v3.20.4
Stockholders' Equity (Schedule of Share Repurchase Authorizations) (Details) - Class A Common Stock - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
1 Months Ended 12 Months Ended 13 Months Ended 25 Months Ended 37 Months Ended
Dec. 31, 2020
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2020
Dec. 31, 2020
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2017
Dec. 31, 2016
Class of Stock [Line Items]                    
Board Authorization $ 28,500 $ 28,500     $ 28,500 $ 28,500 $ 28,500      
Dollar-value of shares repurchased   4,473 $ 6,497 $ 4,933            
Remaining authorization 9,831 $ 9,831 $ 8,304 $ 6,801 9,831 9,831 $ 9,831 $ 8,304    
Shares repurchased   14.3 26.4 26.2     87.9      
Average price paid per share   $ 312.68 $ 245.89 $ 188.26     $ 212.41      
December 2016 Share Repurchase Plan                    
Class of Stock [Line Items]                    
Board Authorization                   $ 4,000
Dollar-value of shares repurchased   $ 0   $ 1,234            
Remaining authorization     $ 0 $ 0       $ 0    
Shares repurchased   0.0 0.0 7.2       28.2    
Average price paid per share   $ 0 $ 0 $ 171.11       $ 141.99    
December 2017 Share Repurchase Plan                    
Class of Stock [Line Items]                    
Board Authorization                 $ 4,000  
Dollar-value of shares repurchased   $ 0 $ 301 $ 3,699            
Remaining authorization 0 $ 0 $ 0 $ 301 0 0 $ 0 $ 0    
Shares repurchased   0.0 1.6 19.0     20.6      
Average price paid per share   $ 0 $ 188.38 $ 194.77     $ 194.27      
December 2018 Share Repurchase Plan                    
Class of Stock [Line Items]                    
Board Authorization       $ 6,500            
Dollar-value of shares repurchased   $ 304 $ 6,196              
Remaining authorization 0 $ 0 $ 304 $ 6,500 0 $ 0 $ 0 304    
Shares repurchased   1.0 24.8     25.8        
Average price paid per share   $ 304.89 $ 249.58     $ 251.72        
December 2019 Share Repurchase Plan                    
Class of Stock [Line Items]                    
Board Authorization     $ 8,000         8,000    
Dollar-value of shares repurchased   $ 4,169                
Remaining authorization 3,831 $ 3,831 $ 8,000   $ 3,831 $ 3,831 3,831 $ 8,000    
Shares repurchased   13.3     13.3          
Average price paid per share   $ 313.26     $ 313.26          
December 2020 Share Repurchase Plan                    
Class of Stock [Line Items]                    
Board Authorization 6,000 $ 6,000     $ 6,000 6,000 6,000      
Remaining authorization $ 6,000 $ 6,000     $ 6,000 $ 6,000 $ 6,000      
Shares repurchased 0.0                  
Average price paid per share $ 0