) on disposition											$ 2,300.0
Gain (loss) on sale											1,500.0
Exit costs											$ 41.0
Period increase (decrease) | MMBoe											241
Proved developed reserves | MMBoe											190		190
Proved undeveloped reserves | MMBoe											51		51
Saddle Butte
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration			$ 681.0
Cash consideration			663.0
Liabilities assumed			18.0					18.0
Property, plant and equipment									206.0			206.0
Intangible assets									340.0			340.0
Goodwill									$ 111.0			$ 111.0
Clayton Williams Energy
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Long-Term Debt											$ 595.0		$ 595.0
Consideration						2,500.0
Cash consideration						$ 637.0
Shares exchange in acquisition (shares) | shares						56,000,000
Fair value of common stock issued						$ 1,900.0
Goodwill						$ 1,300.0
Bolt-on acquisition in the Delaware Basin
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Productive oil wells | well											7		7
Payments to acquire oil and gas properties													$ 301.0
Undeveloped Leasehold Costs											$ 246.0		$ 246.0
Number of productive wells | well											4		4
Noble Midstream Partners LP | Blanco River DevCo
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage acquired					15.00%
Step acquisition, percentage acquired					40.00%
Noble Midstream Partners LP | Colorado River DevCo
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration					$ 270.0
Percentage acquired					20.00%
Tamar and Dalit Fields
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership interest																25.00%	32.50%
CNX Midstream Partners
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Equity owned (units) | shares									14,200,000			14,200,000			21,700,000
Advantage Joint Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Payments to acquire interest							$ 66.5
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Tamar and Dalit Fields
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discount percent	15.00%
Tax effect	$ 86.0
Gain (loss) on divestiture	376.0
Gain attributable to change in fair value	$ 190.0
Percentage of divestiture farmed out	7.50%
Estimated capacity | MMBoe																		84
Shares received in divestiture (in shares) | shares	38,500,000
Value of shares issued	$ 224.0
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Southwest Royalties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale								$ 60.0
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Other Divestitures
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total transaction value									$ 12.0			$ 12.0
Gain (loss) on divestiture												4.0
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Gulf of Mexico Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total transaction value		$ 480.0
Gain (loss) on divestiture									(19.0)
Asset Impairments										$ 168.0		$ 168.0
Proceeds from divestiture									$ 383.0
Estimated capacity | MMBoe														23
Assets		$ 100.0
Asset basis, price per barrel (in usd per barrel) | $ / bbl		2
Price benchmark (in usd per barrel) | $ / bbl		63
Greenfield Midstream | Saddle Butte
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration			$ 343.0
Leaseholds and Leasehold Improvements | Marcellus Shale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets				$ 883.0
Corporate Joint Venture | Advantage Pipeline
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership							5000.00%
Consideration							$ 133.0
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
Cash consideration					$ 245.0
Shares exchange in acquisition (shares) | shares					562,430
Gas and oil area developed | a					111,000
Proceeds from issuance					$ 138.0
Proceeds from Noble Midstream Services Revolving Credit Facility					$ 90.0