Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net earnings	$ 43,253	$ 81,792	$ 4,322
Other comprehensive income:
Unrealized appreciation of investments	74	142	(438)
Applicable income taxes	(19)	(31)	84
Foreign currency translation	1,284	323	(1,531)
Applicable income taxes	3	(28)	62
Defined benefit pension plans	(355)	(711)	(571)
Applicable income taxes	74	155	143
Other, net	(42)	(48)	(12)
Other comprehensive income, net	1,019	(198)	(2,263)
Comprehensive income	44,272	81,594	2,059
Comprehensive income attributable to noncontrolling interests	751	405	249
Comprehensive income attributable to Berkshire Hathaway shareholders	$ 43,521	$ 81,189	$ 1,810