v3.26.1
Segment Information - Operating Financial Information (Detail) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Segment Reporting Information [Line Items]    
Operating revenues $ 34,440 $ 33,485
Depreciation and amortization expense 4,892 4,577
Total Operating Expenses 26,198 25,507
Operating Income 8,242 7,978
Service    
Segment Reporting Information [Line Items]    
Cost of wireless equipment 7,167 6,950
Wireless equipment    
Segment Reporting Information [Line Items]    
Operating revenues 5,681 5,398
Cost of wireless equipment 6,506 6,106
Operating Segments Excluding Intersegment Elimination | Service    
Segment Reporting Information [Line Items]    
Operating revenues 22,789 22,438
Operating Segments Excluding Intersegment Elimination | Wireless equipment    
Segment Reporting Information [Line Items]    
Operating revenues 5,681 5,398
Operating Segments Excluding Intersegment Elimination | Other    
Segment Reporting Information [Line Items]    
Operating revenues 5,323 4,988
Operating Segments Excluding Intersegment Elimination | Consumer | Service    
Segment Reporting Information [Line Items]    
Operating revenues 19,108 18,728
Operating Segments Excluding Intersegment Elimination | Consumer | Wireless equipment    
Segment Reporting Information [Line Items]    
Operating revenues 4,824 4,532
Operating Segments Excluding Intersegment Elimination | Consumer | Other    
Segment Reporting Information [Line Items]    
Operating revenues 2,449 2,285
Operating Segments Excluding Intersegment Elimination | Business | Service    
Segment Reporting Information [Line Items]    
Operating revenues 3,681 3,710
Operating Segments Excluding Intersegment Elimination | Business | Wireless equipment    
Segment Reporting Information [Line Items]    
Operating revenues 857 866
Operating Segments Excluding Intersegment Elimination | Business | Other    
Segment Reporting Information [Line Items]    
Operating revenues 2,874 2,703
Intersegment Eliminations    
Segment Reporting Information [Line Items]    
Operating revenues 79 80
Intersegment Eliminations | Consumer    
Segment Reporting Information [Line Items]    
Operating revenues 72 73
Intersegment Eliminations | Business    
Segment Reporting Information [Line Items]    
Operating revenues 7 7
Operating Segments    
Segment Reporting Information [Line Items]    
Operating revenues 33,872 32,904
Cost of wireless equipment 6,505 6,106
Centrally managed network and shared service costs 6,879 7,003
Depreciation and amortization expense 4,811 4,563
Other segment expenses 7,079 7,144
Total Operating Expenses 25,274 24,816
Operating Income 8,598 8,088
Operating Segments | Consumer    
Segment Reporting Information [Line Items]    
Operating revenues 26,453 25,618
Cost of wireless equipment 5,303 4,912
Centrally managed network and shared service costs 4,430 4,521
Depreciation and amortization expense 3,730 3,543
Other segment expenses 5,276 5,218
Total Operating Expenses 18,739 18,194
Operating Income 7,714 7,424
Operating Segments | Business    
Segment Reporting Information [Line Items]    
Operating revenues 7,419 7,286
Cost of wireless equipment 1,202 1,194
Centrally managed network and shared service costs 2,449 2,482
Depreciation and amortization expense 1,081 1,020
Other segment expenses 1,803 1,926
Total Operating Expenses 6,535 6,622
Operating Income $ 884 $ 664