Business segment data - Revenues (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenues	$ 58,344	$ 58,843	$ 54,254	$ 52,163	$ 51,731	$ 59,070	$ 51,549	$ 48,593	$ 223,604	$ 210,943	$ 194,699
Operating Businesses [Member]
Segment Reporting Information [Line Items]
Revenues									215,825	200,843	190,691
Operating Businesses [Member] | Insurance Group [Member]
Segment Reporting Information [Line Items]
Interest, dividend and other investment income									4,522	4,562	4,370
Revenues									50,403	45,856	45,623
Operating Businesses [Member] | Insurance Group [Member] | GEICO [Member]
Segment Reporting Information [Line Items]
Premiums earned									25,483	22,718	20,496
Operating Businesses [Member] | Insurance Group [Member] | BH Primary [Member]
Segment Reporting Information [Line Items]
Premiums earned									6,257	5,394	4,377
Operating Businesses [Member] | Insurance Group [Member] | General Re [Member]
Segment Reporting Information [Line Items]
Premiums earned									5,637	5,975	6,264
Operating Businesses [Member] | Insurance Group [Member] | BHRG [Member]
Segment Reporting Information [Line Items]
Premiums earned									8,504	7,207	10,116
Operating Businesses [Member] | Insurance Group [Member] | General Re and BHRG [Member]
Segment Reporting Information [Line Items]
Premiums earned									45,881	41,294	41,253
Operating Businesses [Member] | BNSF [Member]
Segment Reporting Information [Line Items]
Revenues									19,829	21,967	23,239
Operating Businesses [Member] | Berkshire Hathaway Energy [Member]
Segment Reporting Information [Line Items]
Revenues									17,859	18,231	17,614
Operating Businesses [Member] | Manufacturing Businesses [Member]
Segment Reporting Information [Line Items]
Revenues									46,506	36,136	36,773
Operating Businesses [Member] | McLane Company [Member]
Segment Reporting Information [Line Items]
Revenues									48,075	48,223	46,640
Operating Businesses [Member] | Service and Retailing Businesses [Member]
Segment Reporting Information [Line Items]
Revenues									25,478	23,466	14,276
Operating Businesses [Member] | Finance and Financial Products Reportable Segment [Member]
Segment Reporting Information [Line Items]
Revenues									7,675	6,964	6,526
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Investment and derivative gains/losses									8,304	10,347	4,081
Segment Reconciling Items [Member] | Kraft Heinz (previously Heinz Holding) [Member]
Segment Reporting Information [Line Items]
Investments in Kraft Heinz									180	852	720
Corporate, Eliminations and Other [Member]
Segment Reporting Information [Line Items]
Revenues									$ (705)	$ (1,099)	$ (793)