Capital Stock (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Percent of stock owned by active and retired employees	100.00%
Common stock stated value per share	$ 20.00	$ 20.00
Cash dvidends	$ 137.2	$ 90.7	$ 107.2
Common stock, subscriptions ( in shares)	1,056,109
Common shares subscribed (in dollars)	$ 21.1
Common stock dividend declared, percent			5.00%
Preferred stock shares authorized	10,000,000	10,000,000
Preferred stock par or stated value per share (USD per share)	$ 0.01	$ 0.01
Preferred stock outstanding (in shares)	0	0
2017 Voting Trust | Common Stock
Class of Stock [Line Items]
Percent of shares held in voting trust	83.00%