FAIR VALUE MEASUREMENT (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2016
Derivatives:
Derivative Asset		$ 20	$ 80
Derivatives: [Abstract]
Derivative Liability		$ 89	$ 24
Derivative Asset, Current, Statement of Financial Position [Extensible Enumeration]		Other current assets	Other current assets
Derivative Asset, Noncurrent, Statement of Financial Position [Extensible Enumeration]		Other assets	Other assets
Other current assets		$ 535	$ 375
Other assets		1,813	1,810
Deepwater Gulf of Mexico Interests | Freeport-McMoRan Oil & Gas
Derivatives:
Contingent receivable	$ 4			$ 150
Derivatives: [Abstract]
Other assets		0	38
Discontinued Operation, Contingent Receivable, Impairment, Net	32
Discontinued Operation, Contingent Receivable, Impairment	42
Discontinued Operation, Contingent Receivable, Decrease To Accrued Royalty Interest Payable	$ 10
NAV
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure		27	27
Assets [Abstract]
Trust Assets Fair Value Disclosure		66	65
Derivatives:
Derivative Asset		0	0
Contingent receivable		0	0
Derivatives: [Abstract]
Derivative Liability		0	0
Long-term debt, including current portion		0	0
Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure		9	6
Assets [Abstract]
Trust Assets Fair Value Disclosure		19	17
Derivatives:
Derivative Asset		4	3
Contingent receivable		0	0
Derivatives: [Abstract]
Derivative Liability		18	1
Long-term debt, including current portion		0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure		0	0
Assets [Abstract]
Trust Assets Fair Value Disclosure		132	130
Derivatives:
Derivative Asset		16	77
Contingent receivable		0	0
Derivatives: [Abstract]
Derivative Liability		71	23
Long-term debt, including current portion		8,807	9,364
Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure		0	0
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Derivatives:
Derivative Asset		0	0
Contingent receivable		3	42
Derivatives: [Abstract]
Derivative Liability		0	0
Long-term debt, including current portion		0	0
Carrying Amount, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure		36	33
Assets [Abstract]
Trust Assets Fair Value Disclosure		217	212
Derivatives:
Derivative Asset		20	80
Contingent receivable		3	50
Derivatives: [Abstract]
Derivative Liability		89	24
Long-term debt, including current portion		8,948	9,422
Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure		36	33
Assets [Abstract]
Trust Assets Fair Value Disclosure		217	212
Derivatives:
Derivative Asset		20	80
Contingent receivable		3	42
Derivatives: [Abstract]
Derivative Liability		89	24
Long-term debt, including current portion		8,807	9,364
Embedded Derivative Financial Instruments
Derivatives:
Derivative Asset		10	76
Derivatives: [Abstract]
Derivative Liability		60	23
Embedded Derivative Financial Instruments | NAV
Derivatives:
Derivative Asset		0	0
Derivatives: [Abstract]
Derivative Liability		0	0
Embedded Derivative Financial Instruments | Level 1
Derivatives:
Derivative Asset		0	0
Derivatives: [Abstract]
Derivative Liability		0	0
Embedded Derivative Financial Instruments | Level 2
Derivatives:
Derivative Asset		10	76
Derivatives: [Abstract]
Derivative Liability		60	23
Embedded Derivative Financial Instruments | Level 3
Derivatives:
Derivative Asset		0	0
Derivatives: [Abstract]
Derivative Liability		0	0
Embedded Derivative Financial Instruments | Carrying Amount, Fair Value Disclosure [Member]
Derivatives:
Derivative Asset		10	76
Derivatives: [Abstract]
Derivative Liability		60	23
Embedded Derivative Financial Instruments | Estimate of Fair Value Measurement [Member]
Derivatives:
Derivative Asset		10	76
Derivatives: [Abstract]
Derivative Liability		60	23
Copper derivatives
Derivatives:
Derivative Asset		10	4
Derivatives: [Abstract]
Derivative Liability		29	1
Copper derivatives | NAV
Derivatives:
Derivative Asset		0
Copper derivatives | NAV | Futures and Swaps
Derivatives: [Abstract]
Derivative Liability		0
Copper derivatives | NAV | Forward Contracts
Derivatives: [Abstract]
Derivative Liability		0	0
Copper derivatives | Level 1
Derivatives:
Derivative Asset		4
Copper derivatives | Level 1 | Futures and Swaps
Derivatives: [Abstract]
Derivative Liability		17
Copper derivatives | Level 1 | Forward Contracts
Derivatives: [Abstract]
Derivative Liability		1	1
Copper derivatives | Level 2
Derivatives:
Derivative Asset		6
Copper derivatives | Level 2 | Futures and Swaps
Derivatives: [Abstract]
Derivative Liability		11
Copper derivatives | Level 2 | Forward Contracts
Derivatives: [Abstract]
Derivative Liability		0	0
Copper derivatives | Level 3
Derivatives:
Derivative Asset		0
Copper derivatives | Level 3 | Futures and Swaps
Derivatives: [Abstract]
Derivative Liability		0
Copper derivatives | Level 3 | Forward Contracts
Derivatives: [Abstract]
Derivative Liability		0	0
Copper derivatives | Carrying Amount, Fair Value Disclosure [Member]
Derivatives:
Derivative Asset		10
Copper derivatives | Carrying Amount, Fair Value Disclosure [Member] | Futures and Swaps
Derivatives: [Abstract]
Derivative Liability		28
Copper derivatives | Carrying Amount, Fair Value Disclosure [Member] | Forward Contracts
Derivatives: [Abstract]
Derivative Liability		1	1
Copper derivatives | Estimate of Fair Value Measurement [Member]
Derivatives:
Derivative Asset		10
Copper derivatives | Estimate of Fair Value Measurement [Member] | Futures and Swaps
Derivatives: [Abstract]
Derivative Liability		28
Copper derivatives | Estimate of Fair Value Measurement [Member] | Forward Contracts
Derivatives: [Abstract]
Derivative Liability		1	1
Future | NAV
Derivatives:
Derivative Asset			0
Future | Level 1
Derivatives:
Derivative Asset			3
Future | Level 2
Derivatives:
Derivative Asset			1
Future | Level 3
Derivatives:
Derivative Asset			0
Future | Carrying Amount, Fair Value Disclosure [Member]
