Acquisitions - HPES Merger (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended
	Sep. 25, 2017	Apr. 01, 2017	Dec. 18, 2017	Dec. 31, 2017	Mar. 31, 2017
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Goodwill				$ 9,320	$ 1,855	[1]
HPES
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 of HPE stockholders		50.10%
Number of shares to acquired entity stockholders		141,865,656
Number of shares to acquired entity stockholders, net		141,741,712
Number of shares to acquired entity stockholders, cancelled		123,944
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Cash and cash equivalents		$ 974
Accounts receivable		4,092
Other current assets		535
Total current assets		5,601
Property and equipment		2,799
Intangible assets		6,169
Other assets		1,614
Total assets acquired		16,183
Accounts payable, accrued payroll, accrued expenses, and other current liabilities		(4,496)
Deferred revenue		(1,267)
Long-term debt, net of current maturities		(4,817)
Long-term deferred tax liabilities and income tax payable		(1,570)
Other liabilities		(1,336)
Total liabilities assumed		(13,486)
Net identifiable assets acquired		2,697
Add: Fair value of non-controlling interests		(55)
Goodwill		7,208
Total estimated consideration transferred		$ 9,850
Adjustment to settle obligations	$ 203		$ 203
Computer Sciences Corporation
Business Acquisition [Line Items]
Closing price (in dollars per share)					$ 69.01

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