Income Taxes (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Temporary surtax on allocated income	$ 1
January 1, 2018 through December 31, 2019 [Member]
Percentage of surtax	2.50%
January 1, 2020 through December 31, 2021 [Member]
Percentage of surtax	1.50%