Investments - Offsetting of Assets and Liabilities (Details) - Free-standing derivatives - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Asset derivatives:
Gross Amounts	$ 10.6	$ 16.8
Gross Amounts Offset in the Consolidated Balance Sheets	0.0	0.0
Net Amounts of Assets/ Liabilities Presented in the Consolidated Balance Sheets	10.6	16.8
Gross Amounts Not Offset in the Consolidated Balance Sheets, Financial Instruments	9.8	13.7
Gross Amounts Not Offset in the Consolidated Balance Sheets, Cash Collateral Received	3.5	2.6
Net Amount	$ (2.7)	$ 0.5

Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

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