Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2023	Sep. 25, 2022	Oct. 01, 2023	Sep. 25, 2022
Disaggregation of Revenue [Line Items]
Total Revenues	$ 274.6	$ 228.6	$ 763.3	$ 649.0
Kratos Government Solutions
Disaggregation of Revenue [Line Items]
Total Revenues	217.9	178.6	606.5	490.0
Kratos Government Solutions | U.S. Government
Disaggregation of Revenue [Line Items]
Total Revenues	132.1	114.6	376.1	308.3
Kratos Government Solutions | International
Disaggregation of Revenue [Line Items]
Total Revenues	52.2	39.8	145.1	110.6
Kratos Government Solutions | U.S. Commercial and other customers
Disaggregation of Revenue [Line Items]
Total Revenues	33.6	24.2	85.3	71.1
Unmanned Systems
Disaggregation of Revenue [Line Items]
Total Revenues	56.7	50.0	156.8	159.0
Unmanned Systems | U.S. Government
Disaggregation of Revenue [Line Items]
Total Revenues	53.4	43.5	148.3	145.5
Unmanned Systems | International
Disaggregation of Revenue [Line Items]
Total Revenues	2.1	5.9	6.4	11.3
Unmanned Systems | U.S. Commercial and other customers
Disaggregation of Revenue [Line Items]
Total Revenues	1.2	0.6	2.1	2.2
Fixed price | Kratos Government Solutions
Disaggregation of Revenue [Line Items]
Total Revenues	155.2	125.1	414.7	346.3
Fixed price | Unmanned Systems
Disaggregation of Revenue [Line Items]
Total Revenues	42.4	33.6	118.3	105.8
Cost plus fee | Kratos Government Solutions
Disaggregation of Revenue [Line Items]
Total Revenues	49.5	43.3	155.1	112.7
Cost plus fee | Unmanned Systems
Disaggregation of Revenue [Line Items]
Total Revenues	11.4	14.9	30.0	50.6
Time and materials | Kratos Government Solutions
Disaggregation of Revenue [Line Items]
Total Revenues	13.2	10.2	36.7	31.0
Time and materials | Unmanned Systems
Disaggregation of Revenue [Line Items]
Total Revenues	$ 2.9	$ 1.5	$ 8.5	$ 2.6