Accounts payable, accruals and other liabilities Represents the line item on the balance sheet for the reported amount. Accounts Payable and Accrued Liabilities [Member] Trade and other receivables Accumulated depreciation Accumulated depreciation Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive income Accumulated other comprehensive income Additional collateral posting requirements Capital in excess of par value Adjustments to reconcile net earnings to operating cash flows: Allowances for uncollectible accounts Allowances for uncollectible accounts Provisions for consumer loan losses Loan charge-offs, net of recoveries Amendment Flag Amortized cost and estimated fair value of securities with fixed maturities [Line Items] Amortized cost and estimated fair value of securities with fixed maturities [Line Items] Total assets Total assets Assets [Abstract] ASSETS Assets held for lease [Member] Cost of investment in gain position Unrealized losses related to securities that have been in an unrealized loss position for 12 months or more Balance Sheet Location [Domain] Banks, insurance and finance [Member] Banks, insurance and finance [Member] Represents the Berkshire Hathaway Finance Corporation, which is part of the Finance and Financial Products reporting business units. Berkshire Hathaway Finance Corporation [Member] Represents Berkshire Hathaway Primary Group. Berkshire Hathaway Primary Group [Member] Represents Berkshire Hathaway Reinsurance Group, which part of the Insuranc and Other reporting business units. Berkshire Hathaway Reinsurance Group [Member] Building and building improvements [Member] Represents the entity Burlington Northern Santa Fe Corporation ("BNSF"), which is part of the Railroad, Utilities and Energy reporting business units. Burlington Northern Santa Fe [Member] Business Acquisition, Acquiree [Domain] Business Acquisition [Axis] Acquisition of common stock outstanding, paid in cash Amount of cash per share to be paid to acquire an entity. Common stock to be acquired in a business acquisition (dollars per share) Amount of cash expected to be paid to acquire the entity. Aggregate cash consideration to be paid for an acquisition, amount The percentage of the acquisition funded through existing cash balances. Percentage of acquisition funded through existing cash balances, percentage The percentage of the acquisition funded through new debt. Percentage of acquisition funded through new debt, percentage Business Acquisition [Line Items] Acquisition of common stock outstanding, percentage Number of voting equity interests acquired in the business combination. Acquisition of remaining common stock outstanding, shares The amount of cash paid to acquire noncontrolling interest of less than 100% owned consolidated subsidiary. Aggregate cash consideration paid for noncontrolling interest acquisiton, amount This element represents the total consideration transferred to acquire noncontrolling interest of less than 100% owned consolidated subsidiary. Aggregate consideration for noncontrolling interest acquisition, amount Aggregate consideration for acquisition of common stock outstanding, amount Significant business acquisitions Holding gain recognized for the difference between the fair value and carrying value of shares held under the equity method One-time holding gain related to the BNSF acquisition In a business combination achieved in stages, this element represents the acquisition-date number of shares in the acquiree held by the acquirer immediately before the acquisition date. Shares owned prior to acquisition, shares The total amount of revenues from transporting cargo and freight between locations and the total regulated and unregulated operating revenues of utilities and energy businesses, and other revenues related to these activities. Operating revenues Carrying Value [Member] Cash and cash equivalents Cash and cash equivalents at end of first six months Cash and cash equivalents at beginning of year Cash and cash equivalents: Increase (decrease) in cash and cash equivalents Increase (decrease) in cash and cash equivalents Non-cash investing and financing activities: Supplemental cash flow information Cash paid during the period for [Abstract] Cash paid during the period for: Class of Stock [Domain] Collateral posting requirements under contracts with collateral provisions Commercial, industrial and other [Member] Commercial, industrial and other [Member] Commercial loans and finance receivables. Commercial loans And finance receivables [Member] Class A [Member] Class B [Member] Common stock and capital in excess of par value Common Stock [Line Items] Common Stock [Line Items] Common Stock, par value per share Common Stock, shares authorized Common Stock, Shares, Outstanding Balance, end of period (in shares) Balance, beginning of year (in shares) Schedule of common stock. Common Stock [Table] Option to convert preferred stock when the common stock price exceeds a set threshold price per share. Common stock threshold price, per share Common Stock, Value, Issued Common stock The number of votes an owner is entitled per Class B share. Number of votes entitled per share, number Comprehensive income attributable to Berkshire Hathaway Comprehensive income attributable to Berkshire Hathaway Comprehensive income attributable to Berkshire Hathaway: Comprehensive income of noncontrolling interests Construction in progress [Member] Consumer installment loans and finance receivables. Consumer installment loans and