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, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 49,014	$ 43,494	$ 141,747	$ 122,324
Other revenues	21,569	19,530	62,549	58,805
Total revenues	70,583	63,024	204,296	181,129
Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,643	4,943	16,691	15,782
Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,005	4,322	14,518	11,682
Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,758	4,036	13,525	10,373
Grocery and Convenience Store Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	7,933	7,905	23,104	23,051
Food and Beverage Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,478	3,968	12,838	11,561
Auto Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,423	2,195	7,485	5,999
Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,655	3,781	13,776	10,426
Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8,981	7,988	25,762	22,260
Electricity and Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,138	4,356	14,048	11,190
Manufacturing Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16,505	14,216	47,890	40,490
Other revenues	951	929	2,821	2,686
Total revenues	17,456	15,145	50,711	43,176
Manufacturing Businesses [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,600	4,889	16,549	15,639
Manufacturing Businesses [Member] | Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,005	4,322	14,518	11,682
Manufacturing Businesses [Member] | Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,758	4,036	13,525	10,373
Manufacturing Businesses [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	742	599	2,199	1,691
Manufacturing Businesses [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	400	370	1,099	1,105
McLane Company [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	12,586	12,017	36,451	35,010
Other revenues	26	23	78	69
Total revenues	12,612	12,040	36,529	35,079
McLane Company [Member] | Grocery and Convenience Store Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	7,933	7,905	23,104	23,051
McLane Company [Member] | Food and Beverage Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,478	3,968	12,838	11,561
McLane Company [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	175	144	509	398
Service and Retailing [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	7,452	6,296	22,264	17,337
Other revenues	1,202	966	3,287	2,884
Total revenues	8,654	7,262	25,551	20,221
Service and Retailing [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	43	54	142	143
Service and Retailing [Member] | Auto Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,423	2,195	7,485	5,999
Service and Retailing [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,913	3,182	11,577	8,735
Service and Retailing [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,073	865	3,060	2,460
BNSF [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,747	5,135	16,875	15,059
Other revenues	14	14	42	42
Total revenues	5,761	5,149	16,917	15,101
BNSF [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,747	5,135	16,875	15,059
Berkshire Hathaway Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,724	5,830	18,267	14,428
Other revenues	289	396	755	964
Total revenues	7,013	6,226	19,022	15,392
Berkshire Hathaway Energy [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,586	1,474	4,219	3,238
Berkshire Hathaway Energy [Member] | Electricity and Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,138	4,356	14,048	11,190
Insurance, Corporate and Other [Member]
Disaggregation of Revenue [Line Items]
Other revenues	19,087	17,202	55,566	52,160
Total revenues	$ 19,087	$ 17,202	$ 55,566	$ 52,160