Unaudited Selected Quarterly Data (Table) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended												12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017		Sep. 30, 2017	Jun. 30, 2017		Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in Accounting Estimate [Line Items]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount													$ (10)	$ 56
Selected Quarterly Financial Information [Abstract]
Sales and service revenues	$ 2,199	$ 2,083	$ 2,020	$ 1,874	$ 1,996		$ 1,863	$ 1,858		$ 1,724			8,176	7,441	$ 7,068
Operating income (loss)	213	290	257	191	231		241	241	[1]	168			951	881	876
Earnings (loss) before income taxes	219	295	262	195	187		220	218	[1]	147			971	772	784
Net earnings (loss)	$ 212	$ 229	$ 239	$ 156	$ 64	[2]	$ 149	$ 147	[1]	$ 119			$ 836	$ 479	$ 573
Dividends declared per share	$ 0.86	$ 0.72	$ 0.72	$ 0.72	$ 0.72		$ 0.60	$ 0.60		$ 0.60	$ 0.60	$ 0.50	$ 3.02	$ 2.52	$ 2.10
Basic earnings (loss) per share	4.96	5.29	5.41	3.48	1.41	[2]	3.28	3.22	[1]	2.57			19.09	10.48	12.24
Diluted earnings (loss) per share	$ 4.94	$ 5.29	$ 5.40	$ 3.48	$ 1.41	[2]	$ 3.27	$ 3.21	[1]	$ 2.56			$ 19.09	$ 10.46	$ 12.14
Ingalls contract [Member]
Change in Accounting Estimate [Line Items]
Increase (decrease) in operating income due to net cumulative catch-up adjustments								$ 30							$ 74
Reduction in income tax rate [Member]
Change in Accounting Estimate [Line Items]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount					$ 56								$ (10)	$ 56

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

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