finance receivables [Member] Consumer Products Member Consumer products [Member] Changes in shares outstanding as a result of conversion from one class to another and other transactions occurring from time to time. Conversions of Class A common stock to Class B common stock and exercises of replacement stock options issued in the BNSF acquisition Represents the remaining amount to be received on the redemption of the convertible perpetual capital instrument. Capital instrument remaining amount to be received Corporate bonds [Member] Corporate Joint Venture [Member] Cost of sales and services Total costs and expenses Total costs and expenses Costs and expenses: The aggregate costs related to services rendered and total operating expenses. Cost of sales and operating expenses Credit default contracts [Member] Credit default obligations Represents a) Preferred stock that are cumulative and perpetual and b) Warrants. Cumulative Perpetual Preferred Stock And Warrant [Member] Cumulative Preferred Stock [Member] Current Fiscal Year End Date Customer relationships [Member] Debt Disclosure [Text Block] Notes payable and other borrowings Par amount of debt Debt Instrument, Interest Rate, Stated Percentage Investments in fixed maturities [Member] Average Interest Rate, percentage Depreciation Depreciation expense Derivative contract assets Weighted average remaining life of derivative contract, years Derivative contracts gains and losses [Line Items] Derivative contracts gains and losses [Line Items] Derivative contracts gains and losses [Table] Derivative contracts gains and losses [Table] Derivative Contract Type [Domain] Derivative Asset, Fair Value, Gross Asset Assets Counterparty netting - assets Derivative Liability, Fair Value, Gross Liability Liabilities Counterparty netting - liabilities Net derivative contract (assets)/liabilities Derivative Instrument Risk [Axis] Derivative contracts Derivative contract liabilities Derivative [Line Items] Derivatives, Fair Value, by Balance Sheet Location [Axis] Derivative [Table] New accounting pronouncements Disclosure - Business segment data - Earnings before income taxes [Abstract] Disclosure - Business segment data - Earnings before income taxes [Abstract] Disclosure - Business segment data - Revenues [Abstract] Disclosure - Business segment data - Revenues [Abstract] Disclosure - Common stock - Narrative [Abstract] Disclosure - Common stock - Narrative [Abstract] Disclosure - Common stock - roll-forward [Abstract] Disclosure - Common stock - roll-forward [Abstract] Disclosure - Derivative contracts [Abstract] Disclosure - Derivative contracts [Abstract] Disclosure - Derivative contracts - gains and losses [Abstract] Disclosure - Derivative contracts - gains and losses [Abstract] Disclosure - Derivative contracts - Narrative [Abstract] Disclosure - Derivative contracts - Narrative [Abstract] Disclosure - Fair value measurements - Financial assets and liabilities measured and carried at fair value on a recurring basis [Abstract] Disclosure - Fair value measurements - Financial assets and liabilities measured and carried at fair value on a recurring basis [Abstract] Disclosure - Fair value measurements - Financial Instruments [Abstract] Disclosure - Fair value measurements - Financial Instruments [Abstract] Disclosure - Fair value measurements - Significant unobservable inputs [Abstract] Disclosure - Fair value measurements - Significant unobservable inputs [Abstract] Disclosure - Goodwill and other intangible assets [Abstract] Disclosure - Goodwill and other intangible assets [Abstract] Disclosure - Goodwill and other intangible assets - Intangible assets [Abstract] Disclosure - Goodwill and other intangible assets - Intangible assets [Abstract] Disclosure - Goodwill and other intangible assets - Intangible assets - Narrative [Abstract] Disclosure - Goodwill and other intangible assets - Intangible assets - Narrative [Abstract] Disclosure - Inventories [Abstract] Disclosure - Inventories [Abstract] Disclosure - Investment gains/losses [Abstract] Disclosure - Investment gains/losses [Abstract] Disclosure - Investment gains/losses - Narrative [Abstract] Disclosure - Investment gains/losses - Narrative [Abstract] Disclosure - Investments in equity securities [Abstract] Disclosure - Investments in equity securities [Abstract] Disclosure - Investments in equity securities - fair value by segment [Abstract] Disclosure - Investments in equity securities - fair value by segment [Abstract] Disclosure - Investments in equity securities - Narrative [Abstract] Disclosure - Investments in equity securities - Narrative [Abstract] Disclosure - Investments in fixed maturity securities [Abstract] Disclosure - Investments in fixed maturity securities [Abstract] Disclosure - Investments in fixed maturity securities - Amortized cost and estimated fair value of securities with fixed maturities [Abstract] Disclosure - Investments in fixed maturity securities - Amortized cost and estimated fair value of securities with fixed maturities [Abstract] Disclosure - Investments in fixed maturity securities - fair value by segment [Abstract] Disclosure - Investments in fixed maturity securities - fair value by segment [Abstract] Disclosure - Investments in fixed maturity securities - Narrative [Abstract] Disclosure - Investments in fixed maturity securities - Narrative [Abstract] Disclosure - Notes payable and other borrowings [Abstract] Disclosure - Notes payable and other borrowings [Abstract] Disclosure - Notes payable and other borrowings - Narrative [Abstract] Disclosure - Notes payable and other borrowings - Narrative [Abstract] Disclosure - Other investments [Abstract] Disclosure - Other investments [Abstract] Disclosure - Other investments - Narrative [Abstract] Disclosure - Other investments - Narrative [Abstract] Disclosure - Property, plant and equipment [Abstract] Disclosure - Property, plant and equipment [Abstract] Disclosure - Property, plant and equipment - Narrative [Abstract] Disclosure - Property, plant and equipment - Narrative [Abstract] Disclosure - Receivables [Abstract] Disclosure - Receivables [Abstract] Disclosure - Receivables - Narrative [Abstract] Disclosure - Receivables - Narrative [Abstract] Disclosure - Significant Business Acquisitions [Abstract] Disclosure - Significant Business Acquisitions [Abstract] Disclosure - Supplemental cash flow information [Abstract] Disclosure - Supplemental cash flow information [Abstract] Document - Document and Entity Information [Abstract] Document - Document and Entity Information [Abstract] Document Fiscal Period Focus Document Fiscal Year Focus Document Information [Line Items] Document Period End Date Document Type Represents Dow Chemical Company. The Dow Chemical Company [Member] Net earnings per share attributable to Berkshire Hathaway shareholders: Net earnings per share attributable to Berkshire Hathaway shareholders Effects of foreign currency exchange rate changes Entities [Table] Entity Central Index Key Entity Common Stock, Shares Outstanding Entity [Domain] Entity Filer Category Entity Registrant Name Equity Component [Domain] Equity index put options [Member] Represents the undiscounted liability assuming the contracts are settled on their future expiration dates based on the index values at the most recent balance sheet date. Aggregate intrinsic value of equity index put option contracts Fair value as of the balance sheet date of equity index put option derivative assets, net of derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized on the balance sheet. Equity index put options Economic interest Equity method investment carrying value prior to investment in subsidiaries Equity Securities [Member] Class A equivalent shares outstanding. Class A equivalent shares outstanding Fair Value [Member] Represents a decrease in additional paid in capital for excess consideration paid over the carrying amount of the noncontrolling interest in the acquisition of certain noncontrolling interests. Excess of the consideration over noncontrolling interest Insurance underwriting expenses This element represents, for the fair value measurement of assets and liabilities using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issuances, and settlements (net); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs). Reconciliations of assets and liabilities measured and carried at fair value on a recurring basis with the use of significant unobservable inputs (Level 3) Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, by Asset Class [Domain] Fair Value by Asset Class [Axis] Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis] Fair values of financial assets and liabilities Fair Value, Hierarchy [Axis] Fair Value, Disclosure Item Amounts [Domain] Fair value measurements Quoted Prices (Level 1) [Member] Significant Other Observable Inputs (Level 2) [Member] Significant Unobservable Inputs (Level 3) [Member] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair value measurements Financial assets and liabilities measured and carried at fair value on a recurring basis [Line Items] Fair value measurements Financial assets and liabilities measured and carried at fair value on a recurring basis [Line Items] Schedule of Fair Value Measurements Financial assets and liabilities measured and carried at fair value on a recurring basis. Fair value measurements Financial assets and liabilities measured and carried at fair value on a recurring basis [Table] Fair Value Measurements [Line Items] Fair Value Measurements [Line Items] Fair value measurements Significant unobservable inputs [Line Items] Fair value measurements Significant unobservable inputs [Line Items] Schedule of Fair Value Measurements Significant unobservable inputs. Fair value measurements Significant unobservable inputs [Table] Schedule of Fair Value Measurements. Fair Value Measurements [Table] This element represents acquisitions which have taken place during the period in relation to assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3). Acquisitions Earnings Other comprehensive income Purchases, sales, issuances and settlements Transfers into (out of) Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Ending Balance Beginning Balance This element represents dispositions which have taken place during the period in relation to assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3). Dispositions This element represents amounts recorded to regulatory assets and liabilities arising from net derivative contract liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3). Regulatory assets and liabilities Represents the Finance and Financial Products reporting business units. Finance and Financial Products [Member] Financial Instruments, Owned, Other, at Fair Value Other investments Financial Statement Line Items with Differences in Reported Amount and Reporting Currency Denominated Amounts [Domain] Finite Lived and Indefinite Lived Intangible Assets [Line Items] Finite Lived and Indefinite Lived Intangible Assets [Line Items]