Offsetting of Assets and Liabilities (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Offsetting Assets and Liabilities [Line Items]
Collateral received	$ 0.7	$ 2.8
Gross amounts not offset in the balance sheet	0.0	0.0
Aggregate fair value of all derivative instruments with credit-risk-related contingent features that are in a liability position	1,163.8	111.5
Collateral deposited with derivative counterparties for derivatives instruments with credit-risk-related contingent features that are in a liability position	1,068.3	84.2
Net maximum amount of termination payments that could have been required	95.5	27.3
Net Investment Hedges
Offsetting Assets and Liabilities [Line Items]
Collateral received	257.5
Gross amounts not offset in the balance sheet	$ 150.5
Cash collateral received from derivative counterparties and not offset against derivative assets		93.5
Cash collateral deposited with derivative counterparties not offset against derivative liabilities		$ 43.4