Statement Of Comprehensive Income [Abstract]

argenx SE - Filing #1859505

Concept	2021-01-01 to 2021-12-31	2021-01-01 to 2021-12-31	2021-01-01 to 2021-12-31	2021-01-01 to 2021-12-31	2021-01-01 to 2021-12-31	2020-01-01 to 2020-12-31	2020-01-01 to 2020-12-31	2020-01-01 to 2020-12-31	2020-01-01 to 2020-12-31	2019-01-01 to 2019-12-31	2019-01-01 to 2019-12-31	2019-01-01 to 2019-12-31	2019-01-01 to 2019-12-31
Statement of comprehensive income [abstract]
Profit (loss)	—	—	408,265,000 USD	408,265,000 USD	408,265,000 USD	608,455,000 USD	608,455,000 USD	—	608,455,000 USD	—	181,208,000 USD	181,208,000 USD	181,208,000 USD
Other comprehensive income [abstract]
Components of other comprehensive income that will not be reclassified to profit or loss, net of tax [abstract]
Other comprehensive income, net of tax, gains (losses) from investments in equity instruments	—	—	—	39,290,000 USD	—	—	— USD	—	—	—	—	—	— USD
Components of other comprehensive income that will be reclassified to profit or loss, net of tax [abstract]
Exchange differences on translation [abstract]
Gains (losses) on exchange differences on translation of foreign operations, net of tax	—	—	—	3,048,000 USD	—	—	— USD	—	—	—	—	—	— USD
Other comprehensive income, net of tax, exchange differences on translation of foreign operations	—	—	—	— USD	—	—	162,273,000 USD	—	—	—	—	—	8,587,000 USD
Other comprehensive income	3,048,000 USD	39,290,000 USD	42,338,000 USD	42,338,000 USD	—	—	162,273,000 USD	162,273,000 USD	162,273,000 USD	8,587,000 USD	8,587,000 USD	—	8,587,000 USD
Comprehensive income	3,048,000 USD	39,290,000 USD	450,603,000 USD	450,603,000 USD	408,265,000 USD	608,455,000 USD	446,182,000 USD	162,273,000 USD	446,182,000 USD	8,587,000 USD	189,795,000 USD	181,208,000 USD	189,795,000 USD
Comprehensive income attributable to [abstract]
Comprehensive income, attributable to owners of parent	—	—	—	450,603,000 USD	—	—	446,182,000 USD	—	—	—	—	—	189,795,000 USD