Retirement and Other Benefit Plans (Schedule Of Asset Allocation For Pension Plans Acceptable Range And Target Allocation By Asset Category) (Details)	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2017
Cash and Cash Equivalents [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		2.00%	3.00%
Cash and Cash Equivalents [Member] | Maximum [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	5.00%
Cash and Cash Equivalents [Member] | Minimum [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	0.00%
Cash and Cash Equivalents [Member] | Target Allocation 2019 [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	8211.00%
Return seeking [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		44.00%	62.00%
Return seeking [Member] | Maximum [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	47.00%
Return seeking [Member] | Minimum [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	39.00%
Return seeking [Member] | Target Allocation 2019 [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	37.00%
Hedge Funds, Equity [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		54.00%	35.00%
Hedge Funds, Equity [Member] | Maximum [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	61.00%
Hedge Funds, Equity [Member] | Minimum [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	53.00%
Hedge Funds, Equity [Member] | Target Allocation 2019 [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	63.00%