Equity method investments - Unaudited financial information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 25, 2021
Schedule Of Equity Method Investments [Line Items]
Assets	$ 1,069,978		$ 948,465	$ 959,388
Liabilities	499,208		466,784
Sales/ Total revenues and other income	364,482		302,020	$ 276,185
The Kraft Heinz Company [Member]
Schedule Of Equity Method Investments [Line Items]
Assets	90,339		90,513
Liabilities	40,617		41,643
Sales/ Total revenues and other income	26,640		26,485		$ 26,042
Net earnings attributable to common shareholders	$ 2,855		2,363		$ 1,012
Occidental Petroleum Corporation [Member]
Schedule Of Equity Method Investments [Line Items]
Assets		$ 71,827	72,609
Liabilities		42,515	$ 42,524
Sales/ Total revenues and other income		29,715
Net earnings attributable to common shareholders		$ 4,471