v3.7.0.1
Operating Financial Information for Reportable Segments (Detail) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Segment Reporting Information [Line Items]    
Operating Revenues $ 29,814 $ 32,171
Operating income (Loss) 7,181 7,942
Wireless    
Segment Reporting Information [Line Items]    
Operating Revenues 20,878 22,004
Operating income (Loss) 7,076 7,880
Wireline    
Segment Reporting Information [Line Items]    
Operating Revenues 7,876 7,923
Operating income (Loss) 293 (67)
Operating Segments    
Segment Reporting Information [Line Items]    
Operating Revenues 28,754 29,927
Operating income (Loss) 7,369 7,813
Operating Segments | Wireless    
Segment Reporting Information [Line Items]    
Operating Revenues 20,776 21,919
Operating Segments | Wireline    
Segment Reporting Information [Line Items]    
Operating Revenues 7,635 7,686
Operating Segments | Reportable Segment    
Segment Reporting Information [Line Items]    
Operating Revenues 28,411 29,605
Operating Segments | Service | Wireless    
Segment Reporting Information [Line Items]    
Operating Revenues 15,730 16,769
Operating Segments | Equipment Revenue | Wireless    
Segment Reporting Information [Line Items]    
Operating Revenues 3,764 3,954
Operating Segments | Other External Operating Non-Service Revenues | Wireless    
Segment Reporting Information [Line Items]    
Operating Revenues 1,282 1,196
Operating Segments | Consumer Markets | Wireline    
Segment Reporting Information [Line Items]    
Operating Revenues 3,201 3,180
Operating Segments | Enterprise Solutions | Wireline    
Segment Reporting Information [Line Items]    
Operating Revenues 2,466 2,501
Operating Segments | Partner Solutions | Wireline    
Segment Reporting Information [Line Items]    
Operating Revenues 1,016 1,053
Operating Segments | Business Markets | Wireline    
Segment Reporting Information [Line Items]    
Operating Revenues 890 870
Operating Segments | Other | Wireline    
Segment Reporting Information [Line Items]    
Operating Revenues 62 82
Operating Segments | Intersegment Revenues    
Segment Reporting Information [Line Items]    
Operating Revenues 343 322
Operating Segments | Intersegment Revenues | Wireless    
Segment Reporting Information [Line Items]    
Operating Revenues 102 85
Operating Segments | Intersegment Revenues | Wireline    
Segment Reporting Information [Line Items]    
Operating Revenues $ 241 $ 237