Share-Based Compensation - Schedule Of Estimated Fair Value Of Option Using Black-Scholes Option Pricing Model, Weighted Average Assumptions (Detail) - $ / shares	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
STOCK OPTION PLANS
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk free interest rate	1.10%	1.60%	1.50%
Expected term (years)	4 years 2 months	4 years 3 months 18 days	4 years 3 months 18 days
Volatility (percent)	26.00%	28.00%	31.00%
Weighted average fair value at grant date (usd per share)	$ 141.18	$ 131.47	$ 122.39
EMPLOYEE STOCK PURCHASE PLAN
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk free interest rate	0.60%	0.40%	0.20%
Expected term (years)	1 year 2 months 12 days	1 year 2 months 12 days	1 year 2 months 12 days
Volatility (percent)	30.00%	31.00%	33.00%
Weighted average fair value at grant date (usd per share)	$ 172.71	$ 146.72	$ 124.60
RESTRICTED STOCK UNITS
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value at grant date (usd per share)	$ 553.76	$ 511.92	$ 441.36

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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- Definition

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

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- Definition

Weighted average expected volatility rate of share-based compensation awards.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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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 share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-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=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-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=27013229&loc=d3e301413-122809

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