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).

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-Publisher FASB
-Name Accounting Standards Codification
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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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- Definition

The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Gross number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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The number of exercisable share options (fully vested and expected to vest) that may be converted as of the balance sheet date.

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As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are fully vested or expected to vest.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average grant-date fair value of options vested.

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Number of share options (or share units) exercised during the current period.

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Stock-Based Compensation - Summary of Activity in Corporation's Active Stock Plans (Detail) - $ / shares	6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options exercised, Number of Shares	(752,075)	(67,075)
Director deferred stock units outstanding [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance, Number of Shares	53,659
Granted, Number of Units	5,447
Stock Awards Vested and Expected to Vest, Exercisable, Number	(6,098)
Ending Balance, Number of Shares	53,008		53,659
Beginning Balance, Director Deferred, Weighted-Average Grant-Date Fair Value	$ 61.48
Granted, Directors Deferred, Weighted-Average Grant-Date Fair Value	95.37
Ending Balance, Director Deferred, Weighted-Average Grant-Date Fair Value	64.87		$ 61.48
Stock Award Vested, Weighted Average Grant Date Fair Value	$ 62.29
Non-Vested Stock Awards/Stock Units Outstanding [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance, Number of Shares	256,850
Stock Awards Vested and Expected to Vest, Exercisable, Number	(1,730)
Ending Balance, Number of Shares	254,250		256,850
Forfeited/expired, Number of Shares	(870)
Stock Award Vested, Weighted Average Grant Date Fair Value	$ 76.07
Beginning Balance, Weighted-Average Grant-Date Fair Value	73.43
Ending Balance, Weighted-Average Grant-Date Fair Value	73.40		$ 73.43
Forfeited/expired, Weighted-Average Exercise Price	$ 76.07
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Number of Units			29,240
Stock Options Outstanding [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance, Number of Shares	4,089,028
Ending Balance, Number of Shares	3,311,289		4,089,028
Stock options exercised, Number of Shares	(744,247)
Forfeited/expired, Number of Shares	(33,492)
Beginning Balance, Weighted-Average Exercise Price	$ 62.67
Stock options exercised, Weighted-Average Exercise Price	59.32
Forfeited/expired, Weighted-Average Exercise Price	69.35
Ending Balance, Weighted-Average Exercise Price	$ 63.36		$ 62.67
Maximum [Member] \| Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance, Number of Shares	43,860
Ending Balance, Number of Shares	43,860		43,860
Beginning Balance, Weighted-Average Grant-Date Fair Value	$ 69.70
Ending Balance, Weighted-Average Grant-Date Fair Value	$ 69.70		$ 69.70