Discontinued Operations (Schedule Of Cash Flows Of Discontinued Operations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash paid for income taxes	$ 4	$ 25	$ 52
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation		4	11
Amortization	1	4	11
Cash paid for income taxes	372
Capital expenditures	$ (2)	$ (4)	$ (20)