Earnings Per Share (Computation Of Basic And Diluted Earnings Per Share) (Detail) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Basic earnings per share:
Net income (loss)		$ (36)	$ (61)	$ (109)	$ (167)
Less: undistributed earnings allocated to participating securities		0	0	0	0
Net income (loss) available to common shareholders		$ (36)	$ (61)	$ (109)	$ (167)
Basic weighted average shares	[1]	49,826,695	49,488,368	49,729,610	49,373,883
Net income (loss) per basic common share		$ (0.72)	$ (1.23)	$ (2.2)	$ (3.38)
Diluted earnings per share:
Net income (loss)		$ (36)	$ (61)	$ (109)	$ (167)
Less: undistributed earnings allocated to participating securities		0	0	0	0
Net income (loss) available to common shareholders		$ (36)	$ (61)	$ (109)	$ (167)
Diluted weighted average shares		49,826,695	49,488,368	49,729,610	49,373,883
Net income (loss) per diluted common share		$ (0.72)	$ (1.23)	$ (2.2)	$ (3.38)
Potentially dilutive securities excluded from the calculation of diluted EPS because of antidilutive affect		5,000,000	4,900,000	5,000,000	4,900,000

[1] Includes 0.8 million and 0.9 million of participating securities that met the service condition and were eligible to receive nonforfeitable dividends or dividend equivalents for each of the three months and six months ended June 30, 2022 and 2021, respectively.