Fair value measurements - Financial assets and liabilities (Detail) - USD ($) $ in Millions		Sep. 30, 2022		Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		$ 18,602		$ 16,434
Investments in equity securities		306,167	[1]	350,719	[2]
Insurance and Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		18,602		16,434
Investments in equity securities		306,167		350,719
The Kraft Heinz Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		10,853		11,683
U.S. Treasury, U.S. government corporations and agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		8,775		3,303
Foreign governments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		8,505		10,994
Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		1,029		1,774
Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		293		363
Fair Value, Measurements, Recurring [Member] | Quoted Prices (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in equity securities		294,094		339,225
Derivative contract assets	[3]	$ 68		$ 6
Derivative Asset, Statement of Financial Position [Extensible Enumeration]		Other		Other
Derivative contract liabilities	[3]	$ 2		$ 2
Derivative Liability, Statement of Financial Position [Extensible Enumeration]		Accounts payable, accruals and other liabilities		Accounts payable, accruals and other liabilities
Fair Value, Measurements, Recurring [Member] | Quoted Prices (Level 1) [Member] | The Kraft Heinz Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value				$ 11,683
Fair Value, Measurements, Recurring [Member] | Quoted Prices (Level 1) [Member] | The Kraft Heinz Company and Occidental Petroleum Corporation [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		$ 22,796
Fair Value, Measurements, Recurring [Member] | Quoted Prices (Level 1) [Member] | U.S. Treasury, U.S. government corporations and agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		8,740		3,261
Fair Value, Measurements, Recurring [Member] | Quoted Prices (Level 1) [Member] | Foreign governments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		8,207		10,286
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in equity securities		7		8
Loans and finance receivables		1,744		2,178
Derivative contract assets	[3]	$ 593		$ 230
Derivative Asset, Statement of Financial Position [Extensible Enumeration]		Other		Other
Derivative contract liabilities	[3]	$ 133		$ 150
Derivative Liability, Statement of Financial Position [Extensible Enumeration]		Accounts payable, accruals and other liabilities		Accounts payable, accruals and other liabilities
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Insurance and Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable and other borrowings		$ 36,314		$ 42,292
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Railroad, Utilities and Energy [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable and other borrowings		66,991		87,065
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. Treasury, U.S. government corporations and agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		35		42
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign governments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		298		708
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		1,029		1,774
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		293		363
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in equity securities		12,066		11,486
Loans and finance receivables		20,915		19,996
Derivative contract assets	[3]	$ 70		$ 93
Derivative Asset, Statement of Financial Position [Extensible Enumeration]		Other		Other
Derivative contract liabilities	[3]	$ 126		$ 224
Derivative Liability, Statement of Financial Position [Extensible Enumeration]		Accounts payable, accruals and other liabilities		Accounts payable, accruals and other liabilities
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Insurance and Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable and other borrowings		$ 48		$ 47
Fair Value, Measurements, Recurring [Member] | Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in equity securities		306,167		350,719
Loans and finance receivables		22,094		20,751
Derivative contract assets	[3]	$ 731		$ 329
Derivative Asset, Statement of Financial Position [Extensible Enumeration]		Other		Other
Derivative contract liabilities	[3]	$ 261		$ 376
Derivative Liability, Statement of Financial Position [Extensible Enumeration]		Accounts payable, accruals and other liabilities		Accounts payable, accruals and other liabilities
Fair Value, Measurements, Recurring [Member] | Carrying Value [Member] | Insurance and Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable and other borrowings		$ 41,535		$ 39,272
Fair Value, Measurements, Recurring [Member] | Carrying Value [Member] | Railroad, Utilities and Energy [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable and other borrowings		74,961		74,990
Fair Value, Measurements, Recurring [Member] | Carrying Value [Member] | The Kraft Heinz Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value				13,112
Fair Value, Measurements, Recurring [Member] | Carrying Value [Member] | The Kraft Heinz Company and Occidental Petroleum Corporation [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		23,949
Fair Value, Measurements, Recurring [Member] | Carrying Value [Member] | U.S. Treasury, U.S. government corporations and agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		8,775		3,303
Fair Value, Measurements, Recurring [Member] | Carrying Value [Member] | Foreign governments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		8,505		10,994
Fair Value, Measurements, Recurring [Member] | Carrying Value [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		1,029		1,774
Fair Value, Measurements, Recurring [Member] | Carrying Value [Member] | Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		293		363
Fair Value, Measurements, Recurring [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in equity securities		306,167		350,719
Loans and finance receivables		22,659		22,174
Derivative contract assets	[3]	$ 731		$ 329
Derivative Asset, Statement of Financial Position [Extensible Enumeration]		Other		Other
Derivative contract liabilities	[3]	$ 261		$ 376
Derivative Liability, Statement of Financial Position [Extensible Enumeration]		Accounts payable, accruals and other liabilities		Accounts payable, accruals and other liabilities
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | Insurance and Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable and other borrowings		$ 36,362		$ 42,339
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | Railroad, Utilities and Energy [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable and other borrowings		66,991		87,065
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | The Kraft Heinz Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value				11,683
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | The Kraft Heinz Company and Occidental Petroleum Corporation [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		22,796
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | U.S. Treasury, U.S. government corporations and agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		8,775		3,303
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | Foreign governments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		8,505		10,994
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		1,029		1,774
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in fixed maturity securities		$ 293		$ 363

[1] Approximately 73% of the aggregate fair value was concentrated in five companies (American Express Company – $20.5 billion; Apple Inc. – $126.5 billion; Bank of America Corporation – $31.2 billion; The Coca-Cola Company – $22.4 billion and Chevron Corporation – $24.4 billion).

[2] Approximately 73% of the aggregate fair value was concentrated in four companies (American Express Company – $24.8 billion; Apple Inc. – $161.2 billion; Bank of America Corporation – $46.0 billion and The Coca-Cola Company – $23.7 billion).

[3] Assets are included in other assets and liabilities are included in accounts payable, accruals and other liabilities.