Taxation (Operating Loss and Tax Credit Carryforwards, and Their Expiration Dates) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Operating Loss and Tax Credit Carryforwards [Line Items]
Gross value of NOLs and capital losses	$ 3,313,000,000	$ 2,583,700,000
Expirations of Tax Benefit Carryforwards
Within 1 year	1,000,000
Winthin 1 to 2 years	800,000
Winthin 2 to 3 years	3,400,000
Winthin 3 to 4 years	10,300,000
Winthin 4 to 5 years	42,100,000
Winthin 5 to 6 years	20,100,000
After 6 years	244,000,000
Indefinitely	364,600,000
Unremitted earnings of the Company's foreign subsidiaries	8,100
US federal tax
Operating Loss and Tax Credit Carryforwards [Line Items]
Tax credit carryforwards	38,700,000	32,200,000
US state
Operating Loss and Tax Credit Carryforwards [Line Items]
Tax credit carryforwards	82,800,000	61,500,000
UK
Operating Loss and Tax Credit Carryforwards [Line Items]
Tax credit carryforwards	4,000,000	6,700,000
Republic of Ireland
Operating Loss and Tax Credit Carryforwards [Line Items]
Tax credit carryforwards	75,200,000	78,800,000
Foreign Tax Jurisdictions
Operating Loss and Tax Credit Carryforwards [Line Items]
Tax credit carryforwards	347,800,000	273,100,000
R&D and Other Tax Credits
Operating Loss and Tax Credit Carryforwards [Line Items]
Tax credit carryforwards	$ 137,800,000	$ 48,300,000