v3.19.3.a.u2
Document Entity Information - USD ($)
$ / shares in Units, $ in Billions
12 Months Ended
Dec. 31, 2019
Feb. 12, 2020
Jun. 30, 2019
Cover [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Annual Report true    
Document Period End Date Dec. 31, 2019    
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus FY    
Document Transition Report false    
Current Fiscal Year End Date --12-31    
Entity Central Index Key 0000732717    
Entity File Number 001-8610    
Entity Registrant Name AT&T INC.    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 43-1301883    
Entity Address, Address Line One 208 S. Akard St.    
Entity Address, City or Town Dallas    
Entity Address, State or Province TX    
Entity Address, Postal Zip Code 75202    
City Area Code 210    
Local Phone Number 821-4105    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Well-known Seasoned Issuer Yes    
Entity Shell Company false    
Share Price     $ 33.51
Entity Public Float     $ 245
Entity Common Stock, Shares Outstanding   7,172,884,070  
Common Shares (Par Value $1.00 Per Share)      
Entity Listings [Line Items]      
Title of 12(b) Security Common Shares (Par Value $1.00 Per Share)    
Entity Trading Symbol T    
Security Exchange Name NYSE    
Depositary Shares, each representing a 1/1000th interest in a share of 5.000% Perpetual Preferred Stock, Series A      
Entity Listings [Line Items]      
Title of 12(b) Security Depositary Shares, each representing a 1/1000th interest in a share of 5.000% Perpetual Preferred Stock, Series A    
Entity Trading Symbol TPRA    
Security Exchange Name NYSE    
Depositary Shares, each representing a 1/1000th interest in a share of 4.750% Perpetual Preferred Stock, Series C      
Entity Listings [Line Items]      
Title of 12(b) Security Depositary Shares, each representing a 1/1000th interest in a share of 4.750% Perpetual Preferred Stock, Series C    
Entity Trading Symbol TPRC    
Security Exchange Name NYSE    
AT&T Inc. Floating Rate Due August 3 2020 Member [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. Floating Rate Global Notes due August 3, 2020    
Entity Trading Symbol T 20C    
Security Exchange Name NYSE    
AT&T Inc. 1.875% Global Notes due December 4, 2020 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 1.875% Global Notes due December 4, 2020    
Entity Trading Symbol T 20    
Security Exchange Name NYSE    
AT&T Inc. 2.650% Global Notes due December 17, 2021 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 2.650% Global Notes due December 17, 2021    
Entity Trading Symbol T 21B    
Security Exchange Name NYSE    
AT&T Inc. 1.450% Global Notes due June 1, 2022 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 1.450% Global Notes due June 1, 2022    
Entity Trading Symbol T 22B    
Security Exchange Name NYSE    
AT&T Inc. 2.500% Global Notes due March 15, 2023 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 2.500% Global Notes due March 15, 2023    
Entity Trading Symbol T 23    
Security Exchange Name NYSE    
AT&T Inc. 2.750% Global Notes due May 19, 2023 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 2.750% Global Notes due May 19, 2023    
Entity Trading Symbol T 23C    
Security Exchange Name NYSE    
AT&T Inc. Floating Rate Due September 5, 2023 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. Floating Rate Global Notes due September 5, 2023    
Entity Trading Symbol T 23D    
Security Exchange Name NYSE    
AT&T Inc. 1.050% Global Notes due September 5, 2023 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 1.050% Global Notes due September 5, 2023    
Entity Trading Symbol T 23E    
Security Exchange Name NYSE    
AT&T Inc. 1.300% Global Notes due September 5, 2023 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 1.300% Global Notes due September 5, 2023    
Entity Trading Symbol T 23A    
Security Exchange Name NYSE    
AT&T Inc. 1.950% Global Notes due September 15, 2023 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 1.950% Global Notes due September 15, 2023    
Entity Trading Symbol T 23F    
Security Exchange Name NYSE    
AT&T Inc. 2.400% Global Notes due March 15, 2024 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 2.400% Global Notes due March 15, 2024    
Entity Trading Symbol T 24A    
