Employee benefit plan catch-up contributions eligible age.

No definition available.

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- Definition

Employee benefit plan conversion of preferred stock.

+ References

No definition available.

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- Definition

Employee benefit plan debt maturity year.

+ References

No definition available.

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- Definition

Employee benefit plan debt repaid year.

+ References

No definition available.

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- Definition

Employee benefit plan employer contribution matching amount.

+ References

No definition available.

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- Definition

Employee benefit plan employer contribution vested percentage.

+ References

No definition available.

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- Definition

Employee benefit plan employer discretionary contributions amount.

+ References

No definition available.

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Data Type:	xbrli:monetaryItemType
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- Definition

Employee benefit plan forfeited.

+ References

No definition available.

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- Definition

Employee benefit plan forfeited allocated to participant accounts.

+ References

No definition available.

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- Definition

Employee benefit plan immediate lump sum distributions transferred to individual retirement account.

+ References

No definition available.

+ Details

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- Definition

Employee benefit plan non participating eligible employees contribution rate.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
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- Definition

Employee benefit plan note receivable from participant interest rate.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
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- Definition

Employee benefit plan note receivable from participant repayment term.

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
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Period Type:	duration

- Definition

Employee benefit plan number of common stock transferred out of Plan.

+ References

No definition available.

+ Details

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Data Type:	xbrli:sharesItemType
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- Definition

Employee benefit plan participant contribution automatic increased rate.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
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Period Type:	duration

- Definition

Employee benefit plan participant contribution automatically enrolled pre tax deferral rate.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
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- Definition

Employee benefit plan participant contribution discretionary contribution percentage.

+ References

No definition available.

+ Details

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Namespace Prefix:	brka_
Data Type:	dtr-types:percentItemType
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- Definition

Employee benefit plan participant maximum annual catch up contribution amount.

+ References

No definition available.

+ Details

Name:	brka_EmployeeBenefitPlanParticipantMaximumAnnualCatchUpContributionAmount
Namespace Prefix:	brka_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Employee benefit plan preferred stock conversion converted into common stock.

+ References

No definition available.

+ Details

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Namespace Prefix:	brka_
Data Type:	xbrli:sharesItemType
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- Definition

Employee benefit plan stock split conversion ratio.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Employee benefits plan participants contribution to increase the percentage rate automatically.

+ References

No definition available.

+ Details

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Namespace Prefix:	brka_
Data Type:	dtr-types:percentItemType
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- Definition

Amount of debt of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Interest rate on debt of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-02)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 235
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479143/962-235-S50-1

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-SubTopic 205
-Topic 962
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

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- Definition

Percentage of employer matching contribution on eligible participant contribution to employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

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Period Type:	duration

- Definition

Percentage of participant compensation eligible for employer matching contribution for participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

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Period Type:	duration

- Definition

Amount of plan asset, in forfeited nonvested account, no longer allocated to participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 962
-SubTopic 325
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478873/962-325-55-17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (j)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of shares or units of investment held by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Employee Retirement Income Security Act of 1974
-Number 2520
-Section 103
-Subsection 6
-Paragraph d
-Subparagraph (1)(ii)
-Publisher DOL-EBSA

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Employee Retirement Income Security Act of 1974
-Number 2520
-Section 103
-Subsection 10
-Paragraph b
-Subparagraph (4)
-Publisher DOL-EBSA

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Employee Retirement Income Security Act of 1974
-Number 2520
-Section 103
-Subsection 10
-Paragraph b
-Subparagraph (3)
-Publisher DOL-EBSA

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Employee Retirement Income Security Act of 1974
-Number 2520
-Section 103
-Subsection 10
-Paragraph b
-Subparagraph (2)(i)(B)
-Publisher DOL-EBSA

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Employee Retirement Income Security Act of 1974
-Number 2520
-Section 103
-Subsection 10
-Paragraph b
-Subparagraph (1)(i)(B)
-Publisher DOL-EBSA

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-05(a)(Schedule I))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-02(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

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- Definition

Number of shares or units of investment purchased by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

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- Definition

Number of shares or units of investment sold by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

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- Definition

Amount of maximum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Amount of maximum pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), is permitted to contribute.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

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- Definition

Percentage of maximum pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), is permitted to contribute to total pretax annual compensation.

