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Stock-Based Compensation Plans (Schedule of Stock Option Activity, Additional Disclosures) (Details) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share-based Payment Arrangement [Abstract]      
Intrinsic value of options exercised $ 0 $ 0 $ 0
Weighted-average fair value of options exercised $ 0 $ 0 $ 0