Defined Benefit Pension Plans (Weighted-Average Assumptions Used) (Details) |
9 Months Ended | |
|---|---|---|
Sep. 30, 2020 |
Sep. 30, 2019 |
|
| Qualified Pension Plan [Member] | ||
| Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] | ||
| Equivalent single discount rate for benefit obligations | 3.42% | 4.38% |
| Equivalent single discount rate for service cost | 3.54% | 4.44% |
| Equivalent single discount rate for interest cost | 3.07% | 4.12% |
| Expected long-term return on plan assets | 5.75% | 5.75% |
| Rate of compensation increase | 3.75% | 3.75% |
| Non-Qualified Retirement Plans [Member] | ||
| Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] | ||
| Equivalent single discount rate for benefit obligations | 3.30% | 4.28% |
| Equivalent single discount rate for service cost | 3.62% | 4.48% |
| Equivalent single discount rate for interest cost | 2.93% | 3.98% |
| Rate of compensation increase | 3.75% | 3.75% |