Acquisitions (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Nov. 30, 2012 employees
Business Acquisition [Line Items]
Number of employees	24,800
Defense Systems Engineering and Support (DSES) division of ARINC Incorporated
Business Acquisition [Line Items]
Business acquisition, percentage of voting interests acquired		100.00%
Number of employees		900
Business acquisition, cash paid		$ 155.1
Business acquisition, preliminary purchase price		154.0
Business acquisition, preliminary working capital adjustment		1.1
Business acquisition, expected recovery from acquiree		2.8
Business acquisition, preliminary purchase price allocation		152.2
Business acquisition, transaction costs	$ 4.0