Goodwill (Details) $ in Millions	6 Months Ended
Sep. 30, 2018 USD ($)
Changes in the carrying amount of goodwill by segment [Roll Forward]
Balance as of March 31, 2018	$ 2,022
Additions	1,240
Allocations from DXC	11
Balance as of September 30, 2018	3,273
Defense and Intelligence
Changes in the carrying amount of goodwill by segment [Roll Forward]
Balance as of March 31, 2018	977
Additions	1,157
Allocations from DXC	11
Balance as of September 30, 2018	2,145
Civilian and Health Care
Changes in the carrying amount of goodwill by segment [Roll Forward]
Balance as of March 31, 2018	1,045
Additions	83
Allocations from DXC	0
Balance as of September 30, 2018	$ 1,128

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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266

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- Definition

Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Amount of transfers into (out of) an asset representing the 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/2009/role/commonPracticeRef
-Publisher FASB
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-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (g)
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