Condensed Consolidated Statements of Earnings and Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
Pension and postretirement activity, tax	$ (0.2)	$ 1.6	$ (0.8)	$ 1.5
Deferred gain on hedging activity, tax	$ 1.3	$ 0.1	$ (0.3)	$ (3.7)
Diluted net earnings per share	$ 0.72	$ 0.37	$ 0.81	$ 0.61