Earnings (Loss) per Share - Schedule of Earnings (Loss) per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Net Income (Loss) Attributable to Parent [Abstract]
Net income (loss) attributable to DXC common shareholders:	$ 1,098	$ 82	$ 649	$ (1,874)
Common share information:
Weighted average common shares outstanding for basic and diluted net (loss) EPS (in shares)	254,320	255,090	254,030	260,240
Dilutive effect of stock options and equity awards (in shares)	1,430	960	1,170	0
Weighted Average Number of Shares Outstanding, Diluted	255,750	256,050	255,200	260,240
Earnings (loss) per share:
Basic (in dollars per share)	$ 4.32	$ 0.32	$ 2.55	$ (7.20)
Diluted (in dollars per share)	$ 4.29	$ 0.32	$ 2.54	$ (7.20)