Pension and Other Benefit Plans - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Mar. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Employer contribution	$ 39	$ 71
Expected employer contributions during remainder of Fiscal 2020	32	32
Contractual termination benefit	0	17
Deferred compensation plan, liability	$ 58	$ 58	$ 59
Non-employee directors
Defined Benefit Plan Disclosure [Line Items]
Maximum deferral percentage		100.00%