Earnings Per Common Share (Calculations) (Details) - $ / shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Earnings Per Share, Diluted [Abstract]
Weighted average common shares outstanding	236.0	236.4	235.9	236.5
Effect of dilutive securities:
Stock options	0.6	0.5	0.5	0.7
Other stock compensation plans	0.7	0.7	0.7	0.7
Potentially dilutive common shares	1.3	1.2	1.2	1.4
Adjusted weighted average common shares outstanding	237.3	237.6	237.1	237.9
Dividends per common share (in dollars per share)	$ 0.62	$ 0.59	$ 1.24	$ 1.18
Outstanding stock options excluded from the computation of diluted earnings per share due to their antidilutive effect	0.4	1.0	0.9	0.5