CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2020	Mar. 31, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 199	$ 74
Intangible assets, accumulated amortization	4,545	4,347
Property and equipment, accumulated depreciation	$ 4,295	$ 3,818
DXC stockholders’ equity:
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	750,000,000	750,000,000
Common stock, issued (in shares)	256,800,719	255,674,040
Common stock in treasury, at cost (in shares)	2,410,917	2,148,708