CAPITAL STOCK - Schedule of SBC Expense and TRS Fair Value Adjustments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Employee SBC expense	$ 15.6	$ 12.7	$ 56.8	$ 47.3
Total TRS FVAs: losses (gains)	(113.3)	7.7	(191.6)	(39.5)
Combined effect of employee SBC expense and TRS FVAs	(97.7)	20.4	(134.8)	7.8
Cost of sales
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Employee SBC expense	6.8	5.6	24.2	20.2
Total TRS FVAs: losses (gains)	(48.5)	2.7	(81.6)	(17.2)
SG&A
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Employee SBC expense	8.8	7.1	32.6	27.1
Total TRS FVAs: losses (gains)	(64.8)	5.0	(110.0)	(22.3)
SG&A | Director
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Employee SBC expense	$ 0.6	$ 0.6	$ 1.7	$ 1.8