1.0.0.3trueConsolidated Statements of Cash Flows (USD $)In Millionsfalse1$falsefalseSharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170false2$falsefalseSharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170false3$falsefalseSharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDStandardhttp://www.xbrl.org/2003/iso4217USDiso4217022us-gaaptruenadurationstringNo definition available.falsefalsefalsefalsefalsetruefalsefalsefalse1falsefalse00falsefalse2falsefalse00falsefalse3falsefalse00falsefalseNo definition available.false32us-gaap_ProfitLossus-gaaptruecreditdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1truetrue84410000008441falsefalse2truetrue55960000005596falsefalse3truetrue1356700000013567falsefalseNo definition available.No authoritative reference available.false42us-gaaptruenadurationstringNo definition available.falsefalsefalsefalsefalsetruefalsefalsefalse1falsefalse00falsefalse2falsefalse00falsefalse3falsefalse00falsefalseNo definition available.false52us-gaap_GainLossOnInvestmentsus-gaaptruecreditdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue28370000002837falsefalse2falsetrue640000000640falsefalse3falsetrue-5598000000-5598falsefalseNo definition available.No authoritative reference available.false62us-gaap_Depreciationus-gaaptruedebitdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue31270000003127falsefalse2falsetrue28100000002810falsefalse3falsetrue24070000002407falsefalseNo definition available.No authoritative reference available.false72us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesOtherus-gaaptruedebitdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue-149000000-149falsefalse2falsetrue-1248000000-1248falsefalse3falsetrue-268000000-268falsefalseNo definition available.No authoritative reference available.false82us-gaaptruenadurationstringNo definition available.falsefalsefalsefalsefalsetruefalsefalsefalse1falsefalse00falsefalse2falsefalse00falsefalse3falsefalse00falsefalseNo definition available.false92us-gaap_IncreaseDecreaseInLossAndLossAdjustmentExpenseReserveus-gaaptruecreditdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue21650000002165falsefalse2falsetrue14660000001466falsefalse3falsetrue-1164000000-1164falsefalseNo definition available.No authoritative reference available.false102brka_IncreaseDecreaseInDeferredChargesReinsuranceAssumedbrkafalsedebitdurationmonetaryThe change during the reporting period in deferred charges reinsurance assumed.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue-39000000-39falsefalse2falsetrue6400000064falsefalse3falsetrue196000000196falsefalseThe change during the reporting period in deferred charges reinsurance assumed.No authoritative reference available.false112us-gaap_IncreaseDecreaseInUnearnedPremiumsus-gaaptruedebitdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue-21000000-21falsefalse2falsetrue13110000001311falsefalse3falsetrue-713000000-713falsefalseNo definition available.No authoritative reference available.false122us-gaap_IncreaseDecreaseInReceivablesus-gaaptruecreditdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue697000000697falsefalse2falsetrue-2222000000-2222falsefalse3falsetrue-977000000-977falsefalseNo definition available.No authoritative reference available.false132brka_IncreaseDecreaseInDerivativeContractAssetsAndLiabilitiesbrkafalsecreditdurationmonetaryThe change during the period in derivative contract assets and liabilities due to cash payments and receipts and changes in...falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue-5441000000-5441falsefalse2falsetrue78270000007827falsefalse3falsetrue29380000002938falsefalseThe change during the period in derivative contract assets and liabilities due to cash payments and receipts and changes in the value of derivative instruments.No authoritative reference available.false142brka_IncreaseDecreaseInIncomeTaxesbrkafalsedebitdurationmonetaryThe change during the period due to cash payments and receipts from taxing authorities for taxes that are based on the...falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue20350000002035falsefalse2falsetrue-2057000000-2057falsefalse3falsetrue553000000553falsefalseThe change during the period due to cash payments and receipts from taxing authorities for taxes that are based on the reporting entity's earnings and the change during the reporting period for deferred and other tax assets and liabilities.No authoritative reference available.false152us-gaap_IncreaseDecreaseInOtherOperatingCapitalNetus-gaaptruecreditdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue21940000002194falsefalse2falsetrue-2935000000-2935falsefalse3falsetrue16090000001609falsefalseNo definition available.No authoritative reference available.false162us-gaap_NetCashProvidedByUsedInOperatingActivitiesus-gaaptruenadurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue1584600000015846falsefalse2falsetrue1125200000011252falsefalse3falsetrue1255000000012550falsefalseNo definition available.No authoritative reference available.true172us-gaaptruenadurationstringNo definition available.falsefalsefalsefalsefalsetruefalsefalsefalse1falsefalse00falsefalse2falsefalse00falsefalse3falsefalse00falsefalseNo definition available.false182brka_PaymentsToAcquireMarketableSecuritiesFixedMaturitiesbrkafalsecreditdurationmonetaryThe cash outflow from purchases of investments in securities having predetermined or determinable maturity dates.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue-10798000000-10798falsefalse2falsetrue-35615000000-35615falsefalse3falsetrue-13394000000-13394falsefalseThe cash outflow from purchases of investments in securities having predetermined or determinable maturity dates.No authoritative reference available.false192brka_PaymentsToAcquireMarketableSecuritiesEquitySecuritiesbrkafalsecreditdurationmonetaryThe cash outflow from purchases of investments in common stocks and other forms of securities that provide ownership...falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue-4570000000-4570falsefalse2falsetrue-10140000000-10140falsefalse3falsetrue-19111000000-19111falsefalseThe cash outflow from purchases of investments in common stocks and other forms of securities that provide ownership interests in a corporation.No authoritative reference available.false202us-gaap_PaymentsToAcquireOtherInvestmentsus-gaaptruecreditdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue-7068000000-7068falsefalse2falsetrue-14452000000-14452falsefalse3falsefalse00falsefalseNo definition available.No authoritative reference available.false212brka_ProceedsFromSaleOfMarketableSecuritiesFixedMaturitiesbrkafalsedebitdurationmonetaryThe cash inflow associated with the sale of investments in securities having predetermined or determinable maturity dates.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue43380000004338falsefalse2falsetrue1479600000014796falsefalse3falsetrue78210000007821falsefalseThe cash inflow associated with the sale of investments in securities having predetermined or determinable maturity dates.No authoritative reference available.false222brka_ProceedsFromRedemptionsAndMaturitiesOfMarketableSecuritiesFixedMaturitiesbrkafalsedebitdurationmonetaryThe cash inflow associated with redemption or maturity of investments in securities having predetermined or determinable...falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue52340000005234falsefalse2falsetrue1855000000018550falsefalse3falsetrue91580000009158falsefalseThe cash inflow associated with redemption or maturity of investments in securities having predetermined or determinable maturity dates.No authoritative reference available.false232brka_ProceedsFromSaleOfMarketableSecuritiesEquitySecuritiesbrkafalsedebitdurationmonetaryThe cash inflow associated with the sale of investments in common stocks and other forms of securities that provide ownership...falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue56260000005626falsefalse2falsetrue68400000006840falsefalse3falsetrue80540000008054falsefalseThe cash inflow associated with the sale of investments in common stocks and other forms of securities that provide ownership interests in a corporation.No authoritative reference available.false242us-gaap_PaymentsToAcquireLoansReceivableus-gaaptruecreditdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue-854000000-854falsefalse2falsetrue-1446000000-1446falsefalse3falsetrue-1008000000-1008falsefalseNo definition available.No authoritative reference available.false252us-gaap_ProceedsFromCollectionOfLoansReceivableus-gaaptruedebitdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue796000000796falsefalse2falsetrue740000000740falsefalse3falsetrue12290000001229falsefalseNo definition available.No authoritative reference available.false262us-gaap_PaymentsToAcquireBusinessesAndInterestInAffiliatesus-gaaptruecreditdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue-108000000-108falsefalse2falsetrue-6050000000-6050falsefalse3falsetrue-1602000000-1602falsefalseNo definition available.No authoritative reference