Investments - Schedule of Unrealized Loss (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	$ 20,644	$ 27,288
Gross Unrealized Losses	2,286	3,039
Additional impairment losses	0
AAA
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	1,376	1,800
Gross Unrealized Losses	243	282
AA
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	3,827	4,247
Gross Unrealized Losses	623	730
A
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	5,025	6,330
Gross Unrealized Losses	440	582
BBB
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	7,758	11,548
Gross Unrealized Losses	639	980
U.S. Government, Government agencies and Government-sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	1,980	2,567
Gross Unrealized Losses	267	373
Non-investment grade
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	678	796
Gross Unrealized Losses	$ 74	$ 92

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss.

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