Net Income Per Common Share - Calculations for Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net income (loss)—basic and diluted	$ (273)	$ 620
Denominator:
Basic weighted-average common shares outstanding (in shares)	160.4	161.0
Diluted weighted-average shares	160.4	162.5
Earnings (loss) per share:
Basic (in USD per share)	$ (1.70)	$ 3.85
Diluted (in USD per share)	$ (1.70)	$ 3.82
Number of anti-dilutive stock-based awards (in shares)	2.3	1.0
Stock Options
Denominator:
Effect of stock-based awards (in shares)	0.0	0.9
Nonvested shares
Denominator:
Effect of stock-based awards (in shares)	0.0	0.6