Notes payable and other borrowings (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010
Notes payable and other borrowings [Line Items]
Principal payments on debt - 2012	$ 9,112
Principal payments on debt - 2013	8,160
Principal payments on debt - 2014	4,298
Principal payments on debt - 2015	4,287
Principal payments on debt - 2016	1,755
Berkshire Hathaway (Parent) [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	8,287	8,360
Principal payments on debt - 2012	1,700
Principal payments on debt - 2013	2,600
Principal payments on debt - 2014	750
Principal payments on debt - 2015	1,700
Principal payments on debt - 2016	750
Insurance and Other [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	13,768	12,471
Principal payments on debt - 2012	3,390
Principal payments on debt - 2013	2,725
Principal payments on debt - 2014	1,345
Principal payments on debt - 2015	1,918
Principal payments on debt - 2016	869
Insurance and Other [Member] \| Berkshire Hathaway (Parent) [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	8,287	8,360
Average Interest Rate, percentage	2.00%
Maturity date, low end of range	2012
Maturity date, high end of range	2047
Insurance and Other [Member] \| Insurance and Other Subsidiaries [Member]
Notes payable and other borrowings [Line Items]
Short-term borrowings	1,490	1,682
Notes payable and other borrowings	3,991	2,429
Short-term debt, average interest rate	0.20%
Average Interest Rate, percentage	5.90%
Maturity date, low end of range	2012
Maturity date, high end of range	2036
Railroad, Utilities and Energy [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	32,580	31,626
Principal payments on debt - 2012	2,567
Principal payments on debt - 2013	1,774
Principal payments on debt - 2014	1,618
Principal payments on debt - 2015	713
Principal payments on debt - 2016	681
Railroad, Utilities and Energy [Member] \| MidAmerican [Member]
Notes payable and other borrowings [Line Items]
Average Interest Rate, percentage	6.10%
Maturity date, low end of range	2012
Maturity date, high end of range	2037
Senior unsecured debt	5,363	5,371
Railroad, Utilities and Energy [Member] \| MidAmerican Subsidiaries [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	14,552	14,275
Average Interest Rate, percentage	5.20%
Maturity date, low end of range	2012
Maturity date, high end of range	2039
Railroad, Utilities and Energy [Member] \| BNSF [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	12,665	11,980
Average Interest Rate, percentage	5.90%
Maturity date, low end of range	2012
Maturity date, high end of range	2097
Finance and Financial Products [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	14,036	14,477
Principal payments on debt - 2012	3,155
Principal payments on debt - 2013	3,661
Principal payments on debt - 2014	1,335
Principal payments on debt - 2015	1,656
Principal payments on debt - 2016	205
Finance and Financial Products [Member] \| Berkshire Hathaway Finance Corporation [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	11,531	11,535
Average Interest Rate, percentage	4.40%
Maturity date, low end of range	2012
Maturity date, high end of range	2040
Finance and Financial Products [Member] \| Other Finance Subsidiaries [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	$ 2,505	$ 2,942
Average Interest Rate, percentage	4.80%
Maturity date, low end of range	2012
Maturity date, high end of range	2036

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Aggregate amount of short-term and long-term debt maturing or scheduled to be repaid within the next twelve months following the date of the latest balance sheet presented in the financial statements.

+ References

No definition available.

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Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

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When presenting a range of maturity dates, the latest date when the outstanding debt instruments are required to be repaid. May be presented in a variety of ways (for example: year only, month and year, day, month and year, and number of years).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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When presenting a range of maturity dates, the earliest date when the outstanding debt instruments are required to be repaid. May be presented in a variety of ways (for example: year only, month and year, day, month and year, and number of years).

+ References

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Reflects the calculation as of the balance sheet date of the average interest rate weighted by the amount of debt outstanding by type or by instrument at that time.

+ References

No definition available.

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- Definition

Amount of long-term debt maturing in year five following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Paragraph 10

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Amount of long-term debt maturing in year four following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates.

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Amount of long-term debt maturing in year three following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates.

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Amount of long-term debt maturing in year two following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates.

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Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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Reflects the calculation as of the balance sheet date of the average interest rate weighted by the amount of short-term debt outstanding by type or by instrument at that time.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized debt obligations (with maturities initially due after one year or beyond the operating cycle if longer).

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