Other Assets (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Other Assets [Line Items]
Other assets, net of accumulated amortization	$ 1,852	$ 2,027
Sea Launch Receivables [Member]
Other Assets [Line Items]
Other assets, net of accumulated amortization	295	$ 356
Sea Launch Receivables [Member] | S.P. Koroley Rocket And Space Corporation Energia [Member]
Other Assets [Line Items]
Other assets, net of accumulated amortization	162
Sea Launch Receivables [Member] | PO Yuzhnoye Mashinostroitelny Zavod [Member]
Other Assets [Line Items]
Other assets, net of accumulated amortization	89
Sea Launch Receivables [Member] | KB Yuzhnoye [Member]
Other Assets [Line Items]
Other assets, net of accumulated amortization	$ 44