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Retirement Plans (Accumulated and Projected Benefit Obligations) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Sep. 30, 2017
Pension Plans with accumulated benefit obligations in excess of plan assets
Projected benefit obligation	$ 6.2	$ 379.5
Accumulated benefit obligation	6.2	379.5
Fair value of plan assets	5.0	364.2
Pension plans with plan assets in excess of accumulated benefit obligations
Projected benefit obligation	327.1	1.0
Accumulated benefit obligation	327.1	1.0
Fair value of plan assets	$ 338.5	$ 2.1

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Defined Benefit Plan, Pension Plans with Plan Assets in Excess of Accumulated Benefit Obligations [Abstract]

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Amount of accumulated benefit obligation for defined benefit plan with accumulated benefit obligation in excess of plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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