Long-Term Debt (Schedule Of Interest Rate Swap Agreements) (Details) - Interest Rate Swap Contract [Member] - USD ($) $ in Millions	1 Months Ended	6 Months Ended		9 Months Ended				12 Months Ended
	Nov. 30, 2019	Dec. 31, 2019		Sep. 30, 2020		Sep. 30, 2019		Dec. 31, 2019		Nov. 05, 2019	Dec. 31, 2018	[1]
Derivative [Line Items]
Balance at the beginning of the period				$ 550		$ 650		$ 650
Terminated	$ (171)	$ (171)		(4)		(479)
Entered into effect		550
Balance at the end of the period		$ 550		$ 546		$ 171		$ 550
Weighted Average Fixed Rate (as a percent)		1.615%	[1]	1.615%	[1]	1.493%	[1]	1.615%	[1]	1.615%	1.493%

[1] Before the application of the applicable borrowing margin.