Business segment data (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting Information [Line Items]
Revenues	$ 49,762	$ 44,693	$ 95,215	$ 88,560
Total earnings before income taxes	8,916	6,891	15,514	14,186
Operating Businesses [Member]
Segment Reporting Information [Line Items]
Revenues	47,326	43,847	91,334	86,035
Earnings before income taxes from operating businesses	6,555	6,213	11,846	12,098
Operating Businesses [Member] | Berkshire Hathaway Insurance Group [Member]
Segment Reporting Information [Line Items]
Revenues	10,824	10,358	21,191	20,736
Earnings before income taxes from operating businesses	2,135	2,361	3,796	4,746
Operating Businesses [Member] | Berkshire Hathaway Insurance Group [Member] | Geico [Member]
Segment Reporting Information [Line Items]
Premiums earned	5,081	4,597	9,965	8,996
Earnings before income taxes from operating businesses	393	336	746	602
Operating Businesses [Member] | Berkshire Hathaway Insurance Group [Member] | General Re [Member]
Segment Reporting Information [Line Items]
Premiums earned	1,610	1,499	3,167	2,968
Earnings before income taxes from operating businesses	116	24	196	119
Operating Businesses [Member] | Berkshire Hathaway Insurance Group [Member] | Berkshire Hathaway Reinsurance Group [Member]
Segment Reporting Information [Line Items]
Premiums earned	1,583	1,903	3,605	4,699
Earnings before income taxes from operating businesses	(9)	391	174	1,365
Operating Businesses [Member] | Berkshire Hathaway Insurance Group [Member] | Berkshire Hathaway Primary Group [Member]
Segment Reporting Information [Line Items]
Premiums earned	1,049	816	2,002	1,529
Earnings before income taxes from operating businesses	137	75	236	129
Operating Businesses [Member] | Berkshire Hathaway Insurance Group [Member] | Investment Income [Member]
Segment Reporting Information [Line Items]
Interest, dividend and other investment income	1,501	1,543	2,452	2,544
Earnings before income taxes from operating businesses	1,498	1,535	2,444	2,531
Operating Businesses [Member] | BNSF [Member]
Segment Reporting Information [Line Items]
Revenues	5,735	5,322	11,182	10,606
Earnings before income taxes from operating businesses	1,472	1,397	2,641	2,686
Operating Businesses [Member] | Berkshire Hathaway Energy [Member]
Segment Reporting Information [Line Items]
Revenues	4,185	3,056	8,491	6,172
Earnings before income taxes from operating businesses	578	435	1,197	988
Operating Businesses [Member] | McLane Company [Member]
Segment Reporting Information [Line Items]
Revenues	11,722	11,375	22,176	22,160
Earnings before income taxes from operating businesses	126	114	241	246
Operating Businesses [Member] | Manufacturing Businesses [Member]
Segment Reporting Information [Line Items]
Revenues	9,613	8,896	18,254	17,057
Earnings before income taxes from operating businesses	1,369	1,151	2,437	2,099
Operating Businesses [Member] | Other Businesses [Member]
Segment Reporting Information [Line Items]
Revenues	3,605	3,313	6,963	6,404
Earnings before income taxes from operating businesses	453	400	740	682
Operating Businesses [Member] | Finance and Financial Products Reportable Segment [Member]
Segment Reporting Information [Line Items]
Revenues	1,642	1,527	3,077	2,900
Earnings before income taxes from operating businesses	422	355	794	651
Intersegment Eliminations and Other Reconciling Items [Member]
Segment Reporting Information [Line Items]
Investment and derivative gains/losses	2,521	953	3,888	2,664
Revenues	(85)	(107)	(7)	(139)
Interest expense	(77)	(74)	(154)	(146)
Earnings before income taxes from operating businesses	$ (83)	$ (201)	$ (66)	$ (430)