INVESTMENTS - Schedule of Changes in Net Unrealized Appreciation (Depreciation) for Company's Investments (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Increase (decrease) during the period between the fair value and cost of investments carried at fair value, and deferred taxes thereon:
Total other comprehensive income (loss)	$ 177	$ 950	$ 1,118	$ 660
Total URA(D) of securities arising during the period	165	734	762	521
URA(D) of securities
Increase (decrease) during the period between the fair value and cost of investments carried at fair value, and deferred taxes thereon:
Fixed maturity securities - available for sale, held to maturity and short-term investments	202	840	909	563
Equity method investments	0	18	0	18
Total other comprehensive income (loss)	202	857	909	581
Deferred tax benefit (expense)	$ (36)	$ (123)	$ (147)	$ (60)

Amount, before tax, of other comprehensive income (loss) (OCI) for proportionate share of equity method investee's OCI, attributable to parent.

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Amount, after tax and reclassification adjustment, of gain (loss) in value of unsold investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), attributable to parent.

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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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Amount, after adjustment, of tax expense (benefit) for 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 tax expense (benefit) for 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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Amount before tax of other comprehensive income (loss) attributable to parent entity.

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