Pension and Other Benefit Plans - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Mar. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Deferred compensation plan, liability	$ 45		$ 45		$ 48
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Net loss from remeasurement of plan assets and liabilities	(76)	$ (70)	(149)	$ (139)
Curtailment gain	0	0	9	0
Recognition of actuarial loss	0	$ 0	$ 11	$ 0
Foreign Plan [Member] | Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Net loss from remeasurement of plan assets and liabilities	2
Curtailment gain	9
Recognition of actuarial loss	$ 11
Directors
Defined Benefit Plan Disclosure [Line Items]
Maximum deferral percentage			100.00%