v3.20.4
Revenue from Contracts with Customers - Contract Balances (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Apr. 01, 2020
Disaggregation of Revenue [Line Items]      
Contract Assets $ 278 $ 63  
Contract Liabilities 824 560  
Change in contract assets included in other current assets 215    
Change in contracts liabilities included in deferred revenue 264    
Current portion of contract assets 204 50  
Amounts included in the beginning of year contract liability balance $ 545 $ 643  
Sprint      
Disaggregation of Revenue [Line Items]      
Contract Assets     $ 154
Contract Liabilities     $ 336