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, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			$ 85,764
Other revenue			34,909
Total revenues	$ 62,200	$ 57,256	120,673	$ 121,626
Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			13,451
Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			6,351
Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			7,850
Grocery and Convenience Store Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			16,419
Food and Beverage Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			8,124
Auto Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			4,004
Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			6,671
Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			15,804
Electricity and Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			7,090
Manufacturing Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			26,671
Other revenue			81
Total revenues			26,752
Manufacturing Businesses [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			12,922
Manufacturing Businesses [Member] | Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			6,344
Manufacturing Businesses [Member] | Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			5,896
Manufacturing Businesses [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			1,012
Manufacturing Businesses [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			497
McLane Company [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			24,580
Other revenue			36
Total revenues			24,616
McLane Company [Member] | Grocery and Convenience Store Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			16,419
McLane Company [Member] | Food and Beverage Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			8,124
McLane Company [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			37
Service and Retailing Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			11,676
Other revenue			1,921
Total revenues			13,597
Service and Retailing Businesses [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			108
Service and Retailing Businesses [Member] | Auto Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			4,004
Service and Retailing Businesses [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			5,617
Service and Retailing Businesses [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			1,947
BNSF [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			11,411
Other revenue			24
Total revenues			11,435
BNSF [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			11,411
Berkshire Hathaway Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			8,976
Other revenue			586
Total revenues			9,562
Berkshire Hathaway Energy [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			1,886
Berkshire Hathaway Energy [Member] | Electricity and Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			7,090
Finance and Financial Products Reportable Segment [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			2,450
Other revenue			1,976
Total revenues			4,426
Finance and Financial Products Reportable Segment [Member] | Industrial and Commercial Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			421
Finance and Financial Products Reportable Segment [Member] | Building Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			7
Finance and Financial Products Reportable Segment [Member] | Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			1,954
Finance and Financial Products Reportable Segment [Member] | Other Retail and Wholesale Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			42
Finance and Financial Products Reportable Segment [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			26
Insurance Corporate And Other [Member]
Disaggregation of Revenue [Line Items]
Other revenue			30,285
Total revenues			$ 30,285