Notes Payable (Details) (USD $) In Millions	Jun. 30, 2011	Sep. 30, 2010
Unsecured:
Notes payable	$ 1,880.4	$ 2,171.8
Mortgage repurchase facility, maturing 2012	116.3
Homebuilding [Member] | 6% senior notes due 2011, net [Member]
Unsecured:
Notes payable	0	70.1
Homebuilding [Member] | 7.875% senior notes due 2011, net [Member]
Unsecured:
Notes payable	106.0	118.8
Homebuilding [Member] | 5.375% senior notes due 2012 [Member]
Unsecured:
Notes payable	0	146.6
Homebuilding [Member] | 6.875% senior notes due 2013 [Member]
Unsecured:
Notes payable	171.7	174.3
Homebuilding [Member] | 6.125% senior notes due 2014, net [Member]
Unsecured:
Notes payable	145.2	146.0
Homebuilding [Member] | 2% convertible senior notes due 2014, net [Member]
Unsecured:
Notes payable	411.3	391.9
Homebuilding [Member] | 5.625% senior notes due 2014, net [Member]
Unsecured:
Notes payable	137.5	147.1
Homebuilding [Member] | 5.25% senior notes due 2015, net [Member]
Unsecured:
Notes payable	189.1	199.7
Homebuilding [Member] | 5.625% senior notes due 2016, net [Member]
Unsecured:
Notes payable	204.8	225.5
Homebuilding [Member] | 6.5% senior notes due 2016, net [Member]
Unsecured:
Notes payable	392.7	430.1
Homebuilding [Member] | Other secured [Member]
Unsecured:
Notes payable	5.8	35.2
Homebuilding [Member]
Unsecured:
Notes payable	1,764.1	2,085.3
Financial Services [Member]
Unsecured:
Mortgage repurchase facility, maturing 2012	$ 116.3	$ 86.5