Employee Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Components of net periodic benefit cost
Curtailment/settlement	$ 3.8	$ 9.7	$ 4.1
Contract Extension Period						5 years
Amounts included in accumulated other comprehensive income (loss) prior service costs and unrecognized net actuarial losses expected to be recognized in Pension and Supplemental Employee Retirement Plan
Prior service cost included in accumulated other comprehensive income (loss)				$ 1.7
Prior service cost included in accumulated other comprehensive income (loss), net of tax				1.1
Unrecognized net actuarial losses included in accumulated other comprehensive income (loss)				2.3
Unrecognized net actuarial losses included in accumulated other comprehensive income (loss), net of tax				1.5
Pension Plan, Defined Benefit
Change in projected benefit obligation
Plan amendments						$ (8.1)
Components of net periodic benefit cost
Curtailment/settlement					$ (6.8)	(2.8)
United States Pension Plan of US Entity [Member]
Employee benefit plans
Accumulated benefit obligation	395.4			410.3	395.4
Change in projected benefit obligation
Benefit obligation at the beginning of the period				403.2	350.0
Service cost				8.2	8.1	13.2
Interest cost				18.1	17.7	16.1
Actuarial (loss) gain				(3.3)	51.7
Participant contributions				0.2	0.2
Plan amendments				(1.1)	(1.1)
Curtailments				0.0	(2.5)
Benefits paid				(11.1)	(23.1)
Currency translation adjustments				(1.5)	0.0
Benefit obligation at the end of the period	403.2			414.9	403.2	350.0
Defined Benefit Plan, Settlements, Benefit Obligation					1.4
Change in plan assets
Fair value of plan assets at the beginning of the period				320.6	308.0
Actual return on plan assets				4.7	36.2
Company contributions				2.7	2.5
Participant contributions				0.2	0.2
Expenses paid				(2.8)	(3.2)
Benefits paid				(11.1)	(23.1)
Currency translation adjustments				(1.8)	0.0
Fair value of plan assets at the end of the period	320.6			312.5	320.6	308.0
Funded status of plan - underfunded at September 30	(82.6)			(102.4)	(82.6)
Recognized in consolidated balance sheet at September 30
Prepaid benefit cost (long-term asset)	4.0			3.9	4.0
Accrued benefit liability (current liability)	(1.5)			(1.5)	(1.5)
Accrued benefit liability (long-term liability)	(85.1)			(104.8)	(85.1)
Total	(82.6)			(102.4)	(82.6)
Recognized in accumulated other comprehensive income (loss) as of September 30 (net of taxes)
Net actuarial (loss) gain	(42.2)			(47.0)	(42.2)
Prior service (cost) benefit	(9.9)			(9.5)	(9.9)
Total	$ (52.1)			$ (56.5)	$ (52.1)
Weighted-average assumptions as of September 30
Discount rate (as a percent)	4.52%			4.45%	4.52%
Expected return on plan assets (as a percent)	6.25%			6.03%	6.25%
Accumulated benefit obligations in excess of plan assets
Projected benefit obligation	$ 380.6			$ 391.6	$ 380.6
Accumulated benefit obligation	372.2			385.2	372.2
Fair value of plan assets	294.1			285.4	294.1
Components of net periodic benefit cost
Service cost				8.2	8.1	13.2
Interest cost				18.1	17.7	16.1
Expected return on plan assets				(17.9)	(19.8)	(17.0)
Amortization of prior service cost (benefit)				1.7	2.0	1.9
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements and Curtailments				0.0	8.2	2.8
Amortization of net actuarial loss				2.6	0.6	4.4
Expenses paid				2.8	3.2	2.2
Net periodic benefit cost (income)				15.5	20.0	23.6
Other changes in plan assets and benefit obligations recognized in other comprehensive income
Net actuarial loss (gain)				10.0	32.8	(75.9)
Prior service cost				1.1	1.1	8.1
Amortization of prior service benefit (cost)				1.7	2.0	1.9
Curtailment/settlement				0.0	(8.2)	(2.8)
Amortization of net actuarial loss				2.6	0.6	4.4
Total				$ 6.8	$ 23.1	$ (76.9)
