Reconciliation of Segment Assets (Detail) - USD ($) $ in Millions |
Mar. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Segment Reporting Information [Line Items] | ||
| Assets | $ 246,731 | $ 244,180 |
| Operating Segments | ||
| Segment Reporting Information [Line Items] | ||
| Assets | 283,582 | 278,024 |
| Operating Segments | Wireless | ||
| Segment Reporting Information [Line Items] | ||
| Assets | 215,206 | 211,345 |
| Operating Segments | Wireline | ||
| Segment Reporting Information [Line Items] | ||
| Assets | 68,376 | 66,679 |
| Corporate and Other | ||
| Segment Reporting Information [Line Items] | ||
| Assets | 221,012 | 213,787 |
| Eliminations | ||
| Segment Reporting Information [Line Items] | ||
| Assets | $ (257,863) | $ (247,631) |