Financial Instruments - Disclosure of Analysis of Fair Value of Financial Instruments Measured at Fair Value on a Recurring Basis (Details) - GBP (£) £ in Millions | 6 Months Ended | |
Jun. 30, 2023 | Dec. 31, 2022 |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | £ 9,889 | £ 8,560 |
Liabilities at fair value | 2,407 | 1,754 |
Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 1,543 | 951 |
Other financial liabilities at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 864 | 803 |
Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 2,556 | 2,407 |
Other financial assets at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 261 | 129 |
Financial assets at FVOCI | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 7,072 | 6,024 |
Level 1 | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 6,968 | 5,996 |
Liabilities at fair value | 0 | 0 |
Level 1 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 0 | 0 |
Level 1 | Other financial liabilities at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 0 | 0 |
Level 1 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 0 | 0 |
Level 1 | Other financial assets at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 0 | 0 |
Level 1 | Financial assets at FVOCI | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 6,968 | 5,996 |
Level 2 | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 2,783 | 2,410 |
Liabilities at fair value | 2,398 | 1,739 |
Level 2 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 1,534 | 939 |
Level 2 | Other financial liabilities at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 864 | 800 |
Level 2 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 2,520 | 2,370 |
Level 2 | Other financial assets at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 159 | 12 |
Level 2 | Financial assets at FVOCI | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 104 | 28 |
Level 3 | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 138 | 154 |
Liabilities at fair value | 9 | 15 |
Level 3 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 9 | 12 |
Level 3 | Other financial liabilities at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 0 | 3 |
Level 3 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 36 | 37 |
Level 3 | Other financial assets at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 102 | 117 |
Level 3 | Financial assets at FVOCI | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | £ 0 | 0 |
Exchange rate contracts | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Valuation technique | A | |
Liabilities at fair value | £ 440 | 471 |
Exchange rate contracts | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | £ 1,446 | 2,044 |
Valuation technique | A | |
Exchange rate contracts | Level 1 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | £ 0 | 0 |
Exchange rate contracts | Level 1 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 0 | 0 |
Exchange rate contracts | Level 2 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 440 | 471 |
Exchange rate contracts | Level 2 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 1,446 | 2,044 |
Exchange rate contracts | Level 3 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 0 | 0 |
Exchange rate contracts | Level 3 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | £ 0 | 0 |
Interest rate contracts | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Valuation technique | A & C | |
Liabilities at fair value | £ 3,345 | 2,628 |
Interest rate contracts | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | £ 3,235 | 2,406 |
Valuation technique | A & C | |
Interest rate contracts | Level 1 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | £ 0 | 0 |
Interest rate contracts | Level 1 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 0 | 0 |
Interest rate contracts | Level 2 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 3,345 | 2,624 |
Interest rate contracts | Level 2 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 3,232 | 2,399 |
Interest rate contracts | Level 3 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 0 | 4 |
Interest rate contracts | Level 3 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | £ 3 | 7 |
Equity and credit contracts | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Valuation technique | B & D | |
Liabilities at fair value | £ 20 | 25 |
Equity and credit contracts | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | £ 137 | 130 |
Valuation technique | B & D | |
Equity and credit contracts | Level 1 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | £ 0 | 0 |
Equity and credit contracts | Level 1 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 0 | 0 |
Equity and credit contracts | Level 2 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 11 | 17 |
Equity and credit contracts | Level 2 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 104 | 100 |
Equity and credit contracts | Level 3 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 9 | 8 |
Equity and credit contracts | Level 3 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 33 | 30 |
Netting | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | (2,262) | (2,173) |
Netting | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | (2,262) | (2,173) |
Netting | Level 1 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 0 | 0 |
Netting | Level 1 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 0 | 0 |
Netting | Level 2 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | (2,262) | (2,173) |
Netting | Level 2 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | (2,262) | (2,173) |
Netting | Level 3 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 0 | 0 |
Netting | Level 3 | Derivative financial instruments | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 0 | 0 |
Loans and advances to customers | Other financial assets at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | £ 42 | 45 |
Valuation technique | A | |
Loans and advances to customers | Level 1 | Other financial assets at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | £ 0 | 0 |
Loans and advances to customers | Level 2 | Other financial assets at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 0 | 0 |
Loans and advances to customers | Level 3 | Other financial assets at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 42 | 45 |
Debt securities | Other financial assets at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | £ 219 | 84 |
Valuation technique | A, B & D | |
Debt securities | Financial assets at FVOCI | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | £ 7,072 | 6,024 |
Valuation technique | D | |
Debt securities | Level 1 | Other financial assets at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | £ 0 | 0 |
Debt securities | Level 1 | Financial assets at FVOCI | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 6,968 | 5,996 |
Debt securities | Level 2 | Other financial assets at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 159 | 12 |
Debt securities | Level 2 | Financial assets at FVOCI | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 104 | 28 |
Debt securities | Level 3 | Other financial assets at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | 60 | 72 |
Debt securities | Level 3 | Financial assets at FVOCI | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Assets at fair value | £ 0 | 0 |
Debt securities in issue | Other financial liabilities at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Valuation technique | A | |
Liabilities at fair value | £ 463 | 480 |
Debt securities in issue | Level 1 | Other financial liabilities at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 0 | 0 |
Debt securities in issue | Level 2 | Other financial liabilities at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 463 | 477 |
Debt securities in issue | Level 3 | Other financial liabilities at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | £ 0 | 3 |
Structured deposits | Other financial liabilities at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Valuation technique | A | |
Liabilities at fair value | £ 401 | 321 |
Structured deposits | Level 1 | Other financial liabilities at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 0 | 0 |
Structured deposits | Level 2 | Other financial liabilities at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 401 | 321 |
Structured deposits | Level 3 | Other financial liabilities at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | £ 0 | 0 |
Other | Other financial liabilities at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Valuation technique | D | |
Liabilities at fair value | £ 0 | 2 |
Other | Level 1 | Other financial liabilities at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 0 | 0 |
Other | Level 2 | Other financial liabilities at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | 0 | 2 |
Other | Level 3 | Other financial liabilities at FVTPL | | |
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items] | | |
Liabilities at fair value | £ 0 | £ 0 |