Investments in equity securities (Detail) - USD ($) $ in Millions	Jun. 30, 2023	[1]	Dec. 31, 2022	[2]
Summary of Investment Holdings [Line Items]
Cost Basis	$ 115,657		$ 131,610
Net Unrealized Gains	237,752		177,183
Fair Value	353,409		308,793
Banks, insurance and finance [Member]
Summary of Investment Holdings [Line Items]
Cost Basis	23,547		25,893
Net Unrealized Gains	43,056		43,663
Fair Value	66,603		69,556
Consumer Products [Member]
Summary of Investment Holdings [Line Items]
Cost Basis	36,550		40,508
Net Unrealized Gains	169,760		112,384
Fair Value	206,310		152,892
Commercial, industrial and other [Member]
Summary of Investment Holdings [Line Items]
Cost Basis	55,560		65,209
Net Unrealized Gains	24,936		21,136
Fair Value	$ 80,496		$ 86,345

[1] Approximately 78% of the aggregate fair value was concentrated in five companies (American Express Company – $26.4 billion; Apple Inc. – $177.6 billion; Bank of America Corporation – $29.6 billion; The Coca-Cola Company – $24.1 billion and Chevron Corporation – $19.4 billion).

[2] Approximately 75% of the aggregate fair value was concentrated in five companies (American Express Company – $22.4 billion; Apple Inc. – $119.0 billion; Bank of America Corporation – $34.2 billion; The Coca-Cola Company – $25.4 billion and Chevron Corporation – $30.0 billion).