Arrangements With Off-Balance Sheet Risk (Narrative) (Details) $ in Millions			1 Months Ended		222 Months Ended
	Jul. 05, 2018 USD ($)	Apr. 30, 2018 USD ($)	Dec. 31, 2011 USD ($)	Jun. 30, 2011 USD ($)	Dec. 31, 2036	Jun. 30, 2018 USD ($) satellites	Dec. 31, 2017 USD ($)
Guarantees [Line Items]
Number of satellite missions | satellites						4
Additional potentially unrecoverable deferred production costs			$ 114	$ 271
Business Combination, Future Consideration		$ 4,250
ULA [Member]
Guarantees [Line Items]
Delta launch program inventories included in contributed assets						$ 1,360
Delta launch program inventories subject to inventory supply agreement						1,860
Contributed Delta launch program inventories consumed by ULA						1,293
Revenues and cost of sales recorded under inventory supply agreement						1,545
Payments received under inventory supply agreement						1,740
Payments made under inventory supply agreement						48
Contributed Delta Program Launch Inventory [Member] | ULA [Member]
Guarantees [Line Items]
Maximum Potential Payments						67	$ 72
Contract Pricing [Member] | ULA [Member]
Guarantees [Line Items]
Maximum Potential Payments						261	261
Carrying Amount of Liabilities						$ 7	7
Indemnification Agreement [Member]
Guarantees [Line Items]
Number of satellite missions | satellites						3
Other Delta Contracts [Member] | Deferred support costs [Member]
Guarantees [Line Items]
Maximum Potential Payments						$ 85
Other Delta Contracts [Member] | Deferred production costs [Member]
Guarantees [Line Items]
Maximum Potential Payments						91
Other Delta Contracts [Member] | ULA [Member]
Guarantees [Line Items]
Maximum Potential Payments						191	191
Carrying Amount of Liabilities
Deferred Support and Production Costs [Member]
Guarantees [Line Items]
Loss Contingency, Estimate of Possible Loss						317
Credit Guarantee [Member]
Guarantees [Line Items]
Maximum Potential Payments						112	109
Carrying Amount of Liabilities						16	$ 16
Guarantor Obligations, Term					2036
Maximum [Member] | Indemnification Agreement [Member]
Guarantees [Line Items]
Loss Contingency, Estimate of Possible Loss						280
Maximum [Member] | Purchase Agreement Termination Fee [Member]
Guarantees [Line Items]
Loss Contingency, Estimate of Possible Loss						$ 175
Contingent Consideration Type [Domain]
Guarantees [Line Items]
Controlling Interest Ownership Percentage After Acquisition	80.00%
Payments to Acquire Interest in Joint Venture	$ 3,800
Embraer [Member] | Contingent Consideration Type [Domain]
Guarantees [Line Items]
Investments Net Asset Value	$ 4,750