Basic and Diluted Earnings Per Share (Table) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share, Basic and Diluted [Abstract]
Net earnings (loss)	$ 149	$ 107	$ 415	$ 376
Weighted-average common shares outstanding (in shares)	45.4	46.9	45.8	47.0
Net dilutive effect of stock options and awards (in shares)	0.1	0.3	0.1	0.4
Dilutive weighted-average common shares outstanding (in shares)	45.5	47.2	45.9	47.4
Earnings (loss) per share - basic (in dollars per share)	$ 3.28	$ 2.28	$ 9.06	$ 8.00
Earnings (loss) per share - diluted (in dollars per share)	$ 3.27	$ 2.27	$ 9.04	$ 7.93