Fair Value Measurements (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Deferred compensation investment	$ 11.5	$ 10.3
Derivative Asset	3.0	0.6
Assets, Fair Value Disclosure	14.5	10.9
Deferred compensation liabilities	17.3	14.2
Derivative Liabilities	318.7	138.7
Liabilities, Fair Value Disclosure	336.0	152.9
4.57% 2012 Series Bond	1.3	2.9
Capital Lease Obligations	0.0	2.8
Loss on write-down of assets held for sale	(9.3)	(34.2)	$ (5.4)
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Deferred compensation investment	11.5	10.3
Derivative Asset	0.0	0.0
Assets, Fair Value Disclosure	11.5	10.3
Deferred compensation liabilities	0.0	0.0
Derivative Liabilities	0.0	0.0
Liabilities, Fair Value Disclosure	0.0	0.0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Deferred compensation investment	0.0	0.0
Derivative Asset		0.6
Assets, Fair Value Disclosure	3.0	0.6
Deferred compensation liabilities	17.3	14.2
Derivative Liabilities		138.7
Liabilities, Fair Value Disclosure	336.0	152.9
Debt Instrument, Fair Value Disclosure	4,852.2	4,520.8
4.57% 2012 Series Bond	1.3	2.9
Capital Lease Obligations	0.0	2.8
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of assets held-for-sale	10.1	11.4	$ 16.4
Increase (Decrease) in Assets Held-for-sale	9.6	46.2
Loss on write-down of assets held for sale	(9.3)	(34.2)
Proceeds from Sale of Property Held-for-sale	(1.6)	(24.0)
Gain on sale of plant		7.0
Senior Notes | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Instrument, Fair Value Disclosure	4,835.9	4,112.5
Term Loan | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Instrument, Fair Value Disclosure	0.0	374.0
TEUs | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Instrument, Fair Value Disclosure	15.0	28.6
Assets, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative Asset, Fair Value, Gross Asset		0.6
Assets, Total [Member] | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative Asset, Fair Value, Gross Asset	3.0
Liabilities, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative Liability, Fair Value, Gross Liability		$ 138.7
Liabilities, Total [Member] | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative Liability, Fair Value, Gross Liability	$ 318.7