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, 2023			$ 19.4	$ 1,547.8	$ (3,308.0)	$ 11,431.5	$ (39.3)
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0.1	15.5
Cost of Shares Repurchased	$ (504.8)	[1]		0.0			(504.8)
Other Comprehensive Income (Loss)	578.3
Net Income	1,430.4					1,430.4
Dividends to Stockholders (per common share: $0.46; $0.42; $1.30; $1.15)						(219.5)
Balance at End of Year at Sep. 30, 2024	10,951.4		19.5	1,563.3	(2,729.7)	12,642.4	(544.1)
Balance at Beginning of Year at Jun. 30, 2024			19.5	1,558.8	(2,846.2)	12,074.6	(342.1)
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0.0	4.5
Cost of Shares Repurchased	(202.0)	[1]		0.0			(202.0)
Other Comprehensive Income (Loss)	116.5				116.5
Net Income	645.7					645.7
Dividends to Stockholders (per common share: $0.46; $0.42; $1.30; $1.15)						(77.9)
Balance at End of Year at Sep. 30, 2024	10,951.4		19.5	1,563.3	(2,729.7)	12,642.4	(544.1)
Balance at Beginning of Year at Dec. 31, 2024	10,961.1		19.5	1,489.6	(2,523.7)	12,914.0	(938.3)
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0.1	15.8
Cost of Shares Repurchased	(759.2)	[1]		(80.3)			(839.5)
Other Comprehensive Income (Loss)	356.4				356.4
Net Income	564.4					564.4
Dividends to Stockholders (per common share: $0.46; $0.42; $1.30; $1.15)						(229.8)
Balance at End of Year at Sep. 30, 2025	10,908.8		19.6	1,585.7	(2,167.3)	13,248.6	(1,777.8)
Balance at Beginning of Year at Jun. 30, 2025			19.6	1,578.4	(2,040.7)	13,287.2	(1,524.5)
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0.0	7.3
Cost of Shares Repurchased	(253.3)	[1]		0.0			(253.3)
Other Comprehensive Income (Loss)	(126.6)				(126.6)
Net Income	39.7					39.7
Dividends to Stockholders (per common share: $0.46; $0.42; $1.30; $1.15)						(78.3)
Balance at End of Year at Sep. 30, 2025	$ 10,908.8		$ 19.6	$ 1,585.7	$ (2,167.3)	$ 13,248.6	$ (1,777.8)

[1] 2Includes $0.9 million and $1.8 million of commissions for the three and nine months ended September 30, 2025, respectively, and a de minimis amount of commissions for the three and nine months ended September 30, 2024. Also includes $2.4 million and $7.4 million of excise tax for the three and nine months ended September 30, 2025, respectively, and $2.0 million and $4.8 million of excise tax for the three and nine months ended September 30, 2024, respectively.