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Acquisitions (Allocation Of Acquisition Costs) (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Dec. 31, 2013
Business Acquisition [Line Items]        
Cash $ 20us-gaap_PaymentsToAcquireBusinessesGross $ 331us-gaap_PaymentsToAcquireBusinessesGross    
Estimated fair value of deferred/contingent consideration 12mmc_BusinessCombinationContingentandDeferredConsideration 113mmc_BusinessCombinationContingentandDeferredConsideration    
Total Consideration 32us-gaap_BusinessCombinationConsiderationTransferred1 444us-gaap_BusinessCombinationConsiderationTransferred1    
Allocation of purchase price:        
Goodwill 7,160us-gaap_Goodwill 7,159us-gaap_Goodwill 7,241us-gaap_Goodwill 6,893us-gaap_Goodwill
Current Fiscal Period Acquisitions [Member]        
Business Acquisition [Line Items]        
Cash 20us-gaap_PaymentsToAcquireBusinessesGross
/ us-gaap_BusinessAcquisitionAxis
= mmc_CurrentFiscalPeriodAcquisitionsMember
     
Estimated fair value of deferred/contingent consideration 12mmc_BusinessCombinationContingentandDeferredConsideration
/ us-gaap_BusinessAcquisitionAxis
= mmc_CurrentFiscalPeriodAcquisitionsMember
     
Total Consideration 32us-gaap_BusinessCombinationConsiderationTransferred1
/ us-gaap_BusinessAcquisitionAxis
= mmc_CurrentFiscalPeriodAcquisitionsMember
     
Allocation of purchase price:        
Cash and cash equivalents 4us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents
/ us-gaap_BusinessAcquisitionAxis
= mmc_CurrentFiscalPeriodAcquisitionsMember
     
Accounts receivable, net 3us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables
/ us-gaap_BusinessAcquisitionAxis
= mmc_CurrentFiscalPeriodAcquisitionsMember
     
Intangible assets 10us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill
/ us-gaap_BusinessAcquisitionAxis
= mmc_CurrentFiscalPeriodAcquisitionsMember
     
Goodwill 12us-gaap_Goodwill
/ us-gaap_BusinessAcquisitionAxis
= mmc_CurrentFiscalPeriodAcquisitionsMember
     
Other assets 5us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets
/ us-gaap_BusinessAcquisitionAxis
= mmc_CurrentFiscalPeriodAcquisitionsMember
     
Total assets acquired 34mmc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedAssetsIncludingGoodwill
/ us-gaap_BusinessAcquisitionAxis
= mmc_CurrentFiscalPeriodAcquisitionsMember
     
Current liabilities 0us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities
/ us-gaap_BusinessAcquisitionAxis
= mmc_CurrentFiscalPeriodAcquisitionsMember
     
Other liabilities 2us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilities
/ us-gaap_BusinessAcquisitionAxis
= mmc_CurrentFiscalPeriodAcquisitionsMember
     
Total liabilities assumed 2us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities
/ us-gaap_BusinessAcquisitionAxis
= mmc_CurrentFiscalPeriodAcquisitionsMember
     
Net assets acquired $ 32us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet
/ us-gaap_BusinessAcquisitionAxis
= mmc_CurrentFiscalPeriodAcquisitionsMember