Retirement and Postretirement Benefit Plans (Tables)

12 Months Ended

Sep. 30, 2017

Master Defined Benefit Retirement Plan [Member]

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

Schedule of Components of Net Pension Expense

The components of net periodic benefit cost for our defined benefit retirement plans were as follows:

	Year Ended September 30
	2017			2016			2015
Service cost	$	5.8		$	5.0		$	5.4
Interest cost	9.9			10.9			14.6
Expected return on plan assets	(14.6		)	(13.0		)	(16.7		)
Amortization of unrecognized prior service cost, net	0.2			0.3			0.6
Amortization of net loss	6.1			4.5			5.2
Net periodic benefit cost	7.4			7.7			9.1
Settlement charge	—			—			9.6
Special termination benefits	0.1			—			—
Net pension expense	$	7.5		$	7.7		$	18.7

Schedule of Changes in Obligations, Assets and Funded Status

The change in benefit obligations, plan assets and funded status, along with amounts recognized in the Consolidated Balance Sheets for our defined benefit retirement plans were as follows:

	Year Ended September 30
	2017			2016
Change in benefit obligation:
Benefit obligation at beginning of year	$	347.1		$	315.5
Service cost	5.8			5.0
Interest cost	9.9			10.9
Actuarial loss (gain)	(5.7		)	27.4
Benefits paid	(12.5		)	(11.9		)
Special termination benefits	0.1			—
Exchange rate loss	1.1			0.2
Benefit obligation at end of year	345.8			347.1
Change in plan assets:
Fair value of plan assets at beginning of year	267.0			219.1
Actual return on plan assets	28.8			28.8
Employer contributions	1.1			31.0
Benefits paid	(12.5		)	(11.9		)
Fair value of plan assets at end of year	284.4			267.0
Funded status and net amounts recognized	$	(61.4	)	$	(80.1	)
Amounts recorded in the Consolidated Balance Sheets:
Accrued pension benefits, current portion	$	(1.2	)	$	(1.1	)
Accrued pension benefits, long-term	(60.2		)	(79.0		)
Net amount recognized	$	(61.4	)	$	(80.1	)

Schedule of Accumulated Benefit Obligation

Selected information for our plans, including plans with accumulated benefit obligations exceeding plan assets, was as follows:

	September 30
	2017						2016
	PBO		ABO		Plan Assets		PBO		ABO		Plan Assets
Master plan	$	319.8	$	301.5	$	284.1	$	319.6	$	300.7	$	266.8
International plans	20.8		19.0		0.3		22.2		20.3		0.2
Supplemental executive plan	5.2		5.2		—		5.3		5.3		—
	$	345.8	$	325.7	$	284.4	$	347.1	$	326.3	$	267.0

Schedule of Actuarial Assumptions

The weighted average assumptions used in accounting for our domestic pension plans were as follows:

	2017	2016	2015
Weighted average assumptions to determine benefit obligations at the measurement date:
Discount rate for obligation	3.9%	3.7%	4.4%
Rate of compensation increase	3.0%	3.0%	3.0%
Weighted average assumptions to determine benefit cost for the year:
Discount rate for expense	3.7%	4.4%	4.5%
Expected rate of return on plan assets	5.8%	5.8%	6.8%
Rate of compensation increase	3.0%	3.0%	3.0%

Schedule of Allocation of Plan Assets

The weighted average asset allocations of our master defined benefit retirement plan at September 30, 2017 and 2016, by asset category, along with target allocations, are as follows:

	2017 Target Allocation	2016 Target Allocation	2017 Actual Allocation	2016 Actual Allocation
Equity securities	37% - 45%	39 - 49%	42%	43%
Fixed income securities	55% - 63%	51 - 61%	58%	57%
Total			100%	100%

Schedule of Fair Value Measurements of Plan Assets

The following table summarizes the valuation of our pension plan assets by pricing categories:

	Balance at September 30, 2017		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash	$	7.2	$	7.2	$	—	$	—
Equities (a)
U.S. companies	58.6		—		—		—
International companies	59.4		—		—		—
Fixed income securities (a)	159.2		—		—		—
Total plan assets at fair value	$	284.4	$	7.2	$	—	$	—

	Balance at September 30, 2016		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash	$	3.7	$	3.7	$	—	$	—
Equities (a)
U.S. companies	59.3		—		—		—
International companies	56.4		—		—		—
Fixed income securities (a)	147.6		—		—		—
Total plan assets at fair value	$	267.0	$	3.7	$	—	$	—

(a) These investments are commingled funds and/or collective trusts valued using the net asset value ("NAV") unit price provided by the fund administrator. The NAV is based on the value of the underlying assets owned by the fund. During fiscal 2017, we adopted revised disclosure guidance related to investments measured at NAV as a practical expedient, under which they are no longer categorized in the fair value hierarchy. For further descriptions of the asset Levels used in the above chart, refer to Note 1 of our Consolidated Financial Statements.

Schedule of Estimated Future Benefit Payments

The benefit payments, which are expected to be funded through plan assets and company contributions and reflect expected future service, are expected to be paid as follows:

	Pension Benefits
2018	$	13.7
2019	$	13.8
2020	$	14.6
2021	$	15.4
2022	$	16.0
2023-2027	$	91.4

Postretirement Health Care Plan [Member]

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

Schedule of Changes in Obligations, Assets and Funded Status

The change in the accumulated postretirement benefit obligation was as follows:

	Year Ended September 30
	2017			2016
Change in benefit obligation:
Benefit obligation at beginning of year	$	21.6		$	25.1
Service cost	0.4			0.3
Interest cost	0.5			0.8
Plan amendments	(0.7		)	—
Actuarial gain	(1.8		)	(3.7		)
Benefits paid	(0.9		)	(1.5		)
Retiree contributions	0.3			0.6
Benefit obligation at end of year	$	19.4		$	21.6
Amounts recorded in the Consolidated Balance Sheets:
Accrued benefits obligation, current portion	$	1.5		$	1.6
Accrued benefits obligation, long-term	17.9			20.0
Net amount recognized	$	19.4		$	21.6