v3.19.3.a.u2
Stockholders' Equity - Stock Option Award Activity (Details) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Aggregate Intrinsic Value      
Aggregate intrinsic value of the options exercised $ 185 $ 315 $ 359
Employee Stock Option      
Number of Shares      
Beginning balance (in shares) 1,137,000    
Stock options exercised (in shares) (1,137,000)    
Ending balance (in shares) 0 1,137,000  
Weighted-Average Exercise Price      
Beginning Balance (in dollars per share) $ 13.74    
Stock options exercised (in dollars per share) 13.74    
Ending Balance (in dollars per share) $ 0 $ 13.74  
Weighted-Average Remaining Contractual Term      
Balance at period end 0 years    
Aggregate Intrinsic Value      
Balance at period end $ 0    
Options granted (in shares) 0    
Options forfeited or canceled (in shares) 0