INCOME TAXES: (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	May 31, 2019	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
INCOME TAXES
Statutory income tax provision				$ 1,298.7	$ 985.8
Peruvian royalty				45.5	30.2
Mexican royalty				116.3	102.5
Peruvian special mining tax				68.1	51.7
Total provision for income taxes		$ 526.4	$ 395.3	$ 1,528.6	$ 1,170.2
Effective income tax rate (as a percent)				37.20%	36.90%
Global minimum tax rate	15.00%
Peru
INCOME TAXES
Royalty charges				$ 113.6	$ 81.9
Income Taxes Paid				72.5
Increase (Decrease) in Income tax expense (benefit)				15.5
Unrecognized tax benefits		19.2		19.2
Mexico
INCOME TAXES
Mexican royalty				116.3	$ 102.5
Income Taxes Paid				19.5
Increase (Decrease) in Income tax expense (benefit)				12.1
Unrecognized tax benefits		$ 10.7		$ 10.7