Note to Condensed Financial Information - Narrative (Detail) (USD $)				1 Months Ended			1 Months Ended
	Dec. 31, 2011	Dec. 31, 2011 Berkshire Hathaway (Parent) [Member]	Dec. 31, 2010 Berkshire Hathaway (Parent) [Member]	Feb. 28, 2010 Berkshire Hathaway (Parent) [Member] BNSF [Member]	Dec. 31, 2011 Berkshire Hathaway (Parent) [Member] Investment Agreements [Member]	Dec. 31, 2010 Berkshire Hathaway (Parent) [Member] Investment Agreements [Member]	Feb. 28, 2010 Berkshire Hathaway (Parent) [Member] Senior Notes [Member]	Feb. 28, 2010 Berkshire Hathaway (Parent) [Member] Floating Rate Notes Due In 2011 [Member]	Aug. 31, 2011 Berkshire Hathaway (Parent) [Member] Debentures [Member]	Aug. 31, 2011 Berkshire Hathaway (Parent) [Member] Senior Notes Due In 2016 at 2.2% [Member]	Aug. 31, 2011 Berkshire Hathaway (Parent) [Member] Senior Notes Due In 2021 at 3.75% [Member]	Aug. 31, 2011 Berkshire Hathaway (Parent) [Member] Floating Rate Senior Notes Due In 2014 [Member]	Jan. 31, 2012 Berkshire Hathaway (Parent) [Member] Senior Notes Due In 2017 at 1.9% [Member] Issuance of Debt [Member]	Jan. 31, 2012 Berkshire Hathaway (Parent) [Member] Senior Notes Due In 2022 at 3.4% [Member] Issuance of Debt [Member]	Feb. 29, 2012 Berkshire Hathaway (Parent) [Member] Floating Rate Notes Due In 2012 [Member] Redemption of Debt [Member]	Feb. 29, 2012 Berkshire Hathaway (Parent) [Member] Notes Due In 2012 at 1.4% [Member] Redemption of Debt [Member]	Dec. 31, 2011 Berkshire Hathaway (Parent) [Member] Equity Index Put Options and Credit Default Derivatives [Member]
Condensed Financial Statements, Captions [Line Items]
Principal amount of debt issued							$ 8,000,000,000	$ 2,000,000,000	$ 2,000,000,000	$ 750,000,000	$ 500,000,000	$ 750,000,000	$ 1,100,000,000	$ 600,000,000
Cash contributed to subsidiary to fund acquisition				3,900,000,000
Repayment of debt															1,100,000,000	600,000,000
Notes payable and other borrowings		8,287,000,000	8,360,000,000		287,000,000	360,000,000
Maturing: 2012	9,112,000,000	1,700,000,000
Maturing: 2013	8,160,000,000	2,600,000,000
Maturing: 2014	4,298,000,000	750,000,000
Maturing: 2015	4,287,000,000	1,700,000,000
Maturing: 2016	1,755,000,000	750,000,000
Guarantee of subsidiary debt obligations		16,000,000,000
Guarantee of subsidiary obligations under derivative liability contracts																	$ 10,000,000,000