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Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Long-Term Asset Allocation Ranges) (Details) - Pension Plans [Member]
Dec. 31, 2019
Global Equities [Member] | Minimum [Member]  
Long-term asset allocation 26.00%
Global Equities [Member] | Maximum [Member]  
Long-term asset allocation 38.00%
Fixed Income Securities [Member] | Minimum [Member]  
Long-term asset allocation 44.00%
Fixed Income Securities [Member] | Maximum [Member]  
Long-term asset allocation 64.00%
Alternative Securities [Member] | Minimum [Member]  
Long-term asset allocation 10.00%
Alternative Securities [Member] | Maximum [Member]  
Long-term asset allocation 16.00%
Cash and Cash Equivalents [Member] | Minimum [Member]  
Long-term asset allocation 0.00%
Cash and Cash Equivalents [Member] | Maximum [Member]  
Long-term asset allocation 5.00%