Equity method investments - Narrative (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Sep. 30, 2023
Schedule Of Equity Method Investments [Line Items]
Equity method investments	$ 29,066,000,000	$ 28,050,000,000
Equity method earnings	$ 1,973,000,000	1,863,000,000	$ 886,000,000
The Kraft Heinz Company [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment ownership percentage	26.70%
Percentage of excess of carrying values over fair values of investments	9.00%
Equity method investments	$ 13,230,000,000	12,937,000,000
Equity method earnings	$ 758,000,000	628,000,000	269,000,000
Berkadia Commercial Mortgage LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment ownership percentage	50.00%
Berkadia Commercial Mortgage LLC [Member] | Commercial Paper [Member]
Schedule Of Equity Method Investments [Line Items]
Maximum outstanding balance of commercial paper borrowings	$ 1,500,000,000
Berkadia Commercial Mortgage LLC [Member] | Jefferies Financial Group Inc. [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment ownership percentage	50.00%
Pilot Travel Centers LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investments		3,200,000,000
Equity method earnings	$ 105,000,000	812,000,000	$ 474,000,000
Occidental Petroleum Corporation [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment ownership percentage	27.80%
Percentage of excess of carrying values over fair values of investments	6.00%
Equity method investments	$ 15,410,000,000	11,484,000,000
Equity method earnings	$ 1,077,000,000	$ 323,000,000
Occidental Petroleum Corporation [Member] | Common Stock [Member]
Schedule Of Equity Method Investments [Line Items]
Excess of carrying value of investment over investees equity				$ 9,600,000,000