Pension And Other Postretirement Benefits (Schedule Of Allocation Of Plan Assets) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Actual Allocation	100.00%	100.00%
Defined Benefit Plan, Target Allocation Percentage	100 %	100 %
Equity Securities - U.S.
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Actual Allocation	6.00%	5.00%
Equity Securities - International
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Actual Allocation	9.00%	8.00%
Fixed Income Investments
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Actual Allocation	68.00%	71.00%
Hedge Funds
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Actual Allocation	5.00%	5.00%
Private Markets
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Actual Allocation	4.00%	4.00%
Other Investments
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Actual Allocation	8.00%	7.00%
Minimum | Equity Securities - U.S.
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Defined Benefit Plan, Target Allocation Percentage	3	3
Minimum | Equity Securities - International
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Defined Benefit Plan, Target Allocation Percentage	2	3
Minimum | Fixed Income Investments
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Defined Benefit Plan, Target Allocation Percentage	40	38
Minimum | Hedge Funds
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Defined Benefit Plan, Target Allocation Percentage	2	5
Minimum | Private Markets
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Defined Benefit Plan, Target Allocation Percentage	0	3
Minimum | Other Investments
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Defined Benefit Plan, Target Allocation Percentage	0	0
Minimum | Short-term Investments
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Defined Benefit Plan, Target Allocation Percentage	1	0
Maximum | Equity Securities - U.S.
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Defined Benefit Plan, Target Allocation Percentage	10	15
Maximum | Equity Securities - International
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Defined Benefit Plan, Target Allocation Percentage	10	15
Maximum | Fixed Income Investments
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Defined Benefit Plan, Target Allocation Percentage	80	85
Maximum | Hedge Funds
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Defined Benefit Plan, Target Allocation Percentage	8	15
Maximum | Private Markets
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Defined Benefit Plan, Target Allocation Percentage	15	13
Maximum | Other Investments
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Defined Benefit Plan, Target Allocation Percentage	14	10
Maximum | Short-term Investments
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Defined Benefit Plan, Target Allocation Percentage	10	3