Condensed Financial Information - Statements of Earnings and Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
From consolidated subsidiaries:
Investment gains/losses																	$ 9,373	$ 3,575	$ 4,065
Total revenues	$ 51,820		$ 58,989		$ 51,368		$ 48,644		$ 48,259		$ 51,199		$ 49,762		$ 45,453		210,821	194,673	182,150
Cost and expense items:
Interest expense																	3,515	3,253	2,801
Income taxes																	10,532	7,935	8,951
Total costs and expenses																	175,875	166,568	153,354
Net earnings attributable to Berkshire Hathaway shareholders	$ 5,478	[1]	$ 9,428	[1]	$ 4,013	[1]	$ 5,164	[1]	$ 4,155	[1]	$ 4,617	[1]	$ 6,395	[1]	$ 4,705	[1]	24,083	19,872	19,476
Comprehensive income attributable to Berkshire Hathaway shareholders																	15,333	18,579	36,022
Berkshire Hathaway (Parent) [Member]
From consolidated subsidiaries:
Dividends																	10,519	4,969	6,158
Undistributed earnings																	8,508	14,496	13,657
Total income from consolidated subsidiaries																	19,027	19,465	19,815
Investment gains/losses																	6,854
Other income																	841	758	229
Total revenues																	26,722	20,223	20,044
Cost and expense items:
General and administrative																	73	(1)	94
Interest expense																	302	236	228
Income taxes																	2,264	116	246
Total costs and expenses																	2,639	351	568
Net earnings attributable to Berkshire Hathaway shareholders																	24,083	19,872	19,476
Other comprehensive income attributable to Berkshire Hathaway shareholders																	(8,750)	(1,293)	16,546
Comprehensive income attributable to Berkshire Hathaway shareholders																	$ 15,333	$ 18,579	$ 36,022

[1] Includes investment gains/losses, other-than-temporary impairment losses on investments and derivative gains/losses. Derivative gains/losses include significant amounts related to non-cash changes in the fair value of long-term contracts arising from short-term changes in equity prices, interest rates and foreign currency rates, among other factors. After-tax investment and derivative gains/losses for the periods presented above are as follows (in millions): 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Investment and derivative gains/losses - 2015 $ 920 $ 123 $ 4,877 $ 805 Investment and derivative gains/losses - 2014 1,172 2,064 (107 ) 192