v3.21.2
Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Disaggregation of Revenue [Line Items]        
Revenues $ 19,950 $ 17,671 $ 39,709 $ 28,784
Postpaid phone revenues        
Disaggregation of Revenue [Line Items]        
Revenues 9,667 9,341 19,150 14,918
Postpaid other revenues        
Disaggregation of Revenue [Line Items]        
Revenues 825 618 1,645 928
Postpaid service revenues        
Disaggregation of Revenue [Line Items]        
Revenues 10,492 9,959 20,795 15,846
Wireless service revenues | Sprint        
Disaggregation of Revenue [Line Items]        
Revenues 187 211 384 211
Equipment revenues from the lease of mobile communication devices        
Disaggregation of Revenue [Line Items]        
Revenues $ 914 $ 1,421 $ 1,955 $ 1,586