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	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net income (loss)	$ (48)	$ 50	$ (217)	$ 110
Denominator:
Weighted average shares used to compute Basic EPS	134,436	139,324	134,963	138,937
Weighted average effect of dilutive securities:
Stock options		29		207
RSUs/MSUs		1,028		1,674
Weighted average shares used to compute Diluted EPS	134,436	140,381	134,963	140,818
Basic EPS	$ (0.36)	$ 0.36	$ (1.61)	$ 0.79
Diluted EPS	$ (0.36)	$ 0.36	$ (1.61)	$ 0.78