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Prior Service Cost Pension Adjustments Prior Service Cost [Member] Company Selected Measure Name Company Selected Measure Name Sale of Stock [Domain] Sale of Stock [Domain] Income Tax Disclosure [Abstract] Related party notes receivable—current Related party notes receivable—current Financing Receivable, after Allowance for Credit Loss, Current Concentration Risk [Line Items] Concentration Risk [Line Items] Supplemental non-cash financing activities: Noncash Investing and Financing Items [Abstract] Ownership percentage Subsidiary, Ownership Percentage, Parent Pension remeasurement reserve adjustments Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Credit Facility [Domain] Credit Facility [Domain] Related Party Transactions [Abstract] Cash flows from operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Other long-term liabilities Other Sundry Liabilities, Noncurrent HMH Holdings Inc. HMH Holding Inc. [Member] HMH Holding Inc. 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Fiscal Year End Date Current Fiscal Year End Date Members’ equity Members' Equity Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount 6-12 months Six To Twelve Months [Member] Six To Twelve Months Derivatives designated as cash flow hedges Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract] Business Combinations Business Combination [Text Block] Repurchased to satisfy employee's tax holding obligations (in shares) Stock Repurchased During Period, Shares Restructuring Reserve [Roll Forward] Restructuring Reserve [Roll Forward] Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Entity File Number Entity File Number Payout percentage Share-Based Compensation Arrangement by Share-Based Payment Award, Performance Payout Percentage Share-Based Compensation Arrangement by Share-Based Payment Award, Performance Payout Percentage Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Service cost Defined Benefit Plan, Service Cost Share-based compensation Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Summary of PSUs Activity Schedule of Nonvested Performance-Based Units Activity [Table Text Block] Deferred offering costs Deferred Costs, Current Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Restructuring and other expenses Restructuring Costs Common stock, shares issued (in shares) Common Stock, Shares, Issued Measure: Measure [Axis] Treasury stock (in shares) Treasury Stock, Common, Shares Provision reversed during the period Standard Product Warranty, Expense Reversal Standard Product Warranty, Expense Reversal Equity Components [Axis] Equity Components [Axis] Accounts receivable and related party accounts receivable Increase (Decrease) in Accounts Receivable Related Party Related Party [Member] Product and Service [Domain] Product and Service [Domain] Class of Stock [Line Items] Class of Stock [Line Items] Cash paid for income taxes, net Income Tax Paid, after Refund Received Number of shares issued in 2026 that are excluded from calculation of basis and diluted EPS in 2025 Shares Issued In Current Period Excluded From Calculation Of Basis And Diluted Earnings Per Share In Prior Period Shares Issued In Current Period Excluded From Calculation Of Basis And Diluted Earnings Per Share In Prior Period Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] TRA liability and related deferred tax impact from the Corporate Reorganization Transactions Adjustments To Additional Paid In Capital, Tax Receivable Agreement Liability And Tax Impact Of Reorganization Adjustments To Additional Paid In Capital, Tax Receivable Agreement Liability And Tax Impact Of Reorganization Provisions—restructuring Restructuring Reserve, Current Class A Common Stock Class A common stock Common Class A [Member] Entity Interactive Data Current Entity Interactive Data Current Less: Net income (loss) attributable to non-controlling interests Net Income (Loss) Attributable to Noncontrolling Interest Deferred tax liabilities Deferred Income Tax Liabilities, Net Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Entity Small Business Entity Small Business Comprehensive income (loss) attributable to HMH Holding Inc. Comprehensive Income (Loss), Net of Tax, Attributable to Parent Termination Date Trading Arrangement Termination Date Noncontrolling Interest [Table] Noncontrolling Interest [Table] Total segment operating income (loss) Operating Income (Loss), Adjusted Operating Income (Loss), Adjusted Germany GERMANY Development costs Payments For Development Costs Payments For Development Costs Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Stock