Revenue from contracts with customers disaggregated by reportable segment and source of revenue (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 48,110	$ 37,378	$ 92,733	$ 78,830
Other revenues	21,004	19,462	40,980	39,275
Total revenues	69,114	56,840	133,713	118,105
Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,635	4,676	11,048	10,839
Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,114	3,665	9,513	7,360
Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,604	3,009	8,767	6,337
Grocery and Convenience Store Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	7,729	7,287	15,171	15,146
Food and Beverage Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,356	3,787	8,360	7,593
Auto Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,750	1,895	5,062	3,804
Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,762	3,107	9,121	6,645
Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8,962	6,633	16,781	14,272
Electricity and Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,198	3,319	8,910	6,834
Manufacturing Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16,428	12,140	31,385	26,274
Other revenues	947	877	1,870	1,757
Total revenues	17,375	13,017	33,255	28,031
Manufacturing Businesses [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,586	4,631	10,949	10,750
Manufacturing Businesses [Member] | Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,114	3,665	9,513	7,360
Manufacturing Businesses [Member] | Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,604	3,009	8,767	6,337
Manufacturing Businesses [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	754	487	1,457	1,092
Manufacturing Businesses [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	370	348	699	735
McLane Company [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	12,268	11,196	23,865	22,993
Other revenues	27	22	52	46
Total revenues	12,295	11,218	23,917	23,039
McLane Company [Member] | Grocery and Convenience Store Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	7,729	7,287	15,171	15,146
McLane Company [Member] | Food and Beverage Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,356	3,787	8,360	7,593
McLane Company [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	183	122	334	254
Service and Retailing [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	7,860	5,194	14,812	11,041
Other revenues	1,094	827	2,085	1,918
Total revenues	8,954	6,021	16,897	12,959
Service and Retailing [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	49	45	99	89
Service and Retailing [Member] | Auto Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,750	1,895	5,062	3,804
Service and Retailing [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,008	2,620	7,664	5,553
Service and Retailing [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,053	634	1,987	1,595
BNSF [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,763	4,558	11,128	9,924
Other revenues	15	14	28	28
Total revenues	5,778	4,572	11,156	9,952
BNSF [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,763	4,558	11,128	9,924
Berkshire Hathaway Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,791	4,290	11,543	8,598
Other revenues	294	369	466	568
Total revenues	6,085	4,659	12,009	9,166
Berkshire Hathaway Energy [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,593	971	2,633	1,764
Berkshire Hathaway Energy [Member] | Electricity and Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,198	3,319	8,910	6,834
Insurance Corporate And Other [Member]
Disaggregation of Revenue [Line Items]
Other revenues	18,627	17,353	36,479	34,958
Total revenues	$ 18,627	$ 17,353	$ 36,479	$ 34,958