Equity method investments - Summary of carrying value and fair value of investments (Detail) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 29,585	$ 29,066
Kraft Heinz [Member]
Schedule of Equity Method Investments [Line Items]
Carrying Value	13,274	13,230
Fair Value	12,009	12,035
Occidental [Member]
Schedule of Equity Method Investments [Line Items]
Carrying Value	15,873	15,410
Fair Value	16,119	14,552
Other [Member]
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 438	$ 426