Retirement And Other Employee Benefits (Weighted Average Assumptions Used To Determine Projected Benefit Obligation) (Details)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits | Qualified Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate			4.55%
Pension Benefits | Non-Qualified Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.49%	3.89%	4.25%
Pension Benefits | 2017 Plan 1 | Qualified Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.67%	4.31%
Pension Benefits | 2017 Plan 2 | Qualified Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.67%	4.15%
Retirement Health Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.63%	4.21%	4.53%