Earnings Per Share - Reconciliation of Weighted Average Number of Shares of Common Stock Outstanding In Calculating EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net income (loss)	$ (289)	$ 126	$ 113
Denominator:
Weighted average shares used to compute Basic EPS	134,858	138,975	138,116
Weighted average effect of dilutive securities:
Stock options		155	351
RSUs/MSUs		1,528	1,908
Weighted average shares used to compute Diluted EPS	134,858	140,658	140,375
Basic EPS	$ (2.14)	$ 0.91	$ 0.82
Diluted EPS	$ (2.14)	$ 0.89	$ 0.81