Plant and Equipment, Net (Narratives) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2015
Property, Plant and Equipment [Line Items]
Plant and equipment, net	$ 9,619.0		$ 9,636.9
Project suspension costs	14.3	$ 0.0
Energy From Waste [Member]
Property, Plant and Equipment [Line Items]
Plant and equipment, net	938.9
Project suspension costs	14.3
Project suspension costs, after-tax	$ 11.4
Project suspension costs, per share	$ 0.05