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 |
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] | ||||||||||||||||||
| Purchase of treasury shares |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
1,000,000
GBP
|
1,000,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
402,000,000
GBP
|
21,000,000
GBP
|
402,000,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
402,000,000
GBP
|
21,000,000
GBP
|