Pension Plans (Summary of Target Allocations and Invested Asset Allocations) (Details)	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Type [Extensible List]	us-gaap:PensionPlansDefinedBenefitMember	us-gaap:PensionPlansDefinedBenefitMember
Defined Benefit Plan, Sponsor Location [Extensible List]	country:US	country:US
Target allocations, fixed and equity securities	100.00%
Actual invested asset allocations, fixed and equity securities	100.00%	100.00%
Fixed Maturities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations, fixed and equity securities	88.00%
Actual invested asset allocations, fixed and equity securities	87.00%	88.00%
Money Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations, fixed and equity securities	2.00%
Actual invested asset allocations, fixed and equity securities	3.00%	2.00%
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations, fixed and equity securities	90.00%
Actual invested asset allocations, fixed and equity securities	90.00%	90.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations, fixed and equity securities	10.00%
Actual invested asset allocations, fixed and equity securities	10.00%	10.00%