Derivatives:
Derivative Asset			4
Future | Estimate of Fair Value Measurement [Member]
Derivatives:
Derivative Asset			4
U.S. core fixed income fund | NAV
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Marketable Securities		27	27
Assets [Abstract]
Trust Assets Fair Value Disclosure		66	65
U.S. core fixed income fund | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Marketable Securities		0	0
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
U.S. core fixed income fund | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Marketable Securities		0	0
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
U.S. core fixed income fund | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Marketable Securities		0	0
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
U.S. core fixed income fund | Carrying Amount, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Marketable Securities		27	27
Assets [Abstract]
Trust Assets Fair Value Disclosure		66	65
U.S. core fixed income fund | Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Marketable Securities		27	27
Assets [Abstract]
Trust Assets Fair Value Disclosure		66	65
Equity securities | NAV
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Marketable Securities		0	0
Equity securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Marketable Securities		9	6
Equity securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Marketable Securities		0	0
Equity securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Marketable Securities		0	0
Equity securities | Carrying Amount, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Marketable Securities		9	6
Equity securities | Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Marketable Securities		9	6
Government mortgage-backed securities | NAV
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Government mortgage-backed securities | Level 1
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Government mortgage-backed securities | Level 2
Assets [Abstract]
Trust Assets Fair Value Disclosure		54	51
Government mortgage-backed securities | Level 3
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Government mortgage-backed securities | Carrying Amount, Fair Value Disclosure [Member]
Assets [Abstract]
Trust Assets Fair Value Disclosure		54	51
Government mortgage-backed securities | Estimate of Fair Value Measurement [Member]
Assets [Abstract]
Trust Assets Fair Value Disclosure		54	51
Government bonds | NAV
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Government bonds | Level 1
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Government bonds | Level 2
Assets [Abstract]
Trust Assets Fair Value Disclosure		34	37
Government bonds | Level 3
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Government bonds | Carrying Amount, Fair Value Disclosure [Member]
Assets [Abstract]
Trust Assets Fair Value Disclosure		34	37
Government bonds | Estimate of Fair Value Measurement [Member]
Assets [Abstract]
Trust Assets Fair Value Disclosure		34	37
Corporate bonds | NAV
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Corporate bonds | Level 1
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Corporate bonds | Level 2
Assets [Abstract]
Trust Assets Fair Value Disclosure		31	29
Corporate bonds | Level 3
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Corporate bonds | Carrying Amount, Fair Value Disclosure [Member]
Assets [Abstract]
Trust Assets Fair Value Disclosure		31	29
Corporate bonds | Estimate of Fair Value Measurement [Member]
Assets [Abstract]
Trust Assets Fair Value Disclosure		31	29
Money market funds | NAV
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Money market funds | Level 1
Assets [Abstract]
Trust Assets Fair Value Disclosure		19	17
Money market funds | Level 2
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Money market funds | Level 3
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Money market funds | Carrying Amount, Fair Value Disclosure [Member]
Assets [Abstract]
Trust Assets Fair Value Disclosure		19	17
Money market funds | Estimate of Fair Value Measurement [Member]
Assets [Abstract]
Trust Assets Fair Value Disclosure		19	17
Asset-backed securities | NAV
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Asset-backed securities | Level 1
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Asset-backed securities | Level 2
Assets [Abstract]
Trust Assets Fair Value Disclosure		12	12
Asset-backed securities | Level 3
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Asset-backed securities | Carrying Amount, Fair Value Disclosure [Member]
Assets [Abstract]
Trust Assets Fair Value Disclosure		12	12
Asset-backed securities | Estimate of Fair Value Measurement [Member]
Assets [Abstract]
Trust Assets Fair Value Disclosure		12	12
Collateralized mortgage-backed securities | NAV
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Collateralized mortgage-backed securities | Level 1
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Collateralized mortgage-backed securities | Level 2
Assets [Abstract]
Trust Assets Fair Value Disclosure		1	1
Collateralized mortgage-backed securities | Level 3
Assets [Abstract]
Trust Assets Fair Value Disclosure		0	0
Collateralized mortgage-backed securities | Carrying Amount, Fair Value Disclosure [Member]
Assets [Abstract]
Trust Assets Fair Value Disclosure		1	1
Collateralized mortgage-backed securities | Estimate of Fair Value Measurement [Member]
Assets [Abstract]
Trust Assets Fair Value Disclosure		1	1
Bank Time Deposits | Carrying Amount, Fair Value Disclosure [Member]
Derivatives: [Abstract]
Other current assets		700	1,100
Other assets		100	100
Mine Closure And Reclamation Guarantees | Carrying Amount, Fair Value Disclosure [Member]
Derivatives: [Abstract]
Other assets		$ 100	$ 100