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 |
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 |
As at 2021-12-31 |
2021-01-01 to 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
2021-01-01 to 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 |
2020-01-01 to 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 |
2020-01-01 to 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 |
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 |
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 |
As at 2019-12-31 |
As at 2019-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of changes in equity [abstract] | |||||||||||||||||||||||||||||||||||||||||||||
| Statement of changes in equity [line items] | |||||||||||||||||||||||||||||||||||||||||||||
| Equity | — |
1,000,000
GBP
|
— |
93,000,000
GBP
|
16, 550
GBP
|
1 1 , 6 6 0
GBP
|
— | — | — |
5,345,000,000
GBP
|
— |
5,296,000,000
GBP
|
370,000,000
GBP
|
— |
49,000,000
GBP
|
130,000,000
GBP
|
— | — | — |
1 1 7
GBP
|
16 ,85 3
GBP
|
8,000,000
GBP
|
— |
130,000,000
GBP
|
5, 57 7
GBP
|
— | — |
1,000,000
GBP
|
1 1 , 6 5 8
GBP
|
3 70
GBP
|
— | — |
5,585,000,000
GBP
|
— | — | — |
5 ,1 2 5
GBP
|
6,000,000
GBP
|
11 , 6 9 0
GBP
|
5 ,1 3 1
GBP
|
3 70
GBP
|
16, 3 42
GBP
|
1,000,000
GBP
|
2 6
GBP
|
130,000,000
GBP
|
| Changes in equity [abstract] | |||||||||||||||||||||||||||||||||||||||||||||
| Comprehensive income [abstract] | |||||||||||||||||||||||||||||||||||||||||||||
| Profit (loss) |
9,000,000
GBP
|
— |
–
GBP
|
— | — | — |
–
GBP
|
–
GBP
|
83,000,000
GBP
|
— |
–
GBP
|
— | — |
–
GBP
|
— | — |
92,000,000
GBP
|
83,000,000
GBP
|
1 ,1 4 2
GBP
|
— | — | — |
–
GBP
|
— | — |
1 ,1 3 8
GBP
|
–
GBP
|
— | — | — |
–
GBP
|
–
GBP
|
— |
4,000,000
GBP
|
–
GBP
|
1 ,1 3 8
GBP
|
— | — | — | — | — | — | — | — | — |
| Other comprehensive income |
–
GBP
|
— |
–
GBP
|
— | — | — |
–
GBP
|
1 3
GBP
|
37,000,000
GBP
|
— |
–
GBP
|
— | — |
–
GBP
|
— | — |
37,000,000
GBP
|
50,000,000
GBP
|
7 8
GBP
|
— | — | — |
–
GBP
|
— | — |
81,000,000
GBP
|
–
GBP
|
— | — | — |
3,000,000
GBP
|
–
GBP
|
— |
–
GBP
|
–
GBP
|
78,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Comprehensive income |
9,000,000
GBP
|
— |
–
GBP
|
— | — | — |
–
GBP
|
1 3
GBP
|
120,000,000
GBP
|
— |
–
GBP
|
— | — |
–
GBP
|
— | — |
129,000,000
GBP
|
133,000,000
GBP
|
1,06 4
GBP
|
— | — | — |
–
GBP
|
— | — |
1,057,000,000
GBP
|
–
GBP
|
— | — | — |
3,000,000
GBP
|
–
GBP
|
— |
4,000,000
GBP
|
–
GBP
|
1,06 0
GBP
|
— | — | — | — | — | — | — | — | — |
| Increase (decrease) in equity |
41,000,000
GBP
|
— |
24,000,000
GBP
|
— | — | — |
–
GBP
|
2,000,000
GBP
|
2 81
GBP
|
— |
–
GBP
|
— | — |
–
GBP
|
— | — |
2 4 0
GBP
|
3 03
GBP
|
454,000,000
GBP
|
— | — | — |
–
GBP
|
— | — |
51 1
GBP
|
9 1
GBP
|
— | — | — |
32,000,000
GBP
|
–
GBP
|
— |
2,000,000
GBP
|
–
GBP
|
4 52
GBP
|
— | — | — | — | — | — | — | — | — |