Other Assets and Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Homebuilding other assets
Homebuilding other assets	$ 499.6	$ 527.3
Homebuilding [Member]
Homebuilding other assets
Insurance receivables	88.7	126.5
Earnest money and refundable deposits	219.7	136.2
Accounts and notes receivable	35.9	49.2
Prepaid assets	29.5	40.9
Rental properties	56.9	47.1
Debt securities collateralized by residential real estate	0.0	33.9
Other assets	25.5	21.2
Homebuilding other assets	456.2	455.0
Homebuilding accrued expenses and other liabilities
Reserves for legal claims	423.5	451.0	$ 456.9
Employee compensation and related liabilities	183.3	171.8
Warranty liability	104.4	82.0	$ 65.7
Accrued interest	17.9	30.7
Federal and state income tax liabilities	28.1	36.1
Inventory related accruals	31.9	30.0
Homebuyer deposits	54.2	58.9
Accrued property taxes	35.2	32.0
Other liabilities	38.6	34.9
Homebuilding accrued expenses and other liabilities	$ 917.1	$ 927.4