CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total		Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Retained Earnings	Treasury Stock, Common
Balance at Beginning of Year at Dec. 31, 2022			$ 30.8	$ 2,441.0	$ (3,448.3)	$ 13,141.3	$ (3,429.8)
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0.1	9.2
Other Comprehensive Income	$ 286.0				286.0
Net Income	358.3					358.3
Dividends to Stockholders (per common share: $0.365; $0.330)						(69.2)
Cost of Shares Repurchased	(53.6)	[1]					(53.6)
Balance at End of Year at Mar. 31, 2023	9,247.4		30.9	2,431.8	(3,162.3)	13,430.4	(3,483.4)
Balance at Beginning of Year at Dec. 31, 2023	9,651.4		19.4	1,547.8	(3,308.0)	11,431.5	(39.3)
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0.1	(0.4)
Other Comprehensive Income	368.0				368.0
Net Income	395.2					395.2
Dividends to Stockholders (per common share: $0.365; $0.330)						(72.6)
Cost of Shares Repurchased	(123.0)	[1]					(123.0)
Balance at End of Year at Mar. 31, 2024	$ 10,219.5		$ 19.5	$ 1,548.2	$ (2,940.0)	$ 11,754.1	$ (162.3)

[1] 1Includes a de minimis amount of commissions for the three months ended March 31, 2024 and 2023. Also includes $1.1 million and $0.1 million of excise taxes for the three months ended March 31, 2024 and 2023, respectively.