v3.26.1
Commitments and Contingencies - Legal Claims and Insurance (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Sep. 30, 2025
Rollforward of reserves for legal claims          
Reserves for legal claims, beginning of period $ 1,136.7 $ 991.3 $ 1,143.6 $ 949.6  
Increase in reserves 37.1 59.7 87.3 132.3  
Payments (34.7) (14.9) (91.8) (45.8)  
Reserves for legal claims, end of period $ 1,139.1 1,036.1 $ 1,139.1 1,036.1  
Construction Defect Portion of Loss Contingency Accrual 99.00%   99.00%   98.00%
Litigation Settlement, Expense     $ 119.4 142.5  
Insurance receivables $ 123.6 $ 138.5 $ 123.6 $ 138.5 $ 167.0