Acquisitions and Divestitures (Details)			1 Months Ended						3 Months Ended		8 Months Ended	12 Months Ended
	Jan. 31, 2018 USD ($)	Apr. 24, 2017 USD ($) shares	Nov. 30, 2019 USD ($) shares	Feb. 28, 2019 USD ($) a	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jan. 31, 2018 USD ($)	Jun. 30, 2017 USD ($) shares	Dec. 31, 2018 USD ($)	Mar. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($) well	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) a	Dec. 31, 2017 USD ($) a payment well
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on sale												$ 0	$ 843,000,000	$ 326,000,000
Proceeds from divestitures												173,000,000	1,999,000,000	2,073,000,000
Pre-tax loss on divestiture												88,000,000	0	0
Goodwill					$ 110,000,000				$ 110,000,000			110,000,000	110,000,000
Severance, consulting, investment, advisory, legal and other related merger-related fees												0	0	100,000,000
Goodwill impairment									1,300,000,000			0	1,281,000,000	0
Exit costs												88,000,000	0	0
Proceeds from issuance of common limited partners units												$ 243,000,000	0	$ 312,000,000
Noble Midstream Partners LP
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from debt			$ 420,000,000
Saddle Butte
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration transferred	$ 681,000,000
Cash paid	663,000,000
Total purchase price plus liabilities assumed	18,000,000						$ 18,000,000
Property, plant and equipment assumed					206,000,000				206,000,000				206,000,000
Finite-lived intangible assets assumed					$ 340,000,000				$ 340,000,000				$ 340,000,000
Clayton Williams Energy
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration transferred		$ 2,500,000,000
Cash paid		$ 637,000,000
Business acquisition, equity interest issued or issuable, number of shares | shares		56,000,000
Fair value of common stock issued		$ 1,900,000,000
Severance, consulting, investment, advisory, legal and other related merger-related fees		100,000,000
Severance, consulting, investment, advisory, legal, and other merger related fees		64,000,000
Noncash share-based compensation expense		$ 36,000,000
Revenue since acquisition											$ 99,000,000
Pre-tax loss since acquisition											$ 19,000,000
Stock issued (shares) | shares		56,000,000
Immaterial acquisitions
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of productive wells | well											7			7
Delaware Basin
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration transferred														$ 301,000,000
Proceeds allocated to undeveloped leasehold cost														246,000,000
Certain midstream assets | Noble Midstream Partners LP
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from debt								$ 90,000,000
Consideration transferred								270,000,000
Cash paid								$ 245,000,000
Business acquisition, equity interest issued or issuable, number of shares | shares								562,430
Stock issued (shares) | shares								562,430
Proceeds from issuance of common limited partners units								$ 138,000,000
Noble Midstream Partners LP
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Common unit, outstanding (shares) | shares			56,500,000
Common unit outstanding percentage			63.00%
Greendfield Midstream | Saddle Butte
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash paid	$ 343,000,000
Black Diamond
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership interest in equity method investments					54.40%				54.40%				54.40%
Ownership Percentage					54.40%				54.40%				54.40%
Disposal Group, Disposed of by Sale, Not Discontinued Operations | DJ Basin
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Acreage exchange | a													12,900
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Mustang and Wells Ranch
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on sale													$ 0
Acreage exchange | a													12,300
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Reeves County Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Oil and gas producing properties (acres) | a				13,000
Sales proceeds				$ 131,000,000
Gain (loss) on sale				$ 0
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Remaining Midstream Interests And Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total consideration value			$ 1,600,000,000
Proceeds from divestitures			$ 670,000,000
Business acquisition, equity interest issued or issuable, value assigned | shares			38,500,000
Partners' capital account, units, contributed			$ 930,000,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Gulf of Mexico
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on sale										$ (24,000,000)
Total consideration value										480,000,000
Proceeds from divestitures										384,000,000
Impairment charge										168,000,000
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]
Gain (loss) on sale										$ 376,000,000
Ownership interest sold										7.50%
Pre-tax proceeds									$ 163,000,000	$ 484,000,000
Shares received in divestiture of interest in equity method investment (in shares) | shares										38,500,000
Consideration, shares issued, value										$ 224,000,000
Tax effect of gain										86,000,000
Change in fair value										$ 190,000,000
Discount rate for impairment model										15.00%
Gross unrealized loss													$ 27,000,000
Dividend income													31,000,000
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]
Gain (loss) on sale							0
Net proceeds							$ 60,000,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Greeley Crescent Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on sale						$ 0
Proceeds from divestitures						$ 68,000,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Ward County
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestitures					$ 63,000,000
Pre-tax loss on divestiture					16,000,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Marcellus Shale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales proceeds														1,000,000,000.0
Total consideration value											$ 1,200,000,000			1,200,000,000
Consideration adjustment														$ 100,000,000
Additional consideration, number of payments, divestiture | payment														3
Additional consideration, Individual payment amounts														$ 33,300,000
Amounts accrued related to contingent consideration														0
Loss on sale, before tax														2,300,000,000
Loss on sale of property, after tax														1,500,000,000
Exit costs														93,000,000
Asset consideration											3,400,000,000			3,400,000,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Marcellus Shale | Leaseholds and Leasehold Improvements
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset consideration											$ 883,000,000			883,000,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | US Onshore
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestitures														671,000,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | DJ Basin
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestitures														568,000,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Mineral and Royalty Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales proceeds														335,000,000
Gain on disposition of assets														$ 334,000,000
Mineral and royalty assets, area | a														140,000
Midstream
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill					$ 110,000,000				$ 110,000,000				$ 110,000,000
Private Placement | Noble Midstream Partners LP
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from issuance of private placement			$ 250,000,000
Number of common units issued (in shares) | shares			12,000,000