Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator:
Net loss attributable to stockholders		$ (116)	$ (259)	$ (306)	$ (947)
Earnings attributable to participating securities		0	0	0	0
Net loss attributable to stockholders, net of earnings allocated to participating securities		$ (116)	$ (259)	$ (306)	$ (947)
Denominator:
Weighted average shares outstanding – basic		236	235	235	236
Unvested restricted shares		0	0	1	0
Weighted average shares outstanding – diluted		236	235	236	236
Loss per share - Basic	[1]	$ (0.49)	$ (1.10)	$ (1.30)	$ (4.01)
Loss per share - Diluted	[1]	$ (0.49)	$ (1.10)	$ (1.30)	$ (4.01)

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