Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Trading Arrangement: Trading Arrangement [Axis] Title of 12(b) Security Title of 12(b) Security Subsequent Event Subsequent Event [Member] Defined Contribution Plan Tranches [Domain] Defined Contribution Plan Tranches [Domain] Defined Contribution Plan Tranches [Domain] Net loss attributable to Class A common stockholders, diluted Net Income (Loss) Available to Common Stockholders, Diluted Document Fiscal Year Focus Document Fiscal Year Focus Adjustment to Compensation, Amount Adjustment to Compensation Amount Financial Instrument [Axis] Financial Instrument [Axis] Segment Reporting [Abstract] Fair Value, Assets Measured on Recurring Basis Fair Value, Assets Measured on Recurring Basis [Table Text Block] Common stock, value Common Stock, Value, Issued 2026 Lessee, Operating Lease, Liability, to be Paid, Year One Accrued compensation Employee-related Liabilities, Current Restatement Determination Date Restatement Determination Date Proceeds from sale of investments Proceeds from Sale, Maturity and Collection of Investments Accounts receivable, allowance for credit loss Accounts Receivable, Allowance for Credit Loss Exchange of combined interests for Class A common stock (shares) Exchange of Combined Interests Into Class A Common Stock, Shares Exchange of Combined Interests Into Class A Common Stock, Shares Amendment Flag Amendment Flag Current Liabilities Liabilities, Current [Abstract] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Third milestone contribution percentage Contractual Obligation, Milestone Contribution Three, Percentage Contractual Obligation, Milestone Contribution Three, Percentage Remaining Years Lessee, Operating Lease, Liability, to be Paid, after Year Five Shares of Class B common stock Class B Common Shares [Member] Class B Common Shares Treasury Bills US Treasury Bill Securities [Member] Leases [Abstract] Related Party Transactions Related Party Transactions Disclosure [Text Block] Secondary milestone contribution percentage Contractual Obligation, Milestone Contribution Two, Percentage Contractual Obligation, Milestone Contribution Two, Percentage Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Property, Plant, and Equipment [Abstract] Entity Address, State or Province Entity Address, State or Province Schedule of Equity Schedule of Non-Controlling Interests [Table Text Block] Schedule of Non-Controlling Interests PEO Total Compensation Amount PEO Total Compensation Amount Common stock, par value (usd per share) Common Stock, Par or Stated Value Per Share Cash, cash equivalents and restricted cash: Cash and Cash Equivalents [Abstract] Intangible assets, net Intangible Asset, Excluding Goodwill, after Accumulated Amortization Proceeds from issuance of common stock gross Sale Of Stock, Consideration Received On Transaction, Gross Amount Sale Of Stock, Consideration Received On Transaction, Gross Amount Basic (shares) Weighted-average shares for basic loss per share (shares) Weighted Average Number of Shares Outstanding, Basic Retirement Benefits [Abstract] Operations equipment Technology Equipment [Member] Investments Long-Term Investments Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Number of reportable segments Number of Reportable Segments Total current liabilities Liabilities, Current Exercise of common share options and vested RSUs Stock Issued During Period, Value, Exercise of Common Share Options and Vested RSUs Stock Issued During Period, Value, Exercise of Common Share Options and Vested RSUs 2029 Lessee, Operating Lease, Liability, to be Paid, Year Four Beginning of period (shares) End of period (shares) Noncontrolling Interest, Shares Noncontrolling Interest, Shares Entity Address, City or Town Entity Address, City or Town Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Accounts and Other Receivables Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Receivables [Abstract] Statement of Financial Position [Abstract] Document Information [Line Items] Document Information [Line Items] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Vested (shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Class of Stock [Axis] Class of Stock [Axis] Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Net loss attributable to Class A common stockholders, basic Net Income (Loss) Available to Common Stockholders, Basic Accounts and other receivables, net (2025 - $5,452 from related party) Accounts and other receivables, net from related party Accounts and Other Receivables, Net, Current Level 2 Fair Value, Inputs, Level 2 [Member] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Sale of stock, number of shares issued in transaction (shares) Sale Of Stock, Number Of Shares Sold Sale Of Stock, Number Of Shares Sold Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Collaborative Arrangement and Arrangement Other than Collaborative [Table] Collaborative Arrangement and Arrangement Other than Collaborative [Table] Other expenses Other Expenses Subsequent