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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.

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The principal place of business of a joint operation. [Refer: Total for all joint operations [member]; Principal place of business]

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The principal place of business of a subsidiary. [Refer: Principal place of business; Total for all subsidiaries [member]]

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The proportion of ownership interest in a joint operation attributable to the entity. [Refer: Total for all joint operations [member]]

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The proportion of ownership interest in a subsidiary attributable to the entity. [Refer: Total for all subsidiaries [member]]

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The proportion of the voting rights in a joint operation held by the entity. [Refer: Total for all joint operations [member]]

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Interest in Other Entities (Details)			1 Months Ended		12 Months Ended
Interest in Other Entities (Details)	Oct. 31, 2023	Oct. 30, 2023	Oct. 31, 2024	Oct. 30, 2024	Dec. 31, 2024	Dec. 31, 2023
Disclosure of subsidiaries [line items]
Percentage of mineral property assets					90.80%
Waterbury Lake Uranium Corp
Disclosure of subsidiaries [line items]
Participating Interest					100.00%
Place Of Business, Joint Operations					Canada
Ownership interest, Joint Operations					60.00%	60.00%
Waterbury Lake Uranium LP
Disclosure of subsidiaries [line items]
Participating Interest					100.00%
Place Of Business, Joint Operations					Canada
Ownership interest, Joint Operations					70.32%	69.35%
Voting interest percentage					75.00%
Wheeler River Joint Venture
Disclosure of subsidiaries [line items]
Participating Interest					91.86%
Place Of Business, Key Contractual Arrangements					Canada
Ownership Interest, in Key Contractual Arrangements					90.00%	90.00%
Midwest Joint Venture
Disclosure of subsidiaries [line items]
Participating Interest					25.17%
Place Of Business, Key Contractual Arrangements					Canada
Ownership Interest, in Key Contractual Arrangements					25.17%	25.17%
Mann Lake Joint Venture
Disclosure of subsidiaries [line items]
Place Of Business, Key Contractual Arrangements					Canada
Ownership Interest, in Key Contractual Arrangements					30.00%	30.00%
Wolly Joint Venture
Disclosure of subsidiaries [line items]
Participating Interest					20.77%
Place Of Business, Key Contractual Arrangements					Canada
Ownership Interest, in Key Contractual Arrangements					20.77%	20.77%
McClean Lake Joint Venture
Disclosure of subsidiaries [line items]
Participating Interest					22.50%
Place Of Business, Key Contractual Arrangements					Canada
Ownership Interest, in Key Contractual Arrangements					22.50%	22.50%
Denison Mines Inc.
Disclosure of subsidiaries [line items]
Place Of Business, Subsidiaries					Canada
Ownership interest, Subsidiaries					100.00%	100.00%
Denison AB Holdings Corp.
Disclosure of subsidiaries [line items]
Place Of Business, Subsidiaries					Canada
Ownership interest, Subsidiaries					100.00%	100.00%
Denison Waterbury Corp
Disclosure of subsidiaries [line items]
Place Of Business, Subsidiaries					Canada
Ownership interest, Subsidiaries					100.00%	100.00%
Ownership interest, Joint Operations	69.35%	67.41%	70.32%	69.35%	60.00%
9373721 Canada Inc.
Disclosure of subsidiaries [line items]
Place Of Business, Subsidiaries					Canada
Ownership interest, Subsidiaries					100.00%	100.00%
Denison Mines (Bermuda) I Ltd
Disclosure of subsidiaries [line items]
Place Of Business, Subsidiaries					Bermuda
Ownership interest, Subsidiaries					100.00%	100.00%
JCU
Disclosure of subsidiaries [line items]
Participating Interest					50.00%
Place Of Business, Joint Operations					Canada
Ownership interest, Joint Operations					50.00%	50.00%
JCU \| Wheeler River Joint Venture
Disclosure of subsidiaries [line items]
Additional Ownership Interest In Joint venture					5.00%