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		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net income (loss)	$ (153)	$ 34	$ (169)	$ 60
Denominator:
Weighted average shares used to compute Basic EPS	134,213	139,070	135,227	138,744
Weighted average effect of dilutive securities:
Stock options		187		296
RSUs/MSUs		1,548		1,997
Weighted average shares used to compute Diluted EPS	134,213	140,805	135,227	141,037
Basic EPS	$ (1.14)	$ 0.24	$ (1.25)	$ 0.43
Diluted EPS	$ (1.14)	$ 0.24	$ (1.25)	$ 0.43