XML 86 R67.htm IDEA: XBRL DOCUMENT
v3.19.2

Leases - Aggregate Fixed Future Minimum Commitments (Details) $ in Millions | Dec. 31, 2018 USD ($)
--- | ---
Gross Rental Commitments |
2019, Gross Rental Commitments | $ 361
2020, Gross Rental Commitments | 340
2021, Gross Rental Commitments | 277
2022, Gross Rental Commitments | 252
2023, Gross Rental Commitments | 214
Subsequent years, Gross Rental Commitments | 753
Rentals from Subleases |
2019, Rentals from Subleases | 32
2020, Rentals from Subleases | 31
2021, Rentals from Subleases | 12
2022, Rentals from Subleases | 10
2023, Rentals from Subleases | 9
Subsequent years, Rentals from Subleases | 32
Net Rental Commitments |
2019, Net Rental Commitments | 329
2020, Net Rental Commitments | 309
2021 Net Rental Commitments | 265
2022, Net Rental Commitments | 242
2023, Net Rental Commitments | 205
Subsequent years, Net Rental Commitments | $ 721

X
- Definition Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals [Abstract] + References No definition available. + Details
Name: | mmc_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentalsAbstract
Namespace Prefix: | mmc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Operating Leases Future Minimum Payments Due, Net of Sublease Receivable [Abstract] + References No definition available. + Details
Name: | mmc_OperatingLeasesFutureMinimumPaymentsDueNetofSubleaseReceivableAbstract
Namespace Prefix: | mmc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Operating Leases, Future Minimum Payments, Net of Sublease Receivable, Due Current + References No definition available. + Details
Name: | mmc_OperatingLeasesFutureMinimumPaymentsNetofSubleaseReceivableDueCurrent
Namespace Prefix: | mmc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Operating Leases, Future Minimum Payments, Net of Sublease Receivable, Due In Five Years + References No definition available. + Details
Name: | mmc_OperatingLeasesFutureMinimumPaymentsNetofSubleaseReceivableDueInFiveYears
Namespace Prefix: | mmc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Operating Leases, Future Minimum Payments, Net of Sublease Receivable, Due In Four Years + References No definition available. + Details
Name: | mmc_OperatingLeasesFutureMinimumPaymentsNetofSubleaseReceivableDueInFourYears
Namespace Prefix: | mmc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Operating Leases Future Minimum Payments, Net of Sublease Receivable, Due In Three Years + References No definition available. + Details
Name: | mmc_OperatingLeasesFutureMinimumPaymentsNetofSubleaseReceivableDueInThreeYears
Namespace Prefix: | mmc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Operating Leases, Future Minimum Payments, Net of Sublease Receivable, Due In Two Years + References No definition available. + Details
Name: | mmc_OperatingLeasesFutureMinimumPaymentsNetofSubleaseReceivableDueInTwoYears
Namespace Prefix: | mmc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Operating Leases, Future Minimum Payments, Net of Sublease Receivable, Due Thereafter + References No definition available. + Details
Name: | mmc_OperatingLeasesFutureMinimumPaymentsNetofSubleaseReceivableDueThereafter
Namespace Prefix: | mmc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lease payments to be received by lessor in fifth fiscal year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 30 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919396-209981 + Details
Name: | us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of lease payments to be received by lessor in fourth year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 30 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919396-209981 + Details
Name: | us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of lease payments to be received by lessor in next fiscal year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 30 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919396-209981 + Details
Name: | us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of lease payments to be received by lessor after fifth fiscal year following latest statement of financial position date for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 30 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919396-209981 + Details
Name: | us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of lease payments to be received by lessor in third fiscal year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 30 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919396-209981 + Details
Name: | us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of lease payments to be received by lessor in second fiscal year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 30 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919396-209981 + Details
Name: | us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77902758&loc=d3e41502-112717 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 3) -URI http://asc.fasb.org/extlink&oid=82846649&loc=d3e38371-112697 + Details
Name: | us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77902758&loc=d3e41502-112717 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 3) -URI http://asc.fasb.org/extlink&oid=82846649&loc=d3e38371-112697 + Details
Name: | us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 3) -URI http://asc.fasb.org/extlink&oid=82846649&loc=d3e38371-112697 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77902758&loc=d3e41502-112717 + Details
Name: | us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 3) -URI http://asc.fasb.org/extlink&oid=82846649&loc=d3e38371-112697 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77902758&loc=d3e41502-112717 + Details
Name: | us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 3) -URI http://asc.fasb.org/extlink&oid=82846649&loc=d3e38371-112697 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77902758&loc=d3e41502-112717 + Details
Name: | us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77902758&loc=d3e41502-112717 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 3) -URI http://asc.fasb.org/extlink&oid=82846649&loc=d3e38371-112697 + Details
Name: | us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant