Share-Based Compensation (Summary of PSU Activity) (Details) - PSUs	9 Months Ended
Sep. 30, 2020 $ / shares shares
One-Year Program
Number of Awards
Unvested balances at beginning of period (in shares) \| shares	317,251
Granted (in shares) \| shares	26,780
Vested (in shares) \| shares	(10,104)
Forfeited (in shares) \| shares	(26,984)
Unvested balances at end of period (in shares) \| shares	306,943
Weighted-Average Grant Date Fair Value
Unvested balances at beginning of period (in dollars per share) \| $ / shares	$ 80.87
Granted (in dollars per share) \| $ / shares	84.17
Vested (in dollars per share) \| $ / shares	75.85
Forfeited (in dollars per share) \| $ / shares	82.27
Unvested balances at end of period (in dollars per share) \| $ / shares	$ 81.20
Three-Year Program
Number of Awards
Unvested balances at beginning of period (in shares) \| shares	797,451
Granted (in shares) \| shares	320,328
Vested (in shares) \| shares	(300,767)
Forfeited (in shares) \| shares	(6,557)
Unvested balances at end of period (in shares) \| shares	810,455
Weighted-Average Grant Date Fair Value
Unvested balances at beginning of period (in dollars per share) \| $ / shares	$ 98.31
Granted (in dollars per share) \| $ / shares	107.42
Vested (in dollars per share) \| $ / shares	81.57
Forfeited (in dollars per share) \| $ / shares	97.33
Unvested balances at end of period (in dollars per share) \| $ / shares	$ 108.13

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

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 (c)(1)(iv)(3)
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- Definition

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

+ References

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-Publisher FASB
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-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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-Name Accounting Standards Codification
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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

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-Name Accounting Standards Codification
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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a 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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-Publisher FASB
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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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-Publisher FASB
-Name Accounting Standards Codification
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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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