Business segment data - Additional tabular disclosures (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Interest expense	$ 3,497	$ 3,515	$ 3,253
Income tax expense	9,240	10,532	7,935
Capital expenditures	12,954	16,082	15,185
Depreciation of tangible assets	7,411	6,673	6,215
Goodwill at year-end	79,486	62,708	60,714
Total assets	620,854	552,257	525,867
Operating Businesses [Member]
Segment Reporting Information [Line Items]
Interest expense	3,332	3,245	3,013
Income tax expense	7,597	7,554	7,543
Capital expenditures	12,954	16,082	15,185
Depreciation of tangible assets	7,411	6,673	6,215
Goodwill at year-end	79,486	62,708
Identifiable assets at year-end	513,317	454,217	442,946
Operating Businesses [Member] \| Insurance Group [Member]
Segment Reporting Information [Line Items]
Income tax expense	1,585	1,475	1,768
Capital expenditures	128	115	94
Depreciation of tangible assets	85	77	69
Goodwill at year-end	15,474	15,536
Identifiable assets at year-end	234,037	219,451	225,432
Operating Businesses [Member] \| Insurance Group [Member] \| GEICO [Member]
Segment Reporting Information [Line Items]
Goodwill at year-end	1,471	1,471
Identifiable assets at year-end	55,041	48,291	45,439
Operating Businesses [Member] \| Insurance Group [Member] \| General Re [Member]
Segment Reporting Information [Line Items]
Goodwill at year-end	13,494	13,527
Identifiable assets at year-end	30,321	26,478	28,692
Operating Businesses [Member] \| Insurance Group [Member] \| BHRG and BH Primary [Member]
Segment Reporting Information [Line Items]
Goodwill at year-end	509	538
Identifiable assets at year-end	148,675	144,682	151,301
Operating Businesses [Member] \| BNSF [Member]
Segment Reporting Information [Line Items]
Interest expense	992	928	833
Income tax expense	2,124	2,527	2,300
Capital expenditures	3,819	5,651	5,243
Depreciation of tangible assets	2,079	1,932	1,804
Goodwill at year-end	14,845	14,845
Identifiable assets at year-end	69,277	66,613	62,840
Operating Businesses [Member] \| Berkshire Hathaway Energy [Member]
Segment Reporting Information [Line Items]
Interest expense	1,715	1,830	1,623
Income tax expense	403	450	589
Capital expenditures	5,090	5,875	6,555
Depreciation of tangible assets	2,560	2,451	2,177
Goodwill at year-end	9,266	9,333
Identifiable assets at year-end	76,428	74,221	71,285
Operating Businesses [Member] \| Manufacturing Businesses [Member]
Segment Reporting Information [Line Items]
Interest expense	164	50	69
Income tax expense	1,945	1,548	1,544
Capital expenditures	1,813	1,292	1,324
Depreciation of tangible assets	1,287	938	943
Goodwill at year-end	32,041	14,833
Identifiable assets at year-end	69,900	34,141	34,509
Operating Businesses [Member] \| McLane Company [Member]
Segment Reporting Information [Line Items]
Interest expense		13	14
Income tax expense	169	195	169
Capital expenditures	258	338	241
Depreciation of tangible assets	165	161	159
Goodwill at year-end	734	656
Identifiable assets at year-end	5,896	5,871	5,419
Operating Businesses [Member] \| Service and Retailing Businesses [Member]
Segment Reporting Information [Line Items]
Interest expense	50	40	11
Income tax expense	669	651	576
Capital expenditures	804	574	591
Depreciation of tangible assets	611	504	461
Goodwill at year-end	5,745	6,163
Identifiable assets at year-end	17,450	16,299	11,303
Operating Businesses [Member] \| Finance and Financial Products Reportable Segment [Member]
Segment Reporting Information [Line Items]
Interest expense	411	384	463
Income tax expense	702	708	597
Capital expenditures	1,042	2,237	1,137
Depreciation of tangible assets	624	610	602
Goodwill at year-end	1,381	1,342
Identifiable assets at year-end	40,329	37,621	32,158
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Interest expense	230	374	313
Investment and derivative gains/losses, tax	1,807	3,622	760
Interest expense, tax	(81)	(131)	(110)
Goodwill at year-end	79,486	62,708	60,714
Segment Reconciling Items [Member] \| Kraft Heinz (previously Heinz Holding) [Member]
Segment Reporting Information [Line Items]
Investments in Kraft Heinz, tax	397	(111)	41
Corporate, Eliminations and Other [Member]
Segment Reporting Information [Line Items]
Interest expense	(65)	(104)	(73)
Income tax expense	(480)	(402)	(299)
Identifiable assets at year-end	$ 28,051	$ 35,332	$ 22,207

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized, excluding goodwill.

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Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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