Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2015	Sep. 30, 2014
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 29.7	$ 39.1
Common stock, shares authorized	450,000,000	450,000,000
Common stock, shares issued	173,806,991	173,770,641