Statement Of Changes In Equity [Abstract]
| 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 |
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 |
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 |
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 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of changes in equity [abstract] | |||||||||||||||||||||||
| Statement of changes in equity [line items] | |||||||||||||||||||||||
| Increase (decrease) through change in equity of subsidiaries, equity |
3,000,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
3,000,000
GBP
|
–
GBP
|
1,000,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
1,000,000
GBP
|
–
GBP
|
–
GBP
|
| Purchase of treasury shares |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
2,000,000
GBP
|
–
GBP
|
2,000,000
GBP
|
–
GBP
|
–
GBP
|
2,000,000
GBP
|
–
GBP
|
14,000,000
GBP
|
14,000,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
14,000,000
GBP
|
| Cancellation of treasury shares |
–
GBP
|
1, 384
GBP
|
669,000,000
GBP
|
1 , 182
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
27 0
GBP
|
197,000,000
GBP
|
–
GBP
|
–
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Reduction of issued capital |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
1,418,000,000
GBP
|
–
GBP
|
–
GBP
|
1,418,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |