XML 103 R95.htm IDEA: XBRL DOCUMENT
v3.24.2.u1

Long-duration insurance contracts - Summary of Other Information Relating to Long-Duration Insurance Liabilities (Detail) - USD ($) $ in Millions | Jun. 30, 2024 | Jun. 30, 2023
--- | --- | ---
Periodic Payment Annuity [Member] |  |
Liability for Future Policy Benefit, Activity [Line Items] |  |
Undiscounted expected future benefits | $ 30,867 | $ 31,232
Weighted average discount rate | 5.70% | 5.30%
Weighted average accretion rate | 4.80% | 4.80%
Weighted average duration (in years) | 16 years | 18 years
Life and Health [Member] |  |
Liability for Future Policy Benefit, Activity [Line Items] |  |
Undiscounted expected future gross premiums | $ 94,942 | $ 108,089
Discounted expected future gross premiums | 55,787 | 65,599
Undiscounted expected future benefits | $ 86,253 | $ 103,012
Weighted average discount rate | 5.20% | 5.00%
Weighted average accretion rate | 2.70% | 3.30%
Weighted average duration (in years) | 13 years | 14 years

X
- 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/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-6 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b)(6) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b)(5) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-6 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-6 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-6 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-6 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 65 -Paragraph 2 -Subparagraph (g)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480016/944-40-65-2 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-6 Reference 9: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 29E -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-29E Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-6 + Details
Name: | us-gaap_LiabilityForFuturePolicyBenefitActivityLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Current weighted-average discount rate used to measure liability for future policy benefit. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b)(6) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-6 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 29E -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-29E + Details
Name: | us-gaap_LiabilityForFuturePolicyBenefitCurrentWeightedAverageDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount, before effect of reinsurance, of discounted balance for expected future gross premium component of liability for future policy benefit. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-6 + Details
Name: | us-gaap_LiabilityForFuturePolicyBenefitExpectedFutureGrossPremiumDiscountedBeforeReinsurance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, before effect of reinsurance, of undiscounted balance for expected future gross premium component of liability for future policy benefit. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-6 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 29E -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-29E + Details
Name: | us-gaap_LiabilityForFuturePolicyBenefitExpectedFutureGrossPremiumUndiscountedBeforeReinsurance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, before effect of reinsurance, of undiscounted balance for expected future policy benefit and expense component of liability for future policy benefit. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-6 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 29E -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-29E + Details
Name: | us-gaap_LiabilityForFuturePolicyBenefitExpectedFuturePolicyBenefitUndiscountedBeforeReinsurance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Weighted-average duration of liability for future policy benefit, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b)(5) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-6 + Details
Name: | us-gaap_LiabilityForFuturePolicyBenefitWeightedAverageDuration
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Definition Original weighted-average discount rate at contract issue date used to measure liability for future policy benefit. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b)(6) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-6 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 29E -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-29E + Details
Name: | us-gaap_LiabilityForFuturePolicyBenefitWeightedAverageInterestAccretionRate
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | srt_ProductOrServiceAxis=brka_PeriodicPaymentAnnuitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=brka_LifeAndHealthInsuranceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |