Net Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Numerator:
Net earnings	$ 491.6	$ 506.8	$ 502.9
Distributed and allocated undistributed net earnings to unvested restricted stockholders	0.0	0.0	(0.2)
Net Income (Loss) Available to Common Stockholders, Basic, Total	$ 491.6	$ 506.8	$ 502.7
Denominator
Weighted average number of common shares outstanding - basic (in shares)	145,900,000	150,900,000	155,200,000
Basic net earnings per common share
Basic net earnings per common share (in dollars per share)	$ 3.37	$ 3.36	$ 3.24
Numerator:
Net earnings available to common stockholders	$ 491.6	$ 506.8	$ 502.7
Denominator:
Weighted average number of common shares outstanding - basic (in shares)	145,900,000	150,900,000	155,200,000
Effect of dilutive stock shares and units (in shares)	1,500,000	1,500,000	800,000
Weighted average number of common shares outstanding - diluted under treasury stock (in shares)	147,400,000	152,400,000	156,000,000.0
Diluted net earnings per common share - (in dollars per share)	$ 3.33	$ 3.32	$ 3.22
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Diluted (in shares)	147,400,000	152,400,000	156,000,000.0
PSU Awards
Denominator:
Weighted average number of common shares outstanding - diluted under treasury stock (in shares)	800,000	600,000	0
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Diluted (in shares)	800,000	600,000	0
SLO Awards
Denominator:
Weighted average number of common shares outstanding - diluted under treasury stock (in shares)	0	0	0
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Diluted (in shares)	0	0	0