CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY (UNAUDITED) - USD ($) shares in Millions, $ in Millions		Total	Total Moody's Shareholders' Equity	Common Stock	Capital Surplus	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss	Non- Controlling Interests
Beginning Balance (in shares) at Dec. 31, 2020				342.9			155.8
Beginning Balance at Dec. 31, 2020		$ 1,763	$ 1,569	$ 3	$ 735	$ 11,011	$ (9,748)	$ (432)	$ 194
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income		736	736			736
Dividends		(116)	(115)			(115)			(1)
Stock-based compensation		45	45		45
Shares issued for stock-based compensation plans at average cost, net		(65)	(65)		(41)		$ (24)
Shares issued for stock-based compensation plans at average cost, net (in shares)							0.6
Treasury shares repurchased (in shares)							(0.5)
Treasury shares repurchased		(132)	(132)				$ (132)
Accelerated Share Repurchase pending final settlement		0
Currency translation adjustment, net of net investment hedge activity (net of tax)		(9)	(11)					(11)	2
Net actuarial gains and prior service cost (net of tax)		0
Amortization of prior service costs and actuarial losses		2	2					2
Net realized and unrealized gain on cash flow hedges (net of tax)		1	1					1
Ending Balance (in shares) at Mar. 31, 2021				342.9			155.7
Ending Balance at Mar. 31, 2021		2,225	2,030	$ 3	739	11,632	$ (9,904)	(440)	195
Beginning Balance (in shares) at Dec. 31, 2021				342.9			157.3
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		498	498			498
Dividends		(129)	(128)			(128)			(1)
Stock-based compensation		46	46		46
Shares issued for stock-based compensation plans at average cost, net		(74)	(74)		(42)		$ (32)
Shares issued for stock-based compensation plans at average cost, net (in shares)							0.5
Shares issued as consideration to acquire kompany	[1]	44	44		35		$ 9
Shares issued as consideration to acquire kompany (shares)	[1]						0.1
Treasury shares repurchased (in shares)							(1.7)
Treasury shares repurchased		(560)	(560)				$ (560)
Accelerated Share Repurchase pending final settlement		(98)	(98)		(98)
Currency translation adjustment, net of net investment hedge activity (net of tax)		(60)	(60)					(60)	0
Net actuarial gains and prior service cost (net of tax)		(2)	(2)					(2)
Amortization of prior service costs and actuarial losses		0
Net realized and unrealized gain on cash flow hedges (net of tax)		1	1					1
Ending Balance (in shares) at Mar. 31, 2022				342.9			158.4
Ending Balance at Mar. 31, 2022		$ 2,582	$ 2,394	$ 3	$ 826	$ 13,132	$ (11,096)	$ (471)	$ 188

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