Revenue - Adoption of 606 (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Apr. 01, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenues	$ 20,753	$ 21,733	$ 7,607
Costs of services	14,946	16,317	5,549
Selling, general and administrative (excludes depreciation and amortization and restructuring costs)	1,959	1,890	1,282
Interest income	(128)	(89)	(35)
Income tax expense (benefit)	288	(242)	(74)
Net income (loss) attributable to DXC common stockholders	1,257	1,751	$ (123)
Assets:
Receivables, net of allowance for doubtful accounts	5,181	5,481
Other current assets	359	469
Deferred tax assets	355	373
Other assets	3,429	3,207
Liabilities:
Accrued expenses and other current liabilities	3,355	3,120
Deferred revenue and advance contract payments	1,630	1,641
Income taxes payable	208	127
Non-current deferred revenue	256	795
Non-current income tax liabilities and deferred tax liabilities	1,184	1,166
Equity:
Retained earnings	478	1,301
Accumulated other comprehensive loss	(244)	$ 58
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenues	30
Costs of services	2
Selling, general and administrative (excludes depreciation and amortization and restructuring costs)	(73)
Interest income	(13)
Income tax expense (benefit)	22
Net income (loss) attributable to DXC common stockholders	66
Assets:
Receivables, net of allowance for doubtful accounts	(18)
Other current assets	(52)
Deferred tax assets	(21)
Other assets	(22)
Liabilities:
Accrued expenses and other current liabilities	(1)
Deferred revenue and advance contract payments	(87)			$ (381)
Income taxes payable	2			(40)
Non-current deferred revenue	(235)
Non-current income tax liabilities and deferred tax liabilities	36
Equity:
Retained earnings	177			$ 114
Accumulated other comprehensive loss	(5)
Calculated under Revenue Guidance in Effect before Topic 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenues	20,723
Costs of services	14,944
Selling, general and administrative (excludes depreciation and amortization and restructuring costs)	2,032
Interest income	(141)
Income tax expense (benefit)	266
Net income (loss) attributable to DXC common stockholders	1,191
Assets:
Receivables, net of allowance for doubtful accounts	5,199
Other current assets	411
Deferred tax assets	376
Other assets	3,451
Liabilities:
Accrued expenses and other current liabilities	3,356
Deferred revenue and advance contract payments	1,717
Income taxes payable	206
Non-current deferred revenue	491
Non-current income tax liabilities and deferred tax liabilities	1,148
Equity:
Retained earnings	301
Accumulated other comprehensive loss	$ (239)