Fair Value Measurements - Fair Value Inputs (Details) - USD ($) | 3 Months Ended | 6 Months Ended | | | | |
Jun. 30, 2023 | Jun. 30, 2022 | Jun. 30, 2023 | Jun. 30, 2022 | Mar. 31, 2023 | Dec. 31, 2022 | Mar. 31, 2022 | Dec. 31, 2021 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | $ 6,943,800,000 | | $ 6,943,800,000 | | | $ 6,894,800,000 | | |
Equity securities | 247,000,000 | | 247,000,000 | | | 243,200,000 | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases | 19,600,000 | $ 9,900,000 | 39,000,000 | $ 23,600,000 | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 | 0 | 0 | 400,000 | 5,300,000 | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value | 201,500,000 | 191,300,000 | 201,500,000 | 191,300,000 | $ 210,200,000 | 230,000,000 | $ 218,900,000 | $ 251,400,000 |
Included in Condensed Consolidated Statement of Operations | (800,000) | (200,000) | (900,000) | (5,900,000) | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 | (100,000) | (5,700,000) | (100,000) | (5,700,000) | | | | |
Included in Other Comprehensive Income (Loss) | 700,000 | (8,800,000) | 2,400,000 | (11,800,000) | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements | 0 | 0 | 0 | 0 | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales | (28,100,000) | (22,800,000) | (69,300,000) | (65,600,000) | | | | |
Fair Value, Equity Securities FV-NI, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 0 | | 0 | | | 0 | | |
Fair Value, Equity Method Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 90,500,000 | | 90,500,000 | | | 95,900,000 | | |
Other Funds | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fair Value, Alternative Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 0 | | 0 | | | 200,000 | | |
Fair Value, Equity Method Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 0 | | 0 | | | 0 | | |
Equity Securities | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases | 1,100,000 | 0 | 1,100,000 | 0 | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 | 0 | 0 | 400,000 | 0 | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value | 2,200,000 | 1,700,000 | 2,200,000 | 1,700,000 | 2,000,000 | 2,100,000 | 1,500,000 | 1,500,000 |
Included in Condensed Consolidated Statement of Operations | (900,000) | 0 | (1,400,000) | 0 | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 | 0 | | 0 | 0 | | | | |
Included in Other Comprehensive Income (Loss) | 0 | 200,000 | 0 | 200,000 | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements | 0 | 0 | 0 | 0 | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales | 0 | 0 | 0 | 0 | | | | |
Redeemable Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases | 0 | 2,000,000 | 0 | 2,000,000 | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 | | 0 | 0 | 0 | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value | 6,700,000 | 6,900,000 | 6,700,000 | 6,900,000 | $ 6,800,000 | 6,800,000 | $ 5,600,000 | $ 6,100,000 |
Included in Condensed Consolidated Statement of Operations | 0 | 0 | 0 | 0 | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 | | 0 | 0 | 0 | | | | |
Included in Other Comprehensive Income (Loss) | (100,000) | (700,000) | (100,000) | (1,200,000) | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements | 0 | 0 | 0 | 0 | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales | 0 | $ 0 | 0 | $ 0 | | | | |
Fair Value Measured at Net Asset Value Per Share | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Total Assets | 444,900,000 | | 444,900,000 | | | 430,700,000 | | |
Fair Value, Alternative Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 110,700,000 | | 110,700,000 | | | 96,300,000 | | |
Fair Value, Measurements, Recurring | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Convertible debt at fair value | 46,200,000 | | 46,200,000 | | | 43,300,000 | | |
Total Assets | 7,240,200,000 | | 7,240,200,000 | | | 7,183,000,000 | | |
Derivative Asset | 3,200,000 | | 3,200,000 | | | 1,700,000 | | |
Liabilities, Fair Value Disclosure | | | | | | 400,000 | | |
Fair Value, Measurements, Recurring | Investments in Fixed Maturities | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 6,943,800,000 | | 6,943,800,000 | | | 6,894,800,000 | | |
Fair Value, Measurements, Recurring | U.S. Government and Government Agencies and Authorities | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 545,500,000 | | 545,500,000 | | | 528,000,000 | | |
Fair Value, Measurements, Recurring | States and Political Subdivisions | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 1,461,000,000 | | 1,461,000,000 | | | 1,568,900,000 | | |
Fair Value, Measurements, Recurring | Foreign Governments | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 4,000,000 | | 4,000,000 | | | 4,100,000 | | |
Fair Value, Measurements, Recurring | Bonds and Notes | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 3,633,400,000 | | 3,633,400,000 | | | 3,539,400,000 | | |
Fair Value, Measurements, Recurring | Redeemable Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 7,900,000 | | 7,900,000 | | | 8,000,000 | | |
Fair Value, Measurements, Recurring | Collateralized Loan Obligations | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 987,200,000 | | 987,200,000 | | | 953,900,000 | | |
Fair Value, Measurements, Recurring | Other Mortgage- and Asset-backed | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 304,800,000 | | 304,800,000 | | | 292,500,000 | | |
Fair Value, Measurements, Recurring | Equity Securities | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 247,000,000 | | 247,000,000 | | | 243,200,000 | | |
Fair Value, Measurements, Recurring | Exchange Traded Funds | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 7,300,000 | | 7,300,000 | | | 12,200,000 | | |
Fair Value, Measurements, Recurring | Limited Liability Companies and Limited Partnerships | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 197,000,000 | | 197,000,000 | | | 189,100,000 | | |
Fair Value, Measurements, Recurring | Designated as Hedging Instrument | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Derivative Asset | | | | | | (400,000) | | |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Convertible debt at fair value | 0 | | 0 | | | | | |
Total Assets | 128,300,000 | | 128,300,000 | | | 117,000,000 | | |
Convertible Securities, Fair Value Disclosures | | | | | | 0 | | |
Derivative Asset | 0 | | 0 | | | 0 | | |
