The ratio in which the development cost will be split if a candidate is co-developed under the collaboration agreement.

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- Definition

The amount of development regulatory and commercial milestone payments to be made by the company under the agreement.

+ References

No definition available.

+ Details

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- Definition

The amount of milestone payment receivable under the collaboration agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	gmab_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of collaboration agreements, development regulatory and commercial milestone payment.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Represents the cost and profit sharing ratio.

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No definition available.

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Namespace Prefix:	gmab_
Data Type:	xbrli:pureItemType
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- Definition

The amount of cash in flow from initial payments received.

+ References

No definition available.

+ Details

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Namespace Prefix:	gmab_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of milestone payment receivable under an collaboration agreement.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

The percentage of royalties of worldwide net sales ofatumumab for the treatment of non-cancer under the agreement.

+ References

No definition available.

+ Details

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- Definition

The amount of lump sum payment received under an collaboration agreement for lost potential royalties.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Term from first sale of the product after which obligation to pay royalties under the agreement will expire.

+ References

No definition available.

+ Details

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Namespace Prefix:	gmab_
Data Type:	xbrli:durationItemType
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- Definition

The percentage of tiered royalty under the collaboration agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	gmab_
Data Type:	dtr-types:percentItemType
Balance Type:	na
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- Definition

The amount of upfront fee payment made under an collaboration agreement.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

The amount of upfront fee payable under an collaboration agreement.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

The percentage of discover research and development cost responsible by the entity.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
Balance Type:	na
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- Definition

Represents number of additional candidates selected for development.

+ References

No definition available.

+ Details

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- Definition

Number of additional programs party to the agreement is entitled to work on.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
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- Definition

Number of additional proprietary targets of license.

+ References

No definition available.

+ Details

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Namespace Prefix:	gmab_
Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

Represents the number of delivery license programs.

+ References

No definition available.

+ Details

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Namespace Prefix:	gmab_
Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

Number of license exercised under the agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	gmab_
Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

Number of license options remaining to be exercised under the agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	gmab_
Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

Represents the number of performance obligations.

+ References

No definition available.

+ Details

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Namespace Prefix:	gmab_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of potential target pair combinations.

+ References

No definition available.

+ Details

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Namespace Prefix:	gmab_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of proprietary targets of license.

+ References

No definition available.

+ Details

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Namespace Prefix:	gmab_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The period for which the entity has the option to obtain commercial license.

+ References

No definition available.

+ Details

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Namespace Prefix:	gmab_
Data Type:	xbrli:durationItemType
Balance Type:	na
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- Definition

The number of options to obtain commercial license.

+ References

No definition available.

+ Details

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Namespace Prefix:	gmab_
Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

Percentage of investment in common shares.

+ References

No definition available.

+ Details

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Namespace Prefix:	gmab_
Data Type:	dtr-types:percentItemType
Balance Type:	na
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- Definition

The ratio of share of profits before income taxes.

+ References

No definition available.

+ Details

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Data Type:	xbrli:pureItemType
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- Definition

The percentage of royalties on sales.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
Balance Type:	na
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- Definition

+ References

No definition available.

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Data Type:	xbrli:stringItemType
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- Definition

Threshold number of clinical candidates evaluated for development.

+ References

No definition available.

+ Details

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Namespace Prefix:	gmab_
Data Type:	xbrli:integerItemType
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- Definition

The amount of cash in flow from upfront milestone payments.

+ References

No definition available.

+ Details

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Namespace Prefix:	gmab_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

The amount of investments accounted for using the equity method. The equity method is a method of accounting whereby the investment is initially recognised at cost and adjusted thereafter for the post-acquisition change in the investor's share of net assets of the investee. The investor's profit or loss includes its share of the profit or loss of the investee. The investor's other comprehensive income includes its share of the other comprehensive income of the investee. [Refer: At cost [member]]

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- Definition

The amount of trade receivables and other receivables. [Refer: Trade receivables; Other receivables]

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Number 1
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- Details

