Commitments and Contingencies (Details) (Homebuilding [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Homebuilding [Member]
Changes in warranty liability
Warranty liability, beginning of period	$ 56.6	$ 46.0	$ 56.8	$ 46.2
Warranties issued	6.1	4.3	11.6	8.3
Changes in liability for pre-existing warranties	1.6	1.5	5.2	3.4
Settlements made	(7.0)	(2.9)	(16.3)	(9.0)
Warranty liability, end of period	$ 57.3	$ 48.9	$ 57.3	$ 48.9

Represents the aggregate Increase or Decrease in the liability during the reporting period for accruals related to preexisting standard product warranties (including adjustments related to changes in estimates). Does not include any Increase or Decrease in the liability for accruals related to extended product warranties.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 45

-Paragraph 14

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph ((c)(4))

-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

Name:	us-gaap_StandardProductWarrantyAccrualPreexistingIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration