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Fixed Maturity Securities In An Unrealized Loss Position (Non-Investment Grade Fixed Maturity Securities) (Details) $ in Thousands | Jun. 30, 2022 USD ($) position | Dec. 31, 2021 USD ($)
--- | --- | ---
Corporate |  |
Debt Securities, Available-for-sale [Line Items] |  |
Aggregate Fair Value | $ 5,275,097 | $ 2,633,955
Gross Unrealized Loss | 331,893 | 32,410
State and municipal |  |
Debt Securities, Available-for-sale [Line Items] |  |
Aggregate Fair Value | 1,885,012 | 531,880
Gross Unrealized Loss | 105,287 | 9,559
Mortgage-backed |  |
Debt Securities, Available-for-sale [Line Items] |  |
Aggregate Fair Value | 1,339,398 | 664,881
Gross Unrealized Loss | 118,819 | 11,662
Asset-backed |  |
Debt Securities, Available-for-sale [Line Items] |  |
Aggregate Fair Value | 3,981,949 | 3,908,329
Gross Unrealized Loss | $ 129,549 | $ 18,794
Noninvestment Grade Investments at Loss Position |  |
Debt Securities, Available-for-sale [Line Items] |  |
Number of Securities | position | 69 |
Aggregate Fair Value | $ 187,894 |
Gross Unrealized Loss | $ 60,318 |
Noninvestment Grade Investments at Loss Position | Foreign government |  |
Debt Securities, Available-for-sale [Line Items] |  |
Number of Securities | position | 42 |
Aggregate Fair Value | $ 124,609 |
Gross Unrealized Loss | $ 52,655 |
Noninvestment Grade Investments at Loss Position | Corporate |  |
Debt Securities, Available-for-sale [Line Items] |  |
Number of Securities | position | 12 |
Aggregate Fair Value | $ 46,437 |
Gross Unrealized Loss | $ 5,739 |
Noninvestment Grade Investments at Loss Position | State and municipal |  |
Debt Securities, Available-for-sale [Line Items] |  |
Number of Securities | position | 1 |
Aggregate Fair Value | $ 13,248 |
Gross Unrealized Loss | $ 1,756 |
Noninvestment Grade Investments at Loss Position | Mortgage-backed |  |
Debt Securities, Available-for-sale [Line Items] |  |
Number of Securities | position | 11 |
Aggregate Fair Value | $ 3,513 |
Gross Unrealized Loss | $ 144 |
Noninvestment Grade Investments at Loss Position | Asset-backed |  |
Debt Securities, Available-for-sale [Line Items] |  |
Number of Securities | position | 3 |
Aggregate Fair Value | $ 87 |
Gross Unrealized Loss | $ 24 |

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