Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Tax Contingency [Line Items]
Effective income tax rate	(5.80%)	22.00%	(8.60%)	29.20%
Tax effect of discontinued operation			$ 0	$ 18
Change amount to be repatriated			506
Liability for uncertain tax positions, adjustment	$ 43
Minimum
Income Tax Contingency [Line Items]
Reasonably possible reduction in liability for uncertain tax positions	13		13
Maximum
Income Tax Contingency [Line Items]
Reasonably possible reduction in liability for uncertain tax positions	17		17
Perspecta
Income Tax Contingency [Line Items]
Tax indemnification receivable	77		77
Tax indemnification payable	64		64
HPES
Income Tax Contingency [Line Items]
Tax indemnification payable	132		132
Tax indemnification receivable, net	18		18
Tax indemnification receivable, tax indemnification payable	107		107
Tax indemnification receivable, uncertain tax positions	$ 43		$ 43