Equity method investments - Unaudited financial information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022	Mar. 30, 2024	Dec. 30, 2023	Sep. 30, 2023
Schedule Of Equity Method Investments [Line Items]
Assets	$ 1,070,035	$ 1,069,978
Liabilities	492,250	499,208
Sales/ Total revenues and other income	89,869		$ 85,393
The Kraft Heinz Company [Member]
Schedule Of Equity Method Investments [Line Items]
Assets					$ 90,309	$ 90,339
Liabilities					$ 40,621	$ 40,617
Sales/ Total revenues and other income	6,411		6,489
Net earnings attributable to common shareholders	$ 801		$ 836
Occidental Petroleum Corporation [Member]
Schedule Of Equity Method Investments [Line Items]
Assets		74,008					$ 71,287
Liabilities		43,659					$ 42,515
Sales/ Total revenues and other income		7,529		$ 8,326
Net earnings attributable to common shareholders		$ 1,029		$ 1,727