Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2024-12-31 |
As at 2023-12-31 |
As at 2022-12-31 |
As at 2021-12-31 |
|---|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | ||||
| Intangible assets and goodwill [abstract] | ||||
| Intangible assets and goodwill |
1,539,000,000
GBP
|
1,548,000,000
GBP
|
— | — |
| Investments accounted for using equity method [abstract] | ||||
| Investments in joint ventures accounted for using equity method |
289,000,000
GBP
|
245,000,000
GBP
|
— | — |
| Categories of financial assets [abstract] | ||||
| Financial assets at fair value through other comprehensive income [abstract] | ||||
| Financial assets at fair value through other comprehensive income |
9,040,000,000
GBP
|
8,481,000,000
GBP
|
— | — |
| Cash and cash equivalents [abstract] | ||||
| Cash and cash equivalents |
29,181,000,000
GBP
|
36,781,000,000
GBP
|
42,871,000,000
GBP
|
46,715,000,000
GBP
|
| Non-current assets or disposal groups classified as held for sale or as held for distribution to owners [abstract] | ||||
| Non-current assets or disposal groups classified as held for sale |
12,000,000
GBP
|
13,000,000
GBP
|
— | — |
| Miscellaneous assets [abstract] | ||||
| Net defined benefit asset |
439,000,000
GBP
|
723,000,000
GBP
|
— | — |
| Derivative financial assets |
1,204,000,000
GBP
|
1,432,000,000
GBP
|
— | — |
| Loans and advances | — | — | — | — |
| Loans and advances to banks |
1,032,000,000
GBP
|
1,080,000,000
GBP
|
— | — |
| Loans and advances to customers |
199,408,000,000
GBP
|
207,435,000,000
GBP
|
— | — |
| Cash and bank balances at central banks |
29,881,000,000
GBP
|
38,214,000,000
GBP
|
44,190,000,000
GBP
|
— |
| Mandatory reserve deposits at central banks |
1,580,000,000
GBP
|
2,311,000,000
GBP
|
2,223,000,000
GBP
|
— |
| Bank balances at central banks other than mandatory reserve deposits |
28,301,000,000
GBP
|
35,903,000,000
GBP
|
41,967,000,000
GBP
|
— |
| Reverse repurchase agreements and cash collateral on securities borrowed |
10,338,000,000
GBP
|
12,468,000,000
GBP
|
— | — |
| Other assets |
1,887,000,000
GBP
|
2,043,000,000
GBP
|
— | — |
| Miscellaneous liabilities [abstract] | ||||
| Net defined benefit liability |
23,000,000
GBP
|
66,000,000
GBP
|
— | — |
| Derivative financial liabilities |
702,000,000
GBP
|
818,000,000
GBP
|
— | — |
| Deposit liabilities | — | — | — | — |
| Deposits from banks |
13,993,000,000
GBP
|
20,332,000,000
GBP
|
— | — |
| Deposits from customers [abstract] | ||||
| Deposits from customers |
180,967,000,000
GBP
|
190,850,000,000
GBP
|
— | — |
| Subordinated liabilities [abstract] | ||||
| Subordinated liabilities |
2,385,000,000
GBP
|
2,386,000,000
GBP
|
— | — |
| Debt instruments issued |
35,673,000,000
GBP
|
33,910,000,000
GBP
|
— | — |
| Repurchase agreements and cash collateral on securities lent |
8,617,000,000
GBP
|
8,411,000,000
GBP
|
— | — |
| Other liabilities |
1,852,000,000
GBP
|
2,479,000,000
GBP
|
— | — |
| Issued capital [abstract] | ||||
| Issued capital |
3,105,000,000
GBP
|
3,105,000,000
GBP
|
— | — |
| Retained earnings [abstract] | ||||
| Retained earnings |
3,521,000,000
GBP
|
4,295,000,000
GBP
|
— | — |
| Net assets (liabilities) [abstract] | ||||
| Assets |
259,944,000,000
GBP
|
275,448,000,000
GBP
|
— | — |
| Liabilities |
246,171,000,000
GBP
|
260,825,000,000
GBP
|
— | — |
| Assets less current liabilities [abstract] |