XML 94 R55.htm IDEA: XBRL DOCUMENT
v3.25.1

Basis of Presentation - Non controlling interest (Details) | Dec. 31, 2024
--- | ---
DeepGreen Engineering Pte. Ltd. |
Basis of Presentation |
Proportion of Interest Held by the Company | 100.00%
DeepGreen Metals ULC |
Basis of Presentation |
Proportion of Interest Held by the Company | 100.00%
The Metals Company USA, LLC |
Basis of Presentation |
Proportion of Interest Held by the Company | 100.00%
DeepGreen TOML Holding 1 Ltd. |
Basis of Presentation |
Proportion of Interest Held by the Company | 100.00%
DeepGreen TOML Holding 2 Ltd. |
Basis of Presentation |
Proportion of Interest Held by the Company | 100.00%
DeepGreen TOML Singapore Ltd. |
Basis of Presentation |
Proportion of Interest Held by the Company | 100.00%
Koloa Moana Resources Ltd. |
Basis of Presentation |
Proportion of Interest Held by the Company | 100.00%
Nauru Ocean Resources Inc. |
Basis of Presentation |
Proportion of Interest Held by the Company | 100.00%
Offshore Minerals Pty. Ltd. |
Basis of Presentation |
Proportion of Interest Held by the Company | 100.00%
The Metals Company Australia Pty Ltd |
Basis of Presentation |
Proportion of Interest Held by the Company | 100.00%
TMC The Metals Company UK Limited |
Basis of Presentation |
Proportion of Interest Held by the Company | 100.00%
Tonga Off shore Mining Limited |
Basis of Presentation |
Proportion of Interest Held by the Company | 100.00%
Seafloor Mineral Ventures |
Basis of Presentation |
Proportion of Interest Held by the Company | 100.00%

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_MinorityInterestLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The parent entity's interest in net assets of the subsidiary, expressed as a percentage. + References No definition available. + Details
Name: | us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | srt_OwnershipAxis=tmc_DeepgreenEngineeringPte.Ltd.Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=tmc_DeepgreemMetalsUlcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=tmc_MetalsCompanyUsaLlcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=tmc_DeepgreenTomlHolding1Ltd.Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=tmc_DeepgreenTomlHolding2Ltd.Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=tmc_DeepgreenTomlSingaporeLtd.Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=tmc_KoloaMoanaResourcesLtd.Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=tmc_NauruOceanResourcesInc.Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=tmc_OffshoreMineralsPty.Ltd.Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=tmc_MetalsCompanyAustraliaPtyLtdMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=tmc_TmcMetalsCompanyUkLimitedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=tmc_TongaOffshoreMiningLimitedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=tmc_SeafloorMineralVenturesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |