Related Party Disclosures (Details) $ in Millions	12 Months Ended
	Sep. 30, 2022 USD ($) Lot	Sep. 30, 2021 USD ($) Lot	Sep. 30, 2020 USD ($) Lot
Related Party Transaction [Line Items]
Number of Units in Real Estate Property | Lot	61,800	64,400
Number of Lots Sold | Lot		15,915	10,373
Due to Related Parties, Current	$ 3.2	$ 6.7
D.R. Horton, Inc. [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party	4.1	4.0	$ 5.0
Related Party Transaction, Expenses from Transactions with Related Party	7.4	4.7	2.7
Costs and Expenses, Related Party	6.6	6.1	4.0
Deferred Revenue, Period Increase (Decrease)	1.8	(5.6)	2.3
Related Party Transaction, Purchases from Related Party	2.8	5.7	6.2
D.R. Horton, Inc. [Member] | Reimbursement To Parent [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	0.7	0.5	0.2
D.R. Horton, Inc. [Member] | Deposits [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	8.7	30.8	27.0
D.R. Horton, Inc. [Member] | Other Expense [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	58.9	61.3	36.3
Residential Real Estate [Member] | Real Estate
Related Party Transaction [Line Items]
Residential lot sales	$ 1,455.5	$ 1,293.1	$ 880.3
D.R. Horton, Inc. [Member]
Related Party Transaction [Line Items]
Number of Lots Sold | Lot	14,895	14,839	10,164
Revenue from Related Parties	$ 1,230.0	$ 1,212.1	$ 859.7
D.R. Horton, Inc. [Member] | Land [Member]
Related Party Transaction [Line Items]
Number of Lots Sold | Lot	0	85	143
Revenue from Related Parties	$ 0.0	$ 25.9	$ 25.6
D.R. Horton, Inc. [Member] | Under Contract [Member]
Related Party Transaction [Line Items]
Number of Units in Real Estate Property | Lot	17,800	21,000
Related Party Transaction, Purchase Obligation from Parent	$ 1,389.7	$ 1,582.7
D.R. Horton, Inc. [Member] | Under Contract [Member] | Cash [Member]
Related Party Transaction [Line Items]
Related Party Deposit Liabilities	130.1	143.1
D.R. Horton, Inc. [Member] | Under Contract [Member] | Notes Payable, Other Payables [Member]
Related Party Transaction [Line Items]
Related Party Deposit Liabilities	$ 0.0	$ 0.7
D.R. Horton, Inc. [Member] | Right of First Offer [Member]
Related Party Transaction [Line Items]
Number of Units in Real Estate Property | Lot	18,900	18,200