Unrealized Losses on Debt Investments (Detail) - USD ($) $ in Millions	Dec. 31, 2025	Jun. 30, 2025
Unrealized Losses on Investments [Line Items]
Less than 12 Months - Fair Value	$ 830	$ 4,560
Less than 12 Months - Unrealized Losses	(9)	(65)
12 Months or Greater - Fair Value	31,365	38,176
12 Months or Greater - Unrealized Losses	(1,137)	(1,560)
Total Fair Value	32,195	42,736
Total Unrealized Losses	(1,146)	(1,625)
U.S. government and agency securities
Unrealized Losses on Investments [Line Items]
Less than 12 Months - Fair Value	350	2,569
Less than 12 Months - Unrealized Losses	(4)	(51)
12 Months or Greater - Fair Value	28,600	34,608
12 Months or Greater - Unrealized Losses	(1,042)	(1,411)
Total Fair Value	28,950	37,177
Total Unrealized Losses	(1,046)	(1,462)
Foreign government bonds
Unrealized Losses on Investments [Line Items]
Less than 12 Months - Fair Value	48	43
Less than 12 Months - Unrealized Losses	(3)	(2)
12 Months or Greater - Fair Value	83	106
12 Months or Greater - Unrealized Losses	(3)	(7)
Total Fair Value	131	149
Total Unrealized Losses	(6)	(9)
Mortgage- and asset-backed securities
Unrealized Losses on Investments [Line Items]
Less than 12 Months - Fair Value	0	841
Less than 12 Months - Unrealized Losses	0	(4)
12 Months or Greater - Fair Value	202	189
12 Months or Greater - Unrealized Losses	(21)	(23)
Total Fair Value	202	1,030
Total Unrealized Losses	(21)	(27)
Corporate notes and bonds
Unrealized Losses on Investments [Line Items]
Less than 12 Months - Fair Value	432	1,107
Less than 12 Months - Unrealized Losses	(2)	(8)
12 Months or Greater - Fair Value	2,318	3,105
12 Months or Greater - Unrealized Losses	(53)	(98)
Total Fair Value	2,750	4,212
Total Unrealized Losses	(55)	(106)
Municipal securities
Unrealized Losses on Investments [Line Items]
Less than 12 Months - Fair Value	0	0
Less than 12 Months - Unrealized Losses	0	0
12 Months or Greater - Fair Value	162	168
12 Months or Greater - Unrealized Losses	(18)	(21)
Total Fair Value	162	168
Total Unrealized Losses	$ (18)	$ (21)

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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 continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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