Revenue from contracts with customers disaggregated by reportable segment and source of revenue (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 45,169	$ 45,427	$ 132,021	$ 131,191
Other revenue	19,803	18,023	57,227	52,932
Total revenues	64,972	63,450	189,248	184,123
Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,390	6,513	19,444	19,964
Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,101	3,477	11,796	9,828
Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,528	4,008	10,487	11,858
Grocery and Convenience Store Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8,298	8,709	24,375	25,128
Food and Beverage Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,202	4,079	12,648	12,203
Auto Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,250	2,083	6,312	6,087
Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,470	3,661	10,561	10,332
Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8,717	8,630	25,069	24,434
Electricity and Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,213	4,267	11,329	11,357
Manufacturing Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	14,944	14,870	44,415	43,928
Other revenue	937	795	2,715	2,346
Total revenues	15,881	15,665	47,130	46,274
Manufacturing Businesses [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,346	6,466	19,308	19,809
Manufacturing Businesses [Member] | Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,101	3,477	11,796	9,828
Manufacturing Businesses [Member] | Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,528	4,008	10,487	11,858
Manufacturing Businesses [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	524	524	1,602	1,541
Manufacturing Businesses [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	445	395	1,222	892
McLane Company [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	12,580	12,804	37,146	37,384
Other revenue	24	18	68	54
Total revenues	12,604	12,822	37,214	37,438
McLane Company [Member] | Grocery and Convenience Store Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8,298	8,709	24,375	25,128
McLane Company [Member] | Food and Beverage Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,202	4,079	12,648	12,203
McLane Company [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	80	16	123	53
Service and Retailing Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,274	6,247	18,475	17,986
Other revenue	1,080	964	3,323	3,298
Total revenues	7,354	7,211	21,798	21,284
Service and Retailing Businesses [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	44	47	136	155
Service and Retailing Businesses [Member] | Auto Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,250	2,083	6,312	6,087
Service and Retailing Businesses [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,946	3,137	8,959	8,791
Service and Retailing Businesses [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,034	980	3,068	2,953
BNSF [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,967	6,099	17,517	17,510
Other revenue	15	13	41	37
Total revenues	5,982	6,112	17,558	17,547
BNSF [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,967	6,099	17,517	17,510
Berkshire Hathaway Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,404	5,407	14,468	14,383
Other revenue	316	299	894	885
Total revenues	5,720	5,706	15,362	15,268
Berkshire Hathaway Energy [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,191	1,140	3,139	3,026
Berkshire Hathaway Energy [Member] | Electricity and Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,213	4,267	11,329	11,357
Insurance Corporate And Other [Member]
Disaggregation of Revenue [Line Items]
Other revenue	17,431	15,934	50,186	46,312
Total revenues	$ 17,431	$ 15,934	$ 50,186	$ 46,312