Equity method investments - Summary of carrying value and fair value of investments (Detail) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 30,133	$ 29,066
Kraft Heinz [Member]
Schedule of Equity Method Investments [Line Items]
Carrying Value	13,008	13,230
Fair Value	11,426	12,035
Occidental [Member]
Schedule of Equity Method Investments [Line Items]
Carrying Value	16,672	15,410
Fair Value	13,157	14,552
Other [Member]
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 453	$ 426