Retirement Plans (Schedule Of Net Periodic Benefit Cost (Credit) For Pension And Postretirement Plans) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Interest cost	$ 0	$ 1	$ 2	$ 4
Expected return on plan assets	0	(2)	(3)	(6)
Pension termination-related expense	0	0	28	1
Amortization of net actuarial loss	0	1	0	1
Net periodic cost	$ 0	$ 0	$ 27	$ 0