Stock-Based Compensation - Restricted Stock and RSU Activity (Detail) - $ / shares	1 Months Ended	6 Months Ended
Jan. 31, 2017	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock and RSUs, beginning of period	2,987,588	2,987,588
Restricted Stock and RSUs, Granted		1,032,221
Restricted Stock and RSUs, Converted		(1,294,073)
Restricted Stock and RSUs, Forfeited		(30,438)
Restricted Stock and RSUs, end of period		2,695,298
Weighted-Average Grant Date Fair Value, beginning of period	$ 318.04	$ 318.04
Weighted-Average Grant Date Fair Value, Granted		375.93
Weighted-Average Grant Date Fair Value, Converted		319.78
Weighted-Average Grant Date Fair Value, Forfeited		338.43
Weighted-Average Grant Date Fair Value, end of period		$ 339.14
Performance-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock and RSUs, beginning of period	610,371	610,371
Restricted Stock and RSUs, Granted	293,385	294,584
Restricted Stock and RSUs, Forfeited		(1,430)
Restricted Stock and RSUs, end of period		903,525
Weighted-Average Grant Date Fair Value, beginning of period	$ 315.65	$ 315.65
Weighted-Average Grant Date Fair Value, Granted		375.27
Weighted-Average Grant Date Fair Value, Forfeited		296.12
Weighted-Average Grant Date Fair Value, end of period		$ 335.12
Market Performance-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock and RSUs, beginning of period	803,474	803,474
Restricted Stock and RSUs, Converted		(517,138)
Restricted Stock and RSUs, end of period		286,336
Weighted-Average Grant Date Fair Value, beginning of period	$ 151.20	$ 151.20
Weighted-Average Grant Date Fair Value, Converted		126.76
Weighted-Average Grant Date Fair Value, end of period		$ 195.33

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

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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.

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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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- Definition

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

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- Definition

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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- 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

Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

+ 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 (c)(1)(i)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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