Pensions - Amounts in the Financial statements (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pensions
Fund assets at fair value	£ 37,598	£ 57,787	£ 57,249	£ 51,925	£ 48,752
Present value of fund liabilities	(27,601)	(46,808)	(48,864)	(44,115)	(39,607)
Net surplus	9,997	10,979	8,385	£ 7,810	£ 9,145
Net assets of schemes in surplus	318	602
Net liabilities of schemes in deficit	(98)	(114)
Retirement benefit liability	(220)	(488)	(602)
Asset ceiling/minimum funding
Pensions
Retirement benefit liability	£ 9,777	£ 10,491	£ 7,783

The present value, without deducting any plan assets, of expected future payments required to settle the obligation resulting from employee service in the current and prior periods. [Refer: Plan assets, at fair value]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

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No definition available.

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The amount of deficit or surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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The fair value of defined benefit plan assets. Plan assets comprise assets held by a long-term employee benefit fund and qualifying insurance policies. [Refer: At fair value [member]]

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The amount of surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [member]]

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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The amount of deficit in a defined benefit plan. [Refer: Defined benefit plans [member]]

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The fair value of any plan assets, less the present value of the defined benefit obligation. [Refer: Plan assets [member]]

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