Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Income Tax Contingency [Line Items]
Effective income tax rate		18.40%	35.80%
Tax effect of discontinued operation		$ 0	$ 18
Change amount to be repatriated		506
Forecast | Minimum
Income Tax Contingency [Line Items]
Liability for uncertain tax positions, adjustment	$ (2)
Forecast | Maximum
Income Tax Contingency [Line Items]
Liability for uncertain tax positions, adjustment	$ (6)
Perspecta
Income Tax Contingency [Line Items]
Tax indemnification receivable		95
Tax indemnification payable		69
HPES
Income Tax Contingency [Line Items]
Tax indemnification payable		134
Tax indemnification receivable, net		16
Tax indemnification receivable, uncertain tax positions		49
Tax indemnification receivable, tax indemnification payable		$ 101