Equity method investments - Narrative (Detail) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Jan. 31, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Jun. 30, 2023	Dec. 31, 2022
Schedule Of Equity Method Investments [Line Items]
Equity method investments		$ 27,496,000,000		$ 27,496,000,000			$ 28,050,000,000
Equity method earnings		$ 262,000,000	$ 415,000,000	$ 1,461,000,000	$ 958,000,000
The Kraft Heinz Company [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment ownership percentage		26.50%		26.50%
Equity method investments		$ 13,073,000,000		$ 13,073,000,000			12,937,000,000
Equity method earnings		$ 69,000,000	114,000,000	$ 556,000,000	391,000,000
Occidental Petroleum Corporation [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment ownership percentage		25.30%		25.30%
Equity method investments		$ 13,987,000,000		$ 13,987,000,000			11,484,000,000
Equity method earnings		$ 169,000,000		$ 773,000,000
Occidental Petroleum Corporation [Member] | Common Stock [Member]
Schedule Of Equity Method Investments [Line Items]
Excess of carrying value of investment over investees equity						$ 8,800,000,000
Berkadia Commercial Mortgage LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment ownership percentage		50.00%		50.00%
Berkadia Commercial Mortgage LLC [Member] | Jefferies Financial Group Inc. [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment ownership percentage		50.00%		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		$ 1,500,000,000
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		$ 275,000,000		$ 477,000,000