Other Assets, Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022
Other assets
Earnest money and refundable deposits	$ 1,955.4		$ 1,859.6
Mortgage hedging instruments and commitments	23.2		153.6
Water rights and other water-related assets	323.0		319.6
Margin deposits related to hedging instruments	2.9		0.0
Other receivables	189.0		167.2
Insurance receivables	134.8		165.8	$ 139.0
Prepaid assets	98.1		93.0
Contract assets - insurance agency commissions	103.9		93.9
Lease right of use assets	46.5		46.6
Mortgage servicing rights	2.8		11.1
Other	56.6		80.3
Other assets	2,982.5		2,993.0
Accrued expenses and other liabilities
Reserves for legal claims	849.3		858.9	768.3		$ 729.1
Employee compensation and related liabilities	539.7		531.0
Warranty liability	544.6	$ 531.8	512.4	$ 474.7	$ 464.0	$ 454.3
Inventory related accruals	375.4		353.6
Broker deposits related to hedging instruments	5.6		118.9
Customer deposits	148.9		147.1
Federal and state income tax liabilities	62.4		233.8
Accrued property taxes	46.6		69.2
Lease liabilities	47.2		48.1
Accrued interest	31.1		33.6
Mortgage hedging instruments and commitments	0.5		15.7
Other	125.9		147.6
Accrued expenses and other liabilities	2,777.4		3,103.8
Interest rate lock commitments [Member]
Other assets
Interest rate lock commitments	46.3		2.3
Accrued expenses and other liabilities
Interest rate lock commitments	$ 0.2		$ 33.9