Investments in Unconsolidated Affiliates (Investment in Unconsolidated Affiliates Table) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended		9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2014	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Investments in unconsolidated affiliates
Equity in earnings of unconsolidated affiliates, net of tax	$ 3.9		$ 7.0				$ 18.0	$ 33.3
Total investments in unconsolidated affiliates	392.6						392.6		$ 414.4
Symetra
Investments in unconsolidated affiliates
Equity in Unrealized Gains (Losses) from Investments in Unconsolidated Affiliates	5.7						5.7		37.6
Symetra | Common Stock
Investments in unconsolidated affiliates
Equity in earnings of unconsolidated affiliates, net of tax	4.2		7.0				17.5	34.5
Symetra Common Shares excluding unrealized gains (losses)	386.9						386.9		373.8
Total investments in unconsolidated affiliates	392.6	$ 397.2	$ 409.8	$ 415.5	$ 397.2	$ 415.5	392.6	$ 409.8	411.4	$ 317.3
Hamer, LLC [Member]
Investments in unconsolidated affiliates
Equity in earnings of unconsolidated affiliates, net of tax		$ 1.1		$ 0.4	$ 1.6	$ 0.8
Total investments in unconsolidated affiliates	$ 0.0						$ 0.0		$ 3.0