Pensions - History of defined benefit schemes (Details) - GBP (£) £ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pensions
Fair value of plan assets	£ 57,787	£ 57,249	£ 51,925	£ 48,752	£ 49,746
Present value of plan obligations	46,808	48,864	44,115	39,607	42,378
Net surplus/(deficit)	10,979	8,385	7,810	9,145	7,368
Actual return on plan assets	£ 1,667	£ 7,064	£ 4,930	£ (848)	£ 3,013
Actual return on plan assets - %	2.90%	13.60%	10.10%	(1.70%)	6.10%
Plan liabilities
Pensions
Experience gains/(losses)	£ 237	£ 455	£ 279	£ (81)	£ (93)
Plan assets
Pensions
Experience gains/(losses)	872	6,027	3,556	(2,090)	1,728
Main Scheme
Pensions
Fair value of plan assets	52,021	51,323	46,555	43,806	44,652
Present value of plan obligations	42,020	43,870	39,669	35,466	37,937
Net surplus/(deficit)	10,001	7,453	6,886	8,340	6,715
Actual return on plan assets	£ 1,554	£ 6,422	£ 4,266	£ (768)	£ 2,735
Actual return on plan assets - %	3.00%	13.80%	9.70%	(1.70%)	6.20%
Main Scheme \| Plan liabilities
Pensions
Experience gains/(losses)	£ 241	£ 427	£ 275	£ (122)	£ (107)
Main Scheme \| Plan assets
Pensions
Experience gains/(losses)	£ 841	£ 5,486	£ 3,021	£ (1,891)	£ 1,580

The amount of other comprehensive income, before tax, resulting from actuarial gains (losses) arising from experience adjustments that result in remeasurements of the net defined benefit liability (asset). Experience adjustments deal with the effects of differences between the previous actuarial assumptions and what has actually occurred. [Refer: Other comprehensive income, before tax, gains (losses) on remeasurements of defined benefit plans] [Contrast: Decrease (increase) in net defined benefit liability (asset) resulting from actuarial gains (losses) arising from experience adjustments]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2021-01-01
-Paragraph 135
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2021-en-r&anchor=para_135_b&doctype=Standard
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_ActuarialGainsLossesArisingFromExperienceAdjustmentsBeforeTaxDefinedBenefitPlans
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2021-01-01
-Paragraph 57
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2021-en-r&anchor=para_57_a&doctype=Standard
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_DefinedBenefitObligationAtPresentValue
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

Name:	ifrs-full_DisclosureOfDefinedBenefitPlansLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

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]]

+ References

+ Details

Name:	ifrs-full_PlanAssetsAtFairValue
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

+ Details

Name:	ifrs-full_SurplusDeficitInPlan
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Actual return on plan assets refers to the dividends, interest, and capital gains generated by assets held in a company's pension fund.

+ References

No definition available.

+ Details

Name:	nwg_ActualReturnOnPlanAssets
Namespace Prefix:	nwg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of actual return on plan assets.

+ References

No definition available.

+ Details

Name:	nwg_PercentageOfActualReturnOnPlanAssets
Namespace Prefix:	nwg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ifrs-full_NetDefinedBenefitLiabilityAssetAxis=ifrs-full_PresentValueOfDefinedBenefitObligationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_NetDefinedBenefitLiabilityAssetAxis=ifrs-full_PlanAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_DefinedBenefitPlansAxis=nwg_MainSectionOfRoyalBankOfScotlandGroupPensionFundMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: