Accumulated other comprehensive income (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Line Items]
Ending Balance	$ 44,025	$ 27,500
Portion Attributable to Berkshire Hathaway Shareholders [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	27,500	17,654	20,583
Other comprehensive income, net before reclassifications	18,044
Other comprehensive income, net		9,846	(3,005)
Amounts reclassified from accumulated other comprehensive income	(1,498)
Transactions with noncontrolling interests	(21)		76
Net changes in current period	16,525	9,846	(2,929)
Ending Balance	44,025	27,500	17,654
Unrealized appreciation of investments, net [Member] | Portion Attributable to Berkshire Hathaway Shareholders [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	29,254	19,626	21,638
Other comprehensive income, net before reclassifications	16,379
Other comprehensive income, net		9,647	(2,144)
Amounts reclassified from accumulated other comprehensive income	(1,591)
Transactions with noncontrolling interests		(19)	132
Net changes in current period	14,788	9,628	(2,012)
Ending Balance	44,042	29,254	19,626
Foreign currency translation [Member] | Portion Attributable to Berkshire Hathaway Shareholders [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(120)	(383)	(240)
Other comprehensive income, net before reclassifications	25
Other comprehensive income, net		267	(144)
Amounts reclassified from accumulated other comprehensive income	(31)
Transactions with noncontrolling interests	(20)	(4)	1
Net changes in current period	(26)	263	(143)
Ending Balance	(146)	(120)	(383)
Prior service and actuarial gains/losses of defined benefit pension plans [Member] | Portion Attributable to Berkshire Hathaway Shareholders [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(1,601)	(1,589)	(853)
Other comprehensive income, net before reclassifications	1,534
Other comprehensive income, net		(21)	(720)
Amounts reclassified from accumulated other comprehensive income	114
Transactions with noncontrolling interests	(1)	9	(16)
Net changes in current period	1,647	(12)	(736)
Ending Balance	46	(1,601)	(1,589)
Other AOCI transactions [Member] | Portion Attributable to Berkshire Hathaway Shareholders [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(33)		38
Other comprehensive income, net before reclassifications	106
Other comprehensive income, net		(47)	3
Amounts reclassified from accumulated other comprehensive income	10
Transactions with noncontrolling interests		14	(41)
Net changes in current period	116	(33)	(38)
Ending Balance	$ 83	$ (33)