Event Type [Axis] Subsequent Event Type [Axis] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Services commitments - Other Service Commitments And Others [Member] Service Commitments And Others Deferred revenue Increase (Decrease) in Contract with Customer, Liability Disposal of property, plant and equipment Gain (Loss) on Disposition of Property Plant Equipment Noncontrolling Interests Noncontrolling Interest [Member] Related Party [Axis] Related and Nonrelated Parties [Axis] Defined Contribution Plan Disclosure [Line Items] Defined Contribution Plan Disclosure [Line Items] Property, Plant and Equipment Property, Plant, and Equipment [Text Block] Schedule of Operating Lease Maturity Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block] Document Period End Date Document Period End Date Other changes in assets and liabilities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Net Cash Used in Investing Activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] 2027 Lessee, Operating Lease, Liability, to be Paid, Year Two Security Exchange Name Security Exchange Name Long-lead material work in process Long-lead Material Work In Process Long-lead Material Work In Process Entity Shell Company Entity Shell Company Class B Common Class B [Member] Operating lease liabilities, current Operating Lease, Liability, Current Schedule of Property, Plant and Equipment Property, Plant, and Equipment [Table Text Block] Name Outstanding Recovery, Individual Name Loss per Share of Class A Common Stock: Earnings Per Share [Abstract] Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Document Fiscal Period Focus Document Fiscal Period Focus Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] RSUs vested and exercise of options (shares) Noncontrolling Interest, Exercise of Options and Warrants and Vested RSUs Noncontrolling Interest, Exercise of Options and Warrants and Vested RSUs Total Liabilities Liabilities Trading Symbol Trading Symbol Purchase of property, plant and equipment Payments to Acquire Property, Plant, and Equipment Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Office and computer equipment Office And Computer Equipment [Member] Office And Computer Equipment Defined contribution plan, employer matching contribution, percent of employees' gross pay Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Company Selected Measure Name Company Selected Measure Name Sale of Stock [Domain] Sale of Stock [Domain] Revenue and accounts receivable adjustment Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Modification of Contract Income Tax Disclosure [Abstract] Summary of Noncash Investing and Financing Activities: Noncash Investing and Financing Items [Abstract] Related Party Transactions [Abstract] OPERATING CASH FLOW Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Compensation Amount Outstanding Recovery Compensation Amount Individual: Individual [Axis] Diluted (shares) Weighted-average shares for diluted loss per share (shares) Weighted Average Number of Shares Outstanding, Diluted Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Entity Emerging Growth Company Entity Emerging Growth Company Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Vesting percentage Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage Less: imputed interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Accrued foreign income tax withholding to noncontrolling interests Accrued Foreign Income Tax Withholding To Noncontrolling interests Accrued Foreign Income Tax Withholding To Noncontrolling interests Gross Margin Gross Profit Revenue from Contract with Customer [Abstract] Cash, Cash Equivalents, Investments and Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] ATM Program ATM Program [Member] ATM Program Award Timing Predetermined Award Timing Predetermined [Flag] Net change in right of use assets and lease liabilities Increase (Decrease) In Right-of-Use Assets And Lease Liability Increase (Decrease) In Right-of-Use Assets And Lease Liability Restricted cash Restricted Cash, Current Letters of credit outstanding, amount Letters of Credit Outstanding, Amount Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Equity-based compensation expense APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Level 1 Fair Value, Inputs, Level 1 [Member] Proceeds from the issuance of common stock, net of issuance fees Proceeds From Issuance Of Common Stock Net Of Issuance Fees Proceeds From Issuance Of Common Stock Net Of Issuance Fees Effective income tax rate, percent Effective Income Tax Rate Reconciliation, Percent Organization, Consolidation and Presentation of Financial Statements [Abstract] Total lease payments Lessee, Operating Lease, Liability, to be Paid Investments that converted into short-term investments Investments That Converted In To Short-Term investments Investments That Converted In To Short-Term investments Domestic income taxes Federal, State, and Local, Income Tax Expense (Benefit), Continuing Operations All Executive Categories All