Consolidated Balance Sheets (Parenthetical) (Unaudited) - USD ($) $ in Millions	Dec. 31, 2016	Sep. 30, 2016
EQUITY
Preferred stock, par value (in dollars per share)	$ 0.1	$ 0.1
Preferred stock, shares authorized	30,000,000	30,000,000
Preferred stock, shares issued	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	380,537,875	380,123,258
Common stock, shares outstanding	373,337,804	372,923,187
Treasury stock, shares	7,200,071	7,200,071
Homebuilding [Member]
ASSETS
Valuation allowance for deferred income taxes	$ 10.3	$ 10.3