XML 80 R56.htm IDEA: XBRL DOCUMENT
v3.20.4

Financial Instruments - Information About Interest Rate Swaps (Details) | Dec. 31, 2020 USD ($) interest_rate_swap | Jun. 30, 2020 USD ($) | Feb. 29, 2020 USD ($) interest_rate_swap | Dec. 31, 2019 USD ($)
--- | --- | --- | --- | ---
Derivative [Line Items] |  |  |  |
Par Value of Debt |  | $ 4,500,000,000 |  |
U.S. Dollar Notional | $ 32,784,000,000 |  |  | $ 30,666,000,000
Interest Rate Swap |  |  |  |
Derivative [Line Items] |  |  |  |
Number of Interest Rate Swaps Held | interest_rate_swap |  |  | 5 |
U.S. Dollar Notional |  |  | $ 250,000,000 |
3.875% notes due 2021 | Interest Rate Swap |  |  |  |
Derivative [Line Items] |  |  |  |
Par Value of Debt | $ 1,150,000,000 |  |  |
Number of Interest Rate Swaps Held | interest_rate_swap | 5 |  |  |
U.S. Dollar Notional | $ 1,150,000,000 |  |  |
Fixed-rate notes, stated interest rate (as percent) | 3.875% |  |  |
2.40% notes due 2022 | Interest Rate Swap |  |  |  |
Derivative [Line Items] |  |  |  |
Par Value of Debt | $ 1,000,000,000 |  |  |
Number of Interest Rate Swaps Held | interest_rate_swap | 4 |  |  |
U.S. Dollar Notional | $ 1,000,000,000 |  |  |
Fixed-rate notes, stated interest rate (as percent) | 2.40% |  |  |
2.35% notes due 2022 | Interest Rate Swap |  |  |  |
Derivative [Line Items] |  |  |  |
Par Value of Debt | $ 1,250,000,000 |  |  |
Number of Interest Rate Swaps Held | interest_rate_swap | 5 |  |  |
U.S. Dollar Notional | $ 1,250,000,000 |  |  |
Fixed-rate notes, stated interest rate (as percent) | 2.35% |  |  |

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
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://fasb.org/us-gaap/role/ref/legacyRef -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=120391452&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_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal or face amount used to calculate payment on derivative. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959 + Details
Name: | us-gaap_DerivativeNotionalAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of interest rate derivative instruments held by the entity at the reporting date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959 + Details
Name: | us-gaap_NumberOfInterestRateDerivativesHeld
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=mrk_A3.875NotesDue2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=mrk_A2.40NotesDue2022Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=mrk_A2.35NotesDue2022Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |