Dividends on ordinary shares (Details) - GBP (£) £ in Millions			6 Months Ended
May 15, 2026	Feb. 16, 2026	Jun. 30, 2025
Disclosure Of Dividends [Abstract]
Dividend paid	£ 700	£ 480	£ 640

The amount of dividends paid by the entity on ordinary shares. [Refer: Ordinary shares [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration