Related Party Disclosures (Details) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2023 USD ($) Lot	Jun. 30, 2022 USD ($) Lot	Jun. 30, 2023 USD ($) Lot	Jun. 30, 2022 USD ($) Lot	Sep. 30, 2022 USD ($) Lot
Related Party Transaction [Line Items]
Selling, General and Administrative Expense	$ 26.4	$ 24.1	$ 71.3	$ 69.9
Costs and Expenses, Related Party			$ 1.2	5.6
Number of Units in Real Estate Property | Lot	53,700		53,700		61,800
Revenues	$ 368.9	308.5	$ 887.1	1,137.7
D.R. Horton, Inc. [Member]
Related Party Transaction [Line Items]
Selling, General and Administrative Expense			2.8	3.1
Employee Benefits and Share-Based Compensation			6.6	5.5
D.R. Horton, Inc. [Member]
Related Party Transaction [Line Items]
Deferred Revenue, Period Increase (Decrease)	0.6	0.5	4.0	2.1
Related Party Transaction, Purchases from Related Party	0.1	0.4	0.6	2.0
Accrued Liabilities and Other Liabilities	1.4		1.4		$ 3.2
D.R. Horton, Inc. [Member] | Deposits [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction		4.2	0.1	9.6
D.R. Horton, Inc. [Member] | Other Expense [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	6.7	18.3	17.1	56.1
Residential Real Estate [Member] | Real Estate
Related Party Transaction [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 334.8	$ 295.1	$ 794.3	$ 1,108.2
D.R. Horton, Inc. [Member]
Related Party Transaction [Line Items]
Number of Lots Sold | Lot	3,187	3,038	7,947	11,823
Revenues	$ 270.4	$ 257.6	$ 677.4	$ 975.7
D.R. Horton, Inc. [Member] | Land held for future development
Related Party Transaction [Line Items]
Number of Lots Sold | Lot	45	0	424	0
Revenues	$ 22.8	$ 0.0	$ 55.3	$ 0.0
D.R. Horton, Inc. [Member] | Under Contract [Member]
Related Party Transaction [Line Items]
Number of Units in Real Estate Property | Lot	13,600		13,600		17,800
Related Party Transaction, Purchase Obligation from Parent	$ 1,272.4		$ 1,272.4		$ 1,389.7
D.R. Horton, Inc. [Member] | Under Contract [Member] | Cash [Member]
Related Party Transaction [Line Items]
Related Party Deposit Liabilities	$ 111.6		$ 111.6		$ 130.1
D.R. Horton, Inc. [Member] | Right of First Offer [Member]
Related Party Transaction [Line Items]
Number of Units in Real Estate Property | Lot	16,900		16,900		18,900