Liabilities, Fair Value Disclosure | | | | | | 0 | | |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Investments in Fixed Maturities | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 120,000,000 | | 120,000,000 | | | 103,600,000 | | |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Government and Government Agencies and Authorities | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 120,000,000 | | 120,000,000 | | | 103,600,000 | | |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | States and Political Subdivisions | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | 0 | | |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Foreign Governments | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | 0 | | |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Bonds and Notes | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | 0 | | |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Redeemable Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | | | |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Redeemable Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | | | | | | 0 | | |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Collateralized Loan Obligations | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | 0 | | |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Mortgage- and Asset-backed | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | 0 | | |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity Securities | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 8,300,000 | | 8,300,000 | | | 13,400,000 | | |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Exchange Traded Funds | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 7,300,000 | | 7,300,000 | | | 12,200,000 | | |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Limited Liability Companies and Limited Partnerships | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 0 | | 0 | | | 0 | | |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Designated as Hedging Instrument | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Derivative Liability | | | | | | 0 | | |
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Convertible debt at fair value | 46,200,000 | | 46,200,000 | | | 43,300,000 | | |
Total Assets | 6,713,400,000 | | 6,713,400,000 | | | 6,646,900,000 | | |
Derivative Asset | 3,200,000 | | 3,200,000 | | | 1,700,000 | | |
Derivative Liability | | | | | | (400,000) | | |
Liabilities, Fair Value Disclosure | | | | | | (400,000) | | |
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Investments in Fixed Maturities | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 6,624,500,000 | | 6,624,500,000 | | | 6,563,300,000 | | |
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | U.S. Government and Government Agencies and Authorities | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 425,500,000 | | 425,500,000 | | | 424,400,000 | | |
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | States and Political Subdivisions | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 1,461,000,000 | | 1,461,000,000 | | | 1,568,900,000 | | |
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Foreign Governments | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 4,000,000 | | 4,000,000 | | | 4,100,000 | | |
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Bonds and Notes | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 3,446,000,000 | | 3,446,000,000 | | | 3,323,400,000 | | |
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Redeemable Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 1,200,000 | | 1,200,000 | | | | | |
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Redeemable Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | | | | | | 1,200,000 | | |
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Collateralized Loan Obligations | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 987,200,000 | | 987,200,000 | | | 953,900,000 | | |
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Other Mortgage- and Asset-backed | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 299,600,000 | | 299,600,000 | | | 287,400,000 | | |
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Equity Securities | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 39,500,000 | | 39,500,000 | | | 38,600,000 | | |
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Exchange Traded Funds | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 0 | | 0 | | | 0 | | |
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Limited Liability Companies and Limited Partnerships | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 0 | | 0 | | | 0 | | |
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Convertible debt at fair value | 0 | | 0 | | | 0 | | |
Total Assets | 201,500,000 | | 201,500,000 | | | 230,000,000 | | |
Derivative Asset | 0 | | 0 | | | 0 | | |
Liabilities, Fair Value Disclosure | | | | | | 0 | | |
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Investments in Fixed Maturities | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 199,300,000 | | 199,300,000 | | | 227,900,000 | | |
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | U.S. Government and Government Agencies and Authorities | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | 0 | | |
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | States and Political Subdivisions | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | 0 | | |
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Foreign Governments | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | 0 | | |
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Bonds and Notes | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 187,400,000 | | 187,400,000 | | | 216,000,000 | | |
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Redeemable Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 6,700,000 | | 6,700,000 | | | | | |
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Redeemable Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | | | | | | 6,800,000 | | |
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Collateralized Loan Obligations | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | 0 | | |
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Other Mortgage- and Asset-backed | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 5,200,000 | | 5,200,000 | | | 5,100,000 | | |
