Unrealized Losses on Debt Investments (Detail) - USD ($) $ in Millions	Jun. 30, 2022	Jun. 30, 2021
Unrealized Losses on Investments [Line Items]
Less than 12 Months - Fair Value	$ 69,641	$ 11,389
Less than 12 Months - Unrealized Losses	(2,368)	(132)
12 Months or Greater - Fair Value	3,138	127
12 Months or Greater - Unrealized Losses	(446)	(3)
Total Fair Value	72,779	11,516
Total Unrealized Losses	(2,814)	(135)
U.S. government and agency securities
Unrealized Losses on Investments [Line Items]
Less than 12 Months - Fair Value	59,092	5,294
Less than 12 Months - Unrealized Losses	(1,835)	(111)
12 Months or Greater - Fair Value	2,210	0
12 Months or Greater - Unrealized Losses	(352)	0
Total Fair Value	61,302	5,294
Total Unrealized Losses	(2,187)	(111)
Foreign government bonds
Unrealized Losses on Investments [Line Items]
Less than 12 Months - Fair Value	418	3,148
Less than 12 Months - Unrealized Losses	(18)	(1)
12 Months or Greater - Fair Value	27	5
12 Months or Greater - Unrealized Losses	(6)	(1)
Total Fair Value	445	3,153
Total Unrealized Losses	(24)	(2)
Mortgage- and asset-backed securities
Unrealized Losses on Investments [Line Items]
Less than 12 Months - Fair Value	510	1,211
Less than 12 Months - Unrealized Losses	(26)	(5)
12 Months or Greater - Fair Value	41	87
12 Months or Greater - Unrealized Losses	(4)	(1)
Total Fair Value	551	1,298
Total Unrealized Losses	(30)	(6)
Corporate notes and bonds
Unrealized Losses on Investments [Line Items]
Less than 12 Months - Fair Value	9,443	1,678
Less than 12 Months - Unrealized Losses	(477)	(8)
12 Months or Greater - Fair Value	786	34
12 Months or Greater - Unrealized Losses	(77)	(1)
Total Fair Value	10,229	1,712
Total Unrealized Losses	(554)	(9)
Municipal securities
Unrealized Losses on Investments [Line Items]
Less than 12 Months - Fair Value	178	58
Less than 12 Months - Unrealized Losses	(12)	(7)
12 Months or Greater - Fair Value	74	1
12 Months or Greater - Unrealized Losses	(7)	0
Total Fair Value	252	59
Total Unrealized Losses	$ (19)	$ (7)