Acquisitions - Fiscal 2018 Acquisitions (Details) - USD ($) $ in Millions	Jul. 01, 2017	Sep. 30, 2017	Mar. 31, 2017	[1]
Business Acquisition [Line Items]
Goodwill		$ 9,158	$ 1,855
Tribridge Holdings LLC
Business Acquisition [Line Items]
Purchase consideration	$ 152
Current assets	32
Property and equipment	4
Intangible assets, other than goodwill	62
Current liabilities	24
Goodwill	$ 78
Estimated useful life	12 years

[1] Certain prior year amounts were adjusted to retroactively reflect the legal capital of DXC.