Document and Entity Information In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Trading Symbol	MCO
Entity Registrant Name	MOODYS CORP /DE/
Entity Central Index Key	0001059556
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding	202.2