v3.7.0.1
Changes in Carrying Amount of Wireless Licenses (Detail)
$ in Millions
6 Months Ended
Jun. 30, 2017
USD ($)
Indefinite-lived Intangible Assets [Line Items]  
Beginning balance $ 86,673
Ending balance 88,004
Wireless Licenses  
Indefinite-lived Intangible Assets [Line Items]  
Beginning balance 86,673
Acquisitions (Note 2) 76
Capitalized interest on wireless licenses 239
Reclassifications, adjustments and other 1,016
Ending balance $ 88,004