Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Income Tax Contingency [Line Items]
Effective income tax rate	11.60%	18.40%
Foreign earnings not indefinitely reinvested	$ 501
Minimum
Income Tax Contingency [Line Items]
Reasonably possible reduction in liability for uncertain tax positions	23
Maximum
Income Tax Contingency [Line Items]
Reasonably possible reduction in liability for uncertain tax positions	28
HPES
Income Tax Contingency [Line Items]
Tax indemnification receivable, net	16
Tax indemnification receivable, uncertain tax positions	44
Tax indemnification receivable, tax indemnification payable	86
Tax indemnification payable	114
Perspecta
Income Tax Contingency [Line Items]
Tax indemnification receivable	66
Tax indemnification payable	$ 45