Investments (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended																	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2014 securities	Jun. 30, 2013	Jun. 30, 2014 securities	Jun. 30, 2013	Dec. 31, 2013 securities	Jun. 30, 2014 Collateral Fixed Maturity Securities	Dec. 31, 2013 Collateral Fixed Maturity Securities	Jun. 30, 2014 Canadian Province Of Ontario Securities	Dec. 31, 2013 Canadian Province Of Ontario Securities	Jun. 30, 2014 Canadian Province Of Quebec Securities	Dec. 31, 2013 Canadian Province Of Quebec Securities	Jun. 30, 2014 Available For Sale Securities Amortized