Stock-based Compensation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Share-based Payment activity, additional disclosures [Abstract]
Amortization of Deferred Compensation	$ 13.5						$ 59.5	$ 69.7
Restricted Stock Units (RSUs)
Share-based Payment activity [Roll Forward]
Unvested at beginning of period (in shares)	1,003,400		841,300	939,000.0		912,400	841,300	912,400
Granted (in shares)	175,300			59,900			520,500	248,400
Vested (in shares)	(66,400)			(203,700)			(227,100)	(355,100)
Forfeited (in shares)	(39,600)			(10,200)			(62,000.0)	(20,700)
Unvested at end of period (in shares)	1,072,700	1,003,400		785,000.0	939,000.0		1,072,700	785,000.0
Performance Shares [Member]
Share-based Payment activity [Roll Forward]
Unvested at beginning of period (in shares)	463,600		567,000.0	576,900		646,000.0	567,000.0	646,000.0
Granted (in shares)	2,400			1,600			185,200	114,600
Vested (in shares)	0			0			(257,200)	(175,100)
Forfeited (in shares)	(4,200)			(10,600)			(33,200)	(17,600)
Unvested at end of period (in shares)	461,800	463,600		567,900	576,900		461,800	567,900
Share-based Payment Arrangement [Member]
Share-based Payment activity [Roll Forward]
Unvested at beginning of period (in shares)	1,467,000		1,408,300	1,515,900		1,558,400	1,408,300	1,558,400
Granted (in shares)	177,700			61,500			705,700	363,000.0
Vested (in shares)	(66,400)			(203,700)			(484,300)	(530,200)
Forfeited (in shares)	(43,800)			(20,800)			(95,200)	(38,300)
Unvested at end of period (in shares)	1,534,500	1,467,000		1,352,900	1,515,900		1,534,500	1,352,900
Share-based Payment activity, additional disclosures [Abstract]
Weighted average grant date fair value, beginning of period (in dollars per share)	$ 174.54		$ 170.78	$ 167.23		$ 152.27	$ 170.78	$ 152.27
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	165.96			172.22			143.64	214.90
Weighted average grant date fair value, vested (in dollars per share)	145.97			141.15			120.53	145.10
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	176.43			158.85			161.55	165.51
Weighted average grant date fair value, end of period (in dollars per share)	$ 174.73	$ 174.54		$ 171.51	$ 167.23		$ 174.73	$ 171.51
Weighted average remaining contractual life, unvested shares outstanding	1 year 9 months 10 days	1 year 10 months 6 days	1 year 9 months 14 days	1 year 10 months 6 days	1 year 11 months 23 days	1 year 11 months 26 days	1 year 9 months 10 days	1 year 10 months 6 days
Unamortized deferred compensation cost	$ 99.4						$ 99.4

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
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-Publisher FASB
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Amount of amortization of other deferred costs recognized in the income statement.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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