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, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 45,427		$ 131,191
Other revenue	18,023		52,932
Total revenues	63,450	$ 59,507	184,123	$ 181,133
Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,513		19,964
Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,477		9,828
Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,008		11,858
Grocery and Convenience Store Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8,709		25,128
Food and Beverage Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,079		12,203
Auto Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,083		6,087
Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,661		10,332
Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8,630		24,434
Electricity and Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,267		11,357
Manufacturing Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	13,478		40,149
Other revenue	51		132
Total revenues	13,529		40,281
Manufacturing Businesses [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,384		19,306
Manufacturing Businesses [Member] | Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,473		9,817
Manufacturing Businesses [Member] | Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,838		8,734
Manufacturing Businesses [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	521		1,533
Manufacturing Businesses [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	262		759
McLane Company [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	12,804		37,384
Other revenue	18		54
Total revenues	12,822		37,438
McLane Company [Member] | Grocery and Convenience Store Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8,709		25,128
McLane Company [Member] | Food and Beverage Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,079		12,203
McLane Company [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16		53
Service and Retailing Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,212		17,888
Other revenue	743		2,664
Total revenues	6,955		20,552
Service and Retailing Businesses [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	47		155
Service and Retailing Businesses [Member] | Auto Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,083		6,087
Service and Retailing Businesses [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,117		8,734
Service and Retailing Businesses [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	965		2,912
BNSF [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,099		17,510
Other revenue	13		37
Total revenues	6,112		17,547
BNSF [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,099		17,510
Berkshire Hathaway Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,407		14,383
Other revenue	299		885
Total revenues	5,706		15,268
Berkshire Hathaway Energy [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,140		3,026
Berkshire Hathaway Energy [Member] | Electricity and Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,267		11,357
Finance and Financial Products Reportable Segment [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,427		3,877
Other revenue	1,004		2,980
Total revenues	2,431		6,857
Finance and Financial Products Reportable Segment [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	82		503
Finance and Financial Products Reportable Segment [Member] | Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4		11
Finance and Financial Products Reportable Segment [Member] | Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,170		3,124
Finance and Financial Products Reportable Segment [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	23		65
Finance and Financial Products Reportable Segment [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	148		174
Insurance Corporate And Other [Member]
Disaggregation of Revenue [Line Items]
Other revenue	15,895		46,180
Total revenues	$ 15,895		$ 46,180