{
 "version": "2.2",
 "instance": {
  "t-20260422.htm": {
   "nsprefix": "t",
   "nsuri": "http://att.com/20260422",
   "dts": {
    "inline": {
     "local": [
      "t-20260422.htm"
     ]
    },
    "schema": {
     "local": [
      "t-20260422.xsd"
     ],
     "remote": [
      "http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd",
      "http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd",
      "http://www.xbrl.org/2003/xl-2003-12-31.xsd",
      "http://www.xbrl.org/2003/xlink-2003-12-31.xsd",
      "http://www.xbrl.org/2005/xbrldt-2005.xsd",
      "http://www.xbrl.org/2006/ref-2006-02-27.xsd",
      "http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd",
      "http://www.xbrl.org/lrr/role/net-2009-12-16.xsd",
      "https://www.xbrl.org/2020/extensible-enumerations-2.0.xsd",
      "https://www.xbrl.org/dtr/type/2020-01-21/types.xsd",
      "https://www.xbrl.org/dtr/type/2024-01-31/types.xsd",
      "https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd",
      "https://xbrl.fasb.org/srt/2026/elts/srt-roles-2026.xsd",
      "https://xbrl.fasb.org/srt/2026/elts/srt-types-2026.xsd",
      "https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd",
      "https://xbrl.fasb.org/us-gaap/2026/elts/us-roles-2026.xsd",
      "https://xbrl.fasb.org/us-gaap/2026/elts/us-types-2026.xsd",
      "https://xbrl.sec.gov/country/2026/country-2026.xsd",
      "https://xbrl.sec.gov/dei/2026/dei-2026.xsd",
      "https://xbrl.sec.gov/stpr/2026/stpr-2026.xsd"
     ]
    },
    "definitionLink": {
     "local": [
      "t-20260422_def.xml"
     ]
    },
    "labelLink": {
     "local": [
      "t-20260422_lab.xml"
     ]
    },
    "presentationLink": {
     "local": [
      "t-20260422_pre.xml"
     ]
    }
   },
   "keyStandard": 22,
   "keyCustom": 0,
   "axisStandard": 1,
   "axisCustom": 0,
   "memberStandard": 3,
   "memberCustom": 29,
   "hidden": {
    "total": 2,
    "http://xbrl.sec.gov/dei/2026": 2
   },
   "contextCount": 33,
   "entityCount": 1,
   "segmentCount": 32,
   "elementCount": 59,
   "unitCount": 0,
   "baseTaxonomies": {
    "http://xbrl.sec.gov/dei/2026": 115
   },
   "report": {
    "R1": {
     "role": "http://att.com/role/Cover",
     "longName": "0000001 - Document - Cover",
     "shortName": "Cover",
     "isDefault": "true",
     "groupType": "document",
     "subGroupType": "",
     "menuCat": "Cover",
     "order": "1",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "dei:DocumentType",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "span",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "t-20260422.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "dei:DocumentType",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "span",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "t-20260422.htm",
      "first": true,
      "unique": true
     }
    }
   },
   "tag": {
    "t_ATTInc.3.150GlobalNotesDueJune12030Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc.3.150GlobalNotesDueJune12030Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 3.150% Global Notes due June 1, 2030",
        "label": "ATT Inc. 3.150% Global Notes Due June 1, 2030 [Member]",
        "documentation": "ATT Inc. 3.150% Global Notes Due June 1, 2030"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc.3.600GlobalNotesDueJune12033Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc.3.600GlobalNotesDueJune12033Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 3.600% Global Notes due June 1, 2033",
        "label": "ATT Inc. 3.600% Global Notes Due June 1, 2033 [Member]",
        "documentation": "ATT Inc. 3.600% Global Notes Due June 1, 2033"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc.4.100GlobalNotesDueJune12037Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc.4.100GlobalNotesDueJune12037Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 4.050% Global Notes due June 1, 2037",
        "label": "ATT Inc. 4.100% Global Notes Due June 1, 2037 [Member]",
        "documentation": "ATT Inc. 4.100% Global Notes Due June 1, 2037"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc.FloatingRateGlobalNotesDueSeptember162027Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc.FloatingRateGlobalNotesDueSeptember162027Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. Floating Rate Global Notes due September 16, 2027",
        "label": "ATT Inc. Floating Rate Global Notes due September 16, 2027 [Member]",
        "documentation": "ATT Inc. Floating Rate Global Notes due September 16, 2027"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc0250GlobalNotesDueMarch42026Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc0250GlobalNotesDueMarch42026Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 0.250% Global Notes due March 4, 2026",
        "label": "ATT Inc 0.250% Global Notes Due March 4, 2026 [Member]",
        "documentation": "ATT Inc 0.250% Global Notes Due March 4, 2026"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc0800GlobalNotesDueMarch42030Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc0800GlobalNotesDueMarch42030Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 0.800% Global Notes due March 4, 2030",
