Net investment expense (Details) - GBP (£) £ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Gains (losses) on financial instruments [abstract]
Net gains/(losses) from financial assets mandatorily at fair value	£ 19	£ (116)	£ (39)
Net (losses)/gains from disposal of debt instruments at fair value through other comprehensive income	(68)	248	251
Net (losses)/gains from disposal of financial assets and liabilities measured at amortised cost	(66)	22	(128)
Net losses on other investments	(208)	(234)	(205)
Net investment expense	£ (323)	£ (80)	£ (121)

The amount of income or (expense) arising from investments.

No definition available.

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- Definition

The amount of investment income that the entity does not separately disclose in the same statement or note.

+ References

No definition available.

+ Details

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- Definition

The cumulative gain (loss) on disposal of investments in equity instruments that the entity has designated at fair value through other comprehensive income. [Refer: At fair value [member]; Other comprehensive income]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2022-03-24
-Paragraph 11B
-Subparagraph c
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-URIDate 2022-03-24

+ Details

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- Definition

The gain (loss) arising from the derecognition of financial assets measured at amortised cost. [Refer: Financial assets at amortised cost]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2022-03-24
-Paragraph 82
-Subparagraph aa
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2022-en-r&anchor=para_82_aa&doctype=Standard
-URIDate 2022-03-24

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- Definition

The gains (losses) on financial assets mandatorily measured at fair value through profit or loss in accordance with IFRS 9. [Refer: Financial assets at fair value through profit or loss, mandatorily measured at fair value; Gains (losses) on financial assets at fair value through profit or loss; Financial liabilities]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2022-03-24
-Paragraph 20
-Subparagraph a
-Clause i
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-URIDate 2022-03-24

+ Details

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- References

No definition available.

+ Details

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