Income Taxes (Details 2) - Dec. 31, 2015 £ in Millions, $ in Millions		USD ($)	GBP (£)
U.S. [Member] | Expiring 2017 - 2022 [Member]
Operating and capital loss carryforwards [Line Items]
Operating loss carryforwards		$ 143
U.S. [Member] | Capital loss carryforward [Member] | Expiring 2020 [Member]
Operating and capital loss carryforwards [Line Items]
Capital loss carryforwards		90
United Kingdom [Member]
Operating and capital loss carryforwards [Line Items]
Operating loss carryforwards	[1]	$ 133	£ 90

[1] £90 million