Notes payable and other borrowings (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Notes payable and other borrowings [Line Items]
Principal payments on debt - 2015	7,444
Principal payments on debt - 2016	3,940
Principal payments on debt - 2017	6,029
Principal payments on debt - 2018	7,694
Principal payments on debt - 2019	3,796
Berkshire Hathaway (Parent) [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	8,354	8,311
Principal payments on debt - 2015	1,710
Principal payments on debt - 2016	1,051
Principal payments on debt - 2017	1,144
Principal payments on debt - 2018	808
Principal payments on debt - 2019	755
Insurance and Other [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	11,894	12,440
Principal payments on debt - 2015	2,676
Principal payments on debt - 2016	1,094
Principal payments on debt - 2017	1,428
Principal payments on debt - 2018	1,088
Principal payments on debt - 2019	804
Insurance and Other [Member] \| Berkshire Hathaway (Parent) [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	8,354	8,311
Weighted average interest rate, percentage	2.80%
Insurance and Other [Member] \| Berkshire Hathaway (Parent) [Member] \| Debt [Member]
Notes payable and other borrowings [Line Items]
Maturity date, range, start	2015
Maturity date, range, end	2047
Insurance and Other [Member] \| Insurance and Other Subsidiaries [Member]
Notes payable and other borrowings [Line Items]
Short-term borrowings	839	949
Other borrowings	2,701	3,180
Short-term debt, weighted average interest rate	0.60%
Weighted average interest rate, percentage	6.10%
Insurance and Other [Member] \| Insurance and Other Subsidiaries [Member] \| Debt [Member]
Notes payable and other borrowings [Line Items]
Maturity date, range, start	2015
Maturity date, range, end	2035
Railroad, Utilities and Energy [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	55,579	46,655
Principal payments on debt - 2015	3,043
Principal payments on debt - 2016	1,642
Principal payments on debt - 2017	1,677
Principal payments on debt - 2018	4,241
Principal payments on debt - 2019	2,885
Railroad, Utilities and Energy [Member] \| Berkshire Hathaway Energy [Member]
Notes payable and other borrowings [Line Items]
Weighted average interest rate, percentage	5.10%
Senior unsecured debt	7,860	6,616
Railroad, Utilities and Energy [Member] \| Berkshire Hathaway Energy [Member] \| Debt [Member]
Notes payable and other borrowings [Line Items]
Maturity date, range, start	2017
Maturity date, range, end	2045
Railroad, Utilities and Energy [Member] \| Berkshire Hathaway Energy Subsidiaries [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	28,439	23,033
Weighted average interest rate, percentage	5.10%
Railroad, Utilities and Energy [Member] \| Berkshire Hathaway Energy Subsidiaries [Member] \| Debt [Member]
Notes payable and other borrowings [Line Items]
Maturity date, range, start	2015
Maturity date, range, end	2064
Railroad, Utilities and Energy [Member] \| BNSF [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	19,280	17,006
Weighted average interest rate, percentage	5.00%
Railroad, Utilities and Energy [Member] \| BNSF [Member] \| Debt [Member]
Notes payable and other borrowings [Line Items]
Maturity date, range, start	2015
Maturity date, range, end	2097
Finance and Financial Products [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	12,736	13,129
Principal payments on debt - 2015	1,725
Principal payments on debt - 2016	1,204
Principal payments on debt - 2017	2,924
Principal payments on debt - 2018	2,365
Principal payments on debt - 2019	107
Finance and Financial Products [Member] \| Berkshire Hathaway Finance Corporation [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	11,178	11,178
Weighted average interest rate, percentage	3.10%
Finance and Financial Products [Member] \| Berkshire Hathaway Finance Corporation [Member] \| Debt [Member]
Notes payable and other borrowings [Line Items]
Maturity date, range, start	2015
Maturity date, range, end	2043
Finance and Financial Products [Member] \| Other Finance Subsidiaries [Member]
Notes payable and other borrowings [Line Items]
Notes payable and other borrowings	1,558	$ 1,951
Weighted average interest rate, percentage	5.30%
Finance and Financial Products [Member] \| Other Finance Subsidiaries [Member] \| Debt [Member]
Notes payable and other borrowings [Line Items]
Maturity date, range, start	2015
Maturity date, range, end	2036

The latest date, which may be expressed in a variety of ways, of a range of contractual maturity dates.

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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.

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

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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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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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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