Goodwill and Other Intangible Assets - Purchased Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 29, 2013	Sep. 29, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 30, 2012	Sep. 30, 2012	Jun. 24, 2012	Mar. 25, 2012	Dec. 29, 2013	Dec. 30, 2012	Dec. 25, 2011
Acquired finite-lived intangible assets:
Gross Value	$ 207.7				$ 207.7				$ 207.7	$ 207.7
Accumulated Amortization	(144.7)				(108.5)				(144.7)	(108.5)
Net Value	63.0				99.2				63.0	99.2
Acquired indefinite-lived intangible assets
Total indefinite-lived intangible assets	6.9				6.9				6.9	6.9
Total intangible assets, Gross Value	214.6				214.6				214.6	214.6
Total intangible assets, Net Value	69.9				106.1				69.9	106.1
Consolidated amortization expense related to intangible assets subject to amortization	8.9	9.0	9.0	9.3	11.5	13.0	8.9	10.5	36.2	43.9	38.0
Customer relationships
Acquired finite-lived intangible assets:
Gross Value	97.7				97.7				97.7	97.7
Accumulated Amortization	(53.7)				(36.2)				(53.7)	(36.2)
Net Value	44.0				61.5				44.0	61.5
Contracts and backlog
Acquired finite-lived intangible assets:
Gross Value	80.0				80.0				80.0	80.0
Accumulated Amortization	(78.7)				(64.3)				(78.7)	(64.3)
Net Value	1.3				15.7				1.3	15.7
Developed technology and technical know-how
Acquired finite-lived intangible assets:
Gross Value	22.1				22.1				22.1	22.1
Accumulated Amortization	(8.6)				(6.4)				(8.6)	(6.4)
Net Value	13.5				15.7				13.5	15.7
Trade names
Acquired finite-lived intangible assets:
Gross Value	6.1				6.1				6.1	6.1
Accumulated Amortization	(3.1)				(1.2)				(3.1)	(1.2)
Net Value	3.0				4.9				3.0	4.9
Acquired indefinite-lived intangible assets
Remaining useful life										2 years
Finite-lived intangible assets impairment charge										14.6
Favorable operating lease
Acquired finite-lived intangible assets:
Gross Value	1.8				1.8				1.8	1.8
Accumulated Amortization	(0.6)				(0.4)				(0.6)	(0.4)
Net Value	1.2				1.4				1.2	1.4
Public Safety & Security | Trade names
Acquired indefinite-lived intangible assets
Finite-lived intangible assets impairment charge										12.9
Kratos Government Solutions | Trade names
Acquired indefinite-lived intangible assets
Finite-lived intangible assets impairment charge										$ 1.7