Long-Term Debt And Lease Obligation Long-Term Debt and Lease Obligation Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	5 years
Total lease liability	$ 57	$ 57
Interest Costs Incurred	$ 3
Maximum
Lessee, Lease, Description [Line Items]
Lessee, Finance Lease, Term of Contract	6 years
Minimum
Lessee, Lease, Description [Line Items]
Lessee, Finance Lease, Term of Contract	3 years