        "label": "ATT Inc 0.800% Global Notes Due March 4, 2030 [Member]",
        "documentation": "ATT Inc 0.800% Global Notes Due March 4, 2030"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc1600GlobalNotesDueMay192028Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc1600GlobalNotesDueMay192028Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 1.600% Global Notes due May 19, 2028",
        "label": "ATT Inc 1.600% Global Notes Due May 19, 2028 [Member]",
        "documentation": "ATT Inc 1.600% Global Notes Due May 19, 2028"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc1800GlobalNotesDueSeptember142039Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc1800GlobalNotesDueSeptember142039Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 1.800% Global Notes due September 14, 2039",
        "label": "ATT Inc 1.800% Global Notes Due September 14, 2039 [Member]",
        "documentation": "ATT Inc 1.800% Global Notes Due September 14, 2039"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc1800GlobalNotesDueSeptember52026Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc1800GlobalNotesDueSeptember52026Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 1.800% Global Notes due September 5, 2026",
        "label": "ATT Inc 1.800% Global Notes Due September 5, 2026 [Member]",
        "documentation": "ATT Inc 1.800% Global Notes Due September 5, 2026"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc2050GlobalNotesDueMay192032Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc2050GlobalNotesDueMay192032Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 2.050% Global Notes due May 19, 2032",
        "label": "ATT Inc 2.050% Global Notes Due May 19, 2032 [Member]",
        "documentation": "ATT Inc 2.050% Global Notes Due May 19, 2032"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc2350GlobalNotesDueSeptember52029Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc2350GlobalNotesDueSeptember52029Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 2.350% Global Notes due September 5, 2029",
        "label": "ATT Inc 2.350% Global Notes Due September 5, 2029 [Member]",
        "documentation": "ATT Inc 2.350% Global Notes Due September 5, 2029"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc2450GlobalNotesDueMarch152035Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc2450GlobalNotesDueMarch152035Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 2.450% Global Notes due March 15, 2035",
        "label": "ATT Inc 2.450% Global Notes Due March 15, 2035 [Member]",
        "documentation": "ATT Inc 2.450% Global Notes Due March 15, 2035"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc2600GlobalNotesDueDecember172029Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc2600GlobalNotesDueDecember172029Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 2.600% Global Notes due December 17, 2029",
        "label": "ATT Inc 2.600% Global Notes Due December 17, 2029 [Member]",
        "documentation": "ATT Inc 2.600% Global Notes Due December 17, 2029"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc2600GlobalNotesDueMay192038Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc2600GlobalNotesDueMay192038Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 2.600% Global Notes due May 19, 2038",
        "label": "ATT Inc 2.600% Global Notes Due May 19, 2038 [Member]",
        "documentation": "ATT Inc 2.600% Global Notes Due May 19, 2038"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc2900GlobalNotesDueDecember42026Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc2900GlobalNotesDueDecember42026Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 2.900% Global Notes due December 4, 2026",
        "label": "ATT Inc 2.900% Global Notes Due December 4, 2026 [Member]",
        "documentation": "ATT Inc 2.900% Global Notes Due December 4, 2026"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc3150GlobalNotesDueSeptember42036Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc3150GlobalNotesDueSeptember42036Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 3.150% Global Notes due September 4, 2036",
        "label": "ATT Inc 3.150% Global Notes Due September 4, 2036 [Member]",
        "documentation": "ATT Inc 3.150% Global Notes Due September 4, 2036"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc3375GlobalNotesDueMarch152034Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc3375GlobalNotesDueMarch152034Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 3.375% Global Notes due March 15, 2034",
        "label": "ATT Inc 3.375% Global Notes Due March 15, 2034 [Member]",
        "documentation": "ATT Inc 3.375% Global Notes Due March 15, 2034"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc3550GlobalNotesDueDecember172032Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc3550GlobalNotesDueDecember172032Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 3.550% Global Notes due December 17, 2032",
        "label": "ATT Inc 3.550% Global Notes Due December 17, 2032 [Member]",
        "documentation": "ATT Inc 3.550% Global Notes Due December 17, 2032"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc3750GlobalNotesDueSeptember12050Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc3750GlobalNotesDueSeptember12050Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 3.750% Global Notes due September 1, 2050",
        "label": "ATT Inc 3.750% Global Notes Due September 1, 2050 [Member]",
        "documentation": "ATT Inc 3.750% Global Notes Due September 1, 2050"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc3950GlobalNotesDueApril302031Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc3950GlobalNotesDueApril302031Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 3.950% Global Notes due April 30, 2031",
        "label": "ATT Inc. 3.950% Global Notes due April 30, 2031 [Member]",
        "documentation": "ATT Inc. 3.950% Global Notes due April 30, 2031"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc4000GlobalNotesDueJune12049Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc4000GlobalNotesDueJune12049Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 4.000% Global Notes due June 1, 2049",
        "label": "ATT Inc 4.000% Global Notes Due June 1, 2049 [Member]",
        "documentation": "ATT Inc 4.000% Global Notes Due June 1, 2049"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc4250GlobalNotesDueJune12043Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc4250GlobalNotesDueJune12043Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 4.250% Global Notes due June 1, 2043",
        "label": "ATT Inc 4.250% Global Notes Due June 1, 2043 [Member]",
        "documentation": "ATT Inc 4.250% Global Notes Due June 1, 2043"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc4250GlobalNotesDueMarch12050Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc4250GlobalNotesDueMarch12050Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 4.250% Global Notes due March 1, 2050",
        "label": "ATT Inc 4.250% Global Notes Due March 1, 2050 [Member]",
        "documentation": "ATT Inc 4.250% Global Notes Due March 1, 2050"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc4300GlobalNotesDueNovember182034Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc4300GlobalNotesDueNovember182034Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 4.300% Global Notes due November 18, 2034",
        "label": "ATT Inc. 4.300% Global Notes due November 18, 2034 [Member]",
        "documentation": "ATT Inc. 4.300% Global Notes due November 18, 2034"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc4375GlobalNotesDueSeptember142029Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc4375GlobalNotesDueSeptember142029Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 4.375% Global Notes due September 14, 2029",
        "label": "ATT Inc 4.375% Global Notes Due September 14, 2029 [Member]",
        "documentation": "ATT Inc 4.375% Global Notes Due September 14, 2029"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc4875GlobalNotesDueJune12044Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc4875GlobalNotesDueJune12044Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 4.875% Global Notes due June 1, 2044",
        "label": "ATT Inc 4.875% Global Notes Due June 1, 2044 [Member]",
        "documentation": "ATT Inc 4.875% Global Notes Due June 1, 2044"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc5200GlobalNotesDueNovember182033Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc5200GlobalNotesDueNovember182033Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 5.200% Global Notes due November 18, 2033",
        "label": "ATT Inc 5.200% Global Notes Due November 18, 2033 [Member]",
        "documentation": "ATT Inc 5.200% Global Notes Due November 18, 2033"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc5350GlobalNotesDueNovember12066Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc5350GlobalNotesDueNovember12066Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 5.350% Global Notes due November 1, 2066",
        "label": "ATT Inc 5.350% Global Notes Due November 1, 2066 [Member]",
        "documentation": "ATT Inc 5.350% Global Notes Due November 1, 2066"
       }
      }
     },
     "auth_ref": []
    },
    "t_ATTInc7000GlobalNotesDueApril302040Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://att.com/20260422",
     "localname": "ATTInc7000GlobalNotesDueApril302040Member",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT&amp;T Inc. 7.000% Global Notes due April 30, 2040",
        "label": "ATT Inc 7.000% Global Notes Due April 30, 2040 [Member]",
        "documentation": "ATT Inc 7.000% Global Notes Due April 30, 2040"
       }
      }
     },
     "auth_ref": []
    },
    "dei_AmendmentFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "AmendmentFlag",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Amendment Flag",
        "label": "Amendment Flag",
        "documentation": "Boolean flag that is true when the XBRL content amends previously-filed or accepted submission."
