CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net Income	$ 498	$ 736
Other Comprehensive Income (Loss):
Foreign currency translation adjustment - Pre Tax	(108)	(147)
Foreign currency translation adjustments - Tax	1	6
Foreign currency translation adjustments - Net of Tax	(107)	(141)
Net gains on net investment hedges - Pre Tax	64	175
Net gains on net investment hedges - Tax	(17)	(42)
Net gains on net investment hedges - Net of Tax	47	133
Net investment hedges - reclassification of gains included in net income - Pre Tax	0	(1)
Net investment hedges - reclassification of gains included in net income - Tax	0	0
Net investment hedges - reclassification of gains included in net income - Net of Tax	0	(1)
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:
Amortization of actuarial losses and prior service costs included in net income - Pre Tax	0	3
Amortization of actuarial losses and prior service costs included in net income - Tax	0	(1)
Amortization of actuarial losses and prior service costs included in net income - Net of Tax	0	2
Net actuarial losses and prior service costs - Pre Tax	(3)	0
Net actuarial losses and prior service costs - Tax	1	0
Net actuarial losses and prior service costs - Net of Tax	(2)	0
Total other comprehensive (loss) income - Pre Tax	(46)	31
Total other comprehensive (loss) income - Tax	(15)	(37)
Total other comprehensive (loss) income - Net of Tax	(61)	(6)
Comprehensive income	437	730
Less: comprehensive income attributable to noncontrolling interests	0	2
Comprehensive Income Attributable to Moody's	$ 437	$ 728