Other	6 Months Ended
Jun. 30, 2012
Other [Abstract]
Other Items Disclosure	Debt At June 30, 2012, short-term debt consisted of $467.1 million of securities lending transactions. Regarding activity relative to our long-term debt, during the six months ended June 30, 2012, we made principal payments of $29.2 million and $5.0 million on our senior secured non-recourse floating rate notes issued by Northwind Holdings, LLC and Tailwind Holdings, LLC, respectively. Income Tax At June 30, 2012, we had a liability of $30.9 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. The interest expense (benefit) and penalties related to unrecognized tax benefits in our consolidated statements of income was $(11.0) million and $(10.5) million for the three and six months ended June 30, 2012, respectively, and $1.5 million and $2.6 million for the three and six months ended and June 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, it is reasonably possible that this appeal will be resolved in whole or in part within 12 months and that statutes of limitations may expire in multiple jurisdictions within the same period. As a result, it is reasonably possible that our liability for unrecognized tax benefits could decrease within 12 months by $0 million to $6.0 million. 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. In July 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. We are required to adjust deferred tax assets and liabilities through income on the date of enactment of a rate change. We will record a reduction of approximately $8.0 million to $10.0 million in our income tax expense in the third quarter of 2012 to reflect the impact of the rate change on our net tax liability related to our U.K. operations.

Debt

At June 30, 2012, short-term debt consisted of $467.1 million of securities lending transactions. Regarding activity relative to our long-term debt, during the six months ended June 30, 2012, we made principal payments of $29.2 million and $5.0 million on our senior secured non-recourse floating rate notes issued by Northwind Holdings, LLC and Tailwind Holdings, LLC, respectively.

Income Tax

At June 30, 2012, we had a liability of $30.9 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. The interest expense (benefit) and penalties related to unrecognized tax benefits in our consolidated statements of income was $(11.0) million and $(10.5) million for the three and six months ended June 30, 2012, respectively, and $1.5 million and $2.6 million for the three and six months ended and June 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, it is reasonably possible that this appeal will be resolved in whole or in part within 12 months and that statutes of limitations may expire in multiple jurisdictions within the same period. As a result, it is reasonably possible that our liability for unrecognized tax benefits could decrease within 12 months by $0 million to $6.0 million. 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.

In July 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. We are required to adjust deferred tax assets and liabilities through income on the date of enactment of a rate change. We will record a reduction of approximately $8.0 million to $10.0 million in our income tax expense in the third quarter of 2012 to reflect the impact of the rate change on our net tax liability related to our U.K. operations.