Weighted-average assumptions
Discount rate (as a percent)				4.52%	5.07%	4.24%
Expected return on plan assets (as a percent)				6.25%	6.50%	6.25%
Rate of compensation increase (as a percent)						3.69%
Health care cost trend rate
Payments for Postemployment Benefits				$ 13.5
Supplemental Executive Retirement Plans
Employee benefit plans
Pension and Other Postretirement Defined Benefit Plans, Liabilities				0.8	$ 1.7	$ 1.7
Change in plan assets
Fair value of plan assets at the end of the period				21.6
Other Postretirement Benefit Plan [Member]
Employee benefit plans
Average remaining years of service (in years)						18 years
Accumulated benefit obligation	44.0			37.5	44.0
Change in projected benefit obligation
Benefit obligation at the beginning of the period				44.0	42.5
Service cost				1.7	2.2	$ 7.3
Interest cost				1.7	2.0	3.2
Actuarial (loss) gain				(5.5)	2.4
Participant contributions				0.0	0.1
Plan amendments				0.0	0.0	(24.6)
Curtailments				(2.2)	(3.1)
Benefits paid				(2.2)	(2.1)
Currency translation adjustments				0.0	0.0
Benefit obligation at the end of the period	44.0			37.5	44.0	42.5
Change in plan assets
Fair value of plan assets at the beginning of the period				0.0	0.0
Actual return on plan assets				0.0	0.0
Company contributions				2.2	2.0
Participant contributions				0.0	0.1
Expenses paid				0.0	0.0
Benefits paid				(2.2)	(2.1)
Currency translation adjustments				0.0	0.0
Fair value of plan assets at the end of the period	0.0			0.0	0.0	0.0
Funded status of plan - underfunded at September 30	(44.0)			(37.5)	(44.0)
Recognized in consolidated balance sheet at September 30
Prepaid benefit cost (long-term asset)	0.0			0.0	0.0
Accrued benefit liability (current liability)	(2.4)			(1.6)	(2.4)
Accrued benefit liability (long-term liability)	(41.6)			(35.9)	(41.6)
Total	(44.0)			(37.5)	(44.0)
Recognized in accumulated other comprehensive income (loss) as of September 30 (net of taxes)
Net actuarial (loss) gain	(4.1)			0.8	(4.1)
Prior service (cost) benefit	12.0			9.3	12.0
Total	$ 7.9			$ 10.1	$ 7.9
Weighted-average assumptions as of September 30
Discount rate (as a percent)	4.04%			4.08%	4.04%
Components of net periodic benefit cost
Service cost				$ 1.7	$ 2.2	7.3
Interest cost				1.7	2.0	3.2
Expected return on plan assets				0.0	0.0	0.0
Amortization of prior service cost (benefit)				(0.9)	(1.6)	(0.5)
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements and Curtailments				(3.4)	(10.0)	(2.9)
Amortization of net actuarial loss				0.1	0.2	1.1
Expenses paid				0.0	0.0	0.0
Net periodic benefit cost (income)				(0.8)	(7.2)	8.2
Other changes in plan assets and benefit obligations recognized in other comprehensive income
Net actuarial loss (gain)				(7.7)	(0.8)	(22.0)
Prior service cost				0.0	0.0	(24.6)
Amortization of prior service benefit (cost)				(0.9)	(1.6)	(0.5)
Curtailment/settlement				3.4	10.0	2.9
Amortization of net actuarial loss				0.1	0.2	1.1
Total				$ (3.5)	$ 10.6	$ (44.3)
Weighted-average assumptions
Discount rate (as a percent)				4.04%	4.76%	3.95%
Health care cost trend rate
Health care cost trend rate (as a percent)				7.00%
Assumed health care cost trend rate for next fiscal year (as a percent)				5.00%
Increase in accumulated postretirement benefit obligation with 100 basis points increase in health care cost trend rate				$ 7.5
Increase in net periodic postretirement benefit cost with 100 basis points increase in health care cost trend rate				0.8
Decrease in accumulated postretirement benefit obligation with 100 basis points decrease in health care cost trend rate				5.5
Decrease in net periodic postretirement benefit cost with 100 basis points decrease in health care cost trend rate				$ 0.6