Outstanding Commitments to Fund Equity Method Limited Liability Investments

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- Definition

Percentage of Equity Method Limited Liability Investments reported with a One Month Lag

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Percentage of Equity Method Limited Liability Investments reported without a Lag

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- Definition

Percentage of Unrealized Loss Position to Amortized Cost Basis of Available for Sale Security Average

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Variable Interest Entity, Funding Investment Commitment, Funding

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- Definition

Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), without single maturity date and not allocated over maturity grouping.

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- Definition

Amount of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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- Definition

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current.

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Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount of cumulative impairment loss on investment in equity security without readily determinable fair value.

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Amount of liabilities classified as other.

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Amount due from parties in nontrade transactions, classified as other.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

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Investments - Narrative (Details) - USD ($)	3 Months Ended
Investments - Narrative (Details) - USD ($)	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Mortgage- and Asset-backed Securities Not Due at a Single Maturity Date	$ 1,701,500,000
Fixed maturities, allowance for credit losses	9,100,000	$ 4,600,000	$ 7,500,000	$ 3,300,000
Equity securities	571,500,000		830,600,000
Equity securities, FV-NI, unrealized gain (loss)	(24,000,000)
Equity securities without readily determinable fair value, impairment loss, cumulative amount	10,000,000
Other Receivables	203,400,000		207,300,000
Equity Securities at Fair Value (Cost: 2022 - $466.0; 2021 - $618.7)	$ 571,500,000		830,600,000
Percentage of Equity Method Limited Liability Investments reported with a lag	3.20%
Percentage of Equity Method Limited Liability Investments reported with a One Month Lag	10.80%
Government National Mortgage Association Certificates and Obligations (GNMA)
Debt Securities, Available-for-sale [Line Items]
Mortgage- and Asset-backed Securities Not Due at a Single Maturity Date	$ 390,700,000
Federal National Mortgage Association Certificates and Obligations (FNMA)
Debt Securities, Available-for-sale [Line Items]
Mortgage- and Asset-backed Securities Not Due at a Single Maturity Date	65,800,000
Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC)
Debt Securities, Available-for-sale [Line Items]
Mortgage- and Asset-backed Securities Not Due at a Single Maturity Date	29,500,000
Other Non-Governmental Issuers
Debt Securities, Available-for-sale [Line Items]
Mortgage- and Asset-backed Securities Not Due at a Single Maturity Date	1,215,500,000
Investments in Fixed Maturities
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, unrealized loss position, accumulated loss	288,100,000		32,700,000
12 Months or Longer	35,400,000		5,900,000
Other Receivables	1,900,000		600,000
Other liabilities	73,400,000		12,700,000
Equity Securities
Debt Securities, Available-for-sale [Line Items]
Other Receivables	0
Other liabilities		2,700,000
Equity Securities \| Fair Value, Measurements, Recurring
Debt Securities, Available-for-sale [Line Items]
Equity securities	571,500,000		830,600,000
Equity Securities at Fair Value (Cost: 2022 - $466.0; 2021 - $618.7)	571,500,000		830,600,000
Equity Securities \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Measurements, Recurring
Debt Securities, Available-for-sale [Line Items]
Equity securities	203,900,000		453,800,000
Equity Securities at Fair Value (Cost: 2022 - $466.0; 2021 - $618.7)	203,900,000		453,800,000
Preferred Stocks \| Other Industries \| Fair Value, Measurements, Recurring
Debt Securities, Available-for-sale [Line Items]
Equity securities	16,400,000		17,600,000
Equity Securities at Fair Value (Cost: 2022 - $466.0; 2021 - $618.7)	16,400,000		17,600,000
Preferred Stocks \| Other Industries \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Measurements, Recurring
Debt Securities, Available-for-sale [Line Items]
Equity securities	0		0
Equity Securities at Fair Value (Cost: 2022 - $466.0; 2021 - $618.7)	0		0
Common Stock \| Other Industries \| Fair Value, Measurements, Recurring
Debt Securities, Available-for-sale [Line Items]
Equity securities	1,800,000		2,900,000
Equity Securities at Fair Value (Cost: 2022 - $466.0; 2021 - $618.7)	1,800,000		2,900,000
Common Stock \| Other Industries \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Measurements, Recurring
Debt Securities, Available-for-sale [Line Items]
Equity securities	1,400,000		2,900,000
Equity Securities at Fair Value (Cost: 2022 - $466.0; 2021 - $618.7)	1,400,000		2,900,000
Bonds and Notes
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, unrealized loss position, accumulated loss	130,900,000		16,000,000.0
12 Months or Longer	23,700,000		2,900,000
Fixed maturities, allowance for credit losses	9,100,000	4,300,000	7,500,000	$ 3,000,000.0
Equity Method Investments
Debt Securities, Available-for-sale [Line Items]
Other Receivables	4,700,000		1,200,000
Other liabilities	500,000		0
Variable Interest Entity, Not Primary Beneficiary
Debt Securities, Available-for-sale [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	22,400,000
Variable Interest Entity, Funding Investment Commitment, Funding	0	$ 48,500,000
Variable Interest Entity, Not Primary Beneficiary \| Equity Method Limited Liability Investments
Debt Securities, Available-for-sale [Line Items]
Outstanding commitments to fund equity method limited liability investments	92,200,000
Investment-grade \| Investments in Fixed Maturities
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, unrealized loss position, accumulated loss	270,900,000		23,700,000
Non-investment-grade \| Investments in Fixed Maturities
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, unrealized loss position, accumulated loss	$ 17,200,000		$ 9,000,000
Percentage of unrealized loss position to amortized cost basis of available for sale security average	6.00%		4.00%