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Contingencies and Commitments - Narrative (Details) $ in Millions, $ in Millions			1 Months Ended
	Aug. 23, 2019 AUD ($)	Dec. 13, 2016 AUD ($)	Sep. 30, 2018 action	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Aug. 31, 2019 USD ($)	Aug. 23, 2019 USD ($)	Aug. 12, 2016 USD ($)
Loss Contingencies [Line Items]
Number of actions filed \| action			10
Contracts receivable				$ 211	$ 216
Barrick \| Fluor/TECHINT
Loss Contingencies [Line Items]
Letters of credit outstanding, amount						$ 36
Parent Company \| Barrick \| Fluor/TECHINT
Loss Contingencies [Line Items]
Letters of credit outstanding, amount						24
Partnership Interest \| Barrick \| Fluor/TECHINT
Loss Contingencies [Line Items]
Letters of credit outstanding, amount						$ 12
Pending litigation
Loss Contingencies [Line Items]
Damages sought		$ 1,470
Pending litigation \| Sadara Chemical Company
Loss Contingencies [Line Items]
Damages sought	$ 100
Estimate of possible loss							$ 574
Pending litigation \| Fluor/TECHINT
Loss Contingencies [Line Items]
Estimate of possible loss					$ 364			$ 250