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, 2022			342,900,000
Treasury stock, common, beginning balance (shares) at Dec. 31, 2022						(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	501	501			501			0
Dividends	(140)	(140)			(140)			0
Stock-based compensation	47	47		47
Shares issued for stock-based compensation plans at average cost, net	(48)	(48)		(33)		$ (15)
Shares issued for stock-based compensation plans at average cost, net (in shares)						400,000
Treasury shares repurchased	(42)	(42)		0		$ (42)
Treasury shares repurchased (in shares)						(100,000)
Currency translation adjustment, net of net investment hedge activity (net of tax)	50	53					53	(3)
Net actuarial gains and prior service cost (net of tax)	0
Amortization of losses on cash flow hedges	1	1					1
Common stock, shares issued ending balance (in shares) at Mar. 31, 2023			342,900,000
Treasury stock, common, ending balance (shares) at Mar. 31, 2023						(159,400,000)
Ending Balance at Mar. 31, 2023	$ 3,058	2,891	$ 3	1,068	13,979	$ (11,570)	(589)	167
Common stock, shares issued beginning balance (in shares) at Dec. 31, 2023			342,900,000
Treasury stock, common, beginning balance (shares) at Dec. 31, 2023	(160,430,754)					(160,400,000)
Beginning Balance at Dec. 31, 2023	$ 3,476	3,318	$ 3	1,228	14,659	$ (12,005)	(567)	158
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	577	577			577			0
Dividends	(155)	(155)			(155)			0
Stock-based compensation	54	54		54
Shares issued for stock-based compensation plans at average cost, net	(59)	(59)		(30)		$ (29)
Shares issued for stock-based compensation plans at average cost, net (in shares)						400,000
Purchase of noncontrolling interest	2	0						2
Treasury shares repurchased	(119)	(119)		0		$ (119)
Treasury shares repurchased (in shares)						(300,000)
Currency translation adjustment, net of net investment hedge activity (net of tax)	(41)	(41)					(41)	0
Net actuarial gains and prior service cost (net of tax)	(1)	(1)					(1)
Amortization of losses on cash flow hedges	$ 1	1					1
Common stock, shares issued ending balance (in shares) at Mar. 31, 2024			342,900,000
Treasury stock, common, ending balance (shares) at Mar. 31, 2024	(160,292,910)					(160,300,000)
Ending Balance at Mar. 31, 2024	$ 3,735	$ 3,575	$ 3	$ 1,252	$ 15,081	$ (12,153)	$ (608)	$ 160