Share-Based Compensation Plans (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Maximum of shares available for issuance	14,700,000
Shares available for grant	10,157,026
Share-based employee compensation expense	$ 84.7	$ 70.8	$ 72.5
Unamortized share-based employee compensation, amortization period	5 years
Unamortized share-based employee compensation	$ 198.2
Excess tax (deficiency) benefit from share-based compensation	$ 2.9	$ (3.6)
Option Activity [Roll Forward]
January 1	768,750	866,000	988,050
Granted	4,025,000	0	0
Exercised	(60,000)	0	(57,300)
Forfeited	(44,500)	(97,250)	(64,750)
December 31	4,689,250	768,750	866,000
Exercisable December 31	689,250	768,750	60,000
January 1, Weighted Average Exercise Price	$ 83.65	$ 83.80	$ 80.37
Granted, Weighted Average Exercise Price	72.47	0	0
Exercised, Weighted Average Exercise Price	60.17	0	23.40
Forfeited, Weighted Average Exercise Price	77.93	84.94	84.94
December 31, Weighted Average Exercise Price	74.30	83.65	83.80
Exercisable December 31, Weighted Average Exercise Price	$ 84.94	$ 83.65	$ 68.42
Options Outstanding and Exercisable [Abstract]
Options Outstanding, Shares	4,689,250
Options Exercisable, Shares	689,250
Black-Scholes Assumptions and Weighted Average Fair Value Per Share for Options Granted [Abstract]
Weighted average fair value per option granted	$ 8.47
Expected life	8 years
Risk free interest rate	1.40%
Expected volatility	23.00%
Dividend yield	4.60%
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	4,000,000
Options Outstanding, Weighted Average Remaining Contractual Life	9 years 10 months 24 days
Options Outstanding, Weighted Average Exercise Price	$ 72.47
Options Exercisable, Shares	0
Options Exercisable, Weighted Average Exercise Price	$ 0
Exercise Price Range - $84.00 to $85.00
Options Outstanding and Exercisable [Abstract]
Range of Exercise Prices, lower range limit	84.00
Range of Exercise Prices, upper range limit	$ 85.00
Options Outstanding, Shares	689,250
Options Outstanding, Weighted Average Remaining Contractual Life	1 year 3 months 18 days
Options Outstanding, Weighted Average Exercise Price	$ 84.94
Options Exercisable, Shares	689,250
Options Exercisable, Weighted Average Exercise Price	$ 84.94
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	3,012,988	2,547,001	2,553,902
Granted	1,017,895	1,511,719	956,135
Vested / Distributed	(899,372)	(874,431)	(798,468)
Forfeited	(198,675)	(171,301)	(164,568)
December 31	2,932,836	3,012,988	2,547,001
Restricted Stock and PRSU Activity, Weighted Average Grant Date Fair Value [Roll Forward]
January 1, Weighted Average Grant Date Fair Value	$ 61.44	$ 70.89
Granted, Weighted Average Grant Date Fair Value	68.99	51.26	$ 72.13
December 31, Weighted Average Grant Date Fair Value	$ 63.09	$ 61.44	$ 70.89
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	550,561	538,134	509,844
Granted	165,911	186,197	181,782
Vested / Distributed	(182,582)	(173,770)	(153,492)
December 31	533,890	550,561	538,134
Restricted Stock and PRSU Activity, Weighted Average Grant Date Fair Value [Roll Forward]
January 1, Weighted Average Grant Date Fair Value	$ 70.17	$ 77.99	$ 80.41
Granted, Weighted Average Grant Date Fair Value	74.89	61.36	75.64
Distributed, Weighted Average Grant Date Fair Value	73.72	84.94	83.23
December 31, Weighted Average Grant Date Fair Value	$ 70.42	$ 70.17	$ 77.99
Employee Stock Purchase Plan [Member]
Shares available for grant	8,434,456
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	73,250	91,605	76,040
Proceeds from issuance of shares	$ 5.0	$ 5.2	$ 5.6