Supplemental Cash Flows (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Leases [Abstract]
Operating cash flows from operating leases	$ 0
Operating cash flows from finance leases	0
Financing cash flows from finance leases	$ 0
Weighted-average remaining lease term - operating leases	20 years
Weighted-average remaining lease term - finance leases	12 years
Weighted-average discount rate - operating leases	5.80%
Weighted-average discount rate - finance leases	14.30%