Stock Incentive Plans - Schedule of Options (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018	Apr. 03, 2015	Mar. 31, 2017
Number of Option Shares
Issued due to Separation modification (in shares)		400,170
Exercised (in shares)		(969,103)
Weighted Average Exercise Price
Weighted average exercise price - Issued due to Separation modification (in dollars per share)		$ 31.72
Weighted average exercise price - exercised (in dollars per share)		$ 37.33
Additional Disclosures
Total intrinsic value of options exercised	$ 8	$ 44	$ 136
Stock Options
Number of Option Shares
Outstanding beginning of period (in shares)	2,318,768	2,933,501	4,767,396
Granted (in shares)	0	0	0
HPE options converted to DXC options at HPES Merger (in shares)			2,654,970
CSC options converted to RSUs due to HPES Merger (in shares)			(1,521,519)
Exercised (in shares)	(331,172)		(2,916,045)
Canceled/Forfeited (in shares)	(2,213)	(14,607)	(14,890)
Expired (in shares)	(115,568)	(31,193)	(36,411)
Outstanding end of period (in shares)	1,869,815	2,318,768	2,933,501
Weighted Average Exercise Price
Weighted average exercise price - beginning of period (in dollars per share)	$ 30.40	$ 32.54	$ 38.70
Weighted average exercise price - granted (in dollars per share)	0	0	0
Weighted average exercise price - HPE options converted to DXC options at HPES Merger (in dollars per share)			46.56
Weighted average exercise price - CSC options converted to RSUs due to HPES Merger (in dollars per share)			51.00
Weighted average exercise price - exercised (in dollars per share)	31.36		40.39
Weighted average exercise price - cancelled/forfeited (in dollars per share)	55.95	48.33	69.52
Weighted average exercise price - expired (in dollars per share)	34.97	25.03	36.69
Weighted average exercise price - end of period (in dollars per share)	$ 29.92	$ 30.40	$ 32.54
Additional Disclosures
Weighted average remaining contractual life (in years)	4 years 3 months 7 days	4 years 9 months 18 days	5 years 2 months 26 days	8 years 3 days
Aggregate intrinsic value	$ 0	$ 79	$ 185		$ 145
Total intrinsic value of options exercised	$ 8	$ 44	$ 136
Vested and Expected to Vest
Vested and expected to vest in the future as of period end (in shares)	1,869,815
Exercisable as of period end (in shares)	1,869,815
Weighted average exercise price vested and expected to vest as of period end (in dollars per share)	$ 29.92
Weighted average exercise price exercisable as of period end (in dollars per share)	$ 29.92
Weighted average remaining contractual life vested and expected to vest in the future as of period end (in years)	4 years 3 months 7 days
Weighted average remaining contractual life exercisable as of period end (in years)	4 years 3 months 7 days
Aggregate intrinsic value vested and expected to vest in the future as of period end	$ 0
Aggregate intrinsic value exercisable as of period end	$ 0