Executive Categories [Member] Defined contribution plan, employer matching contribution, percent of match Defined Contribution Plan, Employer Matching Contribution, Percent of Match Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Long-lead material work in process Inventory, Work in Process, Noncurrent Inventory, Work in Process, Noncurrent Depreciation and amortization Depreciation Antidilutive Securities [Axis] Antidilutive Securities [Axis] Operating lease assets Operating Lease, Right-of-Use Asset Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards [Line Items] Beginning of period End of period Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Number of megawatts (mw) Number of Megawatts Number of Megawatts 2029 Contractual Obligation, to be Paid, Year Four Renewal term Lessee, Operating Lease, Renewal Term Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Fair Value Disclosures [Abstract] Noncontrolling Interest [Line Items] Noncontrolling Interest [Line Items] Segment Information Segment Reporting [Text Block] Defined Contribution Plan, Tranche One Defined Contribution Plan, Tranche One [Member] Defined Contribution Plan, Tranche One Expiration Date Trading Arrangement Expiration Date Investments, Fair Value Investments, Fair Value Disclosure Schedule of Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Weighted-Average Shares of Class A Common Stock Outstanding: Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Location, Statement of Income, Balance [Axis] Location, Statement of Income, Balance [Axis] Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Cash Equivalents, Fair Value Cash and Cash Equivalents, Fair Value Disclosure Total Stockholders' Equity Beginning balance Ending balance Equity, Including Portion Attributable to Noncontrolling Interest Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Common stock, shares authorized (shares) Common Stock, Shares Authorized Antidilutive Security, Excluded EPS Calculation [Table] Antidilutive Security, Excluded EPS Calculation [Table] Exercise Price Award Exercise Price INVESTING CASH FLOW Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Document Quarterly Report Document Quarterly Report In-process research and development In-process Research and Development In-process Research and Development Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Exercise of common share options and vested RSUs (shares) Stock Issued During Period, Shares, Exercise of Common Share Options and Vested RSUs Stock Issued During Period, Shares, Exercise of Common Share Options and Vested RSUs Contractual obligation Total Contractual Obligation Schedule of Principal Cash Obligations and Commitments Contractual Obligation, Fiscal Year Maturity [Table Text Block] Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Equity Component [Domain] Equity Component [Domain] PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Sale of stock, consideration received on transaction Sale of Stock, Consideration Received on Transaction Adoption Date Trading Arrangement Adoption Date Counterparty Name [Domain] Counterparty Name [Domain] Total Stockholders’ Equity Excluding Noncontrolling Interests Equity, Attributable to Parent Short-term Investment, Fair Value Short Term Investment, Fair Value Disclosure Short Term Investment, Fair Value Disclosure ASSETS Assets [Abstract] Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Total lease liabilities Present value of lease liabilities Operating Lease, Liability Insider Trading Policies and Procedures [Line Items] Investments, Fair Value Debt Securities, Held-to-Maturity, Fair Value Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Leasehold improvement Property, Plant, and Equipment, before Accumulated Depreciation, Addition CFPP LLC CFPP LLC [Member] CFPP LLC Investment income Interest Income (Expense), Nonoperating Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Number of operating segments Number of Operating Segments Anti-dilutive securities excluded (shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Proceeds from sale of short-term investments Proceeds from Sale of Short-Term Investments Time-based RSUs Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Entity Central Index Key Entity Central Index Key Less: Accumulated depreciation Property, Plant, and Equipment, Accumulated Depreciation, Depletion, and Amortization All Adjustments to Compensation All Adjustments to Compensation [Member] Percentage of revenue earned Related Party Transaction, Revenue Earned, Percentage Related Party Transaction, Revenue Earned, Percentage Stockholders’ Equity Equity [Abstract] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Net Cash Used in Operating Activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Foreign income taxes Foreign Income Tax Expense (Benefit), Continuing Operations Income Statement [Abstract] Document Transition Report Document Transition Report Ownership [Axis] Ownership [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Romanian Tax