Acquisitions - HPES Merger (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended
	Sep. 25, 2017	Apr. 01, 2017	Sep. 30, 2017	Mar. 31, 2017
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Goodwill			$ 9,158	$ 1,855	[1]
Computer Sciences Corporation
Business Acquisition [Line Items]
Closing price (in dollars per share)				$ 69.01
HPES
Business Combinations [Abstract]
Adjustment to settle obligations	$ 175
Business Acquisition [Line Items]
Preliminary fair value of purchase consideration received by HPE stockholders		$ 9,782
Preliminary fair value of HPES options assumed by CSC		68
Total estimated consideration transferred		$ 9,850
Ownership percentage by HPE stockholders		50.10%
Shares transferred to HPE stockholders (in shares)		141,865,656
Net shares transferred to HPE stockholders (in shares)		141,741,712
Cancelled shares (in shares)		123,944
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Cash and cash equivalents		$ 974
Accounts receivable		4,059
Other current assets		538
Total current assets		5,571
Property and equipment		2,918
Intangible assets		6,194
Other assets		1,574
Total assets acquired		16,257
Accounts payable, accrued payroll, accrued expenses, and other current liabilities		(4,572)
Deferred revenue		(1,105)
Long-term debt, net of current maturities		(4,783)
Long-term deferred tax liabilities and income tax payable		(1,659)
Other liabilities		(1,304)
Total liabilities assumed		(13,423)
Net identifiable assets acquired		2,834
Add: Fair value of non-controlling interests		(61)
Goodwill		7,077
Total estimated consideration transferred		$ 9,850
Preliminary adjustments to receivables			$ 94

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