Other Assets, Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023
Other assets
Earnest money and refundable deposits	$ 2,253.8	$ 2,210.6
Water rights and other water-related assets	320.8	319.1
Insurance receivables	120.0	156.8	$ 131.5
Other receivables	136.3	147.1
Prepaid assets	121.8	117.9
Contract assets - insurance agency commissions	121.5	117.5
Margin deposits related to hedging instruments	0.0	71.3
Lease right of use assets	50.1	51.4
Mortgage servicing rights	10.4	5.9
Mortgage hedging instruments and commitments	55.3	2.8
Other	$ 75.7	$ 72.7
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Other assets	$ 3,270.7	$ 3,317.6
Accrued expenses and other liabilities
Reserves for legal claims	939.1	949.6	814.5	$ 858.9
Employee compensation and related liabilities	505.2	569.7
Warranty liability	570.4	566.9	$ 531.8	$ 512.4
Inventory related accruals	452.4	451.2
Customer deposits	72.5	99.7
Accrued property taxes	52.2	77.6
Mortgage hedging instruments and commitments	3.4	63.0
Lease liabilities	52.3	53.3
Accrued interest	28.6	34.8
Federal and state income tax liabilities	248.5	27.7
Broker deposits related to hedging instruments	43.2	0.0
Other	$ 118.1	$ 123.2
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities	Other Liabilities
Accrued expenses and other liabilities	$ 3,096.5	$ 3,016.7
Interest rate lock commitments [Member]
Other assets
Interest rate lock commitments	5.0	44.5
Accrued expenses and other liabilities
Interest rate lock commitments	$ 10.6	$ 0.0