Other	9 Months Ended
Sep. 30, 2012
Other [Abstract]
Other Items Disclosure	Debt At September 30, 2012, short-term debt consisted of $458.3 million of securities lending transactions. In August 2012, we issued $250.0 million of unsecured senior notes in a public offering. These notes, due in 2042, bear interest at a fixed rate of 5.75% and are payable semi-annually. The notes are callable at or above par and rank equally in right of payment with all of our other unsecured and unsubordinated debt. During the nine months ended September 30, 2012, we made principal payments of $38.1 million and $7.5 million on our senior secured non-recourse floating rate notes issued by Northwind Holdings, LLC and Tailwind Holdings, LLC, respectively. Income Tax At September 30, 2012, we had a liability of $32.2 million for unrecognized tax benefits, all of which is associated with deferred tax assets. During the second quarter of 2012, we released a liability for unrecognized tax benefits of $61.1 million along with a corresponding deferred tax asset. We recognized interest expense (benefits) and penalties of less than $0.1 million and $(10.5) million for the three and nine months ended September 30, 2012, respectively, and $1.5 million and $4.1 million for the three and nine months ended September 30, 2011, respectively. During 2010, the Internal Revenue Service (IRS) completed its examination of tax years 2005 and 2006 and issued its revenue agent's report (RAR) in December 2010. In January 2011, we filed a protest to the RAR with respect to all significant adverse proposed adjustments. Although we have not yet reached a final settlement with the IRS for these years, the appeal may be resolved in whole or in part within 12 months, and statutes of limitations may expire in multiple jurisdictions within the same period. As a result of the potential settlement and its effect on subsequent years, it is reasonably possible that our liability for unrecognized tax benefits could decrease within 12 months by $17.2 million to $22.0 million, with a commensurate decrease in deferred tax assets. We believe sufficient provision has been made for all uncertain tax provisions and that any adjustments by tax authorities with respect to such positions would not have a material adverse effect on our financial position, liquidity, or results of operations. During the third quarter of 2012, an income tax rate reduction was enacted which reduced the tax rate in the U.K. from 25 percent to 24 percent retroactive to April 2012 and from 24 percent to 23 percent effective April 2013. During the third quarter of 2011, an income tax rate reduction was enacted which reduced the tax rate in the U.K. from 27 percent to 26 percent retroactive to April 2011 and from 26 percent to 25 percent effective April 2012. We are required to adjust deferred tax assets and liabilities through income on the date of enactment of a rate change, and as such, we recorded a reduction of $9.3 million and $6.8 million to our income tax expense during the third quarters of 2012 and 2011, respectively.

Debt

At September 30, 2012, short-term debt consisted of $458.3 million of securities lending transactions.

In August 2012, we issued $250.0 million of unsecured senior notes in a public offering. These notes, due in 2042, bear interest at a fixed rate of 5.75% and are payable semi-annually. The notes are callable at or above par and rank equally in right of payment with all of our other unsecured and unsubordinated debt.

During the nine months ended September 30, 2012, we made principal payments of $38.1 million and $7.5 million on our senior secured non-recourse floating rate notes issued by Northwind Holdings, LLC and Tailwind Holdings, LLC, respectively.

Income Tax

At September 30, 2012, we had a liability of $32.2 million for unrecognized tax benefits, all of which is associated with deferred tax assets. During the second quarter of 2012, we released a liability for unrecognized tax benefits of $61.1 million along with a corresponding deferred tax asset. We recognized interest expense (benefits) and penalties of less than $0.1 million and $(10.5) million for the three and nine months ended September 30, 2012, respectively, and $1.5 million and $4.1 million for the three and nine months ended September 30, 2011, respectively.

During 2010, the Internal Revenue Service (IRS) completed its examination of tax years 2005 and 2006 and issued its revenue agent's report (RAR) in December 2010. In January 2011, we filed a protest to the RAR with respect to all significant adverse proposed adjustments. Although we have not yet reached a final settlement with the IRS for these years, the appeal may be resolved in whole or in part within 12 months, and statutes of limitations may expire in multiple jurisdictions within the same period. As a result of the potential settlement and its effect on subsequent years, it is reasonably possible that our liability for unrecognized tax benefits could decrease within 12 months by $17.2 million to $22.0 million, with a commensurate decrease in deferred tax assets. We believe sufficient provision has been made for all uncertain tax provisions and that any adjustments by tax authorities with respect to such positions would not have a material adverse effect on our financial position, liquidity, or results of operations.

During the third quarter of 2012, an income tax rate reduction was enacted which reduced the tax rate in the U.K. from 25 percent to 24 percent retroactive to April 2012 and from 24 percent to 23 percent effective April 2013. During the third quarter of 2011, an income tax rate reduction was enacted which reduced the tax rate in the U.K. from 27 percent to 26 percent retroactive to April 2011 and from 26 percent to 25 percent effective April 2012. We are required to adjust deferred tax assets and liabilities through income on the date of enactment of a rate change, and as such, we recorded a reduction of $9.3 million and $6.8 million to our income tax expense during the third quarters of 2012 and 2011, respectively.