Notes payable and other borrowings - Narrative (Detail) (USD $)	1 Months Ended					3 Months Ended
	Jan. 31, 2014 Berkshire Hathaway Finance Corporation [Member] Senior Notes [Member] Finance and Financial Products [Member]	Jan. 31, 2014 Berkshire Hathaway Finance Corporation [Member] Senior Notes Due 2017, Floating Rate [Member] Finance and Financial Products [Member]	Jan. 31, 2014 Berkshire Hathaway Finance Corporation [Member] Senior Notes Due 2018 at 2% [Member] Finance and Financial Products [Member]	Mar. 31, 2014 BNSF [Member] Debentures Due 2024 at 3.75% [Member] Railroad, Utilities and Energy [Member]	Mar. 31, 2014 BNSF [Member] Debentures Due 2044 at 4.9% [Member] Railroad, Utilities and Energy [Member]	Mar. 31, 2014 Berkshire Hathaway Energy Subsidiaries [Member] Term Debt [Member] Railroad, Utilities and Energy [Member]	Mar. 31, 2014 Berkshire Hathaway Subsidiaries [Member] Line of Credit and Commercial Paper Facilities [Member]	Mar. 31, 2014 Berkshire Hathaway (Parent) [Member] Subsidiaries Excluding Berkshire Hathaway Finance Corporation [Member]
Debt Instrument [Line Items]
Principal amount of debt issued	$ 750,000,000	$ 650,000,000	$ 100,000,000	$ 500,000,000	$ 1,000,000,000	$ 425,000,000
Debt instrument, interest rate, stated percentage			2.00%	3.75%	4.90%
Repayment of debt	750,000,000
Unused lines of credit available							6,200,000,000
Guarantee obligation								$ 4,000,000,000