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, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 43,494	$ 45,169	$ 122,324	$ 132,021
Other revenues	19,530	19,803	58,805	57,227
Total revenues	63,024	64,972	181,129	189,248
Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,943	6,390	15,782	19,444
Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,322	4,101	11,682	11,796
Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,036	3,528	10,373	10,487
Grocery and Convenience Store Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	7,905	8,298	23,051	24,375
Food and Beverage Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,968	4,202	11,561	12,648
Auto Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,195	2,250	5,999	6,312
Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,781	3,470	10,426	10,561
Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	7,988	8,717	22,260	25,069
Electricity and Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,356	4,213	11,190	11,329
Manufacturing Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	14,216	14,944	40,490	44,415
Other revenues	929	937	2,686	2,715
Total revenues	15,145	15,881	43,176	47,130
Manufacturing Businesses [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,889	6,346	15,639	19,308
Manufacturing Businesses [Member] | Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,322	4,101	11,682	11,796
Manufacturing Businesses [Member] | Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,036	3,528	10,373	10,487
Manufacturing Businesses [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	599	524	1,691	1,602
Manufacturing Businesses [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	370	445	1,105	1,222
McLane Company [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	12,017	12,580	35,010	37,146
Other revenues	23	24	69	68
Total revenues	12,040	12,604	35,079	37,214
McLane Company [Member] | Grocery and Convenience Store Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	7,905	8,298	23,051	24,375
McLane Company [Member] | Food and Beverage Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,968	4,202	11,561	12,648
McLane Company [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	144	80	398	123
Service and Retailing Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,296	6,274	17,337	18,475
Other revenues	966	1,080	2,884	3,323
Total revenues	7,262	7,354	20,221	21,798
Service and Retailing Businesses [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	54	44	143	136
Service and Retailing Businesses [Member] | Auto Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,195	2,250	5,999	6,312
Service and Retailing Businesses [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,182	2,946	8,735	8,959
Service and Retailing Businesses [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	865	1,034	2,460	3,068
BNSF [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,135	5,967	15,059	17,517
Other revenues	14	15	42	41
Total revenues	5,149	5,982	15,101	17,558
BNSF [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,135	5,967	15,059	17,517
Berkshire Hathaway Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,830	5,404	14,428	14,468
Other revenues	396	316	964	894
Total revenues	6,226	5,720	15,392	15,362
Berkshire Hathaway Energy [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,474	1,191	3,238	3,139
Berkshire Hathaway Energy [Member] | Electricity and Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,356	4,213	11,190	11,329
Insurance Corporate And Other [Member]
Disaggregation of Revenue [Line Items]
Other revenues	17,202	17,431	52,160	50,186
Total revenues	$ 17,202	$ 17,431	$ 52,160	$ 50,186