Other Assets, Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Other assets
Earnest money and refundable deposits	$ 2,210.6	$ 1,859.6
Water rights and other water-related assets	319.1	319.6
Insurance receivables	156.8	165.8
Other receivables	147.1	167.2
Prepaid assets	117.9	93.0
Contract assets - insurance agency commissions	117.5	93.9
Margin deposits related to hedging instruments	71.3	0.0
Lease right of use assets	51.4	46.6
Mortgage servicing rights	5.9	11.1
Mortgage hedging instruments and commitments	2.8	153.6
Other	$ 72.7	$ 80.3
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Total other assets	Total other assets
Total other assets	$ 3,317.6	$ 2,993.0
Accrued expenses and other liabilities
Reserves for legal claims	949.6	858.9	$ 729.1
Employee compensation and related liabilities	569.7	531.0
Warranty liability	566.9	512.4	$ 454.3
Inventory related accruals	451.2	353.6
Customer deposits	99.7	147.1
Accrued property taxes	77.6	69.2
Mortgage hedging instruments and commitments	63.0	15.7
Lease liabilities	53.3	48.1
Accrued interest	34.8	33.6
Federal and state income tax liabilities	27.7	233.8
Broker deposits related to hedging instruments	0.0	118.9
Other	$ 123.2	$ 147.6
Finance Lease, Right-of-Use Asset, Accumulated Amortization	Other Liabilities	Other Liabilities
Total accrued expenses and other liabilities	$ 3,016.7	$ 3,103.8
Interest Rate Lock Commitments
Other assets
Interest rate lock commitments	44.5	2.3
Accrued expenses and other liabilities
Interest rate lock commitments	$ 0.0	$ 33.9