1001 - Document - Cover link:presentationLink link:definitionLink link:calculationLink 1002 - Statement - Statements Of Net Assets Available For Benefits link:presentationLink link:definitionLink link:calculationLink 1003 - Statement - Statement Of Changes In Net Assets Available For Benefits link:presentationLink link:definitionLink link:calculationLink 1004 - Disclosure - The Plan link:presentationLink link:definitionLink link:calculationLink 1005 - Disclosure - Summary Of Significant Accounting Policies link:presentationLink link:definitionLink link:calculationLink 1006 - Disclosure - Plan Participation link:presentationLink link:definitionLink link:calculationLink 1007 - Disclosure - Fair Value Measurements link:presentationLink link:definitionLink link:calculationLink 1008 - Disclosure - Net Asset Value Per Share link:presentationLink link:definitionLink link:calculationLink 1009 - Disclosure - Party-in-Interest and Related Party Transactions link:presentationLink link:definitionLink link:calculationLink 1010 - Disclosure - Tax Status of the Plan link:presentationLink link:definitionLink link:calculationLink 1011 - Disclosure - Financial Assets Carried at Contract Value link:presentationLink link:definitionLink link:calculationLink 1012 - Disclosure - Subsequent Events link:presentationLink link:definitionLink link:calculationLink 1013 - Disclosure - Schedule H, Line 4a – Schedule Of Delinquent Participant Contributions link:presentationLink link:definitionLink link:calculationLink 1014 - Disclosure - Schedule H, Line 4(i) Schedule of Assets (Held at End of Year) link:presentationLink link:definitionLink link:calculationLink 1015 - Disclosure - Summary Of Significant Accounting Policies (Policies) link:presentationLink link:definitionLink link:calculationLink 1016 - Schedule - Fair Value Measurements (Tables) link:presentationLink link:definitionLink link:calculationLink 1017 - Disclosure - Net Asset Value Per Share (Tables) link:presentationLink link:definitionLink link:calculationLink 1018 - Disclosure - Financial Assets Carried at Contract Value (Tables) link:presentationLink link:definitionLink link:calculationLink 1019 - Disclosure - The Plan - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 1020 - Disclosure - Summary Of Significant Accounting Policies - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 1021 - Disclosure - Plan Participation - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 1022 - Disclosure - Fair Value Measurements - Summary of the Financial Assets Carried at Fair Value on a Recurring Basis (Detail) link:presentationLink link:definitionLink link:calculationLink 1023 - Disclosure - Net Asset Value Per Share - Summary of the Plan's Investment with a Reported NAV (Detail) link:presentationLink link:definitionLink link:calculationLink 1024 - Disclosure - Party-in-Interest and Related Party Transactions - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 1025 - Disclosure - Tax Status of the Plan - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 1026 - Disclosure - Financial Assets Carried at Contract Value - Schedule of Financial Assets Carried at Contract Value (Detail) link:presentationLink link:definitionLink link:calculationLink 1027 - Disclosure - Schedule H, Line 4a - Schedule Of Delinquent Participant Contributions (Detail) link:presentationLink link:definitionLink link:calculationLink 1028 - Disclosure - Schedule H, Line 4(i) Schedule of Assets (Held at End of Year) (Detail) link:presentationLink link:definitionLink link:calculationLink 1029 - Disclosure - Financial Assets Carried at Contract Value - Schedule of Financial Assets Carried at Contract Value (Detail) Alternate link:presentationLink link:definitionLink link:calculationLink 1030 - Disclosure - Summary Of Significant Accounting Policies - Additional Information (Detail) Alternate link:presentationLink link:definitionLink link:calculationLink 1031 - Disclosure - Schedule H, Line 4(i) Schedule of Assets (Held at End of Year) (Detail) Alternate link:presentationLink link:definitionLink link:calculationLink Cover [Abstract] Document Information [Table] Legal Entity [Axis] Entity [Domain] EBP 006 [Member] Entity Information [Line Items] Document Type Amendment Flag Document Period End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date EBP, Statement of Net Asset Available for Benefit [Abstract] EBP, Statement of Net Asset Available for Benefit [Table] EBP, Statement of Net Asset Available for Benefit [Line Items] EBP, Asset [Abstract] Assets EBP, Investment, Fair Value [Abstract] Investments EBP, Investment, Excluding