Other Assets and Accrued Expenses and Other Liabilities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Homebuilding other assets
Homebuilding other assets	$ 501.6	$ 507.3
Homebuilding [Member]
Homebuilding other assets
Insurance receivables	202.0	225.0
Earnest money and refundable deposits	80.4	80.0
Accounts and notes receivable	19.5	21.9
Prepaid assets	31.7	29.4
Other Investments	18.6	0
Other assets	102.0	100.5
Homebuilding other assets	454.2	456.8
Homebuilding accrued expenses and other liabilities
Construction defect and other litigation liabilities	529.8	544.9
Employee compensation and related liabilities	100.3	106.4
Warranty liability	56.6	56.8	46.0	46.2
Accrued interest	28.6	32.6
Federal and state income tax liabilities	25.8	21.6
Other liabilities	115.5	131.5
Homebuilding accrued expenses and other liabilities	$ 856.6	$ 893.8