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, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 44,460	$ 44,255	$ 86,852	$ 85,764
Other revenue	19,138	17,945	37,424	34,909
Total revenues	63,598	62,200	124,276	120,673
Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,549	6,843	13,054	13,451
Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,143	3,431	7,695	6,351
Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,669	4,154	6,959	7,850
Grocery and Convenience Store Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8,042	8,261	16,077	16,419
Food and Beverage Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,321	4,127	8,446	8,124
Auto Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,125	2,073	4,062	4,004
Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,626	3,461	7,091	6,671
Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8,556	8,339	16,352	15,804
Electricity and Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,429	3,566	7,116	7,090
Manufacturing Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	15,278	15,172	29,471	29,058
Other revenue	913	739	1,779	1,551
Total revenues	16,191	15,911	31,250	30,609
Manufacturing Businesses [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,503	6,789	12,962	13,343
Manufacturing Businesses [Member] | Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,143	3,431	7,695	6,351
Manufacturing Businesses [Member] | Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,669	4,154	6,959	7,850
Manufacturing Businesses [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	534	519	1,078	1,017
Manufacturing Businesses [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	429	279	777	497
McLane Company [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	12,386	12,408	24,566	24,580
Other revenue	25	19	44	36
Total revenues	12,411	12,427	24,610	24,616
McLane Company [Member] | Grocery and Convenience Store Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8,042	8,261	16,077	16,419
McLane Company [Member] | Food and Beverage Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,321	4,127	8,446	8,124
McLane Company [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	23	20	43	37
Service and Retailing Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,307	6,092	12,201	11,739
Other revenue	1,133	1,194	2,242	2,334
Total revenues	7,440	7,286	14,443	14,073
Service and Retailing Businesses [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	46	54	92	108
Service and Retailing Businesses [Member] | Auto Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,125	2,073	4,062	4,004
Service and Retailing Businesses [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,092	2,942	6,013	5,654
Service and Retailing Businesses [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,044	1,023	2,034	1,973
BNSF [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,837	5,831	11,550	11,411
Other revenue	14	14	26	24
Total revenues	5,851	5,845	11,576	11,435
BNSF [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,837	5,831	11,550	11,411
Berkshire Hathaway Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,652	4,752	9,064	8,976
Other revenue	318	298	578	586
Total revenues	4,970	5,050	9,642	9,562
Berkshire Hathaway Energy [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,223	1,186	1,948	1,886
Berkshire Hathaway Energy [Member] | Electricity and Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,429	3,566	7,116	7,090
Insurance Corporate And Other [Member]
Disaggregation of Revenue [Line Items]
Other revenue	16,735	15,681	32,755	30,378
Total revenues	$ 16,735	$ 15,681	$ 32,755	$ 30,378