Commitments and Contingencies (Details) $ in Millions	9 Months Ended
	Dec. 31, 2018 USD ($)
Minimum purchase commitments [Abstract]
Remainder of 2019	$ 717
2020	2,296
2021	777
2022	375
2023	333
Thereafter	242
Total	$ 4,740
Minimum
Minimum purchase commitments [Abstract]
Long-term purchase commitment, period	1 year
Maximum
Minimum purchase commitments [Abstract]
Long-term purchase commitment, period	6 years