Earnings Per Share (Computation Of Basic And Diluted Earnings Per Share) (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Net loss	$ (158)	$ (91)
Basic and diluted weighted average shares outstanding (a)	72.9	75.8
Basic	$ (2.16)	$ (1.20)
Diluted	$ (2.16)	$ (1.20)
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1.3	1.3