Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net earnings	$ 18,707	$ 4,203	$ 29,713	$ 12,697
Other comprehensive income:
Net change in unrealized appreciation of investments	5	4,952	(132)	18,040
Applicable income taxes	(1)	(1,716)	19	(6,247)
Reclassification of investment appreciation in net earnings	(34)	(646)	(299)	(1,235)
Applicable income taxes	7	226	63	432
Foreign currency translation	(79)	771	(842)	2,127
Applicable income taxes	9	(24)	46	(116)
Prior service cost and actuarial gains/losses of defined benefit pension plans	(13)	(3)	50	(57)
Applicable income taxes	3	6		31
Other, net	(21)	32	(57)	38
Other comprehensive income, net	(124)	3,598	(1,152)	13,013
Comprehensive income	18,583	7,801	28,561	25,710
Comprehensive income attributable to noncontrolling interests	162	203	271	436
Comprehensive income attributable to Berkshire Hathaway shareholders	$ 18,421	$ 7,598	$ 28,290	$ 25,274