Statement Of Changes In Equity [Abstract]

Fortum Oyj - Filing #3292290

Concept	2024-01-01 to 2024-12-31	2024-01-01 to 2024-12-31	2024-01-01 to 2024-12-31	As at 2024-12-31	2024-01-01 to 2024-12-31	As at 2024-12-31	As at 2024-12-31	2024-01-01 to 2024-12-31	2024-01-01 to 2024-12-31	As at 2024-12-31	As at 2024-12-31	As at 2024-12-31	2024-01-01 to 2024-12-31	As at 2024-12-31	2024-01-01 to 2024-12-31	2024-01-01 to 2024-12-31	As at 2024-12-31	As at 2024-12-31	As at 2024-12-31	2024-01-01 to 2024-12-31	2023-01-01 to 2023-12-31	As at 2023-12-31	2023-01-01 to 2023-12-31	2023-01-01 to 2023-12-31	2023-01-01 to 2023-12-31	2023-01-01 to 2023-12-31	As at 2023-12-31	As at 2023-12-31	2023-01-01 to 2023-12-31	As at 2023-12-31	2023-01-01 to 2023-12-31	As at 2023-12-31	2023-01-01 to 2023-12-31	As at 2023-12-31	As at 2023-12-31	As at 2023-12-31	As at 2023-12-31	2023-01-01 to 2023-12-31	As at 2023-12-31	2023-01-01 to 2023-12-31	As at 2022-12-31	As at 2022-12-31	As at 2022-12-31	As at 2022-12-31	As at 2022-12-31	As at 2022-12-31	As at 2022-12-31	As at 2022-12-31	As at 2022-12-31	As at 2022-12-31
Statement of changes in equity [abstract]
Statement of changes in equity [line items]
Equity	—	—	—	73,000,000 EUR	—	6,780,000,000 EUR	53,000,000 EUR	—	—	3,046,000,000 EUR	79,000,000 EUR	1,010,000,000 EUR	—	9,074,000,000 EUR	—	—	127,000,000 EUR	9,154,000,000 EUR	5,000,000 EUR	—	—	8,499,000,000 EUR	—	—	—	—	6,618,000,000 EUR	79,000,000 EUR	—	60,000,000 EUR	—	73,000,000 EUR	—	3,046,000,000 EUR	1,026,000,000 EUR	8,438,000,000 EUR	337,000,000 EUR	—	14,000,000 EUR	—	7,737,000,000 EUR	93,000,000 EUR	9,499,000,000 EUR	67,000,000 EUR	172,000,000 EUR	73,000,000 EUR	3,046,000,000 EUR	3,031,000,000 EUR	7,670,000,000 EUR	2,182,000,000 EUR
Changes in equity [abstract]
Comprehensive income [abstract]
Profit (loss)	1,164,000,000 EUR	EUR	EUR	—	EUR	—	—	1,164,000,000 EUR	EUR	—	—	—	4,000,000 EUR	—	1,160,000,000 EUR	EUR	—	—	—	EUR	2,067,000,000 EUR	—	2,069,000,000 EUR	EUR	2,069,000,000 EUR	2,000,000 EUR	—	—	EUR	—	EUR	—	EUR	—	—	—	—	EUR	—	EUR	—	—	—	—	—	—	—	—	—	—
Comprehensive income	1,663,000,000 EUR	EUR	EUR	—	0 EUR	—	—	1,164,000,000 EUR	15,000,000 EUR	—	—	—	4,000,000 EUR	—	1,659,000,000 EUR	465,000,000 EUR	—	—	—	19,000,000 EUR	1,581,000,000 EUR	—	1,580,000,000 EUR	14,000,000 EUR	2,069,000,000 EUR	1,000,000 EUR	—	—	EUR	—	2,006,000,000 EUR	—	EUR	—	—	—	—	1,844,000,000 EUR	—	186,000,000 EUR	—	—	—	—	—	—	—	—	—	—
Dividends recognised as distributions to owners	1,032,000,000 EUR	EUR	EUR	—	EUR	—	—	1,032,000,000 EUR	EUR	—	—	—	0 EUR	—	1,032,000,000 EUR	EUR	—	—	—	EUR	817,000,000 EUR	—	817,000,000 EUR	EUR	817,000,000 EUR	0 EUR	—	—	EUR	—	EUR	—	EUR	—	—	—	—	EUR	—	EUR	—	—	—	—	—	—	—	—	—	—
Increase (decrease) through other changes, equity	5,000,000 EUR	EUR	EUR	—	25,000,000 EUR	—	—	30,000,000 EUR	EUR	—	—	—	0 EUR	—	5,000,000 EUR	EUR	—	—	—	EUR	5,000,000 EUR	—	5,000,000 EUR	0 EUR	5,000,000 EUR	0 EUR	—	—	EUR	—	EUR	—	EUR	—	—	—	—	EUR	—	EUR	—	—	—	—	—	—	—	—	—	—
Increase (decrease) through changes in ownership interests in subsidiaries that do not result in loss of control, equity	0 EUR	EUR	EUR	—	EUR	—	—	EUR	EUR	—	—	—	25,000,000 EUR	—	25,000,000 EUR	EUR	—	—	—	EUR	15,000,000 EUR	—	0 EUR	EUR	EUR	15,000,000 EUR	—	—	EUR	—	EUR	—	EUR	—	—	—	—	EUR	—	EUR	—	—	—	—	—	—	—	—	—	—