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Other Disclosures - Collaborations and Technology Licenses (Details) € in Millions, kr in Millions, $ in Millions		1 Months Ended					6 Months Ended	12 Months Ended
	Jun. 10, 2020 USD ($) item	Oct. 31, 2020	Jul. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) Option	Jul. 31, 2018 USD ($) item	Dec. 31, 2017 item	Jun. 30, 2021 USD ($) item	Dec. 31, 2021 USD ($) Option item	Dec. 31, 2020 USD ($)	Dec. 31, 2012	Dec. 31, 2021 DKK (kr)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 DKK (kr)	Dec. 31, 2019 EUR (€)	Aug. 31, 2015 USD ($)
Collaborations and Technology Licenses
Investments accounted for using equity method \| kr											kr 371		kr 1,081
Janssen
Collaborations and Technology Licenses
Royalty obligation expiration term after first sale of product								13 years
Milestone payments receivable												$ 191.0
Upfront payment								$ 3.5
Number of additional programs \| item								10
Initial payments received								$ 2.0
Number of license exercised \| item								14
Number of license options remaining to be exercised \| Option								0
Novartis (Arzaerra/Ofatumumab)
Collaborations and Technology Licenses
Royalty percentage for non-cancer treatment								10.00%
Lump sum payment received									$ 30.0
Seagen
Collaborations and Technology Licenses
Cost and profit sharing ratio		50
AbbVie
Collaborations and Technology Licenses
Number of additional candidates selected \| item	4
Upfront payment	$ 750.0		$ 750.0
Ratio of share of profits before income taxes	50
Number of performance obligations \| item	4
Number of delivery license programs \| item	3
Percentage of discover research and development cost responsible by the entity	100.00%
BioNTech
Collaborations and Technology Licenses
Number of additional candidates selected \| item								2
Upfront fee paid								$ 10.0
Novo Nordisk A/S
Collaborations and Technology Licenses
Number of potential target pair combinations \| item						5
Options to obtain commercial licenses \| item						3
CureVac
Collaborations and Technology Licenses
Upfront fee payable				$ 10.0
Collaborative arrangement, Development, Regulatory and commercial milestone payment				$ 280.0
Options to obtain commercial licenses \| Option				3
Option exercisable period				5 years
Investments accounted for using equity method											318		kr 1,067	€ 20
Percentage of investment in common shares								35.00%
Bolt
Collaborations and Technology Licenses
Investments accounted for using equity method							$ 15.0				kr 26
Upfront fee paid							$ 10.0
Threshold number of clinical candidates evaluated for development \| item							3
Co-developed development cost split ratio							50
Milestone payments receivable							$ 285.0
Immatics
Collaborations and Technology Licenses
Development regulatory and commercial milestone payments to be made					$ 550.0
Number of proprietary targets of license \| item					3
Number of additional proprietary targets of license \| item					2
Upfront fee paid					$ 54.0
Bottom of range [member] \| Janssen
Collaborations and Technology Licenses
Tiered royalty percentage										12.00%
Bottom of range [member] \| CureVac
Collaborations and Technology Licenses
Collaborative arrangement, Development, Regulatory and commercial milestone payment				$ 275.0
Top of range [member] \| Janssen
Collaborations and Technology Licenses
Tiered royalty percentage										20.00%
Milestone payments receivable												$ 175.0
Top of range [member] \| Novo Nordisk A/S
Collaborations and Technology Licenses
Collaborative arrangement, Development, Regulatory and commercial milestone payment															$ 250.0
Top of range [member] \| CureVac
Collaborations and Technology Licenses
Collaborative arrangement, Development, Regulatory and commercial milestone payment				$ 368.0
Development Regulatory and Sales Milestone \| Top of range [member] \| AbbVie
Collaborations and Technology Licenses
Receivables	$ 3,150.0
Countries Outside United States and Japan \| Bottom of range [member] \| AbbVie
Collaborations and Technology Licenses
Royalty percent on sales	22.00%
Countries Outside United States and Japan \| Top of range [member] \| AbbVie
Collaborations and Technology Licenses
Royalty percent on sales	26.00%
Clinical Development and Commercial Success Across all Three Programs \| Development Regulatory and Sales Milestone \| AbbVie
Collaborations and Technology Licenses
Receivables	$ 1,150.0
Success of all Four Next Generation Antibody Product Candidates Developed \| Development Regulatory and Sales Milestone \| AbbVie
Collaborations and Technology Licenses
Receivables	$ 2,000.0