Investments - Summary of Investments (Detail) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 5,203	$ 6,303
Gross Unrealized Gains	16	40
Gross Unrealized Losses	(15)	(14)
Estimated Fair Value	5,204	6,329
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	77	173
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	77	173
Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	4,006	4,759
Gross Unrealized Gains	14	34
Gross Unrealized Losses	(1)	0
Estimated Fair Value	4,019	4,793
Certificates of deposit
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	12	11
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	12	11
U.S. government and agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,005	1,257
Gross Unrealized Gains	2	6
Gross Unrealized Losses	0	0
Estimated Fair Value	1,007	1,263
Mortgage-backed and asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	103	103
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(14)	(14)
Estimated Fair Value	$ 89	$ 89

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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