Homebuilding Interest (Details) (Homebuilding [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Homebuilding [Member]
Rollforward of capitalized homebuilding interest
Capitalized interest, beginning of period	$ 81.1	$ 88.6	$ 79.2	$ 91.5
Interest incurred	31.1	31.4	87.2	100.5
Interest expensed:
Directly to interest expense	(6.2)	(10.1)	(18.7)	(41.0)
Amortized to cost of sales	(24.7)	(25.3)	(66.4)	(65.7)
Written off with inventory impairments	(0.1)	(0.2)	(0.1)	(0.9)
Capitalized interest, end of period	$ 81.2	$ 84.4	$ 81.2	$ 84.4