Revenue from contracts with customers disaggregated by reportable segment and source of revenue (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									$ 176,512	$ 175,445
Other revenue									78,104	72,392
Total revenues	$ 65,368	$ 64,972	$ 63,598	$ 60,678	$ 63,714	$ 63,450	$ 62,200	$ 58,473	254,616	247,837	$ 239,933
Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									25,495	25,911
Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									15,620	14,323
Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									14,120	14,790
Grocery and Convenience Store Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									33,057	33,518
Food and Beverage Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									16,767	16,309
Auto Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									8,481	8,181
Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									14,512	14,158
Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									33,641	33,304
Electricity and Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									14,819	14,951
Manufacturing Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									58,992	58,430
Other revenue									3,632	3,340
Total revenues									62,624	61,770
Manufacturing Businesses [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									25,311	25,707
Manufacturing Businesses [Member] | Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									15,620	14,323
Manufacturing Businesses [Member] | Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									14,120	14,790
Manufacturing Businesses [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									2,299	2,091
Manufacturing Businesses [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									1,642	1,519
McLane Company [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									50,363	49,911
Other revenue									95	76
Total revenues									50,458	49,987
McLane Company [Member] | Grocery and Convenience Store Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									33,057	33,518
McLane Company [Member] | Food and Beverage Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									16,767	16,309
McLane Company [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									539	84
Service and Retailing Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									24,940	24,552
Other revenue									4,459	4,297
Total revenues									29,399	28,849
Service and Retailing Businesses [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									184	204
Service and Retailing Businesses [Member] | Auto Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									8,481	8,181
Service and Retailing Businesses [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									12,213	12,067
Service and Retailing Businesses [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									4,062	4,100
BNSF [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									23,302	23,652
Other revenue									55	51
Total revenues									23,357	23,703
BNSF [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									23,302	23,652
Berkshire Hathaway Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									18,915	18,900
Other revenue									1,181	1,070
Total revenues									20,096	19,970
Berkshire Hathaway Energy [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									4,096	3,949
Berkshire Hathaway Energy [Member] | Electricity and Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									14,819	14,951
Insurance Corporate And Other [Member]
Disaggregation of Revenue [Line Items]
Other revenue									68,682	63,558
Total revenues									$ 68,682	$ 63,558