Other Assets, Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Other assets
Earnest money and refundable deposits	$ 1,943.8	$ 1,859.6
Mortgage hedging instruments and commitments	16.5	153.6
Water rights and other water-related assets	310.6	319.6
Margin deposits related to hedging instruments	181.1	0.0
Other receivables	163.9	167.2
Insurance receivables	131.5	165.8	$ 143.6
Prepaid assets	100.8	93.0
Contract assets - insurance agency commissions	97.9	93.9
Lease right of use assets	43.3	46.6
Mortgage servicing rights	18.0	11.1
Other	39.2	80.3
Other assets	3,127.7	2,993.0
Accrued expenses and other liabilities
Reserves for legal claims	814.5	858.9	748.5	$ 729.1
Employee compensation and related liabilities	470.3	531.0
Warranty liability	531.8	512.4	$ 464.0	$ 454.3
Inventory related accruals	363.0	353.6
Broker deposits related to hedging instruments	0.0	118.9
Customer deposits	122.4	147.1
Federal and state income tax liabilities	517.3	233.8
Accrued property taxes	49.5	69.2
Lease liabilities	44.5	48.1
Accrued interest	21.5	33.6
Mortgage hedging instruments and commitments	170.6	15.7
Other	122.0	147.6
Accrued expenses and other liabilities	3,227.4	3,103.8
Interest rate lock commitments [Member]
Other assets
Interest rate lock commitments	81.1	2.3
Accrued expenses and other liabilities
Interest rate lock commitments	$ 0.0	$ 33.9