Taxation (Operating Loss and Tax Credit Carryforwards, and Their Expiration Dates) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Operating Loss and Tax Credit Carryforwards [Line Items]
Gross value of NOLs and capital losses	$ 1,783.5	$ 1,610.1
Expirations of Tax Benefit Carryforwards
Winthin 1 to 2 years	0.8
Winthin 2 to 3 years	1.0
Winthin 3 to 4 years	0.8
Winthin 4 to 5 years	3.2
Winthin 5 to 6 years	2.4
After 6 years	117.9
Indefinitely	299.7
Unremitted earnings of the Company's foreign subsidiaries	7,800
R&D and Other Tax Credits
Operating Loss and Tax Credit Carryforwards [Line Items]
Tax credit carryforwards	66.2	62.1
US Federal
Operating Loss and Tax Credit Carryforwards [Line Items]
NOLs	26.1	45.3
US State
Operating Loss and Tax Credit Carryforwards [Line Items]
NOLs	31.4	19.8
UK
Operating Loss and Tax Credit Carryforwards [Line Items]
NOLs	20.7	24.8
Ireland
Operating Loss and Tax Credit Carryforwards [Line Items]
NOLs	72.6	58.0
Foreign Tax Jurisdictions
Operating Loss and Tax Credit Carryforwards [Line Items]
NOLs	$ 208.8	$ 174.7