Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net earnings	$ 2,002	$ 5,302	$ 3,605
Postretirement benefit plans
Net other comprehensive loss recognized during the period, net of tax benefit of $375 million in 2017, $668 million in 2016 and $192 million in 2015	(1,380)	(1,232)	(351)
Amounts reclassified from accumulated other comprehensive loss, net of tax expense of $437 million in 2017, $382 million in 2016 and $464 million in 2015	802	699	850
Reclassifications from divestiture of IS&GS business	0	(134)	0
Other, net	140	9	(73)
Other comprehensive (loss) income, net of tax	(438)	(658)	426
Comprehensive income	$ 1,564	$ 4,644	$ 4,031