Stock Incentive Plans - Narrative (Details) $ in Millions	3 Months Ended	9 Months Ended
Dec. 31, 2020 USD ($) shares	Dec. 31, 2020 USD ($) anniversary shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Plan term		10 years
Total unrecognized compensation expense related to unvested awards, net of expected forfeitures \| $	$ 0	$ 0
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares to be received (in shares) \| shares	1	1
Total unrecognized compensation expense related to unvested awards, net of expected forfeitures \| $	$ 146	$ 146
Weighted average period over which cost is expected to be recognized (in years)		2 years 21 days
Restricted Stock Units \| Five Years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual installments		5 years
Restricted Stock Units \| Ten Years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual installments		10 years
Restricted Stock Units \| Fifteen Years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual installments		15 years
Restricted Stock Units \| Service-based RSU's
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of anniversaries over which shares are settled \| anniversary		10
Performance-based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Performance period		3 years
Award vesting rights, percentage		25.00%
DXC Share Purchase Plan \| Stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares purchased under plan (in shares) \| shares	12,232	41,425

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