REVENUE: - Revenue by Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenue Recognition
Net sales	$ 2,599.8	$ 2,793.9
Corporate, other and eliminations
Revenue Recognition
Net sales	(41.3)	(38.2)
Mexican Open-Pit | Operating segment
Revenue Recognition
Net sales	1,466.0	1,626.9
Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	146.4	179.5
Peruvian Operations | Operating segment
Revenue Recognition
Net sales	1,028.7	1,025.7
Copper
Revenue Recognition
Net sales	2,043.7	2,147.9
Copper | Corporate, other and eliminations
Revenue Recognition
Net sales	(19.0)	(17.1)
Copper | Mexican Open-Pit | Operating segment
Revenue Recognition
Net sales	1,206.2	1,340.6
Copper | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	27.5	19.5
Copper | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	829.0	804.9
Molybdenum
Revenue Recognition
Net sales	273.6	301.6
Molybdenum | Mexican Open-Pit | Operating segment
Revenue Recognition
Net sales	144.6	160.7
Molybdenum | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	129.0	140.9
Silver
Revenue Recognition
Net sales	111.6	115.1
Silver | Corporate, other and eliminations
Revenue Recognition
Net sales	(21.7)	(18.5)
Silver | Mexican Open-Pit | Operating segment
Revenue Recognition
Net sales	66.7	65.3
Silver | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	35.5	42.8
Silver | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	31.1	25.5
Zinc
Revenue Recognition
Net sales	70.1	92.1
Zinc | Corporate, other and eliminations
Revenue Recognition
Net sales	0.6	0.6
Zinc | Mexican Open-Pit | Operating segment
Revenue Recognition
Net sales	4.3
Zinc | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	65.2	91.5
Other
Revenue Recognition
Net sales	100.8	137.2
Other | Corporate, other and eliminations
Revenue Recognition
Net sales	(1.2)	(3.2)
Other | Mexican Open-Pit | Operating segment
Revenue Recognition
Net sales	44.2	60.3
Other | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	18.2	25.7
Other | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	$ 39.6	$ 54.4