Inventories Long term contracts percentage-of-completion accounting (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 27, 2014	Jun. 28, 2013	Jun. 27, 2014	Jun. 28, 2013
Inventory Disclosure [Abstract]
Decrease to operating income from the quarterly impact of revisions in long term contracts	$ 0.6	$ 2.7		$ 2.7
Increase to operating income from the quarterly impact of revisions in long term contracts			$ 0.2