Notes payable and other borrowings (Detail) (USD $) In Millions, unless otherwise specified					9 Months Ended			9 Months Ended			9 Months Ended					9 Months Ended			9 Months Ended					9 Months Ended			9 Months Ended
	Sep. 30, 2014 Railroad, Utilities and Energy [Member]	Dec. 31, 2013 Railroad, Utilities and Energy [Member]	Sep. 30, 2014 Railroad, Utilities and Energy [Member] Berkshire Hathaway Energy [Member]	Dec. 31, 2013 Railroad, Utilities and Energy [Member] Berkshire Hathaway Energy [Member]	Sep. 30, 2014 Railroad, Utilities and Energy [Member] Berkshire Hathaway Energy [Member] Debt [Member]	Sep. 30, 2014 Railroad, Utilities and Energy [Member] Berkshire Hathaway Energy Subsidiaries [Member]	Dec. 31, 2013 Railroad, Utilities and Energy [Member] Berkshire Hathaway Energy Subsidiaries [Member]	Sep. 30, 2014 Railroad, Utilities and Energy [Member] Berkshire Hathaway Energy Subsidiaries [Member] Debt [Member]	Sep. 30, 2014 Railroad, Utilities and Energy [Member] BNSF [Member]	Dec. 31, 2013 Railroad, Utilities and Energy [Member] BNSF [Member]	Sep. 30, 2014 Railroad, Utilities and Energy [Member] BNSF [Member] Debt [Member]	Sep. 30, 2014 Insurance and Other [Member]	Dec. 31, 2013 Insurance and Other [Member]	Sep. 30, 2014 Insurance and Other [Member] Berkshire Hathaway (Parent) [Member]	Dec. 31, 2013 Insurance and Other [Member] Berkshire Hathaway (Parent) [Member]	Sep. 30, 2014 Insurance and Other [Member] Berkshire Hathaway (Parent) [Member] Debt [Member]	Sep. 30, 2014 Insurance and Other [Member] Insurance and Other Subsidiaries [Member]	Dec. 31, 2013 Insurance and Other [Member] Insurance and Other Subsidiaries [Member]	Sep. 30, 2014 Insurance and Other [Member] Insurance and Other Subsidiaries [Member] Debt [Member]	Sep. 30, 2014 Finance and Financial Products [Member]	Dec. 31, 2013 Finance and Financial Products [Member]	Sep. 30, 2014 Finance and Financial Products [Member] Berkshire Hathaway Finance Corporation [Member]	Dec. 31, 2013 Finance and Financial Products [Member] Berkshire Hathaway Finance Corporation [Member]	Sep. 30, 2014 Finance and Financial Products [Member] Berkshire Hathaway Finance Corporation [Member] Debt [Member]	Sep. 30, 2014 Finance and Financial Products [Member] Other Finance Subsidiaries [Member]	Dec. 31, 2013 Finance and Financial Products [Member] Other Finance Subsidiaries [Member]	Sep. 30, 2014 Finance and Financial Products [Member] Other Finance Subsidiaries [Member] Debt [Member]
Notes payable and other borrowings [Line Items]
Maturity date, range, start					2017			2014			2014					2014			2014					2015			2014
Maturity date, range, end					2043			2054			2097					2047			2035					2043			2036
Short-term debt, weighted average interest rate																	0.40%
Senior unsecured debt			$ 6,366	$ 6,616
Weighted average interest rate, percentage			5.70%			5.30%			5.10%					2.80%			6.00%					3.10%			4.70%
Notes payable and other borrowings	49,694	46,655				23,998	23,033		19,330	17,006		12,328	12,440	8,349	8,311					12,790	13,129	11,177	11,178		1,613	1,951
Short-term borrowings																	817	949
Other borrowings																	$ 3,162	$ 3,180