Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pension, SERP and Retiree medical adjustments, tax	$ 1.0	$ 7.6	$ 35.3
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax	0.5	(0.7)	(4.6)
Unrealized foreign exchange gain (loss) on intercompany loan, tax	0.3	(1.0)	1.8
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	$ 0.0	$ 0.0	$ 0.0