Business Acquisition (Unaudited) (Details 4) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Business Acquisition [Line Items]
Pro forma sales	$ 8,078	$ 7,555	$ 16,078	$ 15,039
Pro forma net earnings	$ 791	$ 572	$ 1,615	$ 1,225
Pro forma basic earnings per share	$ 4.53	$ 3.28	$ 9.26	$ 7.01
Pro forma diluted earnings per share	$ 4.51	$ 3.26	$ 9.21	$ 6.97
Pro Forma Adjustments, Orbital ATK ASC606 Sales adjustment		$ 2		$ 21
Pro Forma Adjustments, Orbital ATK ASC606 Cost of Sales adjustment		(2)		(9)
Pro Forma Adjustments, Orbital ATK intercompany sales elimination	$ (33)	(35)	$ (80)	(65)
Pro Forma Adjustments, Orbital ATK intercompany cost of sales elimination	33	35	80	65
Pro Forma Adjustments, Elimination of nonrecurring transaction costs	64		71
Pro Forma Adjustments, Additional depreciation expense, net of removal of historical depreciation	(7)	(8)	(7)	(10)
Pro Forma Adjustments, Additional interest expense due to debt issued to finance merger		(66)		(133)
Pro Forma Adjustments, Additional amortization expense, net of removal of historical amortization expense	(34)	(65)	(92)	(130)
Pro Forma Adjustments, Elimination of Orbital ATK’s amortization on net actuarial losses and prior service costs and pension/post-retirement costs	$ 20	$ 29	$ 51	$ 54