Plan Interest in Master Trust, Fair Value Investments, at fair value Fair Value EBP, Investment, Excluding Plan Interest in Master Trust, Contract Value Investments, at contract value Putnam Stable Value Fund EBP, Investment, Fair Value Total investments EBP, Receivable [Abstract] Receivables EBP, Note Receivable from Participant Notes receivable from participants EBP, Participant Contribution, Receivable Participants' contributions receivable EBP, Employer Contribution, Receivable Employer's contributions receivable EBP, Other Receivable Other receivables EBP, Receivable Total receivables EBP, Asset Total Assets EBP, Liability [Abstract] Payables EBP, Other Liability Operating and other payables EBP, Net Asset Available for Benefit Net assets available for benefits Beginning of year End of year EBP, Statement of Change in Net Asset Available for Benefit [Abstract] EBP, Statement of Change in Net Asset Available for Benefit [Table] EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Change in Net Asset Available for Benefit, Increase [Abstract] ADDITIONS EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment [Abstract] Investment income: EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Gain (Loss) on Investment Net appreciation in fair value of investments EBP, Change in Net Asset Available for Benefit, Increase from Interest and Dividend Income on Investment Dividends and interest EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment Total investment income EBP, Change in Net Asset Available for Benefit, Increase from Interest Income on Note Receivable from Participant Interest on participant notes receivable EBP, Change in Net Asset Available for Benefit, Increase from Contribution [Abstract] Contributions: EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Excluding Rollover Participants EBP, Change in Net Asset Available for Benefit, Increase from Employer Contribution, Cash and Noncash Employer EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Rollover Rollover EBP, Change in Net Asset Available for Benefit, Increase from Contribution Total contributions EBP, Change in Net Asset Available for Benefit, Increase Total Additions EBP, Change in Net Asset Available for Benefit, Decrease [Abstract] DEDUCTIONS EBP, Change in Net Asset Available for Benefit, Decrease from Payment to Participant Benefits paid to participants Employee Benefit Plan, Change In Net Asset Available For Benefit, Decrease For Corrective Distributions Corrective distributions Employee Benefit Plan, Change In Net Asset Available For Benefit, Decrease For Corrective Distributions. Employee Benefit Plan, Change In Net Asset Available For Benefit, Decrease For Deemed Distributions Deemed distributions Employee Benefit Plan, Change In Net Asset Available For Benefit, Decrease For Deemed Distributions. EBP, Change in Net Asset Available for Benefit, Decrease from Administrative Expense Administrative expenses EBP, Change in Net Asset Available for Benefit, Decrease Total Deductions EBP, Change in Net Asset Available for Benefit, Increase (Decrease) Net increase EBP, Description of Plan and Accounting Change [Abstract] EBP, Description of Plan [Table] EBP, Description of Plan [Line Items] EBP, Description of Plan [Text Block] THE PLAN EBP, Summary of Accounting Policy [Text Block] Summary Of Significant Accounting Policies PLAN PARTICIPATION Plan Participation PLAN PARTICIPATION EBP, Investment, Fair Value and NAV [Abstract] EBP, Investment, Fair Value and NAV [Table] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member] EBP, Investment, Fair Value and NAV [Line Items] EBP, Investment, Fair Value and NAV [Text Block] Fair Value Measurements Net Asset Value Per Share Fair Value Measured at Net Asset Value Per Share [Member] Other EBP, Related Party and Party-in-Interest Transactions [Abstract] EBP, Related Party and Party-in-Interest Transactions [Table] EBP, Related Party and Party-in-Interest Transactions [Line Items] EBP, Related Party and Party-in-Interest Transactions [Text Block] Party-in-Interest and Related Party Transactions EBP, Tax Status [Abstract] EBP, Tax Status [Table] EBP, Tax Status [Line Items] EBP, Tax Status [Text Block] Tax Status of the Plan EBP, Investment, Contract Value [Abstract] Employee Benefit Plan Investment Contract Value [Table] Employee Benefit Plan Investment Contract Value [Line Items] Employee Benefit Plan Investment Contract Value [Text Block] Financial Assets Carried at Contract Value Employee benefit plan investment contract value. EBP, Subsequent Event [Abstract] EBP, Subsequent Event [Table] EBP, Subsequent Event [Line Items] EBP, Subsequent Event [Text Block] Subsequent Events EBP, Schedule of Delinquent Participant Contribution [Abstract] EBP, Schedule of Delinquent Participant Contribution [Table] EBP, Schedule of Delinquent Participant Contribution [Line Items] EBP, Schedule of Delinquent Participant Contribution [Table Text Block] Schedule H, Line 4a – Schedule Of Delinquent Participant Contributions EBP, Schedule of Asset Held for Investment [Abstract] EBP, Schedule of Asset Held for Investment [Table] EBP, Schedule of Asset Held for Investment [Line Items] EBP, Schedule of Asset Held for Investment [Table Text Block] Schedule H, Line 4(i) Schedule of Assets (Held at End of Year) EBP, Accounting Policy [Line Items] EBP, Basis of Accounting [Policy Text Block] Basis of Accounting EBP, Use of Estimate [Policy Text Block] Use of Estimates EBP, Risk and Uncertainty [Policy Text Block] Risks, Uncertainties and Concentrations EBP, Contribution [Policy Text Block] Contributions and Contributions Receivables EBP, Investment [Policy Text Block] Valuation of Investments Employee Benefit Plan Investment Income Policy Text Block Investment Income Employee Benefit Plan Investment Income Policy Text Block Employee Benefit Plan Security Transactions Policy Text Block Security Transactions Employee Benefit Plan Security Transactions Policy Text Block Employee Benefit Plan Vesting and Forfeitures Policy Text Block Vesting and Forfeitures Employee Benefit Plan Vesting and Forfeitures Policy Text Block EBP, Expense [Policy Text Block] Expenses of the Plan Employee Benefit Plan Administration Policy Text Block Administration Employee Benefit Plan Administration Policy Text Block EBP, Note Receivable from Participant [Policy Text Block] Notes Receivable from Participants EBP, Liquidation Basis of Accounting [Policy Text Block] Termination Priorities EBP, Payment to Participant [Policy Text Block] Benefit Payments EBP, Investment, Fair Value and NAV [Table Text Block] Summary of the Financial Assets Carried at Fair Value on a Recurring Basis Summary of the Plan's Investment with a Reported NAV Schedule Of Employee Benefit Plan Investment Contract Value [Table Text Block] Summary of Financial Assets Carried at Contract Value Schedule of employee benefit plan investment contract value. EBP, Change in Net Asset Available for Benefit, Transfer to (from) Plan Investment Type [Axis] Investments [Domain] Other Security Investments [Member] Investment, Identifier [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Maximum [Member] Minimum [Member] EBP, Risk and Uncertainty, Concentration of Investment at Fair Value to Total Investments, Percentage Ebp, risk and uncertainty, concentration of investment at fair value to total investments, percentage Employee Benefit Plan Contribution Receivable Employee benefit plan, contribution, receivable Employee Benefit Plan, Contribution, Receivable EBP, Forfeited Nonvested Account Ebp, forfeited nonvested account EBP, Forfeited Nonvested Account, Decrease from Administrative Expense Ebp, forfeited nonvested account, decrease from administrative expense EBP, Note Receivable from Participant, Account, Maximum Borrowing, to Total Account, Percentage Ebp, note receivable from participant, account, maximum borrowing, to total account, percentage EBP, Note Receivable from Participant, Account, Maximum Borrowing, Amount Ebp, note receivable from participant, account, maximum borrowing, amount EBP, Note Receivable from Participant, Account, Minimum Borrowing, Amount Ebp, note receivable from participant, account, minimum borrowing, amount Employee Benefit Plan Loan Repayment Period Employee benefit plan, loan repayment period Employee Benefit Plan, Loan Repayment Period Employee Benefit Plan Maximum Loan Allowed Employee benefit plan, maximum loan allowed Employee Benefit Plan, Maximum Loan Allowed EBP, Asset Held for Investment, Participant Loan, Interest Rate Ebp, asset held for investment, participant loan, interest rate Employee Benefit Plan Note Receivable From Participant Account Borrowing Standardize Percentage Employee benefit plan note receivable from participant account borrowing standardize percentage Employee benefit plan note receivable from participant account borrowing standardize percentage. Participant Compensation Matched Identifier [Axis] Participant compensation matched identifier. Participant Compensation Matched Identifier [Domain] Participant compensation matched identifier. First 3 percent [Member] First 3 percent 4 percent [Member] 4 percent 5 percent [Member] 5 percent EBP, Number of Participants EBP, number of participants EBP, Participant Contribution, Pretax, Maximum Annual Compensation to Total Compensation, Percentage EBP, participant contribution, pretax, maximum annual compensation to total compensation, percentage Employee Benefit Plan Participant Contribution Posttax Maximum Annual Compensation To Total Compensation Percentage Employee benefit plan participant contribution posttax maximum annual compensation to total compensation percentage Employee benefit plan participant contribution posttax maximum annual compensation to total compensation percentage. EBP, Employer Contribution, Matching Percentage EBP, employer contribution, matching percentage EBP, Employer Contribution, Participant Compensation Matched, Percentage EBP, employer contribution, participant compensation matched, percentage Employee Benefit Plan Contribution Vested Employee benefit plan contribution vested Employee benefit plan, contribution, vested. EBP, Participant Contribution, Automatic, Deferral Rate EBP, participant contribution, automatic, deferral rate Employee Benefit Plan Participant Contribution Automatic Deferral Rate Increase Employee benefit plan participant contribution automatic deferral rate increase Employee benefit plan participant contribution automatic deferral rate increase. Employee Benefit Plan Participant Contribution Automatic Deferral Rate Maximum Employee benefit plan participant contribution automatic deferral rate maximum Employee benefit plan participant contribution automatic deferral rate maximum. Employee Benefit Plan Participant Withdrawal Account Period Minimum Employee benefit plan participant withdrawal account period minimum Employee benefit plan participant withdrawal account period minimum. Mutual Fund [Member] Mutual funds [Member] Separately Managed Accounts [Member] Separately managed accounts [Member] EBP, Employer, Common Stock Fund [Member] Ericsson stock fund [Member] Commingled Funds [Member] Commingled funds [Member] Common Collective Trust [Member] Common collective trusts [Member] EBP, Pooled Separate Account [Member] Pooled separate accounts [Member] EBP, Self-Directed Brokerage Account [Member] Self-directed brokerage accounts [Member] Fair Value, Inputs, Level 1 [Member] Level 1 Fair Value, Inputs, Level 2 [Member] Level 2 Fair Value, Inputs, Level 3 [Member] Level 3 EBP, Investment, Plan Interest in Master Trust, Fair Value EBP, investment, fair value Investment Type Name [Axis] Investment Type Name [Domain] Asset allocation fund [Member] Intermediate-Term Bond [Member] Multiple Investment Trust [Member] Mid-Cap Value Equity Trust [Member] International Large Blend Trust [Member] Small-Cap Value Equity Trust [Member] Large-Cap Value Equity Trust [Member] Employee Benefit Plan Fair Value Investments Entities That Calculate Net Asset Value Per Share Investment Redemption Frequency Redemption Frequency Employee benefit plan fair value investments entities that calculate net asset value per share investment redemption frequency. Employee Benefit Plan Fair Value Investments Entities That Calculate Net Asset Value Per Share Investment Other Redemption Restrictions Other Redemption Restrictions Employee benefit plan fair value investments entities that calculate net asset value per share investment other redemption restrictions. Employee Benefit Plan Fair Value Investments Entities That Calculate Net Asset Value Per Share Investment Redemption Notice Period Redemption Notice Period Employee benefit plan fair value investments entities that calculate net asset value per share investment redemption notice period. EBP, Related Party and Party-in-Interest [Axis] EBP, Related Party and Party-in-Interest [Domain] LM Ericsson Telephone Company [Member] EBP, Investment Acquired, Excluding Plan Interest in Master Trust, Cost EBP, investment acquired, excluding plan interest in master trust, cost EBP, Investment Sold, Excluding Plan Interest in Master Trust, Selling Price EBP, investment sold, excluding plan interest in master trust, selling price EBP, Tax Determination Letter, Date EBP, tax determination letter, date EBP, Schedule of Delinquent Participant Contribution, Corrected EBP, Schedule of Delinquent Participant Contribution, Corrected Entity Tax Identification Number Entity Tax Identification Number EBP, Plan Number EBP, Plan Number EBP, Schedule of Delinquent Participant Contribution, Late Repayment Included [true false] EBP, Schedule of Delinquent Participant Contribution, Late Repayment Included [true false] EBP, Asset Held for Investment, Party-in-Interest [true false]