Inventoried Costs (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 30, 2012
Inventory Disclosure [Abstract]
Raw materials	$ 42.5	$ 48.4
Work in process	39.2	36.5
Finished goods	5.8	7.3
Supplies and other	1.7	2.2
Total inventoried costs	89.2	94.4
Less: customer advances and progress payments	(1.0)	(0.1)
Total inventoried costs	$ 88.2	$ 94.3