Income Taxes - Schedule of Tax Attributes and Valuation Allowances (Details) - USD ($) $ in Millions	Sep. 30, 2019	Sep. 30, 2018
Tax Benefit Amount
Capital loss carryforward	$ 9.5	$ 10.0
Net operating loss carryforwards	18.5	19.6
Tax credit carryforward	16.5	$ 17.9
Subtotal - tax carryforwards	44.5
Other deferred tax assets	71.9
Total	116.4
Valuation Allowance
Tax credit carryforward	71.9
Subtotal	21.9
Total	93.8
Non-United States
Tax Benefit Amount
Net operating loss carryforward, subject to expiration	7.2
Net operating loss carryforward, indefinite	3.3
Capital loss carryforward	9.5
Deferred Tax Assets, Capital Loss Carryforwards, Valuation Allowance	9.5
Valuation Allowance
Net operating loss carryforward, subject to expiration	7.2
Net operating loss carryforward, indefinite	3.1
United States
Tax Benefit Amount
Net operating loss carryforwards	0.4
Valuation Allowance
Net operating loss carryforward, subject to expiration	0.0
State and Local
Tax Benefit Amount
Net operating loss carryforwards	7.6
Tax credit carryforward	16.5
Valuation Allowance
Net operating loss carryforward, subject to expiration	1.4
Tax credit carryforward	$ 0.7