Supplemental Cash Flow Information (Schedule Of Supplemental Information Relating To The Unaudited Condensed Consolidated Statements Of Cash Flows) (Details) - USD ($) $ in Millions		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019
Cash paid for or (received from):
Interest expense	[1]	$ 42	$ 42
Interest and dividend income		(1)	(2)
Income taxes, net of refunds		$ (15)	17
Interest rate swap agreement termination fee			$ 12

[1] For the six months ended June 30, 2019, excludes $12 million received in connection with our partial terminations of the then-existing interest rate swap.