available.false272us-gaap_PaymentsToAcquirePropertyPlantAndEquipmentus-gaaptruecreditdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue-4937000000-4937falsefalse2falsetrue-6138000000-6138falsefalse3falsetrue-5373000000-5373falsefalseNo definition available.No authoritative reference available.false282us-gaap_PaymentsForProceedsFromOtherInvestingActivitiesus-gaaptruecreditdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue11800000001180falsefalse2falsetrue849000000849falsefalse3falsetrue798000000798falsefalseNo definition available.No authoritative reference available.false292us-gaap_NetCashProvidedByUsedInInvestingActivitiesus-gaaptruedebitdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue-11161000000-11161falsefalse2falsetrue-32066000000-32066falsefalse3falsetrue-13428000000-13428falsefalseNo definition available.No authoritative reference available.true302us-gaaptruenadurationstringNo definition available.falsefalsefalsefalsefalsetruefalsefalsefalse1falsefalse00falsefalse2falsefalse00falsefalse3falsefalse00falsefalseNo definition available.false332us-gaap_ProceedsFromRepaymentsOfShortTermDebtus-gaaptruedebitdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue-885000000-885falsefalse2falsetrue11830000001183falsefalse3falsetrue-596000000-596falsefalseNo definition available.No authoritative reference available.false342brka_PaymentsToMinorityShareholdersAndProceedsFromPaymentsForOtherFinancingActivitiesbrkafalsecreditdurationmonetaryThe cash outflow to return capital to noncontrolled interest, which generally occurs when noncontrolling shareholders reduce...falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue-410000000-410falsefalse2falsetrue-132000000-132falsefalse3falsetrue387000000387falsefalseThe cash outflow to return capital to noncontrolled interest, which generally occurs when noncontrolling shareholders reduce their ownership stake (in a subsidiary of the entity). Additionally, the balance includes the net cash inflow (outflow) from other financing activities.No authoritative reference available.false352us-gaap_NetCashProvidedByUsedInFinancingActivitiesus-gaaptruedebitdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue233000000233falsefalse2falsetrue22860000002286falsefalse3falsetrue13660000001366falsefalseNo definition available.No authoritative reference available.true362us-gaap_EffectOfExchangeRateOnCashAndCashEquivalentsus-gaaptruedebitdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue101000000101falsefalse2falsetrue-262000000-262falsefalse3falsetrue9800000098falsefalseNo definition available.No authoritative reference available.false372us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseus-gaaptruenadurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue50190000005019falsefalse2falsetrue-18790000000-18790falsefalse3falsetrue586000000586falsefalseNo definition available.No authoritative reference available.true382us-gaaptruenadurationstringNo definition available.falsefalsefalsefalsefalsetruefalsefalsefalse1falsefalse00falsefalse2falsefalse00falsefalse3falsefalse00falsefalseNo definition available.false392us-gaap_CashAndCashEquivalentsAtCarryingValueus-gaaptruedebitinstantmonetaryNo definition available.falsefalsefalsefalsefalsefalsetruefalsefalse1falsetrue2553900000025539falsefalse2falsetrue4432900000044329falsefalse3falsetrue4374300000043743falsefalseNo definition available.No authoritative reference available.false402us-gaap_CashAndCashEquivalentsAtCarryingValueus-gaaptruedebitinstantmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsetruefalse1falsetrue3055800000030558falsefalse2falsetrue2553900000025539falsefalse3falsetrue4432900000044329falsefalseNo definition available.No authoritative reference available.false410natruenananaNo definition available.falsetruefalsefalsefalsefalsefalsefalsefalse1falsefalse00falsefalse2falsefalse00falsefalse3falsefalse00falsefalseNo definition available.No authoritative reference available.false702us-gaaptruenadurationstringNo definition available.falsefalsefalsefalsefalsetruefalsefalsefalse1falsefalse00falsefalse2falsefalse00falsefalse3falsefalse00falsefalseNo definition available.false712us-gaap_ProceedsFromOtherDebtus-gaaptruedebitdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue289000000289falsefalse2falsetrue134000000134falsefalse3falsetrue121000000121falsefalseNo definition available.No authoritative reference available.false722us-gaap_RepaymentsOfOtherDebtus-gaaptruecreditdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue-739000000-739falsefalse2falsetrue-233000000-233falsefalse3falsetrue-995000000-995falsefalseNo