Share-Based Compensation Plans (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Maximum of shares available for issuance	14,700,000
Shares available for grant	8,604,042
Share-based employee compensation expense	$ 84.8	$ 81.7	$ 84.7
Unamortized share-based employee compensation, amortization period	5 years
Unamortized share-based employee compensation	$ 195.8
Excess tax benefit from share-based compensation	$ 6.7	$ 1.9
Option Activity [Roll Forward]
January 1	5,127,625	4,689,250	768,750
Granted	0	853,875	4,025,000
Exercised	(413,750)	(157,500)	(60,000)
Forfeited	(149,300)	(258,000)	(44,500)
December 31	4,564,575	5,127,625	4,689,250
Exercisable December 31	0	423,750	689,250
January 1, Weighted Average Exercise Price	$ 72.90	$ 74.30	$ 83.65
Granted, Weighted Average Exercise Price	0	68.88	72.47
Exercised, Weighted Average Exercise Price	84.94	84.94	60.17
Forfeited, Weighted Average Exercise Price	72.99	77.69	77.93
December 31, Weighted Average Exercise Price	71.81	72.90	74.30
Exercisable December 31, Weighted Average Exercise Price	$ 0	84.94	84.94
Options Outstanding and Exercisable [Abstract]
Options Outstanding, Shares	4,564,575
Options Exercisable, Shares	0
Black-Scholes Assumptions and Weighted Average Fair Value Per Share for Options Granted [Abstract]
Weighted average fair value per option granted		$ 12.60	$ 8.47
Expected life			8 years
Risk free interest rate			1.40%
Expected volatility			23.00%
Dividend yield			4.60%
Minimum [Member]
Black-Scholes Assumptions and Weighted Average Fair Value Per Share for Options Granted [Abstract]
Expected life		6 years 6 months
Risk free interest rate		3.00%
Expected volatility		24.50%
Dividend yield		4.20%
Maximum [Member]
Black-Scholes Assumptions and Weighted Average Fair Value Per Share for Options Granted [Abstract]
Expected life		7 years 6 months
Risk free interest rate		3.10%
Expected volatility		24.70%
Dividend yield		4.50%
Exercise Price Range - $63.00 to $64.00
Options Outstanding and Exercisable [Abstract]
Range of Exercise Prices, lower range limit	$ 63.00
Range of Exercise Prices, upper range limit	$ 64.00
Options Outstanding, Shares	50,000
Options Outstanding, Weighted Average Remaining Contractual Life	8 years 6 months
Options Outstanding, Weighted Average Exercise Price	$ 63.21
Options Exercisable, Shares	0
Options Exercisable, Weighted Average Exercise Price	$ 0.00
Exercise Price Range - $69.00 to $70.00
Options Outstanding and Exercisable [Abstract]
Range of Exercise Prices, lower range limit	69.00
Range of Exercise Prices, upper range limit	$ 70.00
Options Outstanding, Shares	789,575
Options Outstanding, Weighted Average Remaining Contractual Life	8 years 7 months 6 days
Options Outstanding, Weighted Average Exercise Price	$ 69.23
Options Exercisable, Shares	0
Options Exercisable, Weighted Average Exercise Price	$ 0.00
Exercise Price Range - $72.00 to $73.00
Options Outstanding and Exercisable [Abstract]
Range of Exercise Prices, lower range limit	72.00
Range of Exercise Prices, upper range limit	$ 73.00
Options Outstanding, Shares	3,725,000
Options Outstanding, Weighted Average Remaining Contractual Life	7 years 10 months 24 days
Options Outstanding, Weighted Average Exercise Price	$ 72.47
Options Exercisable, Shares	0
Options Exercisable, Weighted Average Exercise Price	$ 0.00
Stock Options [Member]
Share-based employee compensation, terms of award	The exercise price of stock option awards cannot be less than 100% of the market price of our common stock on the grant date and have a maximum contractual life of 10 years.
Restricted Stock [Member]
Share-based employee compensation, vesting rights	Generally, restricted shares vest ratably over five years from the grant date provided the employee remains employed by us.
Restricted Stock and PRSU Activity [Roll Forward]
January 1	3,010,343	2,932,836	3,012,988
Granted	1,010,575	1,147,496	1,017,895
Vested / Distributed	(915,245)	(889,736)	(899,372)
Forfeited	(303,376)	(180,253)	(198,675)
December 31	2,802,297	3,010,343	2,932,836
Restricted Stock and PRSU Activity, Weighted Average Grant Date Fair Value [Roll Forward]
January 1, Weighted Average Grant Date Fair Value	$ 61.11	$ 63.09
Granted, Weighted Average Grant Date Fair Value	84.33	59.02	$ 68.99
December 31, Weighted Average Grant Date Fair Value	$ 64.84	$ 61.11	$ 63.09
Performance Restricted Stock Units (PRSUs) [Member]
Share-based employee compensation, vesting rights	Each PRSU represents the right to receive one share of common stock on vesting. The ultimate number of PRSUs received by the employee depends on the Company's average return on equity over a three-year period compared to the average return on equity of a peer group of principal competitors over the same period. The PRSUs vest three years from the grant date.
Restricted Stock and PRSU Activity [Roll Forward]
January 1	570,235	533,890	550,561
Granted	178,998	218,127	165,911
Vested / Distributed	(186,197)	(181,782)	(182,582)
December 31	563,036	570,235	533,890
Restricted Stock and PRSU Activity, Weighted Average Grant Date Fair Value [Roll Forward]
January 1, Weighted Average Grant Date Fair Value	$ 71.19	$ 70.42	$ 70.17
Granted, Weighted Average Grant Date Fair Value	92.18	76.79	74.89
Distributed, Weighted Average Grant Date Fair Value	61.36	75.64	73.72
December 31, Weighted Average Grant Date Fair Value	$ 81.11	$ 71.19	$ 70.42
Employee Stock Purchase Plan [Member]
Shares available for grant	8,296,140
Employee Stock Purchase Plan (ESPP) [Abstract]
Discount from market price	95.00%
Maximum percentage of eligible compensation allowable for purchase	10.00%
Shares issued in period	65,644	72,672	73,250
Proceeds from issuance of shares	$ 5.3	$ 5.2	$ 5.0