Revenue Contract Balances (Details) - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Aug. 31, 2021	Aug. 31, 2020	Dec. 31, 2019
Financing Receivable, after Allowance for Credit Loss	$ 192,000,000				$ 109,000,000
Financing Receivable, Allowance for Credit Loss	11,000,000
Contract with Customer, Liability	699,000,000				117,000,000
Contract with Customer, Liability	699,000,000				$ 117,000,000
Contract with Customer, Liability, Revenue Recognized	12,000,000	$ 9,000,000
Mong Duong Subsidiary [Member]
Financing Receivable, after Allowance for Credit Loss	1,300,000,000
Financing Receivable, Allowance for Credit Loss	33,000,000
Angamos [Member] | Minera Escondida and Minera Spence [Member]
Contract with Customer, Liability	546,000,000			$ 655,000,000
Contract with Customer, Liability	$ 546,000,000			$ 655,000,000
Angamos [Member] | Minera Escondida and Minera Spence [Member] | Forecast [Member]
Capitalized Contract Cost, Amortization			$ 55,000,000