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Basis of Presentation - Activities of the subsidiary (Details) - Parent Company [Member]	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Genmab B.V.
Activities of the subsidiary
Ownership and votes (Percentage)	100.00%	100.00%
Genmab Holding B.V.
Activities of the subsidiary
Ownership and votes (Percentage)	100.00%	100.00%
Genmab US, Inc.
Activities of the subsidiary
Ownership and votes (Percentage)	100.00%	100.00%
Genmab K.K.
Activities of the subsidiary
Ownership and votes (Percentage)	100.00%	100.00%

X

- Definition

The proportion of ownership interest and voting rights in a subsidiary attributable to the entity

+ References

No definition available.

+ Details

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X

- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

+ References

No definition available.

+ Details

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- Details

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X

- Details

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X

- Details

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X

- Details

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- Details

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