split, conversion ratio Stockholders' Equity Note, Stock Split, Conversion Ratio Net effect of changes in benefit plans, after taxes Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Non-current debt, net Long-Term Debt Including Related Party Debt, Excluding Current Maturities Long-Term Debt Including Related Party Debt, Excluding Current Maturities Other current liabilities Other current liabilities Other Liabilities, Current Other assets Other Assets, Noncurrent Document Type Document Type Acquisition of business, net of cash Payments to Acquire Businesses, Net of Cash Acquired Other Baker Hughes companies Other Baker Huges Companies [Member] Other Baker Huges Companies Accrued expenses Accrued expenses Accrued Liabilities, Current Fair Value as of Grant Date Award Grant Date Fair Value PCS PCS Segment [Member] PCS Segment Payment-in-kind interest Paid-in-Kind Interest Goodwill [Table] Goodwill [Table] Customer One Customer One [Member] Customer One Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Arrangement Duration Trading Arrangement Duration Statement of Stockholders' Equity [Abstract] Local Phone Number Local Phone Number Consolidation Items [Axis] Consolidation Items [Axis] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Sale of products Product Sales [Member] Product Sales Income (loss) before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Other Noncurrent Liabilities Other Noncurrent Liabilities [Table Text Block] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Ownership Equity, Attributable to Noncontrolling Interest [Roll Forward] 6 months and less Six Months Or Less [Member] Six Months Or Less Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Executive Category: Executive Category [Axis] Summary of RSUs Activity Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Vesting period Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period Transferred at point in time Transferred at Point in Time [Member] Goodwill [Roll Forward] Goodwill [Roll Forward] Counterparty Name [Axis] Counterparty Name [Axis] Liabilities and equity Liabilities and Equity [Abstract] Intangible Asset, Finite-Lived, Class [Domain] Intangible Asset, Finite-Lived, Class [Domain] Schedule of Financial Instruments Measured at Fair Value on a Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Inventories, net Inventories, net Inventory, Net Award Type [Domain] Award Type [Domain] Derivative Maturity [Domain] Derivative Maturity [Domain] Derivative Maturity [Domain] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Movement in Standard Product Warranty Accrual [Roll Forward] Movement in Standard Product Warranty Accrual [Roll Forward] Level 3 Fair Value, Inputs, Level 3 [Member] Supplemental cash flow information: Supplemental Cash Flow Information [Abstract] Contracted term in years Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Term Grant date price of HMH common stock (in dollars per share) Share Price Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Equity interest percentage Subsidiary, Ownership Percentage, Noncontrolling Owner PEO Name PEO Name Geographical [Axis] Geographical [Axis] Accrued expenses Increase (Decrease) in Accrued Liabilities Balance as of January 1, 2026 Balance as of June 30, 2026 Contract with Customer, Liability Hedging reserve adjustments Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] Unallocated corporate costs Segment Reporting, Other Segment Item, Amount Cash acquired Cash Acquired from Acquisition Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Entity Tax Identification Number Derivative Instruments and Hedging Activities Disclosures [Table] Derivative Instruments and Hedging Activities Disclosures [Table] Legal Entity [Axis] Legal Entity [Axis] Purchase of treasury stock Treasury Stock, Value, Acquired, Cost Method Reductions for payments Payments for Restructuring Baker Hughes Holdings LLC Baker Hughes Holdings LLC [Member] Baker Hughes Holdings LLC Accounts payable and accounts payable—related party Increase (Decrease) in Accounts Payable Other Other Accrued Liabilities, Current Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Non-NEOs Non-NEOs [Member] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Number of employees impacted by restructuring plan Restructuring and Related Cost, Number of Positions Eliminated Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Cash consideration paid, including £0.2 million cash acquired Payments to Acquire Businesses, Gross Share-based compensation expense Share-Based Payment Arrangement, Noncash Expense Public duties and taxes Public Duties and Taxes Payable, Current