v3.26.1
Credit risk - Management adjustments to models for impairment (Details) - GBP (£)
£ in Millions
Jun. 30, 2026
Dec. 31, 2025
Disclosure of financial assets [line items]    
Proportion of Management adjustments to total impairment allowance 3.20% 4.90%
Impairment allowance | American Airlines Portfolio | Assets classified as held for sale    
Disclosure of financial assets [line items]    
Financial assets £ 0 £ 200
Total impairment allowance | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 4,230 4,034
Impairment allowance pre management adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 4,094 3,835
Management adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 136 199
Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 66 81
Other adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 70 118
Total loans and advances at amortised cost including debt securities | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 66 81
Total loans and advances at amortised cost including debt securities | Stage 1 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 20 17
Total loans and advances at amortised cost including debt securities | Lifetime expected credit losses | Stage 2 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 46 64
Total loans and advances at amortised cost including debt securities | Lifetime expected credit losses | Stage 3 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets £ 0 £ 0
Total loans and advances at amortised cost    
Disclosure of financial assets [line items]    
Proportion of Management adjustments to total impairment allowance 3.20% 4.90%
Total loans and advances at amortised cost | Assets classified as held for sale    
Disclosure of financial assets [line items]    
Proportion of Management adjustments to total impairment allowance   2.10%
Total loans and advances at amortised cost | Impairment allowance | Assets classified as held for sale    
Disclosure of financial assets [line items]    
Financial assets   £ 236
Total loans and advances at amortised cost | Total impairment allowance | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets £ 4,214 4,015
Total loans and advances at amortised cost | Total impairment allowance | Impairment allowance | Assets classified as held for sale    
Disclosure of financial assets [line items]    
Financial assets   240
Total loans and advances at amortised cost | Impairment allowance pre management adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 4,080 3,817
Total loans and advances at amortised cost | Impairment allowance pre management adjustments | Impairment allowance | Assets classified as held for sale    
Disclosure of financial assets [line items]    
Financial assets   235
Total loans and advances at amortised cost | Modelled ECL | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 3,400 3,400
Total loans and advances at amortised cost | Individually assessed impairments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 700 500
Total loans and advances at amortised cost | Non-modelled exposures | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 0 100
Total loans and advances at amortised cost | Management adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 134 198
Total loans and advances at amortised cost | Management adjustments | Impairment allowance | Assets classified as held for sale    
Disclosure of financial assets [line items]    
Financial assets   5
Total loans and advances at amortised cost | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 64 80
Total loans and advances at amortised cost | Economic uncertainty adjustments | Impairment allowance | Assets classified as held for sale    
Disclosure of financial assets [line items]    
Financial assets   5
Total loans and advances at amortised cost | Other adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 70 118
Total loans and advances at amortised cost | Other adjustments | Impairment allowance | Assets classified as held for sale    
Disclosure of financial assets [line items]    
Financial assets   0
Total loans and advances at amortised cost | Stage 1 | Impairment allowance | Assets classified as held for sale    
Disclosure of financial assets [line items]    
Financial assets   66
Total loans and advances at amortised cost | Stage 1 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 19 16
Total loans and advances at amortised cost | Lifetime expected credit losses | Stage 2 | Impairment allowance | Assets classified as held for sale    
Disclosure of financial assets [line items]    
Financial assets   126
Total loans and advances at amortised cost | Lifetime expected credit losses | Stage 2 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 45 64
Total loans and advances at amortised cost | Lifetime expected credit losses | Stage 3 | Impairment allowance | Assets classified as held for sale    
Disclosure of financial assets [line items]    
Financial assets   44
Total loans and advances at amortised cost | Lifetime expected credit losses | Stage 3 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets £ 0 £ 0
Retail mortgages    
Disclosure of financial assets [line items]    
Proportion of Management adjustments to total impairment allowance 0.00% 24.20%
Retail mortgages | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets £ 37 £ 33
Retail mortgages | Total impairment allowance | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 37 33
Retail mortgages | Impairment allowance pre management adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 37 25
Retail mortgages | Management adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 0 8
Retail mortgages | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 0 0
Retail mortgages | Other adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 0 8
Retail mortgages | Stage 1 | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 8 9
Retail mortgages | Stage 1 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 0 0
Retail mortgages | Lifetime expected credit losses | Stage 2 | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 1 0
