Derivatives (Forward Contract Collateral) (Details) In Millions, unless otherwise specified	Mar. 31, 2014 USD ($)	Mar. 31, 2014 JPY (¥)	Dec. 31, 2013 USD ($)	Dec. 31, 2013 JPY (¥)	Mar. 31, 2014 Forward Contracts USD ($) Rating	Mar. 31, 2014 Forward Contracts SEK	Dec. 31, 2013 Forward Contracts USD ($)	Mar. 31, 2014 Interest Rate Cap Rating	Mar. 31, 2014 Standard & Poor's, A Rating Forward Contracts Barclays USD ($)	Dec. 31, 2013 Standard & Poor's, A Rating Forward Contracts Barclays USD ($)	Mar. 31, 2014 Standard & Poor's, A Rating Forward Contracts Deutsche Bank USD ($)	Dec. 31, 2013 Standard & Poor's, A Rating Forward Contracts Deutsche Bank USD ($)	Mar. 31, 2014 Standard & Poor's, A plus Forward Contracts JP Morgan USD ($)	Dec. 31, 2013 Standard & Poor's, A plus Forward Contracts JP Morgan USD ($)	Mar. 31, 2014 Standard & Poor's, AA- Rating Forward Contracts Goldman Sachs USD ($)	Dec. 31, 2013 Standard & Poor's, AA- Rating Forward Contracts Goldman Sachs USD ($)	Mar. 31, 2014 Standard & Poor's, AA- Rating Forward Contracts HSBC USD ($)	Dec. 31, 2013 Standard & Poor's, AA- Rating Forward Contracts HSBC USD ($)	Mar. 31, 2014 Standard & Poor's, AA- Rating Forward Contracts Royal Bank of Canada USD ($)	Dec. 31, 2013 Standard & Poor's, AA- Rating Forward Contracts Royal Bank of Canada USD ($)
Derivative [Line Items]
Notional amount	$ 1,800.0	¥ 187,900.0	$ 1,900.0	¥ 203,600.0	$ 23.2	150.5	$ 20.4		$ 8.1	$ 5.8	$ 7.1	$ 7.7	$ 0	$ 1.3	$ 4.4	$ 2.1	$ 3.6	$ 3.3	$ 0	$ 0.2
Carrying Value					$ (0.1)		$ (0.1)		$ (0.1)	$ 0		$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ (0.1)	$ 0	$ 0
S and P Credit Ratings					21	21		21