XML 42 R11.htm IDEA: XBRL DOCUMENT
v3.25.1

Fiduciary Assets and Liabilities | 3 Months Ended
--- | ---
Mar. 31, 2025
Fiduciary Assets And Liabilities [Abstract] |
Fiduciary Assets and Liabilities | Fiduciary Assets and Liabilities The Company, in its capacity as an insurance broker or agent, generally collects premiums from insureds and after deducting its commissions, remits the premiums to the respective insurance underwriters. The Company also collects claims or refunds from underwriters on behalf of insureds. Unremitted insurance premiums and claims proceeds are held by the Company in a fiduciary capacity. The Company's fiduciary assets primarily include bank or short-term time deposits and liquid money market funds, classified as cash and cash equivalents. Since cash and cash equivalents held in a fiduciary capacity are not available for corporate use, they are shown separately in the consolidated balance sheets as cash and cash equivalents held in a fiduciary capacity, with a corresponding amount in current liabilities. Risk and Insurance Services revenue includes interest on fiduciary assets of $103 million and $122 million for the three months ended March 31, 2025 and 2024, respectively. Net uncollected premiums and claims and the related payables were $16.3 billion at March 31, 2025, and $15.1 billion at December 31, 2024. The Company is not a principal to the contracts under which the right to receive premiums or the right to receive reimbursement of insured losses arises. Accordingly, net uncollected premiums and claims and the related payables are not assets and liabilities of the Company and are not included in the accompanying consolidated balance sheets. In certain instances, the Company advances premiums, refunds or claims to insurance underwriters or insureds prior to collection. These advances are made from corporate funds and are reflected in the accompanying consolidated balance sheets as receivables.

X
- Definition Fiduciary Assets And Liabilities [Abstract] + References No definition available. + Details
Name: | mmc_FiduciaryAssetsAndLiabilitiesAbstract
Namespace Prefix: | mmc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Describes a general nature of fiduciary assets and liabilities related to and how they are recorded. + References No definition available. + Details
Name: | mmc_FiduciaryAssetsAndLiabilitiesTextBlock
Namespace Prefix: | mmc_
Data Type: | dtr-types1:textBlockItemType
Balance Type: | na
Period Type: | duration