Statement Of Changes In Equity [Abstract]
| Concept |
As at 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 |
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 |
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 |
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 |
2020-01-01 to 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 |
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 |
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 |
5,775,000,000
GBP
|
171,000,000
GBP
|
1,094,000,000
GBP
|
— |
207,000,000
GBP
|
6,000,000
GBP
|
— |
7,856,000,000
GBP
|
— | — | — | — |
7,643,000,000
GBP
|
640,000,000
GBP
|
— |
305,000,000
GBP
|
— | — | — |
4,970,000,000
GBP
|
306,000,000
GBP
|
6,810,000,000
GBP
|
— |
–
GBP
|
— | — | — |
–
GBP
|
170,000,000
GBP
|
3,000,000
GBP
|
1,064,000,000
GBP
|
640,000,000
GBP
|
— | — |
6,813,000,000
GBP
|
— | — |
6,564,000,000
GBP
|
2,845,000,000
GBP
|
6,666,000,000
GBP
|
640,000,000
GBP
|
2,886,000,000
GBP
|
99,000,000
GBP
|
3,000,000
GBP
|
134,000,000
GBP
|
327,000,000
GBP
|
| Changes in equity [abstract] | ||||||||||||||||||||||||||||||||||||||||||||||
| Comprehensive income [abstract] | ||||||||||||||||||||||||||||||||||||||||||||||
| Profit (loss) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
995,000,000
GBP
|
— |
838,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Other comprehensive income | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
141,000,000
GBP
|
— |
288,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Comprehensive income | — | — | — |
22,000,000
GBP
|
— | — |
1,135,000,000
GBP
|
— |
–
GBP
|
1,000,000
GBP
|
–
GBP
|
–
GBP
|
— | — |
–
GBP
|
— |
1,136,000,000
GBP
|
1,113,000,000
GBP
|
1,126,000,000
GBP
|
— | — | — |
1,115,000,000
GBP
|
— |
5,000,000
GBP
|
–
GBP
|
–
GBP
|
— | — | — | — | — |
6,000,000
GBP
|
–
GBP
|
— |
–
GBP
|
1,121,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Issue of equity | — | — | — |
–
GBP
|
— | — |
–
GBP
|
— |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
— | — |
–
GBP
|
— |
–
GBP
|
–
GBP
|
–
GBP
|
— | — | — |
–
GBP
|
— |
–
GBP
|
–
GBP
|
–
GBP
|
— | — | — | — | — |
–
GBP
|
–
GBP
|
— |
–
GBP
|
–
GBP
|
— | — | — | — | — | — | — | — | — |
| Dividends recognised as distributions to owners | — | — | — |
–
GBP
|
— | — |
308,000,000
GBP
|
— |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
— | — |
–
GBP
|
— |
308,000,000
GBP
|
308,000,000
GBP
|
479,000,000
GBP
|
— | — | — |
479,000,000
GBP
|
— |
–
GBP
|
–
GBP
|
–
GBP
|
— | — | — | — | — |
–
GBP
|
–
GBP
|
— |
–
GBP
|
479,000,000
GBP
|
— | — | — | — | — | — | — | — | — |