       }
      }
     },
     "auth_ref": []
    },
    "dei_CityAreaCode": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "CityAreaCode",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "City Area Code",
        "label": "City Area Code",
        "documentation": "Area code of city"
       }
      }
     },
     "auth_ref": []
    },
    "us-gaap_ClassOfStockDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/us-gaap/2026",
     "localname": "ClassOfStockDomain",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Class of Stock [Domain]",
        "label": "Class of Stock [Domain]"
       }
      }
     },
     "auth_ref": []
    },
    "us-gaap_CommonStockMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/us-gaap/2026",
     "localname": "CommonStockMember",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Common Shares (Par Value $1.00 Per Share)",
        "label": "Common Stock [Member]"
       }
      }
     },
     "auth_ref": []
    },
    "dei_CoverAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "CoverAbstract",
     "lang": {
      "en-us": {
       "role": {
        "label": "Cover [Abstract]",
        "documentation": "Cover page."
       }
      }
     },
     "auth_ref": []
    },
    "dei_DocumentPeriodEndDate": {
     "xbrltype": "dateItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "DocumentPeriodEndDate",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Document Period End Date",
        "label": "Document Period End Date",
        "documentation": "For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD."
       }
      }
     },
     "auth_ref": []
    },
    "dei_DocumentType": {
     "xbrltype": "submissionTypeItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "DocumentType",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Document Type",
        "label": "Document Type",
        "documentation": "The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntitiesTable": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "EntitiesTable",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entities [Table]",
        "label": "Entities [Table]",
        "documentation": "Container to assemble all relevant information about each entity associated with the document instance"
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityAddressAddressLine1": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "EntityAddressAddressLine1",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Address, Address Line One",
        "label": "Entity Address, Address Line One",
        "documentation": "Address Line 1 such as Attn, Building Name, Street Name"
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityAddressCityOrTown": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "EntityAddressCityOrTown",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Address, City or Town",
        "label": "Entity Address, City or Town",
        "documentation": "Name of the City or Town"
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityAddressPostalZipCode": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "EntityAddressPostalZipCode",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Address, Postal Zip Code",
        "label": "Entity Address, Postal Zip Code",
        "documentation": "Code for the postal or zip code"
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityAddressStateOrProvince": {
     "xbrltype": "stateOrProvinceItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "EntityAddressStateOrProvince",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Address, State or Province",
        "label": "Entity Address, State or Province",
        "documentation": "Name of the state or province."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityCentralIndexKey": {
     "xbrltype": "centralIndexKeyItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "EntityCentralIndexKey",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Central Index Key",
        "label": "Entity Central Index Key",
        "documentation": "A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK."
       }
      }
     },
     "auth_ref": [
      "r1"
     ]
    },
    "dei_EntityEmergingGrowthCompany": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "EntityEmergingGrowthCompany",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Emerging Growth Company",
        "label": "Entity Emerging Growth Company",
        "documentation": "Indicate if registrant meets the emerging growth company criteria."
       }
      }
     },
     "auth_ref": [
      "r1"
     ]
    },
    "dei_EntityFileNumber": {
     "xbrltype": "fileNumberItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "EntityFileNumber",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity File Number",
        "label": "Entity File Number",
        "documentation": "Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityIncorporationStateCountryCode": {
     "xbrltype": "edgarStateCountryItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "EntityIncorporationStateCountryCode",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Incorporation, State or Country Code",
        "label": "Entity Incorporation, State or Country Code",
        "documentation": "Two-character EDGAR code representing the state or country of incorporation."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityInformationLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "EntityInformationLineItems",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Information [Line Items]",
        "label": "Entity Information [Line Items]",
        "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityRegistrantName": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "EntityRegistrantName",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Registrant Name",
        "label": "Entity Registrant Name",
        "documentation": "The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC."
       }
      }
     },
     "auth_ref": [
      "r1"
     ]
    },
    "dei_EntityTaxIdentificationNumber": {
     "xbrltype": "employerIdItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "EntityTaxIdentificationNumber",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Tax Identification Number",
        "label": "Entity Tax Identification Number",
        "documentation": "The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS."
