Fair value of investment in debt security measured at amortized cost (held-to-maturity) and investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-5A

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aa)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

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Amount of allowance for credit loss for debt security measured at amortized cost (held-to-maturity).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (aaa)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-5

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

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Debt Securities, Available-for-sale and Held-to-maturity, Amortized Cost, Net

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Marketable Securities Debt Maturities Without Single Maturity Date Amortized Cost

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Marketable Securities Debt Maturities Without Single Maturity Date Fair Value

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Marketable Securities Fixed Maturities After Five Through Ten Years Amortized Cost

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Marketable Securities Fixed Maturities After Five Through Ten Years Fair Value

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Marketable Securities Fixed Maturities After One Through Five Years Amortized Cost

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Marketable Securities Fixed Maturities After One Through Five Years Fair Value

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Marketable Securities Fixed Maturities After Ten Years Amortized Cost

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Marketable Securities Fixed Maturities After Ten Years Fair Value

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Marketable Securities Fixed Maturities Within One Year Amortized Cost

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Marketable Securities Fixed Maturities Within One Year Fair Value

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Investments in Fixed Maturity Securities (Amortized cost and fair value of fixed maturity securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Mar. 31, 2026	Dec. 31, 2025	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Amortized Cost, Due in one year or less	$ 1,729,781
Amortized Cost, Due after one year through five years	8,051,862
Amortized Cost, Due after five years through ten years	4,419,675
Amortized Cost, Due after ten years	7,469,359
Amortized Cost, Mortgaged-backed securities	4,594,960
Total investments in fixed maturity securities, Amortized Value	26,265,637
Fair Value, Due in one year or less	1,699,290
Fair Value, Due after one year through five years	7,894,090
Fair Value, Due after five years through ten years	4,403,306
Fair Value, Due after ten years	7,418,231
Fair Value, Mortgage-backed securities	4,485,511
Total investments in fixed maturity securities, Fair Value	25,900,428		$ 25,048,534
Cumulative effect adjustment resulting from changes in accounting principles	$ 0	$ 0	$ 9	$ 14	$ 20	$ 25