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Investment Securities - Investments Held on Deposit or as Collateral (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Debt and Equity Securities, FV-NI [Line Items]
Investments held in trusts	$ 463.7	$ 479.5
Assets held by insurance regulators	4.8	4.8
Other long-term investments	1,428.5	1,377.8
Lloyd’s trust deposits
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	113.2	113.8
Short-term investments
Debt and Equity Securities, FV-NI [Line Items]
Investments pledged as collateral	50.0	50.0
Lloyds Bank
Debt and Equity Securities, FV-NI [Line Items]
Investments held in trusts	113.2
Fair value investments	$ 305.6	$ 342.8

X

- Definition

Carrying amount of cash and investment securities on deposit with state regulatory authorities in connection with capital requirements.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 825
-Section 50
-Paragraph 1A
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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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Amount of long-term investments classified as other.

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Fair value of financial instrument held by the entity for its own account (proprietary securities) for trading or investment purposes that are carried at fair value and pledged to counterparties as collateral for financing transactions.

+ References

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-Name Accounting Standards Codification
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-SubTopic 30
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Investments Held In Trusts

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