(Loss) Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share, Diluted, by Common Class, Including Two Class Method
Performance shares excluded from diluted earnings per share (in shares)	112,100		112,100
Basic earnings per share:
Net earnings	$ (98)	$ 172	$ 31	$ 332
Weighted average shares of common stock outstanding (shares)	206,000,000.0	205,700,000	205,800,000	206,100,000
Basic (loss) earnings per share of common stock (in dollar per share)	$ (0.47)	$ 0.84	$ 0.15	$ 1.61
Diluted (loss) earnings per share:
Net earnings	$ (98)	$ 172	$ 31	$ 332
Weighted average shares of common stock outstanding (shares)	206,000,000.0	205,700,000	205,800,000	206,100,000
Effect of stock-based compensation (shares)	0	1,100,000	600,000	900,000
Weighted average shares of common stock outstanding including dilutive shares (shares)	206,000,000.0	206,800,000	206,400,000	207,000,000.0
Diluted (loss) earnings per share of common stock (in dollar per share)	$ (0.47)	$ 0.83	$ 0.15	$ 1.60
Relative Revenue Growth
Earnings Per Share, Diluted, by Common Class, Including Two Class Method
Performance shares excluded from diluted earnings per share (in shares)	132,600		132,600