XML 72 R58.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Debt (Schedule Of Outstanding Debt) (Details) - USD ($) $ in Millions | Sep. 30, 2017 | Jan. 31, 2017 | Dec. 31, 2016 | Mar. 31, 2016
--- | --- | --- | --- | ---
Debt Instrument [Line Items] |  |  |  |
Commercial paper outstanding | $ 0 |  | $ 50 |
Current portion of long-term debt | 13 |  | 262 |
Short-term debt | 13 |  | 312 |
Long-term debt, current and noncurrent | 5,488 |  | 4,757 |
Long-term debt | 5,475 |  | 4,495 |
2.30% Senior Debt Obligations Due 2017 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term debt, current and noncurrent | $ 0 |  | 250 |
Interest rate | 2.30% |  |  |
2.55% Senior Debt Obligations Due 2018 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term debt, current and noncurrent | $ 250 |  | 249 |
Interest rate | 2.55% |  |  |
2.35% Senior Debt Obligations Due 2019 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term debt, current and noncurrent | $ 299 |  | 299 |
Interest rate | 2.35% |  |  |
2.35% Senior Debt Obligations Due 2020 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term debt, current and noncurrent | $ 498 |  | 497 |
Interest rate | 2.35% |  |  |
4.80% Senior Debt Obligations Due 2021 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term debt, current and noncurrent | $ 498 |  | 498 |
Interest rate | 4.80% |  |  |
2.75% Senior Debt Obligations Due 2022 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term debt, current and noncurrent | $ 496 |  | 0 |
Interest rate | 2.75% | 2.75% |  |
3.30% Senior Debt Obligations Due 2023 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term debt, current and noncurrent | $ 347 |  | 347 |
Interest rate | 3.30% |  |  | 3.30%
4.05% Senior Debt Obligations Due 2023 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term debt, current and noncurrent | $ 248 |  | 248 |
Interest rate | 4.05% |  |  |
3.50% Senior Debt Obligations Due 2024 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term debt, current and noncurrent | $ 596 |  | 596 |
Interest rate | 3.50% |  |  |
3.50% Senior Debt Obligations Due 2025 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term debt, current and noncurrent | $ 496 |  | 495 |
Interest rate | 3.50% |  |  |
3.75% Senior Debt Obligations Due 2026 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term debt, current and noncurrent | $ 596 |  | 596 |
Interest rate | 3.75% |  |  |
5.875% Senior Debt Obligations Due 2033 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term debt, current and noncurrent | $ 297 |  | 297 |
Interest rate | 5.875% |  |  |
4.35% Senior Debt Obligation Due 2047 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term debt, current and noncurrent | $ 492 |  | 0 |
Interest rate | 4.35% | 4.35% |  |
Mortgage Due 2035 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term debt, current and noncurrent | $ 373 |  | 382 |
Interest rate | 5.70% |  |  |
Other |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term debt, current and noncurrent | $ 2 |  | $ 3 |

X
- Definition Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)(a)(3)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(13)(2)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_CommercialPaper
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.13,16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_DebtAndCapitalLeaseObligations
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of short-term debt and current maturity of long-term debt and capital lease obligations due within one year or the normal operating cycle, if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19,20) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LongTermDebtAndCapitalLeaseObligations
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19,20) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LongTermDebtCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mmc_SeniorDebtObligationsDue2017Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mmc_SeniorDebtObligationsDue2018Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mmc_A2.35SeniorDebtObligationsDue2019Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mmc_SeniorDebtObligationsDue2020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mmc_SeniorDebtObligationsDue2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mmc_SeniorDebtObligationsDue2022Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mmc_SeniorDebtObligations3.30Due2023Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mmc_A4.05SeniorDebtObligationsDue2023Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mmc_SeniorDebtObligationsDue2024MemberDomain
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mmc_A3.50SeniorDebtObligationsDue2025Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mmc_A3.75SeniorDebtObligationsDue2026Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mmc_SeniorDebtObligationsDue2033Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mmc_SeniorDebtObligationDue2047Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mmc_MortgageDue2035Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mmc_OtherDebtInstrumentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |