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Income Taxes - Additional Information (Detail) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023
Income Tax Disclosure [Abstract] |  |  |  |
Effective tax rate (percent) | 23.10% | 23.40% | 23.20% | 12.00%
Excess tax benefits from stock compensation |  |  | $ 19 |
Unrecognized tax benefits, period increase (decrease), net of federal tax | $ 5 |  | $ 11 |
Income tax examination, description |  |  | Moody’s is subject to U.S. federal income tax as well as income tax in various state, local and foreign jurisdictions. The Company’s U.S. federal income tax returns for 2019 through 2020 are currently under examination and 2021 through 2022 remain open to examination. The Company’s New York City tax returns for 2018 through 2022 are currently under examination. The Company’s U.K. tax returns for 2017 through 2022 remain open to examination. |

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