PROPERTY: (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Property
Total property	$ 20,364.7	$ 19,785.5
Accumulated depreciation, amortization and depletion	(10,481.4)	(10,002.6)
Total property and mine development, net	9,883.3	9,782.9	$ 9,596.6
Depreciation and depletion expense	836.8	825.7	$ 790.3
Buildings and equipment
Property
Total property	18,013.5	17,439.3
Construction in progress
Property
Total property	1,579.1	1,664.8
Mine development
Property
Total property	348.8	320.7
Mineral assets
Property
Total property	83.2	83.2
Land, other than mineral
Property
Total property	$ 340.1	$ 277.5