Capitalized Interest (Details) - USD ($) $ in Millions		3 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Rollforward of capitalized interest
Capitalized interest, beginning of period		$ 208.0	$ 198.5
Interest incurred	[1]	42.2	40.4
Interest expensed:
Charged to cost of sales		(35.2)	(33.6)
Written off with inventory impairments		0.0	(0.1)
Capitalized interest, end of period		215.0	205.2
Financial Services [Member]
Rollforward of capitalized interest
Interest incurred		$ 1.6	$ 1.6

[1] Interest incurred includes interest incurred on the Company's financial services mortgage repurchase facility of $1.6 million in both the three months ended December 31, 2015 and 2014.