Derivatives - Summary of Gains (Losses) Recognized in Accumulated Other Comprehensive Loss, Net of Tax for Cash Flow Hedges (Details) - USD ($) $ in Millions		3 Months Ended
		Dec. 31, 2023	Dec. 31, 2022
Derivative [Line Items]
Gains (losses) recognized in accumulated other comprehensive loss, net of tax for cash flow hedges	[1]	$ 157.1	$ 145.4
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Natural Gas Commodity Hedge [Member]
Derivative [Line Items]
Gains (losses) recognized in accumulated other comprehensive loss, net of tax for cash flow hedges		$ (7.7)	$ (11.9)

[1] All amounts are net of tax and noncontrolling interests.