v3.4.0.3
Operating Financial Information for Reportable Segments (Detail) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Segment Reporting Information [Line Items]    
Operating Revenues $ 32,171 $ 31,984
Operating income 7,942 7,960
Wireless    
Segment Reporting Information [Line Items]    
Operating Revenues 22,004 22,328
Operating income 7,880 7,810
Wireline    
Segment Reporting Information [Line Items]    
Operating Revenues 9,290 9,469
Operating income 589 405
Operating Segments    
Segment Reporting Information [Line Items]    
Operating Revenues 31,294 31,797
Operating income 8,469 8,215
Operating Segments | Wireless    
Segment Reporting Information [Line Items]    
Operating Revenues 21,919 22,302
Operating Segments | Wireless | Service Revenue    
Segment Reporting Information [Line Items]    
Operating Revenues 16,769 17,896
Operating Segments | Wireless | Equipment Revenue    
Segment Reporting Information [Line Items]    
Operating Revenues 3,954 3,373
Operating Segments | Wireless | Other External Operating Non-Service Revenues    
Segment Reporting Information [Line Items]    
Operating Revenues 1,196 1,033
Operating Segments | Wireline    
Segment Reporting Information [Line Items]    
Operating Revenues 9,040 9,208
Operating Segments | Wireline | Mass Markets Consumer Retail    
Segment Reporting Information [Line Items]    
Operating Revenues 4,022 3,992
Operating Segments | Wireline | Mass Markets Small Business    
Segment Reporting Information [Line Items]    
Operating Revenues 568 600
Operating Segments | Wireline | Mass Markets    
Segment Reporting Information [Line Items]    
Operating Revenues 4,590 4,592
Operating Segments | Wireline | Global Enterprise    
Segment Reporting Information [Line Items]    
Operating Revenues 3,161 3,263
Operating Segments | Wireline | Global Wholesale    
Segment Reporting Information [Line Items]    
Operating Revenues 1,213 1,266
Operating Segments | Wireline | Other    
Segment Reporting Information [Line Items]    
Operating Revenues 76 87
Operating Segments | Reportable Segment    
Segment Reporting Information [Line Items]    
Operating Revenues 30,959 31,510
Intersegment Revenues | Wireless    
Segment Reporting Information [Line Items]    
Operating Revenues 85 26
Intersegment Revenues | Wireline    
Segment Reporting Information [Line Items]    
Operating Revenues 250 261
Intersegment Revenues | Reportable Segment    
Segment Reporting Information [Line Items]    
Operating Revenues $ 335 $ 287