Arrangements With Off-Balance Sheet Risk (Narrative) (Details) $ in Millions	1 Months Ended		231 Months Ended
	Dec. 31, 2011 USD ($)	Jun. 30, 2011 USD ($)	Dec. 31, 2036	Dec. 31, 2017 USD ($) satellites	Dec. 31, 2016 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of satellite missions | satellites				4
Potentially Unrecoverable Costs Under Contracts	$ 114	$ 271
Offsetting capital lease obligation and IRB asset				$ 166	$ 64
ULA [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Delta launch program inventories included in contributed assets				1,360
Delta launch program inventories subject to an inventory supply agreement				1,860
Contributed inventories consumed by ULA				1,288
Inventory Supply Agreement Payments Received				1,740
Payments made under inventory supply agreement				48
Inventory Supply Agreement Revenue and Costs of Sales Recorded				(1,528)
Contributed Delta Program Launch Inventory [Member] | ULA [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Maximum Potential Payments				$ 72	77
Indemnification Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of satellite missions | satellites				3
Other Delta Contracts [Member] | Deferred support costs [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Maximum Potential Payments				$ 85
Other Delta Contracts [Member] | Deferred production costs [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Maximum Potential Payments				91
Other Delta Contracts [Member] | ULA [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Maximum Potential Payments				191	216
Carrying Amount of Liabilities					5
Deferred Support and Production Costs [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Loss Contingency, Estimate of Possible Loss				317
Credit Guarantees [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Maximum Potential Payments				109	29
Carrying Amount of Liabilities				16	$ 2
Guarantor Obligations, Term			2036
Maximum [Member] | Indemnification Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Loss Contingency, Estimate of Possible Loss				$ 277