Retirement Plans (Schedule Of Net Periodic Benefit Cost (Credit) For Pension And Postretirement Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Settlement loss - net periodic benefit cost (credit)	$ 1	$ 1	$ 3
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	10
Net gain (loss) in AOCI expected to be recognized in next year	(17)
Defined Benefit Plan, Benefit Obligation	140	138	154
Interest cost	5	6	6
Expected return on plan assets	(9)	(11)	(11)
Defined Benefit Plan, Amortization of Gain (Loss)	0	1	4
Defined Benefit Plan, Actuarial Net (Gains) Losses	8	(10)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	11	12
Defined Benefit Plan, Plan Assets, Amount	171	157	168
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	25	1
Defined Benefit Plan, Plan Assets, Contributions by Employer	0	0
Defined Benefit Plan, Funded (Unfunded) Status of Plan	31	19
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	31	19
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(3)	(3)	2
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax	(17)	(27)
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	9
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	9
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	9
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	9
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	39
Supplemental Employee Retirement Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	2
Net gain (loss) in AOCI expected to be recognized in next year	0
Defined Benefit Plan, Benefit Obligation	8	9	10
Interest cost	0	0	1
Expected return on plan assets	0	0	0
Defined Benefit Plan, Amortization of Gain (Loss)	0	0	0
Defined Benefit Plan, Actuarial Net (Gains) Losses	0	0
Defined Benefit Plan, Benefit Obligation, Benefits Paid	1	1
Defined Benefit Plan, Plan Assets, Amount	0	0	0
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	0	0
Defined Benefit Plan, Plan Assets, Contributions by Employer	1	1
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(8)	(9)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(8)	(9)
Settlement loss - net periodic benefit cost (credit)	0	0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	0	0	1
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax	(2)	(2)
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	1
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	1
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	1
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	1
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	2
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	0
Net gain (loss) in AOCI expected to be recognized in next year	0
Defined Benefit Plan, Benefit Obligation	1	1	1
Interest cost	0	0	0
Expected return on plan assets	0	0	0
Defined Benefit Plan, Amortization of Gain (Loss)	0	0	0
Defined Benefit Plan, Actuarial Net (Gains) Losses	0	0
Defined Benefit Plan, Benefit Obligation, Benefits Paid	0	0
Defined Benefit Plan, Plan Assets, Amount	0	0	0
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	0	0
Defined Benefit Plan, Plan Assets, Contributions by Employer	0	0
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(1)	(1)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(1)	(1)
Settlement loss - net periodic benefit cost (credit)	0	0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	0	0	$ 0
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax	0	$ 0
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	0
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	0
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	0
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	0
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	$ 0