Arrangements With Off-Balance Sheet Risk (Narrative) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended		3 Months Ended
	Dec. 31, 2011	Jun. 30, 2011	Mar. 31, 2015	Dec. 31, 2014
Guarantees [Line Items]
Number of satellite missions			4
Additional potentially unrecoverable deferred production costs	$ 114	$ 271
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			1,248
Revenues and cost of sales recorded under inventory supply agreement			1,327
Payments received under inventory supply agreement			1,680
Payments made under inventory supply agreement			71
Contributed Delta Program Launch Inventory [Member] | ULA [Member]
Guarantees [Line Items]
Maximum Potential Payments			112	114
Indemnification Agreement [Member]
Guarantees [Line Items]
Maximum exposure to loss			278
Number of satellite missions			3
Indemnification Agreement [Member] | Indemnification Payment [Member]
Guarantees [Line Items]
Maximum exposure to loss			261
Other Delta Contracts [Member] | Deferred support costs [Member]
Guarantees [Line Items]
Maximum Potential Payments			85
Other Delta Contracts [Member] | ULA [Member]
Guarantees [Line Items]
Maximum Potential Payments			140	150
Carrying Amount of Liabilities			5
Deferred Support and Production Costs [Member]
Guarantees [Line Items]
Loss Contingency, Estimate of Possible Loss			317
Other Indemnifications [Member]
Guarantees [Line Items]
Maximum Potential Payments			63	63
Carrying Amount of Liabilities			21	20
Credit Guarantee [Member]
Guarantees [Line Items]
Maximum Potential Payments			30	30
Carrying Amount of Liabilities			$ 2	$ 2
Guarantor Obligations, Term			6