Supplemental Cash Flow Information (Schedule Of Supplemental Information Relating To The Unaudited Condensed Consolidated Statements Of Cash Flows) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Cash paid for or (received from):
Interest expense	[1]	$ 19	$ 30
Interest and dividend income		(1)
Income taxes, net of refunds		1
Interest rate swap agreement termination fee		$ 11

[1] For the three months ended March 31, 2019, excludes $11 million received in connection with the partial termination of the interest rate swap.