Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
ASSETS
Cash and cash equivalents	$ 49,089	$ 46,992
Investments in equity securities	97,163	87,662
Inventories	9,673	9,675
Goodwill	54,407	54,523
Total assets	442,302	427,452
LIABILITIES
Income taxes, principally deferred	49,599	44,494
Total liabilities	240,196	235,864
SHAREHOLDERS' EQUITY
Common stock	8	8
Capital in excess of par value	37,270	37,230
Accumulated other comprehensive income	32,992	27,500
Retained earnings	129,164	124,272
Treasury stock, at cost	(1,363)	(1,363)
Berkshire Hathaway shareholders' equity	198,071	187,647
Noncontrolling interests	4,035	3,941
Total shareholders' equity	202,106	191,588
Total liabilities and shareholders' equity	442,302	427,452
Insurance and Other [Member]
ASSETS
Cash and cash equivalents	43,984	42,358
Investments in fixed maturity securities	30,601	31,449
Investments in equity securities	95,878	86,467
Other investments	16,779	16,057
Receivables	23,470	21,753
Inventories	9,673	9,675
Property, plant and equipment	19,148	19,188
Goodwill	33,207	33,274
Other	19,270	17,875
Total assets	292,010	278,096
LIABILITIES
Losses and loss adjustment expenses	64,345	64,160
Unearned premiums	11,504	10,237
Life, annuity and health insurance benefits	10,393	10,943
Accounts payable, accruals and other liabilities	20,746	21,149
Notes payable and other borrowings	13,399	13,535
Total liabilities	120,387	120,024
Railroad, Utilities and Energy [Member]
ASSETS
Cash and cash equivalents	3,003	2,570
Property, plant and equipment	88,119	87,684
Goodwill	20,164	20,213
Other	13,535	13,441
Total assets	124,821	123,908
LIABILITIES
Accounts payable, accruals and other liabilities	12,571	13,113
Notes payable and other borrowings	36,890	36,156
Total liabilities	49,461	49,269
Finance and Financial Products [Member]
ASSETS
Cash and cash equivalents	2,102	2,064
Investments in fixed maturity securities	782	842
Other investments	5,152	4,952
Loans and finance receivables	12,751	12,809
Goodwill	1,036	1,036
Other	3,648	3,745
Total assets	25,471	25,448
LIABILITIES
Accounts payable, accruals and other liabilities	1,068	1,099
Derivative contract liabilities	6,721	7,933
Notes payable and other borrowings	12,960	13,045
Total liabilities	$ 20,749	$ 22,077