Derivatives - Derivatives Presented on a Net Asset and Net Liability basis (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Assets
Gross Amounts on Balance Sheet	$ 18.5	$ 0.0
Effect of Counter-Party Netting	(18.5)	0.0
Net Amounts	0.0	0.0
Liabilities
Gross Amounts on Balance Sheet	88.6	88.7
Effect of Counter-Party Netting	(18.5)	0.0
Net Amounts	70.1	88.7
Interest rate swaps
Assets
Gross Amounts on Balance Sheet	18.4	0.0
Effect of Counter-Party Netting	(18.4)	0.0
Net Amounts	0.0	0.0
Liabilities
Gross Amounts on Balance Sheet	87.7	87.0
Effect of Counter-Party Netting	(18.4)	0.0
Net Amounts	69.3	87.0
Foreign currency contracts
Assets
Gross Amounts on Balance Sheet	0.1	0.0
Effect of Counter-Party Netting	(0.1)	0.0
Net Amounts	0.0	0.0
Liabilities
Gross Amounts on Balance Sheet	0.9	1.7
Effect of Counter-Party Netting	(0.1)	0.0
Net Amounts	$ 0.8	$ 1.7

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