Condensed consolidated income statement (unaudited) (Parenthetical) £ in Millions	Apr. 24, 2026 GBP (£)
Profit or loss [abstract]
Gain on exit of American Airlines partnership	£ 225

Gain (Loss) From Disposal of Non-Current Assets or Disposal Groups Classified as Held For Sale and Discontinued Operations

No definition available.

Name:	bcs_GainLossFromDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations
Namespace Prefix:	bcs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration