Segment Information - Schedule of Operating Results By Segment (Details) $ in Millions	3 Months Ended	6 Months Ended
Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) segment	Sep. 30, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments \| segment			2
Revenue	$ 1,172	$ 1,068	$ 2,279	$ 1,861
Acquired
Segment Reporting Information [Line Items]
Depreciation and amortization	50	36	98	61
Defense and Intelligence
Segment Reporting Information [Line Items]
Revenue	777	702	1,529	1,139
Civilian and Health Care
Segment Reporting Information [Line Items]
Revenue	395	366	750	722
Operating segments
Segment Reporting Information [Line Items]
Revenue	1,172	1,068	2,279	1,861
Segment profit	153	128	304	225
Depreciation and amortization	90	74	191	138
Operating segments \| Defense and Intelligence
Segment Reporting Information [Line Items]
Revenue	777	702	1,529	1,139
Segment profit	113	87	231	123
Depreciation and amortization	24	18	49	37
Operating segments \| Civilian and Health Care
Segment Reporting Information [Line Items]
Revenue	395	366	750	722
Segment profit	40	41	73	102
Depreciation and amortization	$ 16	$ 20	$ 44	$ 40

The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.

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