Acquisitions - HPES Merger Additional Information (Details) arrangement in Thousands, $ in Millions		3 Months Ended
	Apr. 01, 2017 USD ($) arrangement shares	Jun. 30, 2017 USD ($)	Jul. 01, 2016 USD ($)	Mar. 31, 2017 USD ($) tranche
Business Acquisition [Line Items]
Goodwill		$ 8,774		$ 1,855	[1]
Net income (loss)		173	$ (20)
GBS
Business Acquisition [Line Items]
Goodwill		4,347		1,470
GIS
Business Acquisition [Line Items]
Goodwill		3,711		385
USPS
Business Acquisition [Line Items]
Goodwill		716		0
HPES
Business Acquisition [Line Items]
Shares issued for each share of CSC common stock | shares	1
Shares issued for merger consideration | shares	141,298,797
Percent ownership of CSC stockholders following the Merger	49.90%
Long-term debt, net of current maturities	$ 3,997
Goodwill	$ 6,765
Number of capital lease arrangements | arrangement	6
Acquired restructuring liabilities	$ 333
Revenue from acquiree		4,328
Net income (loss) of acquiree		190
Transaction costs		$ 25
HPES | Workforce Reductions
Business Acquisition [Line Items]
Acquired restructuring liabilities	256
HPES | Data Center Consolidation and Facility Closures
Business Acquisition [Line Items]
Acquired restructuring liabilities	77
HPES | GBS
Business Acquisition [Line Items]
Goodwill	2,800
HPES | GIS
Business Acquisition [Line Items]
Goodwill	3,300
HPES | USPS
Business Acquisition [Line Items]
Goodwill	700
HPES | Senior notes
Business Acquisition [Line Items]
Long-term debt, net of current maturities				1,800
HPES | Term Loan
Business Acquisition [Line Items]
Long-term debt, net of current maturities				$ 2,000
Number of tranches | tranche				3
Senior Notes Issued 2017 | HPES | Senior notes
Business Acquisition [Line Items]
Long-term debt, net of current maturities				$ 1,500
Senior Notes Issued 1999 | HPES | Senior notes
Business Acquisition [Line Items]
Long-term debt, net of current maturities				$ 300
Transaction costs | HPES
Business Acquisition [Line Items]
Net income (loss)	$ 25

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