Earnings per Share - Schedule of Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Net income (loss) attributable to DXC common shareholders:	$ 256	$ 15	$ 415	$ (6)
Common share information:
Weighted average common shares outstanding for basic EPS (in shares)	284,870	140,530	284,350	139,760
Dilutive effect of stock options and equity awards (in shares)	4,420	3,250	5,030	0
Weighted average common shares outstanding for diluted EPS (in shares)	289,290	143,780	289,380	139,760
Earnings (loss) per share:
Basic (in dollars per share)	$ 0.90	$ 0.11	$ 1.46	$ (0.04)
Diluted (in dollars per share)	$ 0.88	$ 0.10	$ 1.43	$ (0.04)