Goodwill and Intangible Assets - Goodwill (Details) (USD $) In Millions, unless otherwise specified	Mar. 29, 2015	Dec. 28, 2014
Goodwill [Line Items]
Gross value	$ 843.8us-gaap_GoodwillGross	$ 843.8us-gaap_GoodwillGross
Less accumulated impairment	247.4	247.4
Net	596.4us-gaap_Goodwill	596.4us-gaap_Goodwill
Public Safety & Security
Goodwill [Line Items]
Gross value	53.9	53.9
Less accumulated impairment	18.3	18.3
Net	35.6	35.6
Kratos Government Solutions
Goodwill [Line Items]
Gross value	678.8	678.8
Less accumulated impairment	215.3	215.3
Net	463.5	463.5
Unmanned Systems
Goodwill [Line Items]
Gross value	111.1	111.1
Less accumulated impairment	13.8	13.8
Net	$ 97.3	$ 97.3

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

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- Definition

Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a,h)

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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