COMMITMENTS AND CONTINGENCIES (Details) $ in Millions							3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 10, 2020 defendant	Sep. 11, 2019 USD ($) plaintiff	Dec. 20, 2017 Action	Jul. 17, 2017 Action defendant	Mar. 21, 2016 USD ($)	Mar. 20, 2016 USD ($)	Sep. 30, 2021 USD ($) sidetrack bond subsidiary	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) sidetrack Action subsidiary bond	Sep. 30, 2020 USD ($)	Dec. 31, 2013 USD ($) source	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Aug. 03, 2020 USD ($)	Dec. 31, 2017 AUD ($)	Apr. 30, 2017 AUD ($)
Commitment And Contingencies [Line Items]
Accrued liability for legal contingencies							$ 68,000,000		$ 68,000,000
Undiscounted reserve for environmental remediation							2,000,000		2,000,000
Standby loan agreed to provide related to ARO														$ 400,000,000
Decommissioning contingency for sold Gulf of Mexico properties (Note 12)							1,186,000,000		1,186,000,000				$ 0
Decommissioning security for sold Gulf of Mexico properties (Note 12)							740,000,000		740,000,000				$ 0
Loss on offshore decommissioning contingency							$ 446,000,000	$ 0	$ 446,000,000	$ 0
Gulf Of Mexico Shelf Operations and Properties | Disposed of by Sale
Commitment And Contingencies [Line Items]
Proceeds from sale of operations and properties											$ 3,750,000,000
Trust account for disposal group, number of net profits interests | source											2
Number of debt instruments held | subsidiary							5		5
Number of bonds held | bond							2		2
Minimum
Commitment And Contingencies [Line Items]
Asset retirement obligation, estimated liability							$ 1,200,000,000		$ 1,200,000,000
Maximum
Commitment And Contingencies [Line Items]
Asset retirement obligation, estimated liability							1,400,000,000		1,400,000,000
3750000000
Commitment And Contingencies [Line Items]
Plaintiffs alleged damages					$ 200,000,000
3750000000 | Minimum
Commitment And Contingencies [Line Items]
Plaintiffs alleged damages						$ 1,100,000,000
Australian Operations Divestiture Dispute | Apache Australia Operation
Commitment And Contingencies [Line Items]
Gain contingency, unrecorded amount																$ 80
Loss contingency, estimated of possible loss amount															$ 200
Canadian Operations Divestiture Dispute
Commitment And Contingencies [Line Items]
Plaintiffs alleged damages		$ 60,000,000
Number of plaintiffs | plaintiff		4
California Litigation
Commitment And Contingencies [Line Items]
Number of actions filed | Action			2	3
Number of defendants | defendant				30
Delaware Litigation
Commitment And Contingencies [Line Items]
Number of defendants | defendant	25
Castex Lawsuit
Commitment And Contingencies [Line Items]
Plaintiffs alleged damages									200,000,000
Loss contingency, estimated of possible loss amount							$ 13,500,000		$ 13,500,000			$ 60,000,000
Number of sidetracks | sidetrack							5		5
Oklahoma Class Actions
Commitment And Contingencies [Line Items]
Plaintiffs alleged damages									$ 200,000,000
Number of actions filed | Action									2