Commitments and Contingencies (Pace, Piedmont and Pasadena - Narrative) (Details) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2012 USD ($) surfaceImpoundmentUnit	Sep. 30, 2008 USD ($)	Sep. 30, 2006 USD ($)	Dec. 31, 2025 USD ($)	Sep. 30, 2025 USD ($)
Environmental
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies							$ 85.1	$ 85.6
Accrual for environmental loss contingencies, maximum payout period							30 years
Pace, Florida
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies						$ 42.0	$ 53.4
Change in estimated exposure		$ 19.0	$ 19.0
Pace, Florida | Environmental
Loss Contingencies [Line Items]
Site Contingency, Cost Review, Period							5 years
Accrual for environmental loss contingencies, maximum payout period							30 years
Pace, Florida | Discontinued operations
Loss Contingencies [Line Items]
Pretax environmental expense		$ 19.0	$ 19.0			$ 42.0
Piedmont, South Carolina
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies					$ 24.0		$ 10.0
Change in estimated exposure	$ 9.0
Piedmont, South Carolina | Discontinued operations
Loss Contingencies [Line Items]
Pretax environmental expense	$ 9.0				$ 24.0
Pasadena, Texas
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies							$ 9.7
Number of closed facilities | surfaceImpoundmentUnit				2
Total anticipated exposure				$ 13.0