Significant accounting policies and practices - Narrative (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2020	Aug. 04, 2022	Dec. 31, 2021	Jan. 01, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Percentage of LIFO Inventory	30.00%
Excess of current or replacement costs over costs determined under LIFO	$ 2,500			$ 1,900
Retained earnings	511,602			534,421
Property and Casualty Contracts [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Unamortized balances of deferred policy acquisition costs	3,200			2,900
Other Assets [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Unamortized balances of deferred policy acquisition costs	$ 3,800			3,400
Maximum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Trade receivables, insurance premium receivables and other receivables collection term	1 year
Insurance interest rate assumption	7.00%
Maximum [Member] | Buildings and improvements [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	50 years
Maximum [Member] | Machinery and equipment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	25 years
Maximum [Member] | Furniture, fixtures and other [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	15 years
Maximum [Member] | Track structure and other roadway [Member] | Railroad [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	100 years
Maximum [Member] | Locomotives, freight cars and other equipment [Member] | Railroad [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	43 years
Maximum [Member] | Utility generation, transmission and distribution systems [Member] | Utilities and Energy [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	80 years
Maximum [Member] | Interstate natural gas pipeline assets [Member] | Utilities and Energy [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	80 years
Maximum [Member] | Independent power plants and other assets [Member] | Utilities and Energy [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	50 years
Maximum [Member] | Equipment held for lease [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	35 years
Minimum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Insurance interest rate assumption	3.00%
Minimum [Member] | Occidental Petroleum Corporation [Member] | Occidental Common Stock [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Voting interests of investee			20.00%
Minimum [Member] | Buildings and improvements [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	5 years
Minimum [Member] | Machinery and equipment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	3 years
Minimum [Member] | Furniture, fixtures and other [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	3 years
Minimum [Member] | Track structure and other roadway [Member] | Railroad [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	10 years
Minimum [Member] | Locomotives, freight cars and other equipment [Member] | Railroad [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	6 years
Minimum [Member] | Utility generation, transmission and distribution systems [Member] | Utilities and Energy [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	5 years
Minimum [Member] | Interstate natural gas pipeline assets [Member] | Utilities and Energy [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	3 years
Minimum [Member] | Independent power plants and other assets [Member] | Utilities and Energy [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	2 years
Minimum [Member] | Equipment held for lease [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful life (in years)	3 years
ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2020
ASU 2016-13 [Member] | Cumulative effect, period of adoption, adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings					$ (388)
ASU 2018-12 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings		$ (700)
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2023
Cumulative increase (decrease) in shareholders equity	$ 1,000	$ (6,400)		$ (4,600)
Percentage of cumulative after tax reduction in consolidated shareholders equity		1.40%		0.90%
Reduction to accumulated other comprehensive income		$ (5,700)