Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net earnings	$ 45,353	$ 24,427	$ 24,414
Other comprehensive income:
Net change in unrealized appreciation of investments	30,450	13,858	(8,520)
Applicable income taxes	(10,566)	(4,846)	3,014
Reclassification of investment appreciation in net earnings	(1,399)	(6,820)	(2,332)
Applicable income taxes	490	2,387	816
Foreign currency translation	2,364	(1,541)	(1,931)
Applicable income taxes	(95)	66	(43)
Prior service cost and actuarial gains/losses of defined benefit pension plans	225	354	424
Applicable income taxes	(45)	(187)	(140)
Other, net	(9)	(17)	(94)
Other comprehensive income, net	21,415	3,254	(8,806)
Comprehensive income	66,768	27,681	15,608
Comprehensive income attributable to noncontrolling interests	555	291	275
Comprehensive income attributable to Berkshire Hathaway shareholders	$ 66,213	$ 27,390	$ 15,333