Public Duties and Taxes Payable, Current Partial Exercise of Underwriters Purchase Option (in shares) Stock Issued During Period, Shares, Conversion of Convertible Securities Schedule of Debt Schedule of Debt [Table Text Block] Deep Blue Deep Blue Oil & Gas Limited [Member] Deep Blue Oil & Gas Limited Customer [Domain] Customer [Domain] Schedule of Inventory, Net of Reserves Schedule of Inventory, Current [Table Text Block] Leases Lessee, Operating Leases [Text Block] Long-Term Debt, Type [Domain] Long-Term Debt, Type [Domain] Net income (loss) per share of common stock (actual)—Basic (in dollars per share) Earnings Per Share, Basic Purchase of treasury shares Payments for Repurchase of Common Stock Contract liabilities Contract with Customer, Liability, Current Total current assets Assets, Current Statistical Measurement [Axis] Statistical Measurement [Axis] Insider Trading Arrangements [Line Items] Long-term debt, net Long-term debt, net—related party Long-Term Debt, Excluding Current Maturities Drillform Drillform [Member] Drillform Award Type [Axis] Award Type [Axis] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Accounts receivable Related party accounts receivable Accounts Receivable, after Allowance for Credit Loss, Current Retained earnings Retained Earnings (Accumulated Deficit) Product and Service [Axis] Product and Service [Axis] Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Common Stock Common Stock [Member] Stock price volatility Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate Contingent consideration Business Combination, Contingent Consideration, Liability Operating lease cost Operating Lease, Cost Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Issuance under the Equity Based Compensation Plan (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Shares Issued in Period Cover [Abstract] Reclassification Reclassification, Comparability Adjustment [Policy Text Block] Expected dividend yield Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Dividend Rate Non-controlling interests Members' Equity Attributable to Noncontrolling Interest Derivative Contract [Domain] Derivative Contract [Domain] Concentration risk, percentage Concentration Risk, Percentage Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Credit Line in China Foreign Line of Credit [Member] Currency translation differences Goodwill, Foreign Currency Translation, Gain (Loss) Equity Awards Adjustments Equity Awards Adjustments [Member] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Total liabilities and shareholders’ equity Liabilities and Equity Performance period Share-Based Compensation Arrangement by Share-Based Payment Award, Performance Period Share-Based Compensation Arrangement by Share-Based Payment Award, Performance Period Employee Stock Option Share-Based Payment Arrangement, Option [Member] Non-controlling interests Equity, Attributable to Noncontrolling Interest Segments [Axis] Segments [Axis] Other current and long-term liabilities Increase (Decrease) in Other Operating Liabilities Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Restructuring and other expenses Restructuring Charges Related and Nonrelated Parties [Domain] Related and Nonrelated Parties [Domain] Inventory Disclosure [Abstract] Tabular List, Table Tabular List [Table Text Block] Additional paid-in capital Additional Paid in Capital Accrued sales and other taxes Sales and Excise Tax Payable, Current Other non-operating income (loss), net Other non-operating income (loss) Other Nonoperating Income (Expense) Name Awards Close in Time to MNPI Disclosures, Individual Name Equity Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Schedule of Other Current Liabilities Other Current Liabilities [Table Text Block] Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Financial Instruments Derivatives and Fair Value [Text Block] Change In Contract With Customer Liability [Roll Forward] Change In Contract With Customer Liability [Roll Forward] Change In Contract With Customer Liability Purchase of HMH B.V. voting shares from Principal Stockholders Payments for Repurchase of Private Placement Adjustment to Compensation: Adjustment to Compensation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Class of Stock [Domain] Class of Stock [Domain] Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Cash paid for interest Interest Paid, Excluding Capitalized Interest, Operating Activity Statement of Cash Flows [Abstract] Foreign exchange forward contracts Foreign Exchange Forward [Member] Hedging Designation [Axis] Hedging Designation [Axis] Beginning balance Ending balance Ownership