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Investment Information - Aging of available for sale securities in an unrealized loss position (Details) $ in Millions	Dec. 31, 2025 USD ($) lots	Dec. 31, 2024 USD ($) lots
Estimated Fair Value
Estimated Fair Value - Less than 12 Months	$ 10,128	$ 12,494
Estimated Fair Value - 12 Months or More	2,765	5,080
Estimated Fair Value - Total	12,893	17,574
Gross Unrealized Losses
Gross Unrealized Losses - Less than 12 Months	(121)	(290)
Gross Unrealized Losses - 12 Months or More	(169)	(404)
Gross Unrealized Losses - Total	$ (290)	$ (694)
Continuous unrealized loss, qualitative disclosures:
Number of positions in an unrealized loss position (lots) | lots	7,240	9,980
Total number of positions (lots) | lots	25,330	20,930
Largest single loss	$ 4	$ 8
Fixed maturities available for sale, at fair value
Estimated Fair Value
Estimated Fair Value - Less than 12 Months	9,514	12,397
Estimated Fair Value - 12 Months or More	2,765	5,080
Estimated Fair Value - Total	12,279	17,477
Gross Unrealized Losses
Gross Unrealized Losses - Less than 12 Months	(120)	(288)
Gross Unrealized Losses - 12 Months or More	(169)	(404)
Gross Unrealized Losses - Total	(289)	(692)
Corporate bonds
Estimated Fair Value
Estimated Fair Value - Less than 12 Months	2,972	4,582
Estimated Fair Value - 12 Months or More	1,364	2,924
Estimated Fair Value - Total	4,336	7,506
Gross Unrealized Losses
Gross Unrealized Losses - Less than 12 Months	(64)	(114)
Gross Unrealized Losses - 12 Months or More	(78)	(232)
Gross Unrealized Losses - Total	(142)	(346)
US government and government agencies
Estimated Fair Value
Estimated Fair Value - Less than 12 Months	3,092	5,130
Estimated Fair Value - 12 Months or More	274	516
Estimated Fair Value - Total	3,366	5,646
Gross Unrealized Losses
Gross Unrealized Losses - Less than 12 Months	(15)	(100)
Gross Unrealized Losses - 12 Months or More	(6)	(49)
Gross Unrealized Losses - Total	(21)	(149)
Non-US government securities
Estimated Fair Value
Estimated Fair Value - Less than 12 Months	2,087	1,650
Estimated Fair Value - 12 Months or More	432	418
Estimated Fair Value - Total	2,519	2,068
Gross Unrealized Losses
Gross Unrealized Losses - Less than 12 Months	(35)	(58)
Gross Unrealized Losses - 12 Months or More	(46)	(49)
Gross Unrealized Losses - Total	(81)	(107)
Residential mortgage backed securities
Estimated Fair Value
Estimated Fair Value - Less than 12 Months	312	571
Estimated Fair Value - 12 Months or More	178	186
Estimated Fair Value - Total	490	757
Gross Unrealized Losses
Gross Unrealized Losses - Less than 12 Months	(3)	(6)
Gross Unrealized Losses - 12 Months or More	(18)	(25)
Gross Unrealized Losses - Total	(21)	(31)
Asset backed securities
Estimated Fair Value
Estimated Fair Value - Less than 12 Months	806	236
Estimated Fair Value - 12 Months or More	332	426
Estimated Fair Value - Total	1,138	662
Gross Unrealized Losses
Gross Unrealized Losses - Less than 12 Months	(2)	(8)
Gross Unrealized Losses - 12 Months or More	(13)	(24)
Gross Unrealized Losses - Total	(15)	(32)
Commercial mortgage backed securities
Estimated Fair Value
Estimated Fair Value - Less than 12 Months	239	180
Estimated Fair Value - 12 Months or More	48	434
Estimated Fair Value - Total	287	614
Gross Unrealized Losses
Gross Unrealized Losses - Less than 12 Months	(1)	(1)
Gross Unrealized Losses - 12 Months or More	(4)	(10)
Gross Unrealized Losses - Total	(5)	(11)
Municipal bonds
Estimated Fair Value
Estimated Fair Value - Less than 12 Months	6	48
Estimated Fair Value - 12 Months or More	137	176
Estimated Fair Value - Total	143	224
Gross Unrealized Losses
Gross Unrealized Losses - Less than 12 Months	0	(1)
Gross Unrealized Losses - 12 Months or More	(4)	(15)
Gross Unrealized Losses - Total	(4)	(16)
Short-term investments
Estimated Fair Value
Estimated Fair Value - Less than 12 Months	614	97
Estimated Fair Value - 12 Months or More	0	0
Estimated Fair Value - Total	614	97
Gross Unrealized Losses
Gross Unrealized Losses - Less than 12 Months	(1)	(2)
Gross Unrealized Losses - 12 Months or More	0	0
Gross Unrealized Losses - Total	$ (1)	$ (2)

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