Security Exchange Name NYSE    
AT&T Inc. 3.500% Global Notes due December 17, 2025 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 3.500% Global Notes due December 17, 2025    
Entity Trading Symbol T 25    
Security Exchange Name NYSE    
AT&T Inc. 0.250% Global Notes due March 4, 2026 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 0.250% Global Notes due March 4, 2026    
Entity Trading Symbol T 26E    
Security Exchange Name NYSE    
AT&T Inc. 1.800% Global Notes due September 5, 2026 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 1.800% Global Notes due September 5, 2026    
Entity Trading Symbol T 26D    
Security Exchange Name NYSE    
AT&T Inc. 2.900% Global Notes due December 4, 2026 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 2.900% Global Notes due December 4, 2026    
Entity Trading Symbol T 26A    
Security Exchange Name NYSE    
AT&T Inc. 4.375% Global Notes due September 14, 2029 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 4.375% Global Notes due September 14, 2029    
Entity Trading Symbol T 29B    
Security Exchange Name NYSE    
AT&T Inc. 2.600% Global Notes due December 17, 2029 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 2.600% Global Notes due December 17, 2029    
Entity Trading Symbol T 29A    
Security Exchange Name NYSE    
AT&T Inc. 0.800% Global Notes due March 4, 2030 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 0.800% Global Notes due March 4, 2030    
Entity Trading Symbol T 30B    
Security Exchange Name NYSE    
AT&T Inc. 3.550% Global Notes due December 17, 2032 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 3.550% Global Notes due December 17, 2032    
Entity Trading Symbol T 32    
Security Exchange Name NYSE    
AT&T Inc. 5.200% Global Notes due November 18, 2033 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 5.200% Global Notes due November 18, 2033    
Entity Trading Symbol T 33    
Security Exchange Name NYSE    
AT&T Inc. 3.375% Global Notes due March 15, 2034 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 3.375% Global Notes due March 15, 2034    
Entity Trading Symbol T 34    
Security Exchange Name NYSE    
AT&T Inc. 2.450% Global Notes Due March 15, 2035 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 2.450% Global Notes due March 15, 2035    
Entity Trading Symbol T 35    
Security Exchange Name NYSE    
AT&T Inc. 3.150% Global Notes due September 4, 2036 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 3.150% Global Notes due September 4, 2036    
Entity Trading Symbol T 36A    
Security Exchange Name NYSE    
AT&T Inc. 1.800% Global Notes due September 14, 2039 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 1.800% Global Notes due September 14, 2039    
Entity Trading Symbol T 39B    
Security Exchange Name NYSE    
AT&T Inc. 7.000% Global Notes Due April 30, 2040 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 7.000% Global Notes due April 30, 2040    
Entity Trading Symbol T 40    
Security Exchange Name NYSE    
AT&T Inc. 4.250% Global Notes due June 1, 2043 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 4.250% Global Notes due June 1, 2043    
Entity Trading Symbol T 43    
Security Exchange Name NYSE    
AT&T Inc. 4.875% Global Notes due June 1, 2044 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 4.875% Global Notes due June 1, 2044    
Entity Trading Symbol T 44    
Security Exchange Name NYSE    
AT&T Inc. 4.250% Global Notes due March 1, 2050 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 4.250% Global Notes due March 1, 2050    
Entity Trading Symbol T 50    
Security Exchange Name NYSE    
AT&T Inc. 5.350% Global Notes due November 1, 2066 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 5.350% Global Notes due November 1, 2066    
Entity Trading Symbol TBB    
Security Exchange Name NYSE    
AT&T Inc. 2.350% Global Notes due September 5, 2029 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 2.350% Global Notes due September 5, 2029    
Entity Trading Symbol T 29D    
Security Exchange Name NYSE    
AT&T Inc. 5.625% Global Notes due August 1, 2067 [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security AT&T Inc. 5.625% Global Notes due August 1, 2067    
Entity Trading Symbol TBC    
Security Exchange Name NYSE