XML 23 R9.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Nature of Operations | 9 Months Ended
--- | ---
Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract] |
Nature of Operations | Nature of Operations Marsh & McLennan Companies, Inc. and its consolidated subsidiaries (the "Company"), a global professional services firm, is organized based on the different services that it offers. Under this structure, the Company’s two segments are Risk and Insurance Services and Consulting. The Risk and Insurance Services segment provides risk management services and insurance broking, reinsurance broking and insurance program management services for businesses, public entities, insurance companies, associations, professional services organizations and private clients. The Company conducts business in this segment through Marsh and Guy Carpenter. The Company conducts business in its Consulting segment through Mercer and Oliver Wyman Group. Mercer provides consulting expertise, advice, services and solutions in the areas of health, wealth and career. As of September 30, 2017, Mercer had assets under delegated management of approximately $210 billion worldwide. Oliver Wyman Group provides specialized management and economic and brand consulting services. Acquisitions impacting the Risk and Insurance Services and Consulting segments are discussed in Note 7 to the consolidated financial statements.

X
- Definition The entire disclosure for the nature of an entity's business, major products or services, principal markets including location, and the relative importance of its operations in each business and the basis for the determination, including but not limited to, assets, revenues, or earnings. For an entity that has not commenced principal operations, disclosures about the risks and uncertainties related to the activities in which the entity is currently engaged and an understanding of what those activities are being directed toward. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -URI http://asc.fasb.org/topic&trid=2134479 + Details
Name: | us-gaap_NatureOfOperations
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration