Earnings (Loss) Per Share - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Net (loss) income attributable to DXC common shareholders:
From continuing operations	$ (149)	$ (5,369)	$ 1,222
From discontinued operations	0	0	35
Net (loss) income attributable to DXC common stockholders	$ (149)	$ (5,369)	$ 1,257
Common share information:
Weighted average common shares outstanding for basic EPS (in shares)	254,140	258,570	277,540
Dilutive effect of stock options and equity awards (in shares)	0	0	3,890
Weighted average common shares outstanding for diluted EPS (in shares)	254,140	258,570	281,430
Basic EPS:
Continuing operations (in dollars per share)	$ (0.59)	$ (20.76)	$ 4.40
Discontinued operations (in dollars per share)	0	0	0.13
Basic EPS (in dollars per share)	(0.59)	(20.76)	4.53
Diluted EPS:
Continuing operations (in dollars per share)	(0.59)	(20.76)	4.35
Discontinued operations (in dollars per share)	0	0	0.12
Diluted EPS (in dollars per share)	$ (0.59)	$ (20.76)	$ 4.47