Percentage Ownership Percentage Schedule of Change in Ownership of HMH B.V Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Table Text Block] Credit Facility [Axis] Credit Facility [Axis] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Total assets Assets, Fair Value Disclosure Name Measure Name Income Taxes Income Tax Disclosure [Text Block] Accounts payable Accounts payable—related party Accounts Payable, Current Pay vs Performance Disclosure [Line Items] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Mexico MEXICO Debt Instrument [Line Items] Debt Instrument [Line Items] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Total consideration Business Combination, Consideration Transferred Effect of changes in fair value of cash flow hedges Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax Accrued expense Warranty expense Product Warranty Expense Derivative Maturity [Axis] Derivative Maturity [Axis] Derivative Maturity Additional paid-in capital Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Name Trading Arrangement, Individual Name Cash and cash equivalents Cash and Cash Equivalent Stock of raw materials Inventory, Raw Materials, Net of Reserves Deferred IPO cost netted with IPO proceeds Debt Issuance Costs Incurred During Noncash or Partial Noncash Transaction Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Company Selected Measure Amount Company Selected Measure Amount Mercury HoldCo Inc. Mercury HoldCo Inc. [Member] Mercury HoldCo Inc. Schedule of Reconciliation of Segment Performance Segment Reporting, Reconciliation of Profit (Loss) by Segment to Consolidated [Table Text Block] Derivative financial instruments—not designated as hedging instruments Not Designated as Hedging Instrument [Member] Depreciation and amortization Depreciation, Depletion and Amortization Schedule of PSU Awards Weighted Average Assumptions Schedule of Share-Based Payment Award, Performance Shares, Valuation Assumptions [Table Text Block] Schedule of Share-Based Payment Award, Performance Shares, Valuation Assumptions Share-based compensation (in shares) Equity-based compensation (in shares) Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture Stock, Class of Stock [Table] Stock, Class of Stock [Table] Net income (loss) Net income (loss) Net income (loss) Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Commitment and Contingencies Commitments, Contingencies, Restructuring And Guarantees [Text Block] Commitments, Contingencies, Restructuring And Guarantees Current assets Assets, Current [Abstract] Derivative financial instruments Derivative Liability Non-PEO NEO Non-PEO NEO [Member] 7.875% Senior Secured Bonds due 2028 Senior Notes [Member] Entity Address, Address Line One Entity Address, Address Line One Vested upon the consummation of the IPO (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Income tax (expense) benefit Tax (benefit) provision Income Tax Expense (Benefit) Foreign currency gain (loss), net Foreign currency gain (loss) Gain (Loss), Foreign Currency Transaction, before Tax Customer Concentration Risk Customer Concentration Risk [Member] Total cost of sales Cost of sales Cost of Product and Service Sold Award Timing Method Award Timing Method [Text Block] Net increase (decrease) in cash and cash equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Numerator (in thousands) Net Income (Loss) Attributable to Parent [Abstract] Provisions for loss contingencies Loss Contingency, Accrual, Current Amortization of net actuarial loss Defined Benefit Plan, Amortization of Gain (Loss) Net income (loss) attributable to HMH Holding Inc. Net Income (Loss) Attributable to Parent Long-Term Debt, Type [Axis] Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Statement [Table] Statement [Table] Voting power percentage Subsidiary, Voting Power Percentage Subsidiary, Voting Power Percentage Number of reportable segments not disclosed flag Number Of Reportable Segments Not Disclosed Flag Number Of Reportable Segments Not Disclosed Flag Restatement Determination Date: Restatement Determination Date [Axis] Schedule of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] HMH B.V. HMH B.V. [Member] HMH B.V. Derivative Instruments and Hedging Activities Disclosures [Line Items] Derivative Instruments and Hedging Activities Disclosures [Line Items] Schedule of Change in Contract Assets and Liabilities Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Basis of Presentation and Summary of Significant Accounting Policies Basis of Presentation and Significant Accounting Policies [Text Block] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract]