Short-Term and Long-Term Debt - Financial Covenants (Details)	Dec. 31, 2020
Debt Instrument [Line Items]
Actual Indebtedness to Total Capitalization Ratio	0.40
Financial Covenants [Abstract]
Actual Indebtedness to Total Capitalization Ratio	0.40
Maximum [Member]
Debt Instrument [Line Items]
Allowed Indebtedness to Total Capitalization Ratio	0.65
Financial Covenants [Abstract]
Allowed Indebtedness to Total Capitalization Ratio	0.65