Reconciliation of Segment Assets (Detail) - USD ($) $ in Millions |
Mar. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Segment Reporting Information [Line Items] | ||
| Assets | $ 244,587 | $ 244,175 |
| Operating Segments | ||
| Segment Reporting Information [Line Items] | ||
| Assets | 264,113 | 263,710 |
| Operating Segments | Wireless | ||
| Segment Reporting Information [Line Items] | ||
| Assets | 190,892 | 185,405 |
| Operating Segments | Wireline | ||
| Segment Reporting Information [Line Items] | ||
| Assets | 73,221 | 78,305 |
| Corporate and Other | ||
| Segment Reporting Information [Line Items] | ||
| Assets | 210,199 | 205,476 |
| Eliminations | ||
| Segment Reporting Information [Line Items] | ||
| Assets | $ (229,725) | $ (225,011) |