v3.7.0.1
Operating Financial Information for Reportable Segments (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Segment Reporting Information [Line Items]        
Operating Revenues $ 30,548 $ 30,532 $ 60,362 $ 62,703
Operating income (Loss) 8,232 4,554 15,413 12,496
Wireless        
Segment Reporting Information [Line Items]        
Operating Revenues 21,282 21,704 42,160 43,708
Operating income (Loss) 7,410 8,017 14,486 15,897
Wireline        
Segment Reporting Information [Line Items]        
Operating Revenues 7,802 7,713 15,570 15,527
Operating income (Loss) 68 (524) 287 (653)
Operating Segments        
Segment Reporting Information [Line Items]        
Operating Revenues 29,084 29,417 57,730 59,235
Operating income (Loss) 7,478 7,493 14,773 15,244
Operating Segments | Wireless        
Segment Reporting Information [Line Items]        
Operating Revenues 21,209 21,612 41,985 43,531
Operating Segments | Wireline        
Segment Reporting Information [Line Items]        
Operating Revenues 7,574 7,474 15,101 15,051
Operating Segments | Reportable Segment        
Segment Reporting Information [Line Items]        
Operating Revenues 28,783 29,086 57,086 58,582
Operating Segments | Service | Wireless        
Segment Reporting Information [Line Items]        
Operating Revenues 15,605 16,692 31,335 33,461
Operating Segments | Equipment Revenue | Wireless        
Segment Reporting Information [Line Items]        
Operating Revenues 4,298 3,704 8,062 7,658
Operating Segments | Other External Operating Non-Service Revenues | Wireless        
Segment Reporting Information [Line Items]        
Operating Revenues 1,306 1,216 2,588 2,412
Operating Segments | Consumer Markets | Wireline        
Segment Reporting Information [Line Items]        
Operating Revenues 3,184 3,165 6,385 6,345
Operating Segments | Enterprise Solutions | Wireline        
Segment Reporting Information [Line Items]        
Operating Revenues 2,387 2,378 4,779 4,802
Operating Segments | Partner Solutions | Wireline        
Segment Reporting Information [Line Items]        
Operating Revenues 1,008 1,002 1,999 2,031
Operating Segments | Business Markets | Wireline        
Segment Reporting Information [Line Items]        
Operating Revenues 921 845 1,803 1,707
Operating Segments | Other | Wireline        
Segment Reporting Information [Line Items]        
Operating Revenues 74 84 135 166
Operating Segments | Intersegment Revenues        
Segment Reporting Information [Line Items]        
Operating Revenues 301 331 644 653
Operating Segments | Intersegment Revenues | Wireless        
Segment Reporting Information [Line Items]        
Operating Revenues 73 92 175 177
Operating Segments | Intersegment Revenues | Wireline        
Segment Reporting Information [Line Items]        
Operating Revenues $ 228 $ 239 $ 469 $ 476