Retail mortgages | Lifetime expected credit losses | Stage 2 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 0 0
Retail mortgages | Lifetime expected credit losses | Stage 3 | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 28 24
Retail mortgages | Lifetime expected credit losses | Stage 3 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets £ 0 £ 0
Retail credit cards    
Disclosure of financial assets [line items]    
Proportion of Management adjustments to total impairment allowance 2.00% 4.50%
Retail credit cards | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets £ 2,647 £ 2,586
Retail credit cards | Total impairment allowance | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 2,690 2,623
Retail credit cards | Impairment allowance pre management adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 2,635 2,505
Retail credit cards | Management adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 55 118
Retail credit cards | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 0 31
Retail credit cards | Other adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 55 87
Retail credit cards | Stage 1 | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 412 395
Retail credit cards | Stage 1 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 0 0
Retail credit cards | Lifetime expected credit losses | Stage 2 | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 785 796
Retail credit cards | Lifetime expected credit losses | Stage 2 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 0 31
Retail credit cards | Lifetime expected credit losses | Stage 3 | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 1,450 1,395
Retail credit cards | Lifetime expected credit losses | Stage 3 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets £ 0 £ 0
Retail other    
Disclosure of financial assets [line items]    
Proportion of Management adjustments to total impairment allowance 3.00% (3.00%)
Retail other | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets £ 32 £ 32
Retail other | Total impairment allowance | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 33 33
Retail other | Impairment allowance pre management adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 32 34
Retail other | Management adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 1 (1)
Retail other | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 0 0
Retail other | Other adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 1 (1)
Retail other | Stage 1 | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 8 7
Retail other | Stage 1 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 0 0
Retail other | Lifetime expected credit losses | Stage 2 | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 6 5
Retail other | Lifetime expected credit losses | Stage 2 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 0 0
Retail other | Lifetime expected credit losses | Stage 3 | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 18 20
Retail other | Lifetime expected credit losses | Stage 3 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets £ 0 £ 0
Corporate loans    
Disclosure of financial assets [line items]    
Proportion of Management adjustments to total impairment allowance 5.40% 5.50%
Corporate loans | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets £ 1,088 £ 966
Corporate loans | Total impairment allowance | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 1,454 1,326
Corporate loans | Impairment allowance pre management adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 1,376 1,253
Corporate loans | Management adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 78 73
Corporate loans | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 64 49
Corporate loans | Other adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 14 24
Corporate loans | Stage 1 | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 144 141
Corporate loans | Stage 1 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 19 16
Corporate loans | Lifetime expected credit losses | Stage 2 | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 239 235
Corporate loans | Lifetime expected credit losses | Stage 2 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 45 33
Corporate loans | Lifetime expected credit losses | Stage 3 | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 705 590
Corporate loans | Lifetime expected credit losses | Stage 3 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets £ 0 £ 0
Debt securities at amortised cost    
Disclosure of financial assets [line items]    
Proportion of Management adjustments to total impairment allowance 12.50% 5.30%
Debt securities at amortised cost | Total impairment allowance | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets £ 16 £ 19
Debt securities at amortised cost | Impairment allowance pre management adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 14 18
Debt securities at amortised cost | Management adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 2 1
Debt securities at amortised cost | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 2 1
Debt securities at amortised cost | Other adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 0 0
Debt securities at amortised cost | Stage 1 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 1 1
Debt securities at amortised cost | Lifetime expected credit losses | Stage 2 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 1 0
Debt securities at amortised cost | Lifetime expected credit losses | Stage 3 | Economic uncertainty adjustments | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 0 0
Cash collateral and settlements | Management adjustments | Barclays Investment Bank | Other financial assets subject to impairment | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets 1 1
Reverse repurchase agreements | Management adjustments | Barclays Investment Bank | Other financial assets subject to impairment | Impairment allowance    
Disclosure of financial assets [line items]    
Financial assets £ 1 £ 1