Leases - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Lessee, Lease, Description [Line Items]
Operating lease term	9 years
Operating lease renewal term	10 years
Operating leases, weighted average remaining lease term	4 years
Finance lease renewal term	25 years
Finance leases, weighted average remaining lease term	16 years
Operating leases, weighted average discount rate	5.60%
Finance leases, weighted average discount rate	6.50%
Rent expense		$ 62	$ 75
Minimum
Lessee, Lease, Description [Line Items]
Finance lease term	2 years
Maximum
Lessee, Lease, Description [Line Items]
Finance lease term	19 years