       }
      }
     },
     "auth_ref": [
      "r1"
     ]
    },
    "dei_LocalPhoneNumber": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "LocalPhoneNumber",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Local Phone Number",
        "label": "Local Phone Number",
        "documentation": "Local phone number for entity."
       }
      }
     },
     "auth_ref": []
    },
    "dei_PreCommencementIssuerTenderOffer": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "PreCommencementIssuerTenderOffer",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Pre-commencement Issuer Tender Offer",
        "label": "Pre-commencement Issuer Tender Offer",
        "documentation": "Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act."
       }
      }
     },
     "auth_ref": [
      "r3"
     ]
    },
    "dei_PreCommencementTenderOffer": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "PreCommencementTenderOffer",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Pre-commencement Tender Offer",
        "label": "Pre-commencement Tender Offer",
        "documentation": "Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act."
       }
      }
     },
     "auth_ref": [
      "r5"
     ]
    },
    "dei_Security12bTitle": {
     "xbrltype": "securityTitleItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "Security12bTitle",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Title of 12(b) Security",
        "label": "Title of 12(b) Security",
        "documentation": "Title of a 12(b) registered security."
       }
      }
     },
     "auth_ref": [
      "r0"
     ]
    },
    "dei_SecurityExchangeName": {
     "xbrltype": "edgarExchangeCodeItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "SecurityExchangeName",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Security Exchange Name",
        "label": "Security Exchange Name",
        "documentation": "Name of the Exchange on which a security is registered."
       }
      }
     },
     "auth_ref": [
      "r2"
     ]
    },
    "us-gaap_SeriesAPreferredStockMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/us-gaap/2026",
     "localname": "SeriesAPreferredStockMember",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Depositary Shares, each representing a 1/1000th interest in a share of 5.000% Perpetual Preferred Stock, Series A",
        "label": "Series A Preferred Stock [Member]"
       }
      }
     },
     "auth_ref": []
    },
    "us-gaap_SeriesCPreferredStockMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/us-gaap/2026",
     "localname": "SeriesCPreferredStockMember",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Depositary Shares, each representing a 1/1000th interest in a share of 4.750% Perpetual Preferred Stock, Series C",
        "label": "Series C Preferred Stock [Member]"
       }
      }
     },
     "auth_ref": []
    },
    "dei_SolicitingMaterial": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "SolicitingMaterial",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Soliciting Material",
        "label": "Soliciting Material",
        "documentation": "Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as soliciting material pursuant to Rule 14a-12 under the Exchange Act."
       }
      }
     },
     "auth_ref": [
      "r4"
     ]
    },
    "us-gaap_StatementClassOfStockAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/us-gaap/2026",
     "localname": "StatementClassOfStockAxis",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Class of Stock [Axis]",
        "label": "Class of Stock [Axis]"
       }
      }
     },
     "auth_ref": []
    },
    "dei_TradingSymbol": {
     "xbrltype": "tradingSymbolItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "TradingSymbol",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Trading Symbol",
        "label": "Trading Symbol",
        "documentation": "Trading symbol of an instrument as listed on an exchange."
       }
      }
     },
     "auth_ref": []
    },
    "dei_WrittenCommunications": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2026",
     "localname": "WrittenCommunications",
     "presentation": [
      "http://att.com/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Written Communications",
        "label": "Written Communications",
        "documentation": "Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act."
       }
      }
     },
     "auth_ref": [
      "r6"
     ]
    }
   }
  }
 },
 "std_ref": {
  "r0": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Exchange Act",
   "Number": "240",
   "Section": "12",
   "Subsection": "b"
  },
  "r1": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Exchange Act",
   "Number": "240",
   "Section": "12",
   "Subsection": "b-2"
  },
  "r2": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Exchange Act",
   "Number": "240",
   "Section": "12",
   "Subsection": "d1-1"
  },
  "r3": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Exchange Act",
   "Number": "240",
   "Section": "13e",
   "Subsection": "4c"
  },
  "r4": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Exchange Act",
   "Number": "240",
   "Section": "14a",
   "Subsection": "12"
  },
  "r5": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Exchange Act",
   "Number": "240",
   "Section": "14d",
   "Subsection": "2b"
  },
  "r6": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Securities Act",
   "Number": "230",
   "Section": "425"
  }
 }
}
