Basic and Diluted Earnings Per Share (Table) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended										12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	[1]	Sep. 30, 2017	Jun. 30, 2017	[2]	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share, Basic and Diluted [Abstract]
Net earnings (loss)	$ 212	$ 229	$ 239	$ 156	$ 64		$ 149	$ 147		$ 119	$ 836	$ 479	$ 573
Weighted-average common shares outstanding (in shares)											43.8	45.7	46.8
Net effect of dilutive												0.1	0.4
Dilutive weighted-average common shares outstanding											43.8	45.8	47.2
Earnings (loss) per share - basic	$ 4.96	$ 5.29	$ 5.41	$ 3.48	$ 1.41		$ 3.28	$ 3.22		$ 2.57	$ 19.09	$ 10.48	$ 12.24
Earnings (loss) per share - diluted	$ 4.94	$ 5.29	$ 5.40	$ 3.48	$ 1.41		$ 3.27	$ 3.21		$ 2.56	$ 19.09	$ 10.46	$ 12.14

[1] (2) In the fourth quarter of 2017, the Tax Act resulted in an increase of $56 million to the Company's income tax expense.

[2] (1) In the second quarter of 2017, the Company recorded a $30 million favorable cumulative adjustment on a contract at the Ingalls segment.