Statement Of Changes In Equity [Abstract]
| Concept |
2021-01-01 to 2021-12-31 |
As at 2021-12-31 |
2021-01-01 to 2021-12-31 |
As at 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 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 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
2020-01-01 to 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
2020-01-01 to 2020-12-31 |
As at 2020-12-31 |
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 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of changes in equity [abstract] | |||||||||||||||||||||||||||||||||||
| Statement of changes in equity [line items] | |||||||||||||||||||||||||||||||||||
| Equity | — |
3 245
SEK
|
— |
8 322
SEK
|
— | — |
8 318
SEK
|
4 569
SEK
|
5,000,000
SEK
|
70,000,000
SEK
|
434,000,000
SEK
|
— | — | — | — |
2 996
SEK
|
4,000,000
SEK
|
7 918
SEK
|
434,000,000
SEK
|
— |
80,000,000
SEK
|
4 569
SEK
|
— |
7 923
SEK
|
— | — | — | — |
7 536
SEK
|
5,000,000
SEK
|
250,000,000
SEK
|
4 569
SEK
|
7 540
SEK
|
2 283
SEK
|
434,000,000
SEK
|
| Changes in equity [abstract] | |||||||||||||||||||||||||||||||||||
| Comprehensive income [abstract] | |||||||||||||||||||||||||||||||||||
| Profit (loss) | — | — |
808,000,000
SEK
|
— | — | — | — | — | — | — | — | — |
808,000,000
SEK
|
808,000,000
SEK
|
733,000,000
SEK
|
— | — | — | — |
733,000,000
SEK
|
— | — | — | — | — | — | — |
733,000,000
SEK
|
— | — | — | — | — | — | — |
| Other comprehensive income | — | — |
150,000,000
SEK
|
— | — |
150,000,000
SEK
|
— | — | — | — | — | — |
150,000,000
SEK
|
— |
330,000,000
SEK
|
— | — | — | — | — | — | — | — | — |
330,000,000
SEK
|
— | — |
330,000,000
SEK
|
— | — | — | — | — | — | — |
| Comprehensive income |
0
SEK
|
— |
958,000,000
SEK
|
— |
0
SEK
|
150,000,000
SEK
|
— | — | — | — | — |
0
SEK
|
958,000,000
SEK
|
808,000,000
SEK
|
403,000,000
SEK
|
— | — | — | — |
733,000,000
SEK
|
— | — |
0
SEK
|
— |
330,000,000
SEK
|
0
SEK
|
0
SEK
|
403,000,000
SEK
|
— | — | — | — | — | — | — |
| Dividends recognised as distributions to owners | — | — |
563,000,000
SEK
|
— | — | — | — | — | — | — | — | — |
563,000,000
SEK
|
563,000,000
SEK
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Increase (decrease) through treasury share transactions, equity | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
19,000,000
SEK
|
— | — | — | — |
19,000,000
SEK
|
— | — | — | — | — | — | — |
19,000,000
SEK
|
— | — | — | — | — | — | — |
| Increase (decrease) through share-based payment transactions, equity | — | — |
4,000,000
SEK
|
— | — | — | — | — | — | — | — | — |
4,000,000
SEK
|
4,000,000
SEK
|
1,000,000
SEK
|
— | — | — | — |
1,000,000
SEK
|
— | — | — | — | — | — | — |
1,000,000
SEK
|
— | — | — | — | — | — | — |