CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Statement of Comprehensive Income [Abstract]
Net Income	$ 553	$ 377	$ 1,130	$ 878
Foreign Currency Adjustments:
Foreign currency translation adjustments - Pre Tax	(39)	51	(154)	160
Foreign currency translation adjustments - Tax	0	0	0	(2)
Foreign currency translation adjustments - Net of Tax	(39)	51	(154)	158
Net gains on net investment hedges - Pre Tax	43	(37)	144	(113)
Net gains on net investment hedges - Tax	(11)	9	(38)	28
Net gains on net investment hedges - Net of Tax	32	(28)	106	(85)
Cash Flow Hedges:
Reclassification of losses included in net income - Pre Tax	0	0	1	1
Reclassification of losses included in net income - Tax	0	(1)	0	(1)
Reclassification of losses included in net income - Net of Tax	0	(1)	1	0
Pension and Other Retirement Benefits:
Amortization of actuarial gains and prior service credits included in net income - Pre Tax	(1)	(2)	(1)	(2)
Amortization of actuarial gains and prior service credits included in net income, tax expense (benefit)	0	1	0	1
Amortization of actuarial gains and prior service credits included in net income	(1)	(1)	(1)	(1)
Net actuarial and prior service costs - Pre Tax	(2)	0	(3)	0
Net actuarial and prior service costs - Tax	1	0	1	0
Net actuarial and prior service costs - Net of Tax	(1)	0	(2)	0
Total other comprehensive (loss) income - Pre Tax	1	12	(13)	46
Total other comprehensive (loss) income - Tax	(10)	9	(37)	26
Total other comprehensive (loss) income - Net of Tax	(9)	21	(50)	72
Comprehensive income	544	398	1,080	950
Less: comprehensive income attributable to noncontrolling interests	0	2	0	(1)
Comprehensive Income Attributable to Moody's	$ 544	$ 396	$ 1,080	$ 951