v3.26.1
Earnings per share - summary of earnings per share calculations (Details) - GBP (£)
£ / shares in Units, £ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Earnings per share [abstract]    
Earnings per share - basic, Earnings £ 3,162 £ 4,490
Earnings per share - diluted, Earnings 3,162 4,490
Adjusted earnings per share - basic, Earnings 3,650 3,573
Adjusted earnings per share - diluted, Earnings 3,650 3,573
Headline basic earnings per share, Earnings 3,436 3,698
Headline diluted earnings per share, Earnings £ 3,436 £ 3,698
Earnings per share - basic (in shares) 2,165,000,000 2,194,000,000
Earnings per share - diluted (in shares) 2,176,000,000 2,205,000,000
Adjusted earnings per share - basic (in shares) 2,165,000,000 2,194,000,000
Adjusted earnings per share - diluted (in shares) 2,176,000,000 2,205,000,000
Headline earnings per share - basic (in shares) 2,165,000,000 2,194,000,000
Headline earnings per share - diluted (in shares) 2,176,000,000 2,205,000,000
Earnings per share, basic (in GBP per share) £ 1.461 £ 2.046
Earnings per share - diluted (in GBP per share) 1.453 2.036
Adjusted earnings per share - basic (in GBP per share) 1.686 1.629
Adjusted earnings per share - diluted (in GBP per share) 1.677 1.620
Headline earnings per share - basic (in GBP per share) 1.587 1.685
Headline earnings per share - diluted (in GBP per share) 1.579 1.677
Adjusted diluted earnings per share (in GBP per share) £ 1.677 £ 1.620