Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net loss attributable to stockholders		$ (86)	$ (276)	$ (392)	$ (1,223)
Earnings attributable to participating securities		0	0	0	0
Net loss attributable to stockholders, net of earnings allocated to participating securities		$ (86)	$ (276)	$ (392)	$ (1,223)
Denominator:
Weighted average shares outstanding – basic		236	235	236	236
Unvested restricted shares		0	0	0	0
Weighted average shares outstanding – diluted		236	235	236	236
Loss per share - Basic	[1]	$ (0.36)	$ (1.17)	$ (1.66)	$ (5.19)
Loss per share - Diluted	[1]	$ (0.36)	$ (1.17)	$ (1.66)	$ (5.19)

[1] Per share amounts are calculated based on unrounded numbers and are calculated independently for each period presented.