Goodwill and Other Purchased Intangible Assets (Unaudited) Goodwill and Other Purchased Intangible Assets (Unaudited) (Details 1) $ in Millions	9 Months Ended
	Sep. 30, 2018 USD ($)
Goodwill [Line Items]
Beginning Balance	$ 12,455
Acquisition of Orbital ATK	6,191
Other	(4)
Ending Balance	18,642
Aerospace Systems [Member]
Goodwill [Line Items]
Beginning Balance	3,742
Acquisition of Orbital ATK	418
Other	0
Ending Balance	4,160
Innovation Systems [Member]
Goodwill [Line Items]
Beginning Balance	0
Acquisition of Orbital ATK	5,225
Other	0
Ending Balance	5,225
Mission Systems [Member]
Goodwill [Line Items]
Beginning Balance	6,696
Acquisition of Orbital ATK	469
Other	(1)
Ending Balance	7,164
Technology Services [Member]
Goodwill [Line Items]
Beginning Balance	2,017
Acquisition of Orbital ATK	79
Other	(3)
Ending Balance	$ 2,093