Equity method investments - Narrative (Detail) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Mar. 31, 2023	Dec. 31, 2022
Schedule Of Equity Method Investments [Line Items]
Equity method investments		$ 27,493,000,000		$ 27,493,000,000			$ 28,050,000,000
Equity method earnings		$ 511,000,000	$ 204,000,000	$ 1,199,000,000	$ 543,000,000
The Kraft Heinz Company [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment ownership percentage		26.50%		26.50%
Equity method investments		$ 13,199,000,000		$ 13,199,000,000			12,937,000,000
Equity method earnings		$ 265,000,000	71,000,000	$ 487,000,000	277,000,000
Occidental Petroleum Corporation [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment ownership percentage		25.10%		25.10%
Equity method investments		$ 13,861,000,000		$ 13,861,000,000			11,484,000,000
Equity method earnings		$ 234,000,000		$ 604,000,000
Occidental Petroleum Corporation [Member] | Common Stock [Member]
Schedule Of Equity Method Investments [Line Items]
Excess of carrying value of investment over investees equity						$ 9,000,000,000
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		$ 95,000,000		$ 202,000,000