Intangible Assets - Summary of Intangible Assets (Details) - USD ($) $ in Millions	Sep. 30, 2017	Mar. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 10,735	$ 4,087
Accumulated Amortization	2,731	2,293	[1]
Net Carrying Value	8,004	1,794	[1]
Software
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	3,180	2,347
Accumulated Amortization	1,707	1,554
Net Carrying Value	1,473	793
Outsourcing contract costs
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	1,323	793
Accumulated Amortization	559	475
Net Carrying Value	764	318
Customer related intangible assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	6,127	851
Accumulated Amortization	447	248
Net Carrying Value	5,680	603
Other intangible assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	105	96
Accumulated Amortization	18	16
Net Carrying Value	$ 87	$ 80

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