Note to Condensed Financial Information - Narrative (Detail) (USD $)			1 Months Ended			1 Months Ended			12 Months Ended		1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended	1 Months Ended				1 Months Ended					0 Months Ended
	Dec. 31, 2012	Feb. 13, 2013 Holdco (investee created to acquire Heinz) [Member] Common Stock [Member] Definitive Merger Agreement to Acquire H.J. Heinz Company [Member]	Feb. 28, 2011 Berkshire Hathaway (Parent) [Member]	Dec. 31, 2012 Berkshire Hathaway (Parent) [Member]	Dec. 31, 2011 Berkshire Hathaway (Parent) [Member]	Feb. 28, 2010 Berkshire Hathaway (Parent) [Member] BNSF [Member]	Aug. 31, 2011 Berkshire Hathaway (Parent) [Member] Senior Notes [Member]	Feb. 28, 2010 Berkshire Hathaway (Parent) [Member] Senior Notes [Member]	Dec. 31, 2012 Berkshire Hathaway (Parent) [Member] Senior Notes [Member]	Dec. 31, 2012 Berkshire Hathaway (Parent) [Member] Senior Notes [Member] Maximum [Member]	Jan. 31, 2012 Berkshire Hathaway (Parent) [Member] Senior Notes Due In 2017 at 1.9% [Member]	Dec. 31, 2012 Berkshire Hathaway (Parent) [Member] Senior Notes Due In 2017 at 1.9% [Member]	Jan. 31, 2012 Berkshire Hathaway (Parent) [Member] Senior Notes Due In 2022 at 3.4% [Member]	Dec. 31, 2012 Berkshire Hathaway (Parent) [Member] Senior Notes Due In 2022 at 3.4% [Member]	Feb. 29, 2012 Berkshire Hathaway (Parent) [Member] Senior Notes Due 2012 [Member]	Jan. 31, 2013 Berkshire Hathaway (Parent) [Member] Financing Transactions [Member] Senior Notes [Member]	Jan. 31, 2013 Berkshire Hathaway (Parent) [Member] Financing Transactions [Member] Senior Notes [Member] Maximum [Member]	Jan. 31, 2013 Berkshire Hathaway (Parent) [Member] Financing Transactions [Member] Senior Notes [Member] Minimum [Member]	Feb. 28, 2013 Berkshire Hathaway (Parent) [Member] Financing Transactions [Member] Senior Notes Due 2013 and 2014 [Member]	Dec. 31, 2012 Berkshire Hathaway (Parent) [Member] Investment Agreements [Member]	Dec. 31, 2011 Berkshire Hathaway (Parent) [Member] Investment Agreements [Member]	Feb. 13, 2013 Berkshire Hathaway (Parent) [Member] Holdco (investee created to acquire Heinz) [Member] Definitive Merger Agreement to Acquire H.J. Heinz Company [Member]	Feb. 13, 2013 Berkshire Hathaway (Parent) [Member] Holdco (investee created to acquire Heinz) [Member] Common Stock [Member] Definitive Merger Agreement to Acquire H.J. Heinz Company [Member]	Feb. 13, 2013 Berkshire Hathaway (Parent) [Member] Holdco (investee created to acquire Heinz) [Member] Preferred Stock [Member] Definitive Merger Agreement to Acquire H.J. Heinz Company [Member]	Dec. 31, 2012 Berkshire Hathaway (Parent) [Member] Equity Index Put Options and Credit Default Derivatives [Member]	Feb. 13, 2013 3G Capital (venture partner) [Member] Holdco (investee created to acquire Heinz) [Member] Definitive Merger Agreement to Acquire H.J. Heinz Company [Member]	Feb. 13, 2013 3G Capital (venture partner) [Member] Holdco (investee created to acquire Heinz) [Member] Common Stock [Member] Definitive Merger Agreement to Acquire H.J. Heinz Company [Member]
Condensed Financial Statements, Captions [Line Items]
Principal amount of debt issued							$ 2,000,000,000	$ 8,000,000,000			$ 1,100,000,000		$ 600,000,000			$ 2,600,000,000
Cash contributed to subsidiary to fund acquisition						3,900,000,000
Repayment of debt			2,000,000,000												1,700,000,000				2,600,000,000
Debt Instrument, Interest Rate, Stated Percentage										3.75%		1.90%		3.40%			4.50%	0.80%
Maturity date, range, start									2014							2016
Maturity date, range, end									2021							2043
Issuance date												January 2012		January 2012		January 2013
Notes payable and other borrowings				8,323,000,000	8,287,000,000															323,000,000	287,000,000
Maturing: 2013	10,511,000,000			2,600,000,000
Maturing: 2014	4,280,000,000			753,000,000
Maturing: 2015	4,796,000,000			1,709,000,000
Maturing: 2016	1,781,000,000			751,000,000
Maturing: 2017	4,152,000,000			1,100,000,000
Guarantee of subsidiary debt obligations				16,000,000,000
Guarantee of subsidiary obligations under derivative liability contracts																									7,900,000,000
Potential business acquisition, cash price per share		$ 72.50
Cash committed to be paid for a potential acquiree's equity securities		23,250,000,000
Commitment to purchase equity securities of an investee																							$ 4,120,000,000	$ 8,000,000,000			$ 4,120,000,000
Investment in preferred stock, stated dividend rate																								9.00%
Voting interest in investee																						50.00%				50.00%