Investments in Unconsolidated Affiliates (Symetra Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended							12 Months Ended			3 Months Ended	6 Months Ended		12 Months Ended			1 Months Ended	3 Months Ended			6 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Symetra	Dec. 31, 2012 Symetra	Dec. 31, 2011 Symetra technique	Jun. 20, 2013 Symetra	Dec. 31, 2013 Common Stock Symetra	Dec. 31, 2012 Common Stock Symetra	Dec. 31, 2011 Common Stock Symetra	Jun. 30, 2013 Warrants	Jun. 20, 2013 Warrants	Jun. 20, 2013 Warrants Symetra	Dec. 31, 2013 Warrants Symetra	Dec. 31, 2012 Warrants Symetra	Dec. 31, 2011 Warrants Symetra	Jan. 31, 2010 IPO Symetra	Mar. 31, 2010 IPO Symetra	Dec. 31, 2011 Minimum Symetra	Dec. 31, 2011 Maximum Symetra	Jun. 20, 2013 Symetra Common Stock	Jun. 20, 2013 equity in earnings of unconsolidated affiliates [Member] Symetra	Jun. 20, 2013 Net unrealized gains (losses) of unconsolidated affiliates [Member] Symetra	Dec. 31, 2011 Best Estimate [Member] Symetra
Investments in unconsolidated affiliates
Shares of symetra financial corporation owned (in shares)				20,050,000	17,400,000
Price per share																	$ 12.00
Investments in unconsolidated affiliates on conversion of warrants					9,490,000		2,650,000
Non-cumulative perpetual preference shares issued																	25,300,000
Number of shares sold in transaction by existing shareholders																	9,700,000
Ownership percentage before transaction																		24.00%
Ownership percentage after transaction																		20.00%
Decrease in carrying value of wymetra from dilution																	$ 16.0
Fair value of investment						261.0
Estimated fair value of investment per share						$ 15													$ 16	$ 30				$ 15
After-tax equity in losses of unconsolidated affiliates						45.9
Equity in net unrealized losses increase relating to amortization of common share impairment						136.6
Ownership interest (as a percent)				17.03%	14.60%
Number of valuation techniques						3
Term of amortization (in years)						30 years
Weight Average Years Remaining				29 years
After tax amortization through equity in earnings				2.7
After tax amortization through equity in net unrealized losses				10.8
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity				183.7
Risk free interest rate (as a percent)													0.34%
Volatility rate (as a percent)													26.50%
Per share price, class of warrant (in dollars per share)								$ 18.96					$ 15.53
Cash dividends received on warrants													1.5
Fair Value Assumptions, Expected Term													1 year 1 month 10 days
Class of Warrant or Right, Exercise Price of Warrants or Rights													11.49
Common shares repurchased and retired during the period		1,329,640																			6,600,000
Treasury Stock Acquired, Average Cost Per Share	$ 564.00	$ 503.00	$ 390.00																		$ 13.44
Unamortized basis difference							19.3															0.4	18.9
Gain (Loss) on Warrants				10.8	17.7	(24.5)		0	0	0	14.5	10.8		10.8	17.7	(24.5)
Dividends received				$ (6.4)	$ (4.9)	$ (4.0)		$ (6.4)	$ (4.9)	$ (4.0)				$ 0	$ 0	$ 0