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	24.2
Other Comprehensive Income	$ 1,553.6
Net Income	1,118.0					1,118.0
Dividends to Stockholders (per common share: $0.365; $0.330; $1.025; $0.930)						(189.5)
Cost of Shares Repurchased	137.5	[1]					137.5
Balance at End of Year at Sep. 30, 2022	8,402.8		30.8	2,432.3	(3,611.0)	12,917.9	(3,367.2)
Balance at Beginning of Year at Jun. 30, 2022			30.8	2,417.4	(3,809.5)	12,473.7	(3,324.6)
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0.0	14.9
Other Comprehensive Income	198.5				198.5
Net Income	510.3					510.3
Dividends to Stockholders (per common share: $0.365; $0.330; $1.025; $0.930)						(66.1)
Cost of Shares Repurchased	42.6	[1]					42.6
Balance at End of Year at Sep. 30, 2022	8,402.8		30.8	2,432.3	(3,611.0)	12,917.9	(3,367.2)
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	13.3
Other Comprehensive Income	297.7				297.7
Net Income	953.2					953.2
Dividends to Stockholders (per common share: $0.365; $0.330; $1.025; $0.930)						(205.8)
Cost of Shares Repurchased	175.4	[1]					175.4
Balance at End of Year at Sep. 30, 2023	9,618.1		30.9	2,454.3	(3,150.6)	13,888.7	(3,605.2)
Balance at Beginning of Year at Jun. 30, 2023			30.9	2,444.9	(3,457.6)	13,758.1	(3,530.4)
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0.0	9.4
Other Comprehensive Income	307.0				307.0
Net Income	202.0					202.0
Dividends to Stockholders (per common share: $0.365; $0.330; $1.025; $0.930)						(71.4)
Cost of Shares Repurchased	74.8	[1]					74.8
Balance at End of Year at Sep. 30, 2023	$ 9,618.1		$ 30.9	$ 2,454.3	$ (3,150.6)	$ 13,888.7	$ (3,605.2)

[1] 1Includes a de minimis amount and $0.1 million of commissions for the three and nine months ended September 30, 2023, respectively, and a de minimis amount and $0.1 million of commissions for the three and nine months ended September 30, 2022, respectively. There was $0.7 million and $1.2 million of excise tax for the three and nine months ended September 30, 2023, respectively. There were no excise taxes during the three and nine months ended September 30, 2022.