CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Millions		Total	Total Moody's Shareholders' Equity	Common Stock	Capital Surplus	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss	Non- Controlling Interests
Common stock, shares issued beginning balance (in shares) at Dec. 31, 2021				342,900,000
Treasury stock, common, beginning balance (shares) at Dec. 31, 2021							(157,300,000)
Beginning Balance at Dec. 31, 2021		$ 2,916	$ 2,727	$ 3	$ 885	$ 12,762	$ (10,513)	$ (410)	$ 189
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income		1,128	1,128			1,128			0
Dividends		(391)	(389)			(389)			(2)
Stock-based compensation		130	130		130
Shares issued for stock-based compensation plans at average cost, net		(64)	(64)		(34)		$ (30)
Shares issued for stock-based compensation plans at average cost, net (in shares)							600,000
Shares issued as consideration to acquire kompany	[1]	44	44		35		$ 9
Shares issued as consideration to acquire kompany (shares)	[1]						100,000
Treasury shares repurchased		(983)	(983)		(3)		$ (980)
Treasury shares repurchased (in shares)							(3,100,000)
Currency translation adjustment, net of net investment hedge activity (net of tax)		(355)	(343)					(343)	(12)
Net actuarial gains and prior service cost (net of tax)		2	2					2
Amortization of prior service credits/ actuarial gains and settlement credit		2	2					2
Net realized and unrealized gain on cash flow hedges		1	1					1
Common stock, shares issued ending balance (in shares) at Sep. 30, 2022				342,900,000
Treasury stock, common, ending balance (shares) at Sep. 30, 2022							(159,700,000)
Ending Balance at Sep. 30, 2022		2,430	2,255	$ 3	1,013	13,501	$ (11,514)	(748)	175
Common stock, shares issued beginning balance (in shares) at Jun. 30, 2022				342,900,000
Treasury stock, common, beginning balance (shares) at Jun. 30, 2022							(159,400,000)
Beginning Balance at Jun. 30, 2022		2,479	2,294	$ 3	965	13,328	$ (11,403)	(599)	185
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income		303	303			303			0
Dividends		(131)	(130)			(130)			(1)
Stock-based compensation		46	46		46
Shares issued for stock-based compensation plans at average cost, net		3	3		2		$ 1
Shares issued for stock-based compensation plans at average cost, net (in shares)							100,000
Treasury shares repurchased		(112)	(112)		0		$ (112)
Treasury shares repurchased (in shares)							(400,000)
Currency translation adjustment, net of net investment hedge activity (net of tax)		(159)	(150)					(150)	(9)
Net actuarial gains and prior service cost (net of tax)		0
Amortization of prior service credits/ actuarial gains and settlement credit		1	1					1
Common stock, shares issued ending balance (in shares) at Sep. 30, 2022				342,900,000
Treasury stock, common, ending balance (shares) at Sep. 30, 2022							(159,700,000)
Ending Balance at Sep. 30, 2022		$ 2,430	2,255	$ 3	1,013	13,501	$ (11,514)	(748)	175
Common stock, shares issued beginning balance (in shares) at Dec. 31, 2022				342,900,000
Treasury stock, common, beginning balance (shares) at Dec. 31, 2022		(159,702,362)					(159,700,000)
Beginning Balance at Dec. 31, 2022		$ 2,689	2,519	$ 3	1,054	13,618	$ (11,513)	(643)	170
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income		1,268	1,267			1,267			1
Dividends		(434)	(425)			(425)			(9)
Stock-based compensation		143	143		143
Shares issued for stock-based compensation plans at average cost, net		(24)	(24)		(22)		$ (2)
Shares issued for stock-based compensation plans at average cost, net (in shares)							700,000
Treasury shares repurchased		(280)	(280)		0		$ (280)
Treasury shares repurchased (in shares)							(900,000)
Currency translation adjustment, net of net investment hedge activity (net of tax)		(10)	(9)					(9)	(1)
Net actuarial gains and prior service cost (net of tax)		1	1					1
Amortization of prior service credits/ actuarial gains and settlement credit		(2)	(2)					(2)
Net realized and unrealized gain on cash flow hedges		$ 1	1					1
Common stock, shares issued ending balance (in shares) at Sep. 30, 2023				342,900,000
Treasury stock, common, ending balance (shares) at Sep. 30, 2023		(159,895,591)					(159,900,000)
Ending Balance at Sep. 30, 2023		$ 3,352	3,191	$ 3	1,175	14,460	$ (11,795)	(652)	161
Common stock, shares issued beginning balance (in shares) at Jun. 30, 2023				342,900,000
Treasury stock, common, beginning balance (shares) at Jun. 30, 2023							(159,400,000)
Beginning Balance at Jun. 30, 2023		3,312	3,144	$ 3	1,124	14,213	$ (11,626)	(570)	168
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income		390	389			389			1
Dividends		(150)	(142)			(142)			(8)
Stock-based compensation		46	46		46
Shares issued for stock-based compensation plans at average cost, net		7	7		5		$ 2
Shares issued for stock-based compensation plans at average cost, net (in shares)							0
Treasury shares repurchased		(171)	(171)				$ (171)
Treasury shares repurchased (in shares)							(500,000)
Currency translation adjustment, net of net investment hedge activity (net of tax)		(83)	(83)					(83)	0
Net actuarial gains and prior service cost (net of tax)		1	1					1
Amortization of prior service credits/ actuarial gains and settlement credit		(1)	(1)					(1)
Net realized and unrealized gain on cash flow hedges		$ 1	1					1
Common stock, shares issued ending balance (in shares) at Sep. 30, 2023				342,900,000
Treasury stock, common, ending balance (shares) at Sep. 30, 2023		(159,895,591)					(159,900,000)
Ending Balance at Sep. 30, 2023		$ 3,352	$ 3,191	$ 3	$ 1,175	$ 14,460	$ (11,795)	$ (652)	$ 161

[1] Represents a non-cash investing activity relating to the issuance of common stock to fund a portion of the purchase price for kompany