definition available.No authoritative reference available.false782us-gaaptruenadurationstringNo definition available.falsefalsefalsefalsefalsetruefalsefalsefalse1falsefalse00falsefalse2falsefalse00falsefalse3falsefalse00falsefalseNo definition available.false792us-gaap_CashAndCashEquivalentsAtCarryingValueus-gaaptruedebitinstantmonetaryNo definition available.falsefalsefalsefalsefalsefalsetruefalsefalse1falsetrue2430200000024302falsefalse2falsetrue3770300000037703falsefalse3falsefalse00falsefalseNo definition available.No authoritative reference available.false802us-gaap_CashAndCashEquivalentsAtCarryingValueus-gaaptruedebitinstantmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsetruefalse1falsetrue2791700000027917falsefalse2falsetrue2430200000024302falsefalse3falsetrue3770300000037703falsefalseNo definition available.No authoritative reference available.false810natruenananaNo definition available.falsetruefalsefalsefalsefalsefalsefalsefalse1falsefalse00falsefalse2falsefalse00falsefalse3falsefalse00falsefalseNo definition available.No authoritative reference available.false1102us-gaaptruenadurationstringNo definition available.falsefalsefalsefalsefalsetruefalsefalsefalse1falsefalse00falsefalse2falsefalse00falsefalse3falsefalse00falsefalseNo definition available.false1112us-gaap_ProceedsFromOtherDebtus-gaaptruedebitdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue12410000001241falsefalse2falsetrue21470000002147falsefalse3falsetrue35380000003538falsefalseNo definition available.No authoritative reference available.false1122us-gaap_RepaymentsOfOtherDebtus-gaaptruecreditdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue-444000000-444falsefalse2falsetrue-2147000000-2147falsefalse3falsetrue-1149000000-1149falsefalseNo definition available.No authoritative reference available.false1182us-gaaptruenadurationstringNo definition available.falsefalsefalsefalsefalsetruefalsefalsefalse1falsefalse00falsefalse2falsefalse00falsefalse3falsefalse00falsefalseNo definition available.false1192us-gaap_CashAndCashEquivalentsAtCarryingValueus-gaaptruedebitinstantmonetaryNo definition available.falsefalsefalsefalsefalsefalsetruefalsefalse1falsetrue280000000280falsefalse2falsetrue11780000001178falsefalse3falsefalse00falsefalseNo definition available.No authoritative reference available.false1202us-gaap_CashAndCashEquivalentsAtCarryingValueus-gaaptruedebitinstantmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsetruefalse1falsetrue429000000429falsefalse2falsetrue280000000280falsefalse3falsetrue11780000001178falsefalseNo definition available.No authoritative reference available.false1210natruenananaNo definition available.falsetruefalsefalsefalsefalsefalsefalsefalse1falsefalse00falsefalse2falsefalse00falsefalse3falsefalse00falsefalseNo definition available.No authoritative reference available.false1502us-gaaptruenadurationstringNo definition available.falsefalsefalsefalsefalsetruefalsefalsefalse1falsefalse00falsefalse2falsefalse00falsefalse3falsefalse00falsefalseNo definition available.false1512us-gaap_ProceedsFromOtherDebtus-gaaptruedebitdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue15840000001584falsefalse2falsetrue51950000005195falsefalse3falsetrue11530000001153falsefalseNo definition available.No authoritative reference available.false1522us-gaap_RepaymentsOfOtherDebtus-gaaptruecreditdurationmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalse1falsetrue-403000000-403falsefalse2falsetrue-3861000000-3861falsefalse3falsetrue-1093000000-1093falsefalseNo definition available.No authoritative reference available.false1582us-gaaptruenadurationstringNo definition available.falsefalsefalsefalsefalsetruefalsefalsefalse1falsefalse00falsefalse2falsefalse00falsefalse3falsefalse00falsefalseNo definition available.false1592us-gaap_CashAndCashEquivalentsAtCarryingValueus-gaaptruedebitinstantmonetaryNo definition available.falsefalsefalsefalsefalsefalsetruefalsefalse1falsetrue957000000957falsefalse2falsetrue54480000005448falsefalse3falsefalse00falsefalseNo definition available.No authoritative reference available.false1602us-gaap_CashAndCashEquivalentsAtCarryingValueus-gaaptruedebitinstantmonetaryNo definition available.falsefalsefalsefalsefalsefalsefalsetruefalse1truetrue22120000002212falsefalse2truetrue957000000957falsefalse3truetrue54480000005448falsefalseNo definition available.No authoritative reference available.falsefalse358falseMillionsUnKnownUnKnownfalsetrue