Maximum percentage of a participant's pay subject to the matching contribution for the Profit Participation Plan.

No definition available.

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- Definition

Minimum age for retiree to enroll in Company's retiree medical plan.

+ References

No definition available.

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- Definition

The interest rate used to adjust for the time value of money for the plan.

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- Definition

An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 30
-Glossary Expected Long-Term Rate of Return on Plan Assets
-URI http://asc.fasb.org/extlink&oid=6512013

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- Definition

The increase in the fair value of plan assets from contributions made by the employer.

+ References

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- Definition

Target allocation of investments of this type to total plan assets presented on a weighted average basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

Target allocation maximum percentage of investments of this type to total plan assets presented on a weighted average basis.

+ References

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- Definition

Target allocation minimum percentage of investments of this type to total plan assets presented on a weighted average basis.

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-Publisher FASB
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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.

+ References

No definition available.

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- Definition

Amount of employer's best estimate of contributions expected to be paid to the plan during the next fiscal year beginning after the date of the latest statement of financial position.

+ References

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- Definition

The amount of the cost recognized during the period for defined contribution plans.

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- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

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- Definition

Dividends paid on stock held by an employee stock ownership plan.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
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-Paragraph 1
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- Definition

Sum of the allocated, committed-to-be-released and suspense shares of the entity held by the plan.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

The amount of pension benefit costs recognized during the period for (1) defined benefit plans and (2) defined contribution plans. For defined benefit plans, pension expense includes the following components: service cost, interest cost, expected return on plan assets, gain (loss) on plan assets, prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments. For defined contribution plans, the pension expense generally equals the firm's contribution to employees' accounts (if the firm contributes) during the period.

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Pension and Other Retirement Benefits - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected rate of return		5.80%
Minimum retirees age		65
Dividends paid on ESOP		$ 0.7	$ 0.6
Moody's share held in ESOP		488,000	490,000
U.S. Defined Contribution Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined contribution compensation expense		$ 21.1	$ 26.8	$ 18.8
International Defined Contribution Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined contribution compensation expense		$ 26.7	30.6	19.7
Defined Contribution Plan [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Employee contribution percentage of employee contribution in participation		50.00%
Maximum employee contribution in profit participation plan		3.00%
Funded Pension Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions		$ 21.6	33.7
Anticipated contribution to plans		22.0
Unfunded Pension Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions		2.7	3.6
Anticipated contribution to plans		4.4
Other Retirement Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions		0.4	$ 0.2
Anticipated contribution to plans		$ 1.0
Discount rate		4.00%	3.65%
Foreign Pension Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension expense		$ 0.6	$ 0.6	$ 0.6
2016 [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected rate of return	6.10%
Equity Securities [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan asset, target asset allocation percentage		60.00%
Equity Securities [Member] \| Revised Investment Policy [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan asset, target asset allocation percentage		53.00%
Plan asset, target asset allocation percentage, minimum		48.00%
Plan asset, target asset allocation percentage, maximum		58.00%
Fixed Income Securities [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan asset, target asset allocation percentage		33.00%
Fixed Income Securities [Member] \| Revised Investment Policy [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan asset, target asset allocation percentage		40.00%
Plan asset, target asset allocation percentage, minimum		35.00%
Plan asset, target asset allocation percentage, maximum		45.00%
Other Investments [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan asset, target asset allocation percentage		7.00%
Other Investments [Member] \| Revised Investment Policy [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan asset, target asset allocation percentage		7.00%
Plan asset, target asset allocation percentage, minimum		4.00%
Plan asset, target asset allocation percentage, maximum		10.00%