SEGMENT AND RELATED INFORMATION: - Financial (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) country item segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Financial information related to segments
Number of reportable segments | segment	3
Number of countries having open-pit operations | country	2
Financial information relating to segments
Net sales	$ 9,895.8	$ 10,047.9	$ 10,934.1
Cost of sales (exclusive of depreciation, amortization and depletion)	4,687.7	4,649.1	3,894.4
Selling, general and administrative	127.2	125.0	125.2
Depreciation, amortization and depletion	833.6	796.3	806.0
Exploration	55.0	41.7	43.4
Operating income	4,192.3	4,435.8	6,065.1
Interest, net	(240.1)	(305.1)	(349.9)
Other income (expense)	3.6	117.1	(18.4)
Income taxes	(1,518.9)	(1,596.1)	(2,299.2)
Equity earnings of affiliate	(2.2)	(3.7)	13.6
Non-controlling interest	(9.5)	(9.5)	(14.1)
Net income attributable to SCC	2,425.2	2,638.5	3,397.1
Capital investment	1,008.6	948.5	892.3
Property and mine development, net	9,782.9	9,596.6	9,464.4
Total assets	16,725.3	17,277.4	18,297.6
Intersegment sale
Financial information relating to segments
Net sales		(299.7)	(145.9)
Corporate, other and eliminations
Financial information relating to segments
Net sales	(151.6)	(299.7)	(145.9)
Cost of sales (exclusive of depreciation, amortization and depletion)	(157.7)	(316.9)	(162.0)
Selling, general and administrative	8.3	9.7	12.3
Depreciation, amortization and depletion	38.4	40.0	37.6
Exploration	11.1	14.7	20.9
Operating income	(51.7)	(47.3)	(54.7)
Capital investment	16.4	9.0	9.5
Property and mine development, net	817.6	746.2	722.9
Total assets	2,228.1	2,470.0	3,806.9
Reportable subsegments
Financial information relating to segments
Net sales	9,895.8
Intersegment sales | Corporate, other and eliminations
Financial information relating to segments
Net sales	$ (151.6)
Mexican Open-Pit
Financial information related to segments
Number of open-pit copper mines | item	2
Mexican Open-Pit | Operating segment
Financial information relating to segments
Net sales	$ 5,562.3	5,772.6	6,109.0
Cost of sales (exclusive of depreciation, amortization and depletion)	2,325.1	2,371.9	1,953.5
Selling, general and administrative	70.1	65.9	62.8
Depreciation, amortization and depletion	386.1	377.0	392.6
Exploration	6.2	3.1	2.3
Operating income	2,774.8	2,954.7	3,697.8
Capital investment	521.8	422.7	463.6
Property and mine development, net	4,590.1	4,512.6	4,463.2
Total assets	8,695.6	8,835.9	8,559.8
Mexican Open-Pit | Reportable subsegments | Operating segment
Financial information relating to segments
Net sales	$ 5,562.3	5,610.9	6,109.0
Mexican Open-Pit | Intersegment sales | Operating segment
Financial information relating to segments
Net sales		161.7
Mexican IMMSA Unit
Financial information related to segments
Number of underground poly metal mines | item	5
Mexican IMMSA Unit | Operating segment
Financial information relating to segments
Net sales	$ 630.8	666.5	600.2
Cost of sales (exclusive of depreciation, amortization and depletion)	545.6	532.8	440.9
Selling, general and administrative	10.4	10.2	10.0
Depreciation, amortization and depletion	70.4	57.6	54.8
Exploration	8.6	5.4	5.7
Operating income	(4.2)	60.6	88.8
Capital investment	147.7	161.8	98.3
Property and mine development, net	751.0	678.5	571.0
Total assets	1,166.1	1,100.7	998.2
Mexican IMMSA Unit | Reportable subsegments | Operating segment
Financial information relating to segments
Net sales	479.2	528.5	454.3
Mexican IMMSA Unit | Intersegment sales | Operating segment
Financial information relating to segments
Net sales	$ 151.6	138.0	145.9
Peruvian Operations
Financial information related to segments
Number of open-pit copper mines | item	2
Peruvian Operations | Operating segment
Financial information relating to segments
Net sales	$ 3,854.3	3,908.5	4,370.8
Cost of sales (exclusive of depreciation, amortization and depletion)	1,974.7	2,061.3	1,662.0
Selling, general and administrative	38.4	39.2	40.1
Depreciation, amortization and depletion	338.7	321.7	321.0
Exploration	29.1	18.5	14.5
Operating income	1,473.4	1,467.8	2,333.2
Capital investment	322.7	355.0	320.9
Property and mine development, net	3,624.2	3,659.3	3,707.3
Total assets	4,635.5	4,870.8	4,932.7
Peruvian Operations | Reportable subsegments | Operating segment
Financial information relating to segments
Net sales	$ 3,854.3	$ 3,908.5	$ 4,370.8