Retirement Plans (Schedule Of Net Periodic Benefit Cost (Credit) For Pension And Postretirement Plans) (Details) - Pension Plan [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 2	$ 2	$ 4	$ 4
Expected return on plan assets	(3)	(3)	(6)	(6)
Amortization of net actuarial (gain) loss	1	2	2	4
Net periodic benefit cost (credit)	1	1	1	2
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	$ 1	$ 0	$ 1	$ 0