Consolidated Balance Sheets (Parenthetical) (Unaudited) - USD ($) $ in Millions	Dec. 31, 2015	Sep. 30, 2015
Statement of Financial Position [Abstract]
Valuation allowance for deferred income taxes	$ 10.1	$ 10.1
Preferred stock, par value	$ 0.1	$ 0.1
Preferred stock, shares authorized	30,000,000	30,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	376,927,248	375,847,442
Common stock, shares outstanding	369,727,177	368,647,371
Treasury stock, shares	7,200,071	7,200,071