Authority Romanian Tax Authority [Member] Romanian Tax Authority PMA renewal term Contractual Obligation, Renewal Term Contractual Obligation, Renewal Term Noncontrolling Interest [Roll Forward] Noncontrolling Interest [Roll Forward] Noncontrolling Interest City Area Code City Area Code Document Information [Table] Document Information [Table] All Individuals All Individuals [Member] Name Forgone Recovery, Individual Name Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Statement [Line Items] Statement [Line Items] Total Assets Assets Operating leases Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract] Equity-Based Compensation Share-Based Payment Arrangement [Text Block] Other Other [Member] Other Nature of Business Nature of Operations [Text Block] Issuance of Class A common stock (shares) Stock Issued During Period, Shares, New Issues PEO PEO [Member] Thereafter Contractual Obligation, to be Paid, after Year Five Long Lead Material Contract Long Lead Material Contract [Member] Long Lead Material Contract First milestone contribution percentage Contractual Obligation, Milestone Contribution One, Percentage Contractual Obligation, Milestone Contribution One, Percentage Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] 2027 Contractual Obligation, to be Paid, Year Two Noncurrent liabilities Other Liabilities, Noncurrent Goodwill Goodwill Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Investments, Amortized Cost Basis Investments Cash Equivalents, Amortized Cost Basis Cash Equivalents, at Carrying Value Subsequent Event Type [Domain] Subsequent Event Type [Domain] 2026 ATM Program 2026 ATM Program [Member] 2026 ATM Program Operating lease liabilities, noncurrent Operating Lease, Liability, Noncurrent Accumulated Deficit Retained Earnings [Member] Money Market Accounts Money Market Funds [Member] Software Software, In-Development, Internally Developed, and Purchased [Member] Fair Value Measurement Fair Value Measurement, Policy [Policy Text Block] Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Common stock, shares outstanding (shares) Beginning balance (shares) Ending balance (shares) Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Corporate Bonds and Paper Corporate Debt Securities [Member] Diluted (usd per share) Diluted loss per share of Class A common stock (usd per share) Earnings Per Share, Diluted Entity Current Reporting Status Entity Current Reporting Status Net Cash Provided by Financing Activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Accrued compensation Increase (Decrease) in Employee Related Liabilities Sale of stock, consideration received on transaction Sale Of Stock, Authorized Shares, Value Sale Of Stock, Authorized Shares, Value Ownership [Domain] Ownership [Domain] Research and development expenses Research and Development Expense Adjustments to reconcile net loss to operating cash flow: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Partnership Milestones Agreement with ENTRA1 Commitments Contingencies and Guarantees [Text Block] Share-Based Payment Arrangement [Abstract] FINANCING CASH FLOW Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Revenue (2025 - $7,431 and $14,700 from related party) Revenue from related party Total Revenue from Contract with Customer, Excluding Assessed Tax Property, plant and equipment, net Property, plant and equipment, net Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization Supply Commitment [Line Items] Supply Commitment [Line Items] Long-lead material liability Increase (Decrease) In Long-Lead Material Liability Increase (Decrease) In Long-Lead Material Liability Equity and Loss Per Share Noncontrolling Interest Disclosure And Earnings Per Share [Text Block] Noncontrolling Interest Disclosure And Earnings Per Share Financial Instruments [Domain] Financial Instruments [Domain] Partnership Milestones Agreement PMA contributions Partnership Milestones Agreement [Member] Partnership Milestones Agreement Total right-of-use assets Lease, Right-of-Use Asset Lease, Right-of-Use Asset Long-Lead Material Work In Process Inventory Disclosure [Text Block] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Number of awards granted (shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Granted Underlying Securities Award Underlying Securities Amount Purchase of short-term investments Payments to Acquire Short-Term Investments Revenue Revenue from Contract with Customer [Text Block] Issuance of Class A common stock Stock Issued During Period, Value, New Issues Prepaid expenses Prepaid Expense, Current Exchange of combined interests for Class A common stock (shares) Noncontrolling Interest, Exchange of Combined Interests Into Class A Common Stock, Shares Noncontrolling Interest, Exchange of Combined Interests Into Class A Common Stock, Shares Weighted average discount rate-operating leases Operating Lease, Weighted Average Discount Rate, Percent Related Party Transaction [Table] Related Party Transaction [Table] Sale of Stock [Axis] Sale of Stock [Axis] Schedule