Fair Value (Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation) (Details) - Fair Value, Measurements, Recurring [Member] $ in Millions	12 Months Ended
	Sep. 30, 2016 USD ($)
Fair Value, Assets [Roll Forward]
Foreign currency derivative, beginning balance	$ 3.3
Foreign currency derivative, ending balance	0.0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets [Roll Forward]
Foreign currency derivative, beginning balance	3.3
Foreign currency derivative, ending balance	0.0
Fair Value, Inputs, Level 3 [Member] | Auction Rate Securities [Member]
Fair Value, Assets [Roll Forward]
Auction rate securities beginning balance	2.3
Changes in fair value included in earnings	0.0
Auction rate securities ending balance	2.3
Fair Value, Inputs, Level 3 [Member] | Derivative [Member]
Fair Value, Assets [Roll Forward]
Foreign currency derivative, beginning balance	3.3
Changes in fair value included in earnings	(3.3)
Foreign currency derivative, ending balance	$ 0.0