Investments (Details 13) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013 item	Jun. 30, 2012 item	Jun. 30, 2013 item	Jun. 30, 2012 item
Mortgage Loan Modifications
Number of mortgage loans modified as a troubled debt restructuring	23	56	58	106
Recorded investment of mortgage loans modified as a troubled debt restructuring	$ 1.2	$ 43.6	$ 4.3	$ 50.3
Number of mortgage loans modified as a troubled debt restructuring in payment default	3	1	15	3
Recorded investment of mortgage loans modified as a troubled debt restructuring in payment default	0.7		0.7
Brick and mortar
Mortgage Loan Modifications
Number of mortgage loans modified as a troubled debt restructuring	1	2	2	3
Recorded investment of mortgage loans modified as a troubled debt restructuring	0.2	41.4	0.9	45.8
Home equity
Mortgage Loan Modifications
Number of mortgage loans modified as a troubled debt restructuring	21	54	53	103
Recorded investment of mortgage loans modified as a troubled debt restructuring	0.8	2.2	2.8	4.5
Number of mortgage loans modified as a troubled debt restructuring in payment default	1	1	13	3
First liens
Mortgage Loan Modifications
Number of mortgage loans modified as a troubled debt restructuring	1		3
Recorded investment of mortgage loans modified as a troubled debt restructuring	0.2		0.6
Number of mortgage loans modified as a troubled debt restructuring in payment default	2		2
Recorded investment of mortgage loans modified as a troubled debt restructuring in payment default	$ 0.7		$ 0.7