Basic and Diluted Earnings Per Share (Table) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share, Basic and Diluted [Abstract]
Net earnings (loss)	$ 239	$ 147	$ 395	$ 266
Weighted-average common shares outstanding (in shares)	44.2	45.7	44.5	46.0
Net dilutive effect of stock options and awards (in shares)	0.1	0.1	0.1	0.1
Dilutive weighted-average common shares outstanding (in shares)	44.3	45.8	44.6	46.1
Earnings (loss) per share - basic (in dollars per share)	$ 5.41	$ 3.22	$ 8.88	$ 5.78
Earnings (loss) per share - diluted (in dollars per share)	$ 5.40	$ 3.21	$ 8.86	$ 5.77