Capitalized Interest (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Rollforward of capitalized interest
Capitalized interest, beginning of period	$ 191.2	$ 208.0
Interest incurred	33.5	42.2
Interest charged to cost of sales	(34.7)	(35.2)
Capitalized interest, end of period	190.0	215.0
Financial Services and Other [Member]
Rollforward of capitalized interest
Interest incurred	$ 1.7	$ 1.6