Notes payable and other borrowings - Narrative (Detail) € in Millions, $ in Millions	1 Months Ended		12 Months Ended
	Mar. 31, 2015 EUR (€)	Feb. 28, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Berkshire Hathaway (Parent) [Member]
Debt Instrument [Line Items]
Repayments of borrowings			$ 1,775	$ 792	$ 2,656
Berkshire Hathaway (Parent) [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Repayments of borrowings		$ 1,700
Berkshire Hathaway (Parent) [Member] | Subsidiaries Excluding Berkshire Hathaway Finance Corporation [Member]
Debt Instrument [Line Items]
Guarantee obligation			$ 3,300
Berkshire Hathaway (Parent) [Member] | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Principal amount of debt issued | €	€ 3,000
Berkshire Hathaway (Parent) [Member] | Senior Unsecured Notes Due 2023 at 0.75% [Member]
Debt Instrument [Line Items]
Principal amount of debt issued | €	€ 750
Debt instrument, interest rate, stated percentage	0.75%
Berkshire Hathaway (Parent) [Member] | Senior Unsecured Notes Due 2027 at 1.125% [Member]
Debt Instrument [Line Items]
Principal amount of debt issued | €	€ 1,250
Debt instrument, interest rate, stated percentage	1.125%
Berkshire Hathaway (Parent) [Member] | Senior Unsecured Notes Due 2035 at 1.625% [Member]
Debt Instrument [Line Items]
Principal amount of debt issued | €	€ 1,000
Debt instrument, interest rate, stated percentage	1.625%
BNSF [Member] | Railroad, Utilities and Energy [Member]
Debt Instrument [Line Items]
Weighted average interest rate, percentage			4.90%
BNSF [Member] | Senior Unsecured Debentures [Member] | Railroad, Utilities and Energy [Member]
Debt Instrument [Line Items]
Principal amount of debt issued			$ 2,500
BNSF [Member] | Senior Unsecured Debentures [Member] | Railroad, Utilities and Energy [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage			3.00%
BNSF [Member] | Senior Unsecured Debentures [Member] | Railroad, Utilities and Energy [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage			4.70%
BNSF [Member] | Senior Unsecured Debentures Due 2025 [Member] | Railroad, Utilities and Energy [Member]
Debt Instrument [Line Items]
Principal amount of debt issued			$ 850
BNSF [Member] | Senior Unsecured Debentures Due 2045 [Member] | Railroad, Utilities and Energy [Member]
Debt Instrument [Line Items]
Principal amount of debt issued			1,650
BNSF [Member] | Secured Amortizing Debt Due 2028 [Member] | Railroad, Utilities and Energy [Member]
Debt Instrument [Line Items]
Principal amount of debt issued			$ 500
Berkshire Hathaway Finance Corporation [Member] | Finance and Financial Products [Member]
Debt Instrument [Line Items]
Weighted average interest rate, percentage			2.70%
Berkshire Hathaway Finance Corporation [Member] | Senior Notes [Member] | Finance and Financial Products [Member]
Debt Instrument [Line Items]
Principal amount of debt issued			$ 1,000
Berkshire Hathaway Finance Corporation [Member] | Senior Notes Due 2017, Floating Rate [Member] | Finance and Financial Products [Member]
Debt Instrument [Line Items]
Principal amount of debt issued			400
Berkshire Hathaway Finance Corporation [Member] | Senior Notes Due 2018, Floating Rate [Member] | Finance and Financial Products [Member]
Debt Instrument [Line Items]
Principal amount of debt issued			600
Berkshire Hathaway Subsidiaries [Member] | Line of Credit and Commercial Paper Facilities [Member]
Debt Instrument [Line Items]
Unused lines of credit available			7,700
Berkshire Hathaway Energy Company and Subsidiaries [Member] | Line of Credit and Commercial Paper Facilities [Member]
Debt Instrument [Line Items]
Unused lines of credit available			$ 5,000
Berkshire Hathaway Energy Subsidiaries [Member] | Railroad, Utilities and Energy [Member]
Debt Instrument [Line Items]
Weighted average interest rate, percentage			4.90%
Berkshire Hathaway Energy Subsidiaries [Member] | Debt Due 2016 to 2046 [Member] | Railroad, Utilities and Energy [Member]
Debt Instrument [Line Items]
Principal amount of debt issued			$ 2,500
Weighted average interest rate, percentage			3.40%