SEGMENT AND RELATED INFORMATION: - Sales (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
SALES VALUE PER SEGMENT:
Net sales	$ 11,433.4	$ 9,895.8	$ 10,047.9
Copper
SALES VALUE PER SEGMENT:
Net sales	8,753.7	7,591.1	7,538.8
Molybdenum
SALES VALUE PER SEGMENT:
Net sales	1,246.4	1,129.7	1,192.7
Zinc
SALES VALUE PER SEGMENT:
Net sales	434.9	301.4	374.2
Silver
SALES VALUE PER SEGMENT:
Net sales	588.0	417.6	402.6
Other
SALES VALUE PER SEGMENT:
Net sales	410.4	456.0	539.7
Operating segment
SALES VALUE PER SEGMENT:
Net sales	11,625.8	10,047.4	10,347.6
Operating segment | Copper
SALES VALUE PER SEGMENT:
Net sales	8,835.1	7,660.4	7,758.8
Operating segment | Molybdenum
SALES VALUE PER SEGMENT:
Net sales	1,246.4	1,129.7	1,192.7
Operating segment | Zinc
SALES VALUE PER SEGMENT:
Net sales	443.6	300.9	373.8
Operating segment | Silver
SALES VALUE PER SEGMENT:
Net sales	684.9	492.2	471.0
Operating segment | Other
SALES VALUE PER SEGMENT:
Net sales	415.8	464.2	551.4
Corporate, other and eliminations
SALES VALUE PER SEGMENT:
Net sales	(192.4)	(151.6)	(299.7)
Corporate, other and eliminations | Copper
SALES VALUE PER SEGMENT:
Net sales	(81.4)	(69.3)	(220.0)
Corporate, other and eliminations | Zinc
SALES VALUE PER SEGMENT:
Net sales	(8.7)	0.5	0.4
Corporate, other and eliminations | Silver
SALES VALUE PER SEGMENT:
Net sales	(96.9)	(74.6)	(68.4)
Corporate, other and eliminations | Other
SALES VALUE PER SEGMENT:
Net sales	(5.4)	(8.2)	(11.7)
Mexican Open-Pit | Operating segment
SALES VALUE PER SEGMENT:
Net sales	6,317.0	5,562.3	5,772.6
Mexican Open-Pit | Operating segment | Copper
SALES VALUE PER SEGMENT:
Net sales	4,981.1	4,442.2	4,579.2
Mexican Open-Pit | Operating segment | Molybdenum
SALES VALUE PER SEGMENT:
Net sales	674.5	689.4	705.3
Mexican Open-Pit | Operating segment | Zinc
SALES VALUE PER SEGMENT:
Net sales	137.3
Mexican Open-Pit | Operating segment | Silver
SALES VALUE PER SEGMENT:
Net sales	342.6	233.7	241.9
Mexican Open-Pit | Operating segment | Other
SALES VALUE PER SEGMENT:
Net sales	181.5	197.0	246.3
Mexican IMMSA Unit | Operating segment
SALES VALUE PER SEGMENT:
Net sales	704.1	630.8	666.5
Mexican IMMSA Unit | Operating segment | Copper
SALES VALUE PER SEGMENT:
Net sales	127.7	89.1	83.6
Mexican IMMSA Unit | Operating segment | Zinc
SALES VALUE PER SEGMENT:
Net sales	306.2	300.9	373.8
Mexican IMMSA Unit | Operating segment | Silver
SALES VALUE PER SEGMENT:
Net sales	191.2	158.3	133.8
Mexican IMMSA Unit | Operating segment | Other
SALES VALUE PER SEGMENT:
Net sales	78.9	82.5	75.3
Peruvian Operations | Operating segment
SALES VALUE PER SEGMENT:
Net sales	4,604.6	3,854.3	3,908.5
Peruvian Operations | Operating segment | Copper
SALES VALUE PER SEGMENT:
Net sales	3,726.2	3,129.1	3,096.0
Peruvian Operations | Operating segment | Molybdenum
SALES VALUE PER SEGMENT:
Net sales	571.9	440.3	487.4
Peruvian Operations | Operating segment | Silver
SALES VALUE PER SEGMENT:
Net sales	151.1	100.2	95.3
Peruvian Operations | Operating segment | Other
SALES VALUE PER SEGMENT:
Net sales	$ 155.4	$ 184.7	$ 229.8