Consolidated statement of comprehensive income (Parenthetical) - GBP (£) £ in Millions		3 Months Ended
Oct. 09, 2018	Mar. 31, 2019
NWB Plc
Disclosure of transactions between related parties [line items]
Contribution under the MoU to strengthen funding of the Main section and NWM section.	£ 2,000
NWM Plc
Disclosure of transactions between related parties [line items]
Contribution under the MoU to strengthen funding of the Main section and NWM section.		£ 53

The amount of employer contributions to retirement benefit plans.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 26
-IssueDate 2020-01-01
-Paragraph 35
-Subparagraph b
-Clause i
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=26&code=ifrs-tx-2020-en-r&anchor=para_35_b_i&doctype=Standard
-URIDate 2020-01-01

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