Leases - Operating Lease Maturities (Details) $ in Millions	Jun. 30, 2019 USD ($)
Leases [Abstract]
Remainder of fiscal year ending March 31, 2020	$ 1,580
Fiscal year ending March 31, 2021	2,187
Fiscal year ending March 31, 2022	1,640
Fiscal year ending March 31, 2023	1,133
Fiscal year ending March 31, 2024	770
Thereafter	1,783
Total lease payments	9,093
Less imputed interest	(1,500)
Total	$ 7,593