Claims, Lawsuits And Other Contingencies (Details) £ in Millions	Dec. 31, 2015 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.

Name:	us-gaap_LossContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration