v3.26.1
Wireless Licenses, Goodwill and Other Intangible Assets - Composition of Other Intangible Assets, Net (Detail) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Finite-Lived Intangible Assets [Line Items]    
Gross Amount $ 38,171 $ 35,668
Accumulated Amortization (25,372) (25,210)
Net Amount 12,799 10,458
Customer Lists    
Finite-Lived Intangible Assets [Line Items]    
Gross Amount 6,879 4,243
Accumulated Amortization (3,289) (3,116)
Net Amount $ 3,590 1,127
Customer Lists | Minimum    
Finite-Lived Intangible Assets [Line Items]    
Other intangible asset, useful life 6 years  
Customer Lists | Maximum    
Finite-Lived Intangible Assets [Line Items]    
Other intangible asset, useful life 13 years  
Non-Network Internal-Use Software    
Finite-Lived Intangible Assets [Line Items]    
Gross Amount $ 28,554 28,749
Accumulated Amortization (20,263) (20,301)
Net Amount $ 8,291 8,448
Non-Network Internal-Use Software | Minimum    
Finite-Lived Intangible Assets [Line Items]    
Other intangible asset, useful life 3 years  
Non-Network Internal-Use Software | Maximum    
Finite-Lived Intangible Assets [Line Items]    
Other intangible asset, useful life 7 years  
Other    
Finite-Lived Intangible Assets [Line Items]    
Gross Amount $ 2,738 2,676
Accumulated Amortization (1,820) (1,793)
Net Amount $ 918 $ 883
Other | Minimum    
Finite-Lived Intangible Assets [Line Items]    
Other intangible asset, useful life 4 years  
Other | Maximum    
Finite-Lived Intangible Assets [Line Items]    
Other intangible asset, useful life 25 years