v2.4.0.8
Changes in Carrying Amount of Goodwill (Detail) (USD $)
In Millions, unless otherwise specified
3 Months Ended 12 Months Ended
Dec. 31, 2013
Dec. 31, 2013
Dec. 31, 2012
Goodwill [Line Items]      
Beginning balance   $ 24,139 $ 23,357
Acquisitions (Note 2) 300 495 760
Reclassifications, adjustments and other     22
Ending balance 24,634 24,634 24,139
Wireless
     
Goodwill [Line Items]      
Beginning balance   18,172 17,963
Acquisitions (Note 2)   204 209
Ending balance 18,376 18,376 18,172
Wireline
     
Goodwill [Line Items]      
Beginning balance   5,967 5,394
Acquisitions (Note 2)   291 551
Reclassifications, adjustments and other     22
Ending balance $ 6,258 $ 6,258 $ 5,967