Leases - Narrative (Details) $ in Millions	6 Months Ended
	Sep. 30, 2019 USD ($)
Operating Leased Assets [Line Items]
Operating leases not yet commenced	$ 42
Financing leases not yet commenced	$ 5
Minimum
Operating Leased Assets [Line Items]
Term of contracts not yet commenced	1 year
Maximum
Operating Leased Assets [Line Items]
Term of contracts not yet commenced	10 years