Statistical Measurement [Domain] Statistical Measurement [Domain] Party-in-Interest Transactions [Text Block] EBP, Related Party and Party-in-Interest Transactions [Text Block] Interest income on notes receivable from participants EBP, Change in Net Asset Available for Benefit, Increase from Interest Income on Note Receivable from Participant Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Participant contributions receivable EBP, Participant Contribution, Receivable EBP, Nonconsolidated, Master Trust [Member] EBP, Nonconsolidated, Master Trust [Member] EBP, Description of Plan and Accounting Change [Abstract] EBP, Description of Plan and Accounting Change [Abstract] Rollover contributions EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Rollover Investment Type [Axis] Investment Type [Axis] Due from broker for securities sold EBP, Other Receivable Number of Shares EBP, Investment, Number of Shares Investment liability at fair value EBP, Investment Liability, Fair Value EBP, Tax Status [Text Block] EBP, Tax Status [Text Block] EBP, Nonconsolidated, Master Trust and Plan Interest in Master Trust [Domain] EBP, Nonconsolidated, Master Trust and Plan Interest in Master Trust [Domain] Total Liabilities EBP, Liability EBP, Description of Plan [Line Items] EBP, Description of Plan [Line Items] EBP, Nonconsolidated, Plan Interest in Master Trust EBP, Nonconsolidated, Plan Interest in Master Trust [Member] EBP, Schedule of Asset Held for Investment [Table] EBP, Schedule of Asset Held for Investment [Table] Investment [Text Block] EBP, Investments [Text Block] The entire disclosure for fully benefit-responsive and nonparticipant-directed investments held by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Notes Receivable from Participants EBP, Asset Held for Investment, Participant Loan, after Deemed Distribution Net Assets Available for Benefits per the Form 5500 EBP, Form 5500 Caption, Net Assets EBP, Investment, Fair Value and NAV [Text Block] EBP, Investment, Fair Value and NAV [Text Block] Net appreciation in fair value of investments EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Unrealized Gain (Loss) on Investment EBP, Investment, Fair Value and NAV [Table] EBP, Investment, Fair Value and NAV [Table] Allowance for Credit Loss EBP, Note Receivable from Participant, Allowance for Credit Loss Distributions payable to participants at December 31, 2024 EBP, Reconciliation to Form 5500, Payment to Participant, Prior Period, Decrease from Deemed Distribution AT&T International Stock Fund AT&T International Stock Fund [Member] AT&T International Stock Fund Contribution, Total Plan Contributions EBP, Change in Net Asset Available for Benefit, Increase from Contribution Administrative expenses payable EBP, Accrued Expense EBP, Party-in-Interest Transactions [Table] EBP, Related Party and Party-in-Interest Transactions [Table] EBP, Fully Benefit-Responsive Investment Contract [Table] EBP, Fully Benefit-Responsive Investment Contract [Table] Equity Funds Equity Funds [Member] Mortgage-backed securities Collateralized Mortgage Obligations [Member] Distributions Dividend distribution to participants Distributions to participants per the financial statements EBP, Change in Net Asset Available for Benefit, Decrease from Payment to Participant Employer contributions receivable EBP, Employer Contribution, Receivable Total Investments EBP, Investment, Fair Value Participant contributions EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Excluding Rollover EBP, Participant-Directed EBP, Participant-Directed [Member] U.S. Stock Market Index Fund U.S. Stock Market Index Fund [Member] This category includes a common/collective trust fund with an objective of providing investment results that approximate the overall performance of the common stocks included in the Dow Jones Total U.S. Stock Market Index. There are currently no redemption restrictions on this investment. Changes in Net Assets: EBP, Change in Net Asset Available for Benefit, Increase (Decrease) [Abstract] EBP, Nonconsolidated, Master Trust and Plan Interest in Master Trust [Axis] EBP, Nonconsolidated, Master Trust and Plan Interest in Master Trust [Axis] Other Investments Non-publicly traded registered investments companies EBP, Other Investment [Member] EBP, Participant-Directed and Nonparticipant-Directed Status [Domain] EBP, Participant-Directed and Nonparticipant-Directed Status [Domain] Employer contributions EBP, Change in Net Asset Available for Benefit, Increase from Employer Contribution, Cash and Noncash Non-US [Member] Non-US [Member] Net Assets Available for Benefits Net Assets Available for Benefits, December 31, 2024 Net Assets Available for Benefits, December 31, 2025 Group Trust net asset Net assets available for benefits EBP, Net Asset Available for Benefit Foreign cash Cash and Cash Equivalents [Member] EBP, Reconciliation of Financial Statement to Form 5500 [Line Items] EBP, Reconciliation of Financial Statement to Form 5500 [Line Items] EBP, Schedule of Asset Held for Investment [Line Items] EBP, Schedule of Asset Held for Investment [Line Items] EBP, Investments [Line Items] EBP, Fully Benefit-Responsive Investment Contract [Line Items] Total Assets EBP, Asset EBP, Asset Foreign cash Interest-Bearing Cash Interest-Bearing Deposits [Member] EBP, Reconciliation of Financial Statement to Form 5500 [Table Text Block] EBP, Reconciliation of Financial Statement to Form 5500 [Table Text Block] EBP, Investment, Plan Interest in Master Trust, Fair Value EBP, Investment, Plan Interest in Master Trust, Fair Value EBP, Reconciliation of Financial Statement to Form 5500 [Table] EBP, Reconciliation of Financial Statement to Form 5500 [Table] Asset Allocation Funds Asset Allocation Funds [Member] This category includes 14 common/collective trust funds also known as Aged-Based Asset Allocation Funds which are well diversified portfolios that adjust the mix of the various underlying investments over time. The change in allocation of investments is designed to move from a more aggressive investment strategy to a more conservative strategy through the projected retirement date and for a number of years thereafter. The year associated with the fund identification denotes the projected year of retirement of the participant selecting the fund. There are currently no redemption restrictions on these investments. Distributions to participants per the Form 5500 EBP, Form 5500 Caption, Benefit Payment and Payments to Provide Benefits EBP, Employer, Common Stock EBP, Employer, Common Stock [Member] Less: investment management expenses EBP, Change in Net Asset Available for Benefit, Decrease from Investment Expense Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] EBP, Tax Status [Abstract] EBP, Tax Status [Abstract] Net Increase Before Transfers EBP, Change in Net Asset Available for Benefit, Increase (Decrease) Cover [Abstract] Cover [Abstract] Maximum Maximum [Member] Asset EBP, Asset [Abstract] Minimum Minimum [Member] EBP, Schedule of Asset Held for Investment [Abstract] EBP, Schedule of Asset Held for Investment [Abstract] Dividends EBP, Change in Net Asset Available for Benefit, Increase from Dividend Income on Investment EBP, Master Trust [Table] EBP, Master Trust [Table] EBP, Reconciliation of Financial Statement to Form 5500 [Text Block] EBP, Reconciliation of Financial Statement to Form 5500 [Text Block] Entity [Domain] Entity [Domain] Asset Held for Investment, Total EBP, Asset Held for Investment Investment, Identifier [Axis] Investment, Identifier [Axis] EBP-43-1301883-021 [Group Trust] EBP-43-1301883-021 [Member] EBP-43-1301883-021 represent AT&T Inc. Group Trust Maturity Date EBP, Investment, Maturity Date Transfer to (from) Plan EBP, Change in Net Asset Available for Benefit, Transfer to (from) Plan EBP, Investment, Fair Value and NAV [Abstract] EBP, Investment, Fair Value and NAV [Abstract] AT&T Stable Value Fund AT&T Stable Value Fund [Member] AT&T Stable Value Fund Investment Fund [Axis] Investment Fund [Axis] Information by investment fund options EBP, Accounting Standard Update and Change in Accounting Principle [Table] EBP, Accounting Standard Update and Change in Accounting Principle [Table] EBP, Tax Status [Line Items] EBP, Tax Status [Line Items] EBP, Statement of Change in Net Asset Available for Benefit [Table] EBP, Statement of Change in Net Asset Available for Benefit [Table] Mutual funds Registered investment companies Mutual Fund [Member] EBP, Description of Plan [Table] EBP, Description of Plan [Table] Asset Held for Investment, Party-in-Interest [true false] EBP, Asset Held for Investment, Party-in-Interest [true false] EBP, Reconciliation of Financial Statement to Form 5500 [Abstract] EBP, Reconciliation of Financial Statement to Form 5500 [Abstract] Assets at contract value (excluding Master Trust) EBP, Investment, Excluding Plan Interest in Master Trust, Contract Value EBP, Other Liability EBP, Other Liability Amendment Flag Amendment Flag Administrative Expenses EBP, Change in Net Asset Available for Benefit, Decrease from Administrative Expense Common/collective trust funds Common Collective Trust [Member] Net income from investment in AT&T Savings Group Investment Trust Interest EBP, Change in Net Asset Available for Benefit, Increase from Interest Income on Investment Fair Value Measured at Net Asset Value Per Share Fair Value Measured at Net Asset Value Per Share [Member] EBP, Fully Benefit-Responsive Investment Contract [Table Text Block] EBP, Fully Benefit-Responsive Investment Contract [Table Text Block] Net Increase After Transfers EBP, Change in Net Asset Available for Benefit, Increase (Decrease) After Transfers Amount of increase (decrease) in net asset available for benefit to participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) after transfers to (from) plan. EBP, Investment, Fair Value and NAV [Table Text Block] EBP, Investment, Fair Value and NAV [Table Text Block] EBP, Statement of Change in Net Asset Available for Benefit [Abstract] EBP, Statement of Change in Net Asset Available for Benefit [Abstract] Government securities US Treasury Securities [Member] Assets at contract value (Master Trust) EBP, Investment, Plan Interest in Master Trust, Contract Value EBP, Related Party and Party-in-Interest Transactions [Abstract] EBP, Related Party and Party-in-Interest Transactions [Abstract] EBP, Related Party and Party-in-Interest Transactions [Line Items] EBP, Related Party and Party-in-Interest Transactions [Line Items] Net investment income of Group Trust Investments EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Other Investment Income (Loss) EBP, Statement of Net Asset Available for Benefit [Abstract] EBP, Statement of Net Asset Available for Benefit [Abstract] Distributions payable to participants EBP, Reconciliation to Form 5500, Net Asset Available for Benefit, Deemed Distribution Assets at contract value EBP, Investment, Contract Value EBP, Description of Plan [Text Block] EBP, Description of Plan [Text Block] Investment income: EBP, Change in Net Asset Available for Benefit, Increase from Interest and Dividend Income on Investment [Abstract] EBP, Summary of Accounting Policy [Text Block] EBP, Summary of Accounting Policy [Text Block] EBP, Participant-Directed and Nonparticipant-Directed Status [Axis] EBP, Participant-Directed and Nonparticipant-Directed Status [Axis] EBP, Statement of Net Asset Available for Benefit [Line Items] EBP, Statement of Net Asset Available for Benefit [Line Items] Entity Central Index Key Entity Central Index Key Investment at Fair Value Assets at fair value EBP, Investment, Excluding Plan Interest in Master Trust, Fair Value Legal Entity [Axis] Legal Entity [Axis] Entity Tax Identification Number Entity Tax Identification Number Total Investment Income EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment EBP, Pooled Separate Account EBP, Pooled Separate Account [Member] EBP-43-1301883-022 [Master Trust] EBP-43-1301883-022 [Member] EBP-43-1301883-022 - Master Trust EBP, Accounting Policy, Accounting Standard Update, and Change in Accounting Principle [Abstract] EBP, Accounting Policy, Accounting Standard Update, and Change in Accounting Principle [Abstract] Interest rate EBP, Investment, Interest Rate Futures Derivative [Member] EBP, Plan Number EBP, Plan Number Geographical [Domain] Geographical [Domain] Contributions: EBP, Change in Net Asset Available for Benefit, Increase from Contribution [Abstract] EBP-58-1533433-004 [BSSP] EBP-58-1533433-004 [Member] EBP-58-1533433-004 - BellSouth Savings and Security Plan Document Type Document Type Fair Value, Inputs, Level 3 Fair Value, Inputs, Level 3 [Member] EBP, Statement of Net Asset Available for Benefit [Table] EBP, Statement of Net Asset Available for Benefit [Table] EBP, Investment, Fair Value and NAV [Line Items] EBP, Investment, Fair Value and NAV [Line Items] EBP, Fully Benefit-Responsive Investment Contract [Abstract] Statistical Measurement [Axis] Statistical Measurement [Axis] EBP, Master Trust [Line Items] EBP, Master Trust [Line Items] Investment Type Category [Axis] Investment Type Category [Axis] Detail information of type of investments. Investment Fund Options [Domain] Investment Fund Options [Domain] Investment Fund Options Notes receivable from participants EBP, Note Receivable from Participant Equities Equity Securities [Member] Fair Value, Inputs, Level 2 Fair Value, Inputs, Level 2 [Member] Investment Type Category [Domain] Investment Type Category [Domain] Detail information of investments. EBP, Schedule of Asset Held for Investment [Table Text Block] EBP, Schedule of Asset Held for Investment [Table Text Block] 103-12 investments Commingled Funds [Member] The objective of these equity commingled funds is to provide diversified exposure to international markets as represented by the All Country World Index ex U.S. that invest in both developed and emerging countries. Liability (Asset) at Fair Value EBP, Other Liability (Asset) at Fair Value EBP, Other Liability (Asset) at Fair Value Amount of liability (asset) held by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), classified as other. Distributions payable to participants at December 31, 2025 EBP, Reconciliation to Form 5500, Payment to Participant, Current Period, Increase from Deemed Distribution International Stock Index Fund International Stock Index Fund [Member] This category includes a common/collective trust fund with an objective of providing investment results that approximate the overall performance of the common stocks included in the All Country World Index ex U.S. Index. Except for a short-term trading fee applicable to certain participant transactions, there are currently no redemption restrictions on this investment. AT&T U.S. Stock Fund AT&T U.S. Stock Fund [Member] AT&T U.S. Stock Fund Investments [Domain] Investments [Domain] Geographical [Axis] Geographical [Axis] EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Statement of Change in Net Asset Available for Benefit [Line Items] Fair Value, Inputs, Level 1 Fair Value, Inputs, Level 1 [Member] Entity Registrant Name Entity Registrant Name UNITED STATES UNITED STATES Investment Income: EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment [Abstract] AT&T common stock Common Stock [Member] EBP, Tax Status [Table] EBP, Tax Status [Table] EBP, Accounting Standard Update and Change in Accounting Principle [Line Items] EBP, Accounting Standard Update and Change in Accounting Principle [Line Items] AT&T Total Return Bond Fund AT&T Total Return Bond Fund [Member] AT&T Total Return Bond Fund EBP, Liability [Abstract] EBP, Liability [Abstract] Corporate debt Corporate Debt Securities [Member] Fair Value, Inputs, Level 1, Level 2, and Level 3 Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member] Total Receivables EBP, Receivable EBP, Liability for Investment Purchase EBP, Liability for Investment Purchase