of Supplemental Balance Sheet Information Lease, Cost [Table Text Block] Commitments and Contingencies Disclosure [Abstract] All Trading Arrangements All Trading Arrangements [Member] Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Loss From Operations Operating Income (Loss) Current Fiscal Year End Date Current Fiscal Year End Date NuScale Corp Class A common stock NuScale Corp [Member] NuScale Corp Foreign income taxes paid Income Tax Paid, Foreign, after Refund Received Investments, Amortized Cost Basis Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount 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] Stock options Equity Option [Member] Entity File Number Entity File Number Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Lease commitments Lease Commitments [Member] Lease Commitments 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] Measure: Measure [Axis] Equity Components [Axis] Equity Components [Axis] Accounts and other receivables (2025 - $979 from related party) Accounts and other receivables from related party Increase (Decrease) in Accounts Receivable Power Plant and NPM related services Power Plant and NPM Engineering, Design and Licensing Services and Fees [Member] Power Plant and NPM Engineering, Design and Licensing Services and Fees Product and Service [Domain] Product and Service [Domain] Related Party Related Party [Member] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Class A Common Class A [Member] Entity Interactive Data Current Entity Interactive Data Current Net loss attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Accounts payable and accrued expenses Accounts Payable and Accrued Liabilities, Current Defined contribution plan expense Defined Contribution Plan, Cost Entity Small Business Entity Small Business 2028 Lessee, Operating Lease, Liability, to be Paid, Year Three Termination Date Trading Arrangement Termination Date Noncontrolling Interest [Table] Noncontrolling Interest [Table] Property, Plant, and Equipment [Line Items] Property, Plant, and Equipment [Line Items] Foreign income tax accrual to noncontrolling interests Foreign Income Tax Withholding To Noncontrolling Interests Foreign Income Tax Withholding To Noncontrolling Interests Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Other accrued liabilities Other Liabilities, Current Other assets Other Assets, Noncurrent Document Type Document Type Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Sponsored cost share Department Of Energy Cost Share Department Of Energy Cost Share Fair Value as of Grant Date Award Grant Date Fair Value Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Award granted, aggregated value Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Granted, Aggregated Value Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Granted, Aggregated Value Arrangement Duration Trading Arrangement Duration Statement of Stockholders' Equity [Abstract] Local Phone Number Local Phone Number Deferred revenue Contract with Customer, Liability, Noncurrent Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name 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] Total property, plant and equipment gross Property, Plant, and Equipment, before Accumulated Depreciation, Depletion, and Amortization Asset under Construction Asset under Construction [Member] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Accounts payable and accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Executive Category: Executive Category [Axis] Supply Commitment [Table] Supply Commitment [Table] Counterparty Name [Axis] Counterparty Name [Axis] Furniture and fixtures Furniture and Fixtures [Member] LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Other Commitments [Table] Other Commitments [Table] 2028 Contractual Obligation, to be Paid, Year Three Award Type [Domain] Award Type [Domain] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Fair Value Measurement Fair Value Disclosures [Text Block] Level 3 Fair Value, Inputs, Level 3 [Member] Purchase of investments Payments to Acquire Long-Term Investments U.S. Government Securities US Government Agencies Debt Securities [Member] Supplemental disclosures of cash flow information: Supplemental Cash Flow Information [Abstract] PEO Name PEO Name Contractual obligation, additional commitment Contractual Obligation, Additional Commitment Contractual Obligation, Additional Commitment Sales and marketing agreements Sales And Marketing Agreements [Member] Sales And Marketing Agreements Leasehold improvements Leasehold Improvements [Member] Long-Lived Asset, Class [Axis] Long-Lived Asset, Class [Axis] Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Entity Tax Identification Number Payment of contractual obligation Payment Of Contractual Obligation Payment Of Contractual Obligation NuScale LLC Class B Units (NCI) NuScale LLC [Member] NuScale LLC Noncontrolling Interest And Loss Per Share [Abstract] Noncontrolling Interest And Loss Per Share Other Commitments [Line Items] Other Commitments [Line Items] Revenue Recognition Revenue [Policy Text Block] Beginning of period End of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Defined Contribution Plan, Tranche Two Defined Contribution Plan, Tranche Two [Member] Defined Contribution Plan, Tranche Two Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] 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] Defined Contribution Plan Tranches [Axis] Defined Contribution Plan Tranches [Axis] Defined Contribution Plan Tranches Equity-based compensation expense Share-Based Payment Arrangement, Noncash Expense Labor costs Labor and Related Expense Lease expense Lease, Cost Income Tax Authority, Name [Domain] Income Tax Authority, Name [Domain] Leases Lessee, Operating Leases [Text Block] Schedule of Right-of-Use Lease Assets and Lease Liabilities Schedule Of Right-Of-Use Lease Assets And Lease Liabilities [Table Text Block] Schedule of Right-of-Use Lease Assets and Lease Liabilities [Table Text Block] Basic (usd per share) Basic loss per share of Class A common stock (usd per share) Earnings Per Share, Basic Deferred revenue Contract with Customer, Liability, Current Total current assets Assets, Current Insider Trading Arrangements [Line Items] Award Type [Axis] Award Type [Axis] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Sale of stock, price per share (in dollars per share) Sale Of Stock, Weighted Average Price Per Share Sale Of Stock, Weighted Average Price Per Share Accumulated deficit Retained Earnings (Accumulated Deficit) Product and Service [Axis] Product and Service [Axis] Restricted cash, noncurrent Restricted Cash, Noncurrent 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] Income Tax Authority, Name [Axis] Income Tax Authority, Name [Axis] Operating lease cost Operating Lease, Cost Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Cover [Abstract] Common stock, voting right per share Common Stock, Voting Right Per Share Common Stock, Voting Right Per Share Equity Awards Adjustments Equity Awards Adjustments [Member] Total Liabilities and Stockholders' Equity Liabilities and Equity Expense recognized for milestone contribution Business Development Employee Stock Option Share-Based Payment Arrangement, Option [Member] Noncontrolling interests Equity, Attributable to Noncontrolling Interest Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Related Party [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 Name Awards Close in Time to MNPI Disclosures, Individual Name 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] General and administrative expenses General and Administrative Expense Long-Lived Asset, Class [Domain] Long-Lived Asset, Class [Domain] Supply chain readiness and manufacturing Supply Chain Readiness And Manufacturing [Member] Supply Chain Readiness And Manufacturing Operating lease residual value guarantees Operating Lease Residual Value Guarantees Operating Lease Residual Value Guarantees Controlling and Non Controlling Interest [Roll Forward] Noncontrolling Interest, Ownership Percentage [Roll Forward] Noncontrolling Interest, Ownership Percentage Property, Plant, and Equipment [Table] Property, Plant, and Equipment [Table] Adjustment to Compensation: Adjustment to Compensation [Axis] Class of Stock [Domain] Class of Stock [Domain] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Statement of Cash Flows [Abstract] 2026 Contractual Obligation, to be Paid, Year One Materials purchase commitments - LLM Purchase Commitment [Member] Cost share obligation, amount Cost Share Obligation, Amount Cost Share Obligation, Amount Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Name Measure Name Income Taxes Income Tax Disclosure [Text Block] Pay vs Performance Disclosure [Line Items] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] 2030 Lessee, Operating Lease, Liability, to be Paid, Year Five Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Additional Paid-in Capital Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Defined Contribution Plan [Table] Defined Contribution Plan [Table] Short-term investments Short-term Investments, Amortized Cost Basis Short-Term Investments Contractual obligation, extended period Contractual Obligation, Extended Period Contractual Obligation, Extended Period 2030 Contractual Obligation, to be Paid, Year Five Interest receivable Interest Receivable Name Trading Arrangement, Individual Name Cash and cash equivalents Cash and Cash Equivalent Company Selected Measure Amount Company Selected Measure Amount Depreciation and amortization Depreciation, Depletion and Amortization Issuance of Class A common stock (shares) Noncontrolling Interest, Issuance Of Class A Common Stock 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Equivalents [Axis] Less: lease incentive allowance Lessee, Operating Lease, Liability, Lease Incentives Lessee, Operating Lease, Liability, Lease Incentives Employee Benefits Defined Contribution Plan [Text Block] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block]