Credit rating at or above AA. A A Or Higher Credit Rating [Member] AA or Higher Credit Rating [Member] Accounts Notes And Loans Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts Notes Loans And Financing Receivable By Receivable Type [Axis] Receivable Type [Axis] Accounts Payable, Accruals and Other Liabilities [Member] Accounts Payable Accruals And Other Liabilities [Member] Accounts Payable, Accruals and Other Liabilities [Member] Accounts Payable And Accrued Liabilities Current And Noncurrent Accounts payable, accruals and other liabilities Accounts Receivable Gross Trade and other receivables Accumulated Depreciation Depletion And Amortization Property Plant And Equipment Accumulated depreciation Accumulated Other Comprehensive Income Loss Net Of Tax Accumulated other comprehensive income Accumulated Other Comprehensive Income [Member] Accumulated other comprehensive income The par value of debt securities purchased as an investment as of the acquisition date. Acquisition Of Debt Securities Par Value When Acquired Acquisition of debt investments, par value when acquired Additional Collateral Aggregate Fair Value Additional collateral posting requirements Additional Paid In Capital Common Stock Capital in excess of par value Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Adjustments to reconcile net earnings to operating cash flows: Allowance For Doubtful Accounts Premiums And Other Receivables Allowances for uncollectible accounts Allowance For Loan And Lease Losses Provision For Loss Net Provisions for consumer loan losses Reflects the amount of loans and leases that have been removed, or charged off, from both loan receivables and the reserve for credit losses, typically because they are considered to be not salvageable or have been purchased by unconsolidated collection entities, net of recoveries of previously reported write-offs. Allowance For Loan And Lease Losses Writeoffs Net Of Recoveries Loan charge-offs, net of recoveries Amendment Flag Amendment Flag Amortization Of Intangible Assets Amortization expense Assets Total assets Assets [Abstract] ASSETS Assets Fair Value Disclosure Fair value of asset Assets Leased To Others [Member] Assets held for lease [Member] Available For Sale Debt Securities Amortized Cost Basis Amortized Cost of Investments Available For Sale Equity Securities Amortized Cost Basis Cost Basis of Investments Cost of investment in gain position Availableforsale Securities Continuous Unrealized Loss Position 12 Months Or Longer Aggregate Losses 2 Unrealized losses related to securities that have been in an unrealized loss position for more than 12 months Available For Sale Securities Debt Maturities Amortized Cost Total - amortized cost Available For Sale Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis Due in one year or less - amortized cost Available For Sale Securities Debt Maturities Next Rolling Twelve Months Fair Value Due in one year or less - fair value Available For Sale Securities Debt Maturities Rolling After Year Ten Amortized Cost Basis Due after ten years - amortized cost Available For Sale Securities Debt Maturities Rolling After Year Ten Fair Value Due after ten years - fair value Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis Due after five years through ten years - amortized cost Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Fair Value Due after five years through ten years - fair value Available For Sale Securities Debt Maturities Rolling Year Two Through Five Amortized Cost Basis Due after one year through five years - amortized cost Available For Sale Securities Debt Maturities Rolling Year Two Through Five Fair Value Due after one year through five years - fair value Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost Mortgage-backed securities - amortized cost Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value Mortgage-backed securities - fair value Available For Sale Securities Debt Securities Fair Value of Investments Fair Value of Investments Investments in fixed maturity securities Available For Sale Securities Equity Securities Investments in equity securities Fair Value of Investments Availableforsale Securities Gross Unrealized Gain Gross unrealized gains Unrealized Gains on Investments Available For Sale Securities Gross Unrealized Losses 1 Unrealized Losses on Investments Availableforsale Securities [Member] Available-for-sale Securities [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Bank of America Corporation [Member] Bank Of America Corporation [Member] Bank of America Corporation [Member] Banks, insurance and finance [Member] 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] Berkshire Hathaway Finance Corporation [Member] Berkshire Hathaway Insurance Group Investment Income [Member] Berkshire Hathaway Insurance Group Investment Income [Member] Berkshire Hathaway Insurance Group Investment Income [Member] Berkshire Hathaway Insurance Group [Member] Berkshire Hathaway Insurance Group [Member] Berkshire Hathaway Insurance Group [Member] Berkshire Hathaway Other Businesses [Member] Berkshire Hathaway Other Businesses [Member] Other Businesses [Member] Represents Berkshire Hathaway Primary Group. Berkshire Hathaway Primary Group [Member] 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] Berkshire Hathaway Reinsurance Group [Member] Building And Building Improvements [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 Corporation [Member] BNSF [Member] Business Acquisition Acquiree [Domain] Business Acquisition, Acquiree [Domain] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition Cost Of Acquired Entity Cash Paid Acquisition paid in cash Business Acquisition [Line Items] Business Acquisition [Line Items] Business Acquisition Percentage Of Voting Interests Acquired Acquisition of common stock outstanding, percentage Business Acquisition Share Price Acquisition of common stock outstanding, dollars per share Business Combination Disclosure [Text Block] Significant business acquisitions 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. Cargo And Freight Revenue And Regulated And Unregulated Operating Revenue Operating revenues Carrying Reported Amount Fair Value Disclosure [Member] Carrying Value [Member] Cash And Cash Equivalents At Carrying Value Cash and cash equivalents at end of first quarter Cash and cash equivalents at beginning of year Cash and cash equivalents Cash And Cash Equivalents At Carrying Value [Abstract] Cash and cash equivalents: Cash And Cash Equivalents Period Increase Decrease Increase in cash and cash equivalents Cash Flow Supplemental Disclosures [Text Block] Supplemental cash flow information Category of gains / losses [Domain] Category Of Gains Losses [Domain] Category of gains / losses [Domain] Class Of Stock [Domain] Class of Stock [Domain] Class Of Stock [Line Items] Class of Stock [Line Items] Class Of Warrant Or Right Number Of Securities Called By Warrants Or Rights Number of common shares that can be purchased Collateral Already Posted Aggregate Fair Value Collateral posting requirements under contracts with collateral provisions Commercial, industrial and other [Member] Commercial Industrial And Other [Member] Commercial, industrial and other [Member] Commercial loans and finance receivables. Commercial Loans And Finance Receivables [Member] Commercial loans and finance receivables [Member] Common Class A [Member] Class A [Member] Common Class B [Member] Class B [Member] The entire disclosure about the entity's classes of common stock authorized, issued, and outstanding, including any changes approved by shareholders, and a rollforward of outstanding shares. Common Stock Disclosure [Text Block] Common stock Common Stock Including Additional Paid In Capital [Member] Common stock and capital in excess of par value Common Stock [Member] Common Stock [Member] Common Stock Par Or Stated Value Per Share Common Stock, par value per share Common Stock Shares Authorized Common Stock, shares authorized Common Stock Shares Issued Shares issued, end of period (in shares) Shares issued, beginning of year (in shares) Common Stock Shares Outstanding Outstanding, end of period (in shares) Outstanding, beginning of year (in shares) Issuer's option to convert preferred stock into common stock when the common stock price exceeds a set threshold price per share. Common Stock Threshold Price Per Share Common stock threshold price, per share, to trigger the issuer's option to convert preferred stock into common stock Common Stock Value Common stock The number of votes to which a shareholder is entitled. Common Stock Voting Rights Number Shares Per Class Of Stock Number of votes entitled per share, number Comprehensive Income Net Of Tax Comprehensive income attributable to Berkshire Hathaway Comprehensive Income Net Of Tax [Abstract] Comprehensive income attributable to Berkshire Hathaway: Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest Comprehensive income of noncontrolling interests Consolidation Less Than Wholly Owned Subsidiary Parent Ownership Interest Changes Purchase Of Interest By Parent Aggregate consideration to acquire noncontrolling interest Construction In Progress [Member] Construction in progress [Member] Consumer installment loans and finance receivables. Consumer Installment Loans And Finance Receivables [Member] Consumer installment loans and finance receivables [Member] Consumer Products Member Consumer Products [Member] Consumer products [Member] Changes in shares outstanding as a result of conversion from one class to another, and issuance of shares upon exercises of stock options by holders whose stock options that granted rights to obtain shares of acquired entities were replaced with stock options to obtain the entity's shares. Conversion Of Shares From One Class To Another And Exercises By Acquirees Of Replacement Stock Options Conversions of Class A common stock to Class B common stock and exercises of replacement stock options issued in a business acquisition Corporate Bond Securities [Member] Corporate bonds [Member] Corporate Joint Venture [Member] Corporate Joint Venture [Member] Cost Of Goods And Services Sold Cost of sales and services Costs And Expenses Total costs and expenses Costs And Expenses [Abstract] Costs and expenses: The aggregate costs related to services rendered and total operating expenses. Costs Of Services And Operating Expenses Cost of sales and operating expenses Credit Default Contracts High Yield Indexes [Member] Credit Default Contracts High Yield Indexes [Member] Credit Default Contracts - High Yield Indexes [Member] Credit Default Contracts Individual Corporate [Member] Credit Default Contracts Individual Corporate [Member] Credit Default Contracts - Individual Corporate [Member] Credit Default Contracts States Municipalities [Member] Credit Default Contracts States Municipalities [Member] Credit Default Contracts - States and Municipalities [Member] Credit Default Option [Member] Credit Default Contracts [Member] Credit Rating [Domain] Credit Rating [Domain] Cumulative Perpetual Preferred Stock And Warrants [Member] Cumulative Perpetual Preferred Stock And Warrants [Member] Cumulative Perpetual Preferred Stock And Warrants [Member] Cumulative Perpetual Preferred Stock [Member] Cumulative Perpetual Preferred Stock [Member] Cumulative Perpetual Preferred Stock [Member] Current Fiscal Year End Date Current Fiscal Year End Date Customer Relationships [Member] Customer relationships [Member] Debentures Due March 2022 at 3.05% [Member] Debentures Due March 2022 At 3.05 [Member] Debentures Due March 2022 at 3.05% [Member] Debentures Due March 2042 at 4.4% [Member] Debentures Due March 2042 At 4.4 [Member] Debentures Due March 2042 at 4.40% [Member] Debentures [Member] Debentures [Member] Debentures [Member] Debt And Capital Lease Obligations Notes payable and other borrowings Notes payable and other borrowings - carrying value Debt Disclosure [Text Block] Notes payable and other borrowings Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument Fair Value Notes payable and other borrowings Notes payable and other borrowings - fair value Debt Instrument Interest Rate Stated Percentage Debt Instrument, Interest Rate, Stated Percentage Debt Instrument [Line Items] Debt Instrument [Line Items] Debt Instrument Name [Domain] Debt Instrument, Name [Domain] Debt Instrument [Table] Schedule of Long-term Debt Instruments [Table] The principal amount of new debt issued during the period, excluding premium or discount, if any. Debt Issued During Period Principal amount of debt issued Debt [Member] Debt [Member] Debt Weighted Average Interest Rate Average Interest Rate, percentage Depreciation Depreciation Depreciation expense Derivative Assets Derivative contract assets Derivative Average Remaining Maturity 1 Weighted average remaining life of derivative contract Derivative Contract Type [Domain] Derivative Contract Type [Domain] Derivative Fair Value Of Derivative Asset Assets Derivative Fair Value Of Derivative Asset Amount Offset Against Collateral Counterparty netting - assets Derivative Fair Value Of Derivative Liability Liabilities Derivative Fair Value Of Derivative Liability Amount Offset Against Collateral Counterparty netting - liabilities Derivative Fair Value Of Derivative Net Net derivative contract (assets)/liabilities Derivative Instrument Risk [Axis] Derivative Instrument Risk [Axis] Derivative Instruments And Hedging Activities Disclosure [Text Block] Derivative contracts Derivative Instruments Gain Loss By Hedging Relationship By Income Statement Location By Derivative Instrument Risk [Table] Derivative Instruments, Gain (Loss) by Hedging Relationship, by Income Statement Location, by Derivative Instrument Risk [Table] Derivative Instruments Gain Loss [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Derivative Liabilities Derivative contract liabilities Derivative [Line Items] Derivative [Line Items] Derivative Notional Amount Notional Value Derivative [Table] Derivative [Table] Disclosure - Business segment data [Abstract] Disclosure Business Segment Data [Abstract] Disclosure - Business segment data [Abstract] Disclosure - Common stock [Abstract] Disclosure Common Stock [Abstract] Disclosure - Common stock [Abstract] Disclosure - Common stock - Narrative [Abstract] Disclosure Common Stock Narrative [Abstract] Disclosure - Common stock - Narrative [Abstract] Disclosure - Derivative contracts [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 - gains and losses [Abstract] Disclosure - Derivative contracts - Narrative [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 recurring basis [Abstract] Disclosure Fair Value Measurements Financial Assets And Liabilities Measured And Carried At Fair Value On Recurring Basis [Abstract] Disclosure - Fair value measurements - Financial assets and liabilities measured and carried at fair value on recurring basis [Abstract] Disclosure - Fair value measurements - Financial Instruments [Abstract] Disclosure Fair Value Measurements Financial Instruments [Abstract] Disclosure - Fair value measurements - Financial Instruments [Abstract] Disclosure - Fair value measurements - Other information [Abstract] Disclosure Fair Value Measurements Other Information [Abstract] Disclosure - Fair value measurements - Other information [Abstract] Disclosure - Fair value measurements - Significant unobservable inputs [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 [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 [Abstract] Disclosure - Goodwill and other intangible assets - Intangible assets - Narrative [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 - Inventories [Abstract] Disclosure - Investment gains/losses and other-than-temporary impairment losses on investments [Abstract] Disclosure Investment Gainslosses And Otherthantemporary Impairment Losses On Investments [Abstract] Disclosure - Investment gains/losses and other-than-temporary impairment losses on investments [Abstract] Disclosure - Investment gains/losses and other-than-temporary impairment losses on investments - Narrative [Abstract] Disclosure Investment Gainslosses And Otherthantemporary Impairment Losses On Investments Narrative [Abstract] Disclosure - Investment gains/losses and other-than-temporary impairment losses on investments - Narrative [Abstract] Disclosure - Investment gains/losses and other-than-temporary impairment losses on investments - Other-than-temporary impairment losses [Abstract] Disclosure Investment Gainslosses And Otherthantemporary Impairment Losses On Investments Otherthantemporary Impairment Losses [Abstract] Disclosure - Investment gains/losses and other-than-temporary impairment losses on investments - Other-than-temporary impairment losses [Abstract] Disclosure - Investments in equity securities [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 - Fair value by segment [Abstract] Disclosure - Investments in fixed maturity securities [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 - Amortized cost and estimated fair value of securities with fixed maturities [Abstract] Disclosure - Investments in fixed maturity securities - Narrative [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 [Abstract] Disclosure - Notes payable and other borrowings - Narrative [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 [Abstract] Disclosure - Other investments - Narrative [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 [Abstract] Disclosure - Property, plant and equipment - Narrative [Abstract] Disclosure Property Plant And Equipment Narrative [Abstract] Disclosure - Property, plant and equipment - Narrative [Abstract] Disclosure - Receivables [Abstract] Disclosure Receivables [Abstract] Disclosure - Receivables [Abstract] Disclosure - Receivables - Narrative [Abstract] Disclosure Receivables Narrative [Abstract] Disclosure - Receivables - Narrative [Abstract] Disclosure - Significant Business Acquisitions - Narrative [Abstract] Disclosure Significant Business Acquisitions Narrative [Abstract] Disclosure - Significant Business Acquisitions - Narrative [Abstract] Disclosure - Supplemental cash flow information [Abstract] Disclosure Supplemental Cash Flow Information [Abstract] Disclosure - Supplemental cash flow information [Abstract] Discounted Cash Flow Method [Member] Discounted Cash Flow Method [Member] Discounted Cash Flow Method [Member] Ratio representing the net earnings per equivalent common share and dividend and distribution rights of Class B shares to Class A shares. Distribution Rights Compared To Class A Common Shares Ratio of earnings per Class B share to earnings per Class A share Ratio of net earnings per equivalent common share and dividend and distribution rights of Class B shares to Class A shares Document - Document and Entity Information [Abstract] Document Documentand Entity Information [Abstract] Document - Document and Entity Information [Abstract] Document Fiscal Period Focus Document Fiscal Period Focus Document Fiscal Year Focus Document Fiscal Year Focus Document Information [Line Items] Document Information [Line Items] Document Period End Date Document Period End Date Document Type Document Type Represents Dow Chemical Company. Dow Chemical Company [Member] The Dow Chemical Company [Member] Earnings Per Share [Abstract] Net earnings per share attributable to Berkshire Hathaway shareholders: Earnings Per Share Basic Net earnings per share attributable to Berkshire Hathaway shareholders Effect Of Exchange Rate On Cash And Cash Equivalents Effects of foreign currency exchange rate changes Entities [Table] Entities [Table] Entity Central Index Key Entity Central Index Key Entity Common Stock Shares Outstanding Entity Common Stock, Shares Outstanding Entity [Domain] Entity [Domain] Entity Filer Category Entity Filer Category Entity Registrant Name Entity Registrant Name Equity Component [Domain] Equity Component [Domain] Equity Contract [Member] 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. Equity Derivative Intrinsic Value Aggregate intrinsic value of equity index put option contracts Equity Method Investment Ownership Percentage Economic interest in joint venture Equity Securities and Other Investments [Member] Equity Securities And Other Investments [Member] Equity Securities and Other Investments [Member] Equity Securities [Member] Equity Securities [Member] The number of Class A shares that would be outstanding if all outstanding Class B shares were converted to Class A shares at the conversion rate. Equivalent Shares Outstanding Class A Class A equivalent shares outstanding Estimate Of Fair Value Fair Value Disclosure [Member] Fair Value [Member]