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Equity Securities | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 2,200,000 | | 2,200,000 | | | 2,100,000 | | |
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Exchange Traded Funds | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 0 | | 0 | | | 0 | | |
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Limited Liability Companies and Limited Partnerships | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 0 | | 0 | | | 0 | | |
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Designated as Hedging Instrument | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Derivative Liability | | | | | | 0 | | |
Finance, Insurance and Real Estate | Fair Value, Measurements, Recurring | Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 30,000,000 | | 30,000,000 | | | 29,000,000 | | |
Finance, Insurance and Real Estate | Fair Value, Measurements, Recurring | Common Stock | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 600,000 | | 600,000 | | | 900,000 | | |
Finance, Insurance and Real Estate | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 0 | | 0 | | | 0 | | |
Finance, Insurance and Real Estate | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Common Stock | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 600,000 | | 600,000 | | | 900,000 | | |
Finance, Insurance and Real Estate | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 30,000,000 | | 30,000,000 | | | 29,000,000 | | |
Finance, Insurance and Real Estate | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Common Stock | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 0 | | 0 | | | 0 | | |
Finance, Insurance and Real Estate | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 0 | | 0 | | | 0 | | |
Finance, Insurance and Real Estate | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Common Stock | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 0 | | 0 | | | 0 | | |
Other Industries | Fair Value, Measurements, Recurring | Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 11,300,000 | | 11,300,000 | | | 10,800,000 | | |
Other Industries | Fair Value, Measurements, Recurring | Common Stock | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 800,000 | | 800,000 | | | 1,200,000 | | |
Other Industries | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 0 | | 0 | | | 0 | | |
Other Industries | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Common Stock | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 400,000 | | 400,000 | | | 300,000 | | |
Other Industries | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 9,500,000 | | 9,500,000 | | | 9,200,000 | | |
Other Industries | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Common Stock | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 0 | | 0 | | | 400,000 | | |
Other Industries | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 1,800,000 | | 1,800,000 | | | 1,600,000 | | |
Other Industries | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Common Stock | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 400,000 | | 400,000 | | | 500,000 | | |
Measured at Net Asset Value | Fair Value, Measurements, Recurring | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Convertible debt at fair value | 0 | | 0 | | | 0 | | |
Total Assets | 197,000,000 | | 197,000,000 | | | 189,100,000 | | |
Derivative Asset | 0 | | 0 | | | 0 | | |
Liabilities, Fair Value Disclosure | | | | | | 0 | | |
Measured at Net Asset Value | Fair Value, Measurements, Recurring | Investments in Fixed Maturities | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | 0 | | |
Measured at Net Asset Value | Fair Value, Measurements, Recurring | U.S. Government and Government Agencies and Authorities | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | 0 | | |
Measured at Net Asset Value | Fair Value, Measurements, Recurring | States and Political Subdivisions | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | 0 | | |
Measured at Net Asset Value | Fair Value, Measurements, Recurring | Foreign Governments | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | 0 | | |
Measured at Net Asset Value | Fair Value, Measurements, Recurring | Bonds and Notes | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | 0 | | |
Measured at Net Asset Value | Fair Value, Measurements, Recurring | Redeemable Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | | | |
Measured at Net Asset Value | Fair Value, Measurements, Recurring | Redeemable Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | | | | | | 0 | | |
Measured at Net Asset Value | Fair Value, Measurements, Recurring | Collateralized Loan Obligations | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | 0 | | |
Measured at Net Asset Value | Fair Value, Measurements, Recurring | Other Mortgage- and Asset-backed | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Fixed maturities at fair value | 0 | | 0 | | | 0 | | |
Measured at Net Asset Value | Fair Value, Measurements, Recurring | Equity Securities | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 197,000,000 | | 197,000,000 | | | 189,100,000 | | |
Measured at Net Asset Value | Fair Value, Measurements, Recurring | Exchange Traded Funds | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 0 | | 0 | | | 0 | | |
Measured at Net Asset Value | Fair Value, Measurements, Recurring | Limited Liability Companies and Limited Partnerships | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 197,000,000 | | 197,000,000 | | | 189,100,000 | | |
Measured at Net Asset Value | Fair Value, Measurements, Recurring | Designated as Hedging Instrument | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Derivative Liability | | | | | | 0 | | |
Measured at Net Asset Value | Finance, Insurance and Real Estate | Fair Value, Measurements, Recurring | Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 0 | | 0 | | | 0 | | |
Measured at Net Asset Value | Finance, Insurance and Real Estate | Fair Value, Measurements, Recurring | Common Stock | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 0 | | 0 | | | 0 | | |
Measured at Net Asset Value | Other Industries | Fair Value, Measurements, Recurring | Preferred Stocks | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | 0 | | 0 | | | 0 | | |
Measured at Net Asset Value | Other Industries | Fair Value, Measurements, Recurring | Common Stock | | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | | | | | |
Equity securities | $ 0 | | $ 0 | | | $ 0 | | |