Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net earnings (loss)	$ (1,071)	$ 4,139
Other comprehensive income:
Net change in unrealized appreciation of investments	(45)	8,377
Applicable income taxes	(2)	(2,872)
Reclassification of investment appreciation in net earnings	(221)	(305)
Applicable income taxes	46	107
Foreign currency translation	601	558
Applicable income taxes	(6)	(69)
Prior service cost and actuarial gains/losses of defined benefit pension plans	(24)	(10)
Applicable income taxes	17	7
Other, net	(31)	3
Other comprehensive income, net	335	5,796
Comprehensive income	(736)	9,935
Comprehensive income attributable to noncontrolling interests	75	103
Comprehensive income attributable to Berkshire Hathaway shareholders	$ (811)	$ 9,832