CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total		Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock, Common
Balance at Beginning of Year at Dec. 31, 2021			$ 30.7	$ 2,408.1	$ (5,164.6)	$ 11,989.4	$ (3,229.7)
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0.1	9.3
Other Comprehensive Income (Loss)	$ 1,355.1
Net Income	607.7					607.7
Dividends to Stockholders (per common share: $0.330; $0.300; $0.660; $0.600)						(123.4)
Cost of Shares Repurchased	94.9	[1]					94.9
Balance at End of Year at Jun. 30, 2022	7,787.8		30.8	2,417.4	(3,809.5)	12,473.7	(3,324.6)
Balance at Beginning of Year at Mar. 31, 2022			30.8	2,395.8	(4,438.5)	12,166.9	(3,267.2)
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0.0	21.6
Other Comprehensive Income (Loss)	629.0				629.0
Net Income	367.3					367.3
Dividends to Stockholders (per common share: $0.330; $0.300; $0.660; $0.600)						(60.5)
Cost of Shares Repurchased	57.4	[1]					57.4
Balance at End of Year at Jun. 30, 2022	7,787.8		30.8	2,417.4	(3,809.5)	12,473.7	(3,324.6)
Balance at Beginning of Year at Dec. 31, 2022	8,735.0		30.8	2,441.0	(3,448.3)	13,141.3	(3,429.8)
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0.1	3.9
Other Comprehensive Income (Loss)	(9.3)				(9.3)
Net Income	751.2					751.2
Dividends to Stockholders (per common share: $0.330; $0.300; $0.660; $0.600)						(134.4)
Cost of Shares Repurchased	100.6	[1]					100.6
Balance at End of Year at Jun. 30, 2023	9,245.9		30.9	2,444.9	(3,457.6)	13,758.1	(3,530.4)
Balance at Beginning of Year at Mar. 31, 2023			30.9	2,431.8	(3,162.3)	13,430.4	(3,483.4)
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0.0	13.1
Other Comprehensive Income (Loss)	(295.3)				(295.3)
Net Income	392.9					392.9
Dividends to Stockholders (per common share: $0.330; $0.300; $0.660; $0.600)						(65.2)
Cost of Shares Repurchased	47.0	[1]					47.0
Balance at End of Year at Jun. 30, 2023	$ 9,245.9		$ 30.9	$ 2,444.9	$ (3,457.6)	$ 13,758.1	$ (3,530.4)

[1] 1Includes $0.1 million of commissions for the three and six months ended June 30, 2023 and $0.1 million of commission for the three and six months ended June 30, 2022. There was $0.4 million and $0.5 million of excise tax for the three and six months ended June 30, 2023, respectively. There were no excise taxes during the three and six months ended June 30, 2022.