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Investments (Summary Of Net Investment Gains (Losses) And The Change In Net Unrealized Gains On Investments) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Gain (Loss) on Securities [Line Items]
Net realized investment gains (losses)	$ 4,695	$ 13,891	$ (13,702)	$ (4,604)
Change in fair value of securities sold during the period	(1,795)	(6,652)	1,345	(11,263)
Change in fair value of securities held at the end of the period	429,986	910,291	876,395	1,705,661
Total change in fair value of equity securities	428,191	903,639	877,740	1,694,398
Net investment gains (losses)	432,886	917,530	864,038	1,689,794
Change in net unrealized losses on available-for-sale investments included in other comprehensive income:	59,823	551,244	595,379	358,877
Fixed Maturity Securities [Member]
Gain (Loss) on Securities [Line Items]
Change in net unrealized losses on available-for-sale investments included in other comprehensive income:	60,844	546,386	585,862	361,659
Short-term investments [Member]
Gain (Loss) on Securities [Line Items]
Change in net unrealized losses on available-for-sale investments included in other comprehensive income:	$ (1,021)	$ 4,858	$ 9,517	$ (2,782)

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- Definition

The net gains or losses on investments during the period, also including gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity.

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

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Amount, before tax and after adjustment, of unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) and unrealized gain (loss) on investment in debt security measured at amortized cost (held-to-maturity) from transfer to available-for-sale.

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