Investments -Schedule of Investments (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 3,951	$ 3,988
Gross Unrealized Gains	20	52
Gross Unrealized Losses	41	32
Estimated Fair Value	3,930	4,008
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,406	2,437
Gross Unrealized Gains	13	35
Gross Unrealized Losses	11	7
Estimated Fair Value	2,408	2,465
Mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	995	963
Gross Unrealized Gains	5	11
Gross Unrealized Losses	25	21
Estimated Fair Value	975	953
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	356	363
Gross Unrealized Gains	1	3
Gross Unrealized Losses	3	2
Estimated Fair Value	354	364
Municipal securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	150	158
Gross Unrealized Gains	1	2
Gross Unrealized Losses	1	1
Estimated Fair Value	150	159
U.S. Treasury notes
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		20
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Estimated Fair Value		20
Other
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	44	47
Gross Unrealized Gains	0	1
Gross Unrealized Losses	1	1
Estimated Fair Value	$ 43	$ 47

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) 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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