Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Mar. 31, 2019	Apr. 01, 2017
Income Tax Contingency [Line Items]
Effective income tax rate	38.60%	44.20%	42.40%	54.50%
Foreign earnings not indefinitely reinvested	$ 504		$ 504
Potential federal and state cost from tax examinations			456
Increase in liability for uncertain tax positions	19
Reasonably possible reduction in liability for uncertain tax positions	$ 46		$ 46
HPES
Income Tax Contingency [Line Items]
Tax indemnification receivable, uncertain tax positions						$ 34
Tax indemnification receivable, tax indemnification payable						68
Tax indemnification payable						$ 123
Perspecta
Income Tax Contingency [Line Items]
Tax indemnification payable					$ 29
Tax indemnification receivable					$ 74