Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Actual Plan Asset Allocations of the Pension Benefit Plans' Assets) (Details) - Pension Plans [Member]	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Actual Plan Asset Allocations	100.00%	100.00%
Domestic and International Equities [Member]
Defined Benefit Plan, Actual Plan Asset Allocations	30.00%	37.00%
Fixed Income Securities [Member]
Defined Benefit Plan, Actual Plan Asset Allocations	58.00%	47.00%
Other (Includes Cash and Cash Equivalents and Alternatives) [Member]
Defined Benefit Plan, Actual Plan Asset Allocations	12.00%	16.00%