Common stock (Tables)

3 Months Ended

Mar. 31, 2016

Equity [Abstract]

Changes in issued, treasury and outstanding Berkshire common stock

Changes in Berkshire’s issued, treasury and outstanding common stock during the first quarter of 2016 are shown in the table below.

	Class A, $5 Par Value (1,650,000 shares authorized)							Class B, $0.0033 Par Value (3,225,000,000 shares authorized)
	Issued			Treasury		Outstanding		Issued		Treasury		Outstanding
Balance at December 31, 2015		820,102			(11,680)		808,422		1,253,866,598		(1,409,762)		1,252,456,836
Conversions of Class A common stock to Class B common stock and exercises of replacement stock options issued in a business acquisition		(1,609	)		—		(1,609)		2,812,057		—		2,812,057
Balance at March 31, 2016		818,493			(11,680)		806,813		1,256,678,655		(1,409,762)		1,255,268,893