INCOME TAXES: - Provision (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
U.S. federal and state:
Current	$ (4.8)	$ 4.6	$ 0.1
Uncertain tax positions	(0.6)	0.6
Provision for income taxes	(5.4)	5.2	0.1
Foreign (Peru and Mexico):
Current	1,985.8	1,491.0	1,443.1
Deferred	(52.2)	(59.1)	118.6
Uncertain tax position	47.1	81.8	34.3
Provision for income taxes	1,980.7	1,513.7	1,596.0
Total provision for income taxes	1,975.3	1,518.9	1,596.1
Earnings by location:
U.S.	31.5	23.3	0.5
Peru	1,796.4	1,151.3	1,167.8
Mexico	3,529.5	2,781.2	3,079.5
Foreign	5,325.9	3,932.5	4,247.3
Income before income taxes	$ 5,357.4	$ 3,955.8	$ 4,247.8