Share-Based Compensation (Assumptions Used) (Details) - $ / shares	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
Share price at grant (in USD per share)	$ 527.49	$ 290.15
Share price at exercise (in USD per share)	$ 531.24	$ 290.15
Expected stock price volatility	30.00%	27.00%
Expected term, in years	6 years 2 months 12 days	6 years
Risk-free interest rate	0.70%	1.40%
Weighted average fair value of options granted (in USD per share)	$ 169.13	$ 84.60

Share Price, Exercise

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- Definition

Share Price, Grant

+ References

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- References

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

+ References

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- Definition

Rate of weighted-average expected volatility for award under share-based payment arrangement.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=122041274&loc=d3e301413-122809

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