CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY (UNAUDITED) (Parenthetical) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Statement of Stockholders' Equity [Abstract]
Dividends declared per share attributable to Moody's common shareholders (in USD per share)	$ 0.56	$ 0.50
Currency translation adjustment, tax	$ 25	$ 7
Amortization of actuarial losses and prior service costs included in net income, tax	1	$ 1
Net realized and unrealized gain on cash flow hedges, tax	$ 12

Aggregate dividends declared during the period for each share of common stock outstanding.

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Amount, after reclassification, of tax expense (benefit) for gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Amount of tax expense (benefit), after reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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