Derivatives (Schedule Of Interest Rate Swaps) (Details) - Cash Flow Hedging [Member] - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Jan. 17, 2019	May 22, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount	$ 200	$ 200	$ 50	$ 150
Weighted average fixed pay rate	2.83%	2.83%
Weighted average 3-month LIBOR receive rate	1.82%	2.04%
Weighted average maturity	1 year 9 months 21 days	2 years 21 days