+ References

+ Details

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Description of The plan - Additional Information (Details) - EBP 002 - USD ($)					1 Months Ended	12 Months Ended
	Jun. 01, 2020	Jan. 21, 2010	Jan. 01, 1999	Dec. 21, 1998	Jul. 31, 1989	Dec. 31, 2025	Dec. 31, 2024
EBP, Description of Plan [Line Items]
Common stock split		5000.00%
Number of Common stock transferred out of Plan	1,545,644
Number of common stock sold						132,943
Participants contribute percentage						50.00%
EBP, Participant Contribution, Pretax, Maximum Annual Compensation, Amount						$ 23,500
Employee benefit plan participant maximum annual catch up contribution amount						$ 7,500
Catch-Up contributions eligible age						50 years
EBP, Employer Contribution, Matching Percentage						100.00%
Employee benefit plan employer contribution matching amount						$ 8,398,588
Discretionary contributions amount						$ 1,376,329
Automatically enrolled pre-tax deferral rate						6.00%
Employee benefit plan participant contribution automatic increased rate						1.00%
Employee benefit Plan non participating eligible employees contribution rate						1.00%
Employee benefit plan forfeited allocated to participant accounts						$ 1,828,842
Employee benefit plan forfeited						389,059
Employee benefit plan, forfeited non-vested						286,869	$ 1,690,717
Employee benefit plan, vested account balance						$ 50,000
Employee benefit plan note receivable from participant repayment term						30 years
Maximum
EBP, Description of Plan [Line Items]
Percentage on employee eligible compensation						6.00%
Discretionary contribution percentage							8.00%
Employee benefit plan immediate lump sum distributions transferred to individual retirement account						$ 1,000
Employee benefits plan participants contribution to increase the percentage rate automatically						6.00%
Employee benefit plan note receivable from participant interest rate						8.50%	9.50%
Minimum
EBP, Description of Plan [Line Items]
Discretionary contribution percentage						5.00%
Employee benefit plan note receivable from participant interest rate						8.25%	9.00%
7-1/4% Cumulative Convertible Preferred Stock
EBP, Description of Plan [Line Items]
Purchase of shares					1,754,386
Preferred Stock
EBP, Description of Plan [Line Items]
Employee benefit plan conversion of preferred stock				1,686,721
Berkshire Common Stock
EBP, Description of Plan [Line Items]
Employee Benefit Plan Preferred Stock Conversion Converted into Common Stock				177,106
Berkshire B ESOP Fund
EBP, Description of Plan [Line Items]
Number of shares held in plan						1,223,981	1,356,924
Berkshire B Unitized Fund
EBP, Description of Plan [Line Items]
Number of shares held in plan						182,639
Aviation Underwriters, Inc
EBP, Description of Plan [Line Items]
EBP, Employer Contribution, Matching Percentage						100.00%
Automatically enrolled pre-tax deferral rate						4.00%
Aviation Underwriters, Inc \| Maximum
EBP, Description of Plan [Line Items]
Percentage on employee eligible compensation						4.00%
Two years
EBP, Description of Plan [Line Items]
Vested Percentage						50.00%
Three years
EBP, Description of Plan [Line Items]
Vested Percentage						75.00%
Four years
EBP, Description of Plan [Line Items]
Vested Percentage						100.00%
Term Loan
EBP, Description of Plan [Line Items]
Term loan					$ 150,000,000
Debt repayment year					2014
Interest rate					9.25%
Term Loan \| Amended Loan
EBP, Description of Plan [Line Items]
Debt repayment year			2034
Interest rate			6.50%
Debt repaid year			2022