Name:	brka_InventoryWorkInProcessAndOtherInventoryNetOfReserves
Namespace Prefix:	brka_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Carrying amount as of the balance sheet date of components used by the Entity which are bought from another entity rather than produced by the Entity, net of valuation reserves and adjustments.

No definition available.

Name:	brka_OtherInventoryPurchasedGoodsNetOfReserves
Namespace Prefix:	brka_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

Name:	us-gaap_InventoryDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of merchandise or goods held by the company that are readily available for sale.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Topic 210
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Name:	us-gaap_InventoryFinishedGoodsNetOfReserves
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 852
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-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Name:	us-gaap_InventoryNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of unprocessed items to be consumed in the manufacturing or production process.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 330
-SubTopic 10
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-Topic 210
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