v3.26.3
Segment Information - Operating Financial Information (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Segment Reporting [Line Items]        
Operating revenues $ 34,313 $ 33,821 $ 103,006 $ 101,810
Depreciation and amortization expense 5,095 4,618 14,995 13,830
Total Operating Expenses 25,663 25,716 78,935 77,555
Operating Income 8,650 8,105 24,071 24,255
Service        
Segment Reporting [Line Items]        
Cost of wireless equipment 7,265 6,863 21,657 20,691
Wireless equipment        
Segment Reporting [Line Items]        
Operating revenues 5,116 5,619 15,821 17,272
Cost of wireless equipment 5,823 6,483 18,188 19,596
Operating Segments Excluding Intersegment Elimination | Service        
Segment Reporting [Line Items]        
Operating revenues 23,408 22,754 69,481 67,845
Operating Segments Excluding Intersegment Elimination | Wireless equipment        
Segment Reporting [Line Items]        
Operating revenues 5,116 5,619 15,821 17,272
Operating Segments Excluding Intersegment Elimination | Other        
Segment Reporting [Line Items]        
Operating revenues 4,849 4,489 14,891 13,825
Operating Segments Excluding Intersegment Elimination | Consumer | Service        
Segment Reporting [Line Items]        
Operating revenues 19,703 19,018 58,374 56,674
Operating Segments Excluding Intersegment Elimination | Consumer | Wireless equipment        
Segment Reporting [Line Items]        
Operating revenues 4,277 4,766 13,279 14,667
Operating Segments Excluding Intersegment Elimination | Consumer | Other        
Segment Reporting [Line Items]        
Operating revenues 2,378 2,243 7,254 6,805
Operating Segments Excluding Intersegment Elimination | Business | Service        
Segment Reporting [Line Items]        
Operating revenues 3,705 3,736 11,107 11,171
Operating Segments Excluding Intersegment Elimination | Business | Wireless equipment        
Segment Reporting [Line Items]        
Operating revenues 839 853 2,542 2,605
Operating Segments Excluding Intersegment Elimination | Business | Other        
Segment Reporting [Line Items]        
Operating revenues 2,471 2,246 7,637 7,020
Intersegment Eliminations        
Segment Reporting [Line Items]        
Operating revenues 82 86 242 247
Intersegment Eliminations | Consumer        
Segment Reporting [Line Items]        
Operating revenues 74 78 220 225
Intersegment Eliminations | Business        
Segment Reporting [Line Items]        
Operating revenues 8 8 22 22
Operating Segments        
Segment Reporting [Line Items]        
Operating revenues 33,455 32,948 100,435 99,189
Cost of wireless equipment 5,822 6,483 18,188 19,596
Centrally managed network and shared service costs 6,901 6,672 20,395 20,289
Depreciation and amortization expense 4,958 4,570 14,615 13,682
Other segment expenses 6,826 6,843 20,596 20,705
Total Operating Expenses 24,507 24,568 73,794 74,272
Operating Income 8,948 8,380 26,641 24,917
Operating Segments | Consumer        
Segment Reporting [Line Items]        
Operating revenues 26,432 26,105 79,127 78,371
Cost of wireless equipment 4,665 5,270 14,626 15,988
Centrally managed network and shared service costs 4,634 4,480 13,654 13,522
Depreciation and amortization expense 3,872 3,568 11,389 10,693
Other segment expenses 5,168 5,123 15,619 15,437
Total Operating Expenses 18,339 18,441 55,288 55,640
Operating Income 8,093 7,664 23,839 22,731
Operating Segments | Business        
Segment Reporting [Line Items]        
Operating revenues 7,023 6,843 21,308 20,818
Cost of wireless equipment 1,157 1,213 3,562 3,608
Centrally managed network and shared service costs 2,267 2,192 6,741 6,767
Depreciation and amortization expense 1,086 1,002 3,226 2,989
Other segment expenses 1,658 1,720 4,977 5,268
Total Operating Expenses 6,168 6,127 18,506 18,632
Operating Income $ 855 $ 716 $ 2,802 $ 2,186