Insurance Liabilities (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in unpaid disability and health claims
Balance at beginning of year, Unpaid disability and health claims	$ 1,066.0	$ 1,006.9	$ 1,061.8
Incurred:
Incurred: Current year	712.0	711.8	1,074.0
Incurred: Prior years	1.0	9.7	(10.8)
Total incurred	713.0	721.5	1,063.2
Payments:
Payments: Current year	432.1	446.3	820.8
Payments: Prior years	202.2	216.1	297.3
Total payments	634.3	662.4	1,118.1
Balance at end of year:
Total balance at end of year, Unpaid disability and health claims: Current year	279.9	265.5	253.2
Total balance at end of year, Unpaid disability and health claims: Prior years	864.8	800.5	753.7
Total balance at end of year, Unpaid disability and health claims	1,144.7	1,066.0	1,006.9
Supplemental information:
Claim adjustment expense liabilities	43.4	46.6	42.9
Reinsurance recoverables for unpaid claims	$ 260.1	$ 239.1	$ 204.7