Statement Of Changes In Equity [Abstract]
| Concept |
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 |
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 |
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 |
As at 2021-01-01 |
As at 2021-01-01 |
As at 2021-01-01 |
As at 2021-01-01 |
As at 2021-01-01 |
As at 2021-01-01 |
As at 2021-01-01 |
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 |
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 |
2020-01-01 to 2020-12-31 |
As at 2020-01-01 |
As at 2020-01-01 |
As at 2020-01-01 |
As at 2020-01-01 |
As at 2020-01-01 |
As at 2020-01-01 |
As at 2020-01-01 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of changes in equity [abstract] | ||||||||||||||||||||||||||||||||||||||||||||||
| Statement of changes in equity [line items] | ||||||||||||||||||||||||||||||||||||||||||||||
| Equity | — |
212,000,000
GBP
|
5, 887
GBP
|
— | — |
7, 6 6 8
GBP
|
— | — | — |
7, 4 3 6
GBP
|
1,252,000,000
GBP
|
— |
232,000,000
GBP
|
85,000,000
GBP
|
— | — |
87,000,000
GBP
|
4 , 921
GBP
|
2,6 1 6
GBP
|
5,923,000,000
GBP
|
1, 2 4 9
GBP
|
4, 643
GBP
|
278,000,000
GBP
|
— |
2,6 1 6
GBP
|
278,000,000
GBP
|
4, 643
GBP
|
87,000,000
GBP
|
— |
5,923,000,000
GBP
|
1, 2 4 9
GBP
|
— | — |
4 , 921
GBP
|
— | — | — | — | — |
87,000,000
GBP
|
5,5 1 1
GBP
|
2,0 8 5
GBP
|
6 ,1 5 6
GBP
|
10 4
GBP
|
1, 2 4 9
GBP
|
5, 4 07
GBP
|
| Changes in equity [abstract] | ||||||||||||||||||||||||||||||||||||||||||||||
| Comprehensive income [abstract] | ||||||||||||||||||||||||||||||||||||||||||||||
| Profit (loss) |
15 4
GBP
|
— | — |
–
GBP
|
1, 75 8
GBP
|
— |
–
GBP
|
–
GBP
|
1 ,9 12
GBP
|
— | — |
–
GBP
|
— | — |
1, 912
GBP
|
1, 7 5 8
GBP
|
— | — | — | — | — | — | — |
1, 3 71
GBP
|
— | — | — | — |
1, 2 9 9
GBP
|
— | — |
–
GBP
|
–
GBP
|
— |
72,000,000
GBP
|
–
GBP
|
1, 2 9 9
GBP
|
–
GBP
|
1, 3 71
GBP
|
— | — | — | — | — | — | — |
| Other comprehensive income |
2,000,000
GBP
|
— | — |
3,000,000
GBP
|
2 ,12 1
GBP
|
— |
–
GBP
|
2,000,000
GBP
|
2 ,1 2 1
GBP
|
— | — |
–
GBP
|
— | — |
2 ,1 2 3
GBP
|
2 ,12 4
GBP
|
— | — | — | — | — | — | — |
1, 27 6
GBP
|
— | — | — | — |
1, 0 8 6
GBP
|
— | — |
17 6
GBP
|
–
GBP
|
— |
14,000,000
GBP
|
–
GBP
|
1, 2 6 2
GBP
|
19 0
GBP
|
1, 0 8 6
GBP
|
— | — | — | — | — | — | — |
| Comprehensive income |
15 6
GBP
|
— | — |
3,000,000
GBP
|
3, 879
GBP
|
— |
–
GBP
|
2,000,000
GBP
|
4 ,033
GBP
|
— | — |
–
GBP
|
— | — |
4,035,000,000
GBP
|
3,8 82
GBP
|
— | — | — | — | — | — | — |
95,000,000
GBP
|
— | — | — | — |
213,000,000
GBP
|
— | — |
17 6
GBP
|
–
GBP
|
— |
58,000,000
GBP
|
–
GBP
|
37,000,000
GBP
|
19 0
GBP
|
285,000,000
GBP
|
— | — | — | — | — | — | — |
| Dividends recognised as distributions to owners |
20 2
GBP
|
— | — |
–
GBP
|
777,000,000
GBP
|
— |
–
GBP
|
— | — | — | — |
–
GBP
|
— | — |
979,000,000
GBP
|
777,000,000
GBP
|
— | — | — | — | — | — | — |
7 74
GBP
|
— | — | — | — |
74 6
GBP
|
— | — |
–
GBP
|
–
GBP
|
— |
28,000,000
GBP
|
–
GBP
|
74 6
GBP
|
— | — | — | — | — | — | — | — | — |
| Increase (decrease) through changes in ownership interests in subsidiaries that do not result in loss of control, equity | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
51,000,000
GBP
|
— | — | — | — |
71,000,000
GBP
|
— | — |
2 2
GBP
|
–
GBP
|
— |
14 4
GBP
|
–
GBP
|
93,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Increase (decrease) through share-based payment transactions, equity |
–
GBP
|
— | — |
–
GBP
|
94,000,000
GBP
|
— |
–
GBP
|
— | — | — | — |
–
GBP
|
— | — |
94,000,000
GBP
|
94,000,000
GBP
|
— | — | — | — | — | — | — |
73,000,000
GBP
|
— | — | — | — |
73,000,000
GBP
|
— | — |
–
GBP
|
–
GBP
|
— |
–
GBP
|
–
GBP
|
73,000,000
GBP
|
— | — | — | — | — | — | — | — | — |