Amount of contribution received by defined benefit plan from employer which increases plan assets.

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Amount of contributions received and expected to be received by defined benefit plan from employer in current fiscal year.

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Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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Retirement Benefits (Narrative) (Details) - Defined Benefit Pension Plan - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Sep. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Company contributions	$ 35.9	$ 40.8	$ 64.1
Minimum
Defined Benefit Plan Disclosure [Line Items]
Total expected contributions for current fiscal year	50.0
Maximum
Defined Benefit Plan Disclosure [Line Items]
Total expected contributions for current fiscal year	$ 70.0
Discontinued Operations
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 1.3