CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net Income	$ 577	$ 501
Foreign Currency Adjustments:
Foreign currency translation adjustments - Pre Tax	(115)	109
Foreign currency translation adjustments - Tax	0	(2)
Foreign currency translation adjustments - Net of Tax	(115)	107
Net gains on net investment hedges - Pre Tax	101	(76)
Net gains on net investment hedges - Tax	(27)	19
Net gains on net investment hedges - Net of Tax	74	(57)
Cash Flow Hedges:
Reclassification of losses included in net income - Pre Tax	1	1
Reclassification of losses included in net income - Tax	0	0
Reclassification of losses included in net income - Net of Tax	1	1
Pension and Other Retirement Benefits:
Net actuarial and prior service costs - Pre Tax	(1)	0
Net actuarial and prior service costs - Tax	0	0
Net actuarial and prior service costs - Net of Tax	(1)	0
Total other comprehensive (loss) income - Pre Tax	(14)	34
Total other comprehensive (loss) income - Tax	(27)	17
Total other comprehensive (loss) income - Net of Tax	(41)	51
Comprehensive income	536	552
Less: comprehensive income (loss) attributable to noncontrolling interests	0	(3)
Comprehensive Income Attributable to Moody's	$ 536	$ 555