Business segment data (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]
Revenues	$ 45,453	$ 43,867
Total earnings before income taxes	6,598	7,295
Operating Businesses [Member]
Segment Reporting Information [Line Items]
Revenues	44,008	42,188
Earnings before income taxes from operating businesses	5,291	5,885
Operating Businesses [Member] | Geico [Member]
Segment Reporting Information [Line Items]
Premiums earned	4,884	4,399
Earnings before income taxes from operating businesses	353	266
Operating Businesses [Member] | General Re [Member]
Segment Reporting Information [Line Items]
Premiums earned	1,557	1,469
Earnings before income taxes from operating businesses	80	95
Operating Businesses [Member] | Berkshire Hathaway Reinsurance Group [Member]
Segment Reporting Information [Line Items]
Premiums earned	2,022	2,796
Earnings before income taxes from operating businesses	183	974
Operating Businesses [Member] | Berkshire Hathaway Primary Group [Member]
Segment Reporting Information [Line Items]
Premiums earned	953	713
Earnings before income taxes from operating businesses	99	54
Operating Businesses [Member] | Berkshire Hathaway Insurance Group Investment Income [Member]
Segment Reporting Information [Line Items]
Interest, dividend and other investment income	951	1,001
Earnings before income taxes from operating businesses	946	996
Operating Businesses [Member] | Berkshire Hathaway Insurance Group [Member]
Segment Reporting Information [Line Items]
Revenues	10,367	10,378
Earnings before income taxes from operating businesses	1,661	2,385
Operating Businesses [Member] | BNSF [Member]
Segment Reporting Information [Line Items]
Revenues	5,447	5,284
Earnings before income taxes from operating businesses	1,169	1,289
Operating Businesses [Member] | Finance and Financial Products Reportable Segment [Member]
Segment Reporting Information [Line Items]
Revenues	1,435	1,373
Earnings before income taxes from operating businesses	372	296
Operating Businesses [Member] | Manufacturing Businesses [Member]
Segment Reporting Information [Line Items]
Revenues	8,641	8,161
Earnings before income taxes from operating businesses	1,068	948
Operating Businesses [Member] | McLane Company [Member]
Segment Reporting Information [Line Items]
Revenues	10,454	10,785
Earnings before income taxes from operating businesses	115	132
Operating Businesses [Member] | Berkshire Hathaway Energy [Member]
Segment Reporting Information [Line Items]
Revenues	4,306	3,116
Earnings before income taxes from operating businesses	619	553
Operating Businesses [Member] | Other Businesses [Member]
Segment Reporting Information [Line Items]
Revenues	3,358	3,091
Earnings before income taxes from operating businesses	287	282
Intersegment Eliminations and Other Reconciling Items [Member]
Segment Reporting Information [Line Items]
Investment and derivative gains/losses	1,367	1,711
Revenues	78	(32)
Interest expense	(77)	(72)
Earnings before income taxes from operating businesses	$ 17	$ (229)