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, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator:
Net income (loss)	$ (40)	$ (153)	$ (120)	$ (169)
Denominator:
Weighted average shares used to compute Basic EPS	137,076	134,213	136,411	135,227
Weighted average effect of dilutive securities:
Weighted average shares used to compute Diluted EPS	137,076	134,213	136,411	135,227
Basic EPS	$ (0.29)	$ (1.14)	$ (0.88)	$ (1.25)
Diluted EPS	$ (0.29)	$ (1.14)	$ (0.88)	$ (1.25)