Claims, Lawsuits And Other Contingencies (Details) £ in Millions	Dec. 31, 2017 GBP (£)
Other Contingencies-Guarantees
Loss Contingencies [Line Items]
Amount reinsured by third party	£ 40

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

No definition available.

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