v3.20.2
Business Combination - Schedule of Components of Consideration Transferred (Details) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 6 Months Ended
Apr. 01, 2020
Feb. 20, 2020
Apr. 29, 2018
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2019
Mar. 31, 2020
Dec. 31, 2019
Business Acquisition [Line Items]                  
Payment received from selling shareholder       $ (5,000) $ 0 $ (5,000) $ 0    
Common stock, shares issued (in shares)       1,238,888,085   1,238,888,085     858,418,615
Common stock, shares outstanding (in shares)       1,237,338,994   1,237,338,994     856,905,400
Share price at closing (in USD per share)               $ 83.90  
Sprint                  
Business Acquisition [Line Items]                  
Common stock, shares issued (in shares)               373,396,310  
Common stock, shares outstanding (in shares)               373,396,310  
Sprint                  
Business Acquisition [Line Items]                  
Fair value of T-Mobile common stock issued to Sprint stockholders $ 31,328                
Fair value of T-Mobile replacement equity awards attributable to pre-combination service 323                
Repayments of Sprint's debt (including accrued interest, prepayment penalties) 7,396                
Value of contingent consideration 1,882                
Payment received from selling shareholder (102)                
Total consideration exchanged $ 40,827                
Exchange ratio (in shares)     0.10256            
Sprint | SoftBank | Common Stock Outstanding                  
Business Acquisition [Line Items]                  
Aggregate surrendered (in shares)   48,751,557