Changes in Estimates (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Changes in Estimates (Details) [Abstract]
Increase in Operating Income Due to Aggregate Net Changes in Contract Estimates	$ 7	$ 13

Aggregate net changes in contract estimates effecting operating income.

No definition available.

Name:	orb_IncreaseDecreaseInOperatingIncomeDueToAggregateNetChangesInContractEstimates
Namespace Prefix:	orb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration