Net Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net (loss) earnings attributable to common stockholders	$ (28)	$ 65	$ 230	$ 438
Basic (loss) earnings per common share:
Weighted-average common shares outstanding	213.9	219.0	215.0	221.2
Net earnings attributable to common stockholders (in dollars per share)	$ (0.13)	$ 0.29	$ 1.07	$ 1.98
Diluted (loss) earnings per common share:
Weighted-average common shares outstanding	213.9	219.0	215.0	221.2
Dilutive common shares—stock options (in shares)	0.0	1.7	0.3	1.3
Diluted weighted-average shares outstanding	213.9	220.7	215.3	222.5
Net earnings attributable to common stockholders diluted (in dollars per share)	$ (0.13)	$ 0.29	$ 1.07	$ 1.97
Antidilutive securities excluded from computation of EPS (in shares)	3.1	1.4	3.3	1.5