Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2024-12-31 |
As at 2024-12-31 |
As at 2024-12-31 |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
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 | — | — |
303,000,000
GBP
|
203,000,000
GBP
|
— | — | — | — | — | — |
| Investments in subsidiaries, joint ventures and associates reported in separate financial statements [abstract] | ||||||||||
| Investments in subsidiaries, joint ventures and associates reported in separate financial statements | — | — |
703,000,000
GBP
|
665,000,000
GBP
|
— | — | — | — | — | — |
| Categories of financial assets [abstract] | ||||||||||
| Financial assets at fair value through profit or loss [abstract] | ||||||||||
| Financial assets at fair value through profit or loss, mandatorily measured at fair value | — | — | — | — | — | — | — | — | — | — |
| Financial assets at fair value through profit or loss, classified as held for trading | — | — |
116,042,000,000
GBP
|
100,696,000,000
GBP
|
— | — | — | — | — | — |
| Cash and cash equivalents [abstract] | ||||||||||
| Cash equivalents [abstract] | ||||||||||
| Other banking arrangements, classified as cash equivalents |
nil
GBP
|
— |
15,908,000,000
GBP
|
28,704,000,000
GBP
|
— |
nil
GBP
|
23,182,000,000
GBP
|
— |
208,000,000
GBP
|
— |
| Other cash and cash equivalents |
nil
GBP
|
— | — | — | — |
2,000,000
GBP
|
— | — |
41,000,000
GBP
|
— |
| Cash and cash equivalents | — | — |
162,928,000,000
GBP
|
177,037,000,000
GBP
|
— | — |
189,907,000,000
GBP
|
— | — |
140,923,000,000
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 | — | — |
21,606,000,000
GBP
|
20,368,000,000
GBP
|
— | — | — | — | — | — |
| Miscellaneous assets [abstract] | ||||||||||
| Restricted cash and cash equivalents | — | — |
19,884,000,000
GBP
|
26,554,000,000
GBP
|
— | — |
23,395,000,000
GBP
|
— | — | — |
| Derivative financial assets | — | — |
198,172,000,000
GBP
|
174,116,000,000
GBP
|
— | — | — | — | — | — |
| Loans and advances | — | — | — | — | — | — | — | — | — | — |
| Loans and advances to banks | — |
114,000,000
GBP
|
14,521,000,000
GBP
|
14,371,000,000
GBP
|
8,103,000,000
GBP
|
— | — |
114,000,000
GBP
|
— | — |
| Loans and advances to customers | — | — |
82,666,000,000
GBP
|
75,491,000,000
GBP
|
— | — | — | — | — | — |
| Cash and bank balances at central banks |
1,511,000,000
GBP
|
— |
119,184,000,000
GBP
|
110,618,000,000
GBP
|
— |
177,000,000
GBP
|
131,433,000,000
GBP
|
— |
1,562,000,000
GBP
|
— |
| Reverse repurchase agreements and cash collateral on securities borrowed | — | — |
53,612,000,000
GBP
|
73,494,000,000
GBP
|
— | — | — | — | — | — |
| Items in course of collection from other banks | — | — | — |
2,114,000,000
GBP
|
— | — | — | — | — | — |
| Classes of other provisions [abstract] | ||||||||||
| Other provisions [abstract] | ||||||||||
| Other provisions | — | — |
275,000,000
GBP
|
390,000,000
GBP
|
— | — | — | — | — | — |
| Categories of financial liabilities [abstract] | ||||||||||
| Financial liabilities at fair value through profit or loss [abstract] | ||||||||||
| Financial liabilities at fair value through profit or loss that meet definition of held for trading | — | — |
42,633,000,000
GBP
|
42,276,000,000
GBP
|
— | — | — | — | — | — |
| Financial liabilities at fair value through profit or loss, designated upon initial recognition or subsequently | — | — |
37,443,000,000
GBP
|
32,545,000,000
GBP
|
— | — | — | — | — | — |
| Miscellaneous liabilities [abstract] | ||||||||||
| Derivative financial liabilities | — | — |
197,082,000,000
GBP
|
171,474,000,000
GBP
|
— | — | — | — | — | — |
| Deposit liabilities | — | — | — | — | — | — | — | — | — | — |
| Deposits from banks | — | — |
26,515,000,000
GBP
|
22,943,000,000
GBP
|
— | — | — | — | — | — |
| Deposits from customers [abstract] | ||||||||||
| Deposits from customers | — | — |
242,303,000,000
GBP
|
222,941,000,000
GBP
|
— | — | — | — | — | — |
| Subordinated liabilities [abstract] | ||||||||||
| Subordinated liabilities | — | — |
16,908,000,000
GBP
|
14,920,000,000
GBP
|
— | — | — | — | — | — |
| Debt instruments issued | — | — |
19,461,000,000
GBP
|
13,443,000,000
GBP
|
— | — | — | — | — | — |
| Repurchase agreements and cash collateral on securities lent | — | — |
40,384,000,000
GBP
|
53,416,000,000
GBP
|
— | — | — | — | — | — |
| Items in course of transmission to other banks | — | — | — |
2,116,000,000
GBP
|
— | — | — | — | — | — |
| Issued capital [abstract] | ||||||||||
| Issued capital | — | — |
797,000,000
GBP
|
797,000,000
GBP
|
— | — | — | — | — | — |
| Retained earnings [abstract] | ||||||||||
| Retained earnings | — | — |
25,040,000,000
GBP
|
24,724,000,000
GBP
|
— | — | — | — | — | — |
| Net assets (liabilities) [abstract] | ||||||||||
| Assets | — | — |
727,330,000,000
GBP
|
702,970,000,000
GBP
|
— | — | — | — | — | — |
| Liabilities | — | — |
700,277,000,000
GBP
|
678,465,000,000
GBP
|
— | — | — | — | — | — |
| Assets less current liabilities [abstract] |