Acquisitions - HPES Merger (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
	Apr. 01, 2017	Mar. 31, 2018	Dec. 31, 2018	Mar. 31, 2017
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Goodwill		$ 7,619	$ 7,593
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 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		938
Accounts receivable		4,102
Other current assets		530
Total current assets		5,570
Property and equipment		2,581
Intangible assets		6,384
Other assets		1,571
Total assets acquired		16,106
Accounts payable, accrued payroll, accrued expenses, and other current liabilities		(4,605)
Deferred revenue		(1,315)
Long-term debt, net of current maturities		(4,806)
Long-term deferred tax liabilities and income tax payable		(1,550)
Other liabilities		(1,322)
Total liabilities assumed		(13,598)
Net identifiable assets acquired		2,508
Add: Fair value of non-controlling interests		(50)
Goodwill		7,392
Total estimated consideration transferred		9,850
Adjustment to settle obligations		$ 203
Computer Sciences Corporation
Business Acquisition [Line Items]
Closing price (in dollars per share)				$ 69.01