Leases - Leases Not Yet Commenced (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Leases Not Yet Commenced [Line Items]
Aggregate commitment amount of leases not yet commenced	$ 848.0
Long-term Contract for Purchase of Electric Power [Domain]
Leases Not Yet Commenced [Line Items]
Number of leases not yet commenced	3
Battery Capacity
Leases Not Yet Commenced [Line Items]
Number of leases not yet commenced	2
Term of leases not yet commenced	25 years
Purchased Electricity
Leases Not Yet Commenced [Line Items]
Term of leases not yet commenced	20 years