Implementation of IFRS 16 (Details) - GBP (£) £ in Millions	Jun. 30, 2019	Dec. 31, 2018
Disclosure of initial application of standards or interpretations [line items]
Lease liabilities	£ 1,813	£ 97
Right-of-use assets	£ 1,716
UK
Disclosure of initial application of standards or interpretations [line items]
Weighted average lessee's incremental borrowing rate	2.43%
US
Disclosure of initial application of standards or interpretations [line items]
Weighted average lessee's incremental borrowing rate	5.10%

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

No definition available.

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- Definition

The amount of liabilities related to the entity's leases. Lease is a contract, or part of a contract, that conveys the right to use an underlying asset for a period of time in exchange for consideration.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2019-01-01
-Name IFRS
-Number 16
-IssueDate 2018-01-01
-Paragraph 47
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=16&date=2018-03-01&anchor=para_47_b&doctype=Standard
-URIDate 2018-03-16

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- Definition

The amount of right-of-use assets that do not meet the definition of investment property. [Refer: Right-of-use assets; Investment property]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2019-01-01
-Name IFRS
-Number 16
-IssueDate 2018-01-01
-Paragraph 47
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=16&date=2018-03-01&anchor=para_47_a&doctype=Standard
-URIDate 2018-03-16

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- Definition

The weighted average lessee's incremental borrowing rate applied to lease liabilities recognised in the statement of financial position at the date of initial application of IFRS 16. The incremental borrowing rate is the rate of interest that a lessee would have to pay to borrow over a similar term, and with a similar security, the funds necessary to obtain an asset of a similar value to the right-of-use asset in a similar economic environment.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2019-01-01
-Name IFRS
-Number 16
-IssueDate 2018-01-01
-Paragraph C12
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=16&date=2018-03-01&anchor=para_C12_a&doctype=Appendix&seq=3
-URIDate 2018-03-16

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