Changes in Estimates (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Changes in Estimates (Details) [Abstract]
Increase in Operating Income Due to Aggregate Net Changes in Contract Estimates	$ 5	$ 18	$ 12	$ 34

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