XML 140 R102.htm IDEA: XBRL DOCUMENT v3.20.4
Stockholders' Deficit - Changes in Common Stock (Details) - shares
shares in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Increase (Decrease) in Stockholders' Equity [Roll Forward]    
Shares outstanding as of beginning of period (in shares) 94 92
Shares issued as part of equity-based compensation plans and the ESPP, net of shares surrendered (in shares) 1 2
Shares outstanding as of end of period (in shares) 95 94