Year the debt matures, in CCYY format.

No definition available.

Name:	brka_DebtInstrumentMaturityYear
Namespace Prefix:	brka_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

- Definition

The principal amount of new debt issued during the period, excluding premium or discount, if any.

+ References

No definition available.

+ Details

Name:	brka_DebtIssuedDuringPeriod
Namespace Prefix:	brka_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The unpaid balance of subsidiary debt that the parent entity has guaranteed full payment of present and future obligations when due.

+ References

No definition available.

+ Details

Name:	brka_GuaranteesOfSubsidiaryDebt
Namespace Prefix:	brka_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of shares exchanged to acquire noncontrolling interest.

+ References

No definition available.

+ Details

Name:	brka_NumberOfSharesExchangedToAcquireNoncontrollingInterest
Namespace Prefix:	brka_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of outstanding common stock purchased that was held by noncontrolling shareholders.

+ References

No definition available.

+ Details

Name:	brka_PercentageOfOutstandingCommonStockPurchased
Namespace Prefix:	brka_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

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.

+ Details

Name:	brka_RepaymentsOfDebtPrincipalInNextTwelveMonths
Namespace Prefix:	brka_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Value of shares exchanged to acquire noncontrolling interest.

+ References

No definition available.

+ Details

Name:	brka_ValueOfSharesExchangedToAcquireNoncontrollingInterest
Namespace Prefix:	brka_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

+ Details

Name:	srt_CondensedFinancialStatementsCaptionsLineItems
Namespace Prefix:	srt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the acquirer obtains control of the acquiree, in YYYY-MM-DD format.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 25
-Paragraph 7
-SubTopic 10
-Topic 805
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479405/805-10-25-7

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-SubTopic 10
-Topic 805
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479328/805-10-50-2

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 25
-Paragraph 6
-SubTopic 10
-Topic 805
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479405/805-10-25-6

+ Details

Name:	us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482949/835-30-55-8

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69B

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69C
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69C

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482900/835-30-50-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-2

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The average effective interest rate during the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(a)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1F
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1F

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-2

+ Details

Name:	us-gaap_DebtInstrumentInterestRateDuringPeriod
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1E
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1E

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-SubTopic 10
-Topic 470
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-1

+ Details

Name:	us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479581/805-30-50-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-13

+ Details

Name:	us-gaap_PaymentsToAcquireBusinessesGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of cash outflow for short-term and long-term debt. Excludes payment of lease obligation.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 15
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-15

+ Details

Name:	us-gaap_RepaymentsOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage of subsidiary's or equity method investee's stock owned by parent immediately after all stock transactions.

+ References

No definition available.

+ Details

Name:	us-gaap_SubsidiaryOrEquityMethodInvesteeCumulativePercentageOwnershipAfterAllTransactions
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_BusinessAcquisitionAxis=brka_AlleghanyCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=brka_InsuranceAndOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=brka_BerkshireHathawayEnergyCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=srt_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=brka_SeniorNotesAndTermLoanDueTwoThousandTwentySevenToTwoThousandFiftyFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=brka_TheKraftHeinzCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note to Condensed Financial Information - Narrative (Detail) $ in Millions, € in Billions, ¥ in Billions		2 Months Ended	12 Months Ended
	Oct. 19, 2022 USD ($)	Oct. 31, 2024 USD ($) shares	Dec. 31, 2024 USD ($)	Dec. 31, 2024 JPY (¥)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2024 JPY (¥)	Dec. 31, 2024 EUR (€)
Condensed Financial Statements, Captions [Line Items]
Debt maturities: 2025			$ 9,366
Debt maturities: 2026			5,748
Debt maturities: 2027			6,420
Debt maturities: 2028			3,963
Debt maturities: 2029			6,326
Alleghany Corporation [Member]
Condensed Financial Statements, Captions [Line Items]
Business acquisition, cash consideration	$ 11,500
Business acquisition, effective date of acquisition	Oct. 19, 2022
Insurance and Other [Member]
Condensed Financial Statements, Captions [Line Items]
Debt maturities: 2025			4,334
Debt maturities: 2026			4,313
Debt maturities: 2027			4,788
Debt maturities: 2028			2,214
Debt maturities: 2029			2,595
Class B Common Stock [Member] \| Berkshire Hathaway Energy ("BHE") [Member]
Condensed Financial Statements, Captions [Line Items]
Number of shares exchanged \| shares		2,291,631
Value of shares exchanged		$ 1,045
Berkshire Hathaway Inc. (Parent) [Member]
Condensed Financial Statements, Captions [Line Items]
Repayments of borrowings			1,854		$ 4,310	$ 602
Principal amount of debt issued							¥ 1,988.0	€ 4.6
Debt maturities: 2025			1,900
Debt maturities: 2026			4,200
Debt maturities: 2027			4,000
Debt maturities: 2028			2,200
Debt maturities: 2029			2,600
Guarantees of subsidiary debt			20,800
Berkshire Hathaway Inc. (Parent) [Member] \| Berkshire Hathaway Energy ("BHE") [Member]
Condensed Financial Statements, Captions [Line Items]
Percentage of outstanding common stock purchased		2.12%
Berkshire Hathaway Inc. (Parent) [Member] \| Insurance and Other [Member] \| Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Repayments of borrowings			1,900
Berkshire Hathaway Inc. (Parent) [Member] \| Insurance and Other [Member] \| Senior Notes [Member] \| Senior Notes and Term Loan Due 2027 to 2054 [Member]
Condensed Financial Statements, Captions [Line Items]
Principal amount of debt issued			$ 5,500	¥ 837.4
Berkshire Hathaway Inc. (Parent) [Member] \| Insurance and Other [Member] \| Senior Notes [Member] \| Senior Notes and Term Loan Due 2027 to 2054 [Member] \| Minimum [Member]
Condensed Financial Statements, Captions [Line Items]
Interest rate during period			0.974%	0.974%
Debt maturity year			2027	2027
Berkshire Hathaway Inc. (Parent) [Member] \| Insurance and Other [Member] \| Senior Notes [Member] \| Senior Notes and Term Loan Due 2027 to 2054 [Member] \| Maximum [Member]
Condensed Financial Statements, Captions [Line Items]
Interest rate during period			2.625%	2.625%
Debt maturity year			2054	2054
Berkshire Hathaway Inc. (Parent) [Member] \| The Kraft Heinz Company [Member]
Condensed Financial Statements, Captions [Line Items]
Equity method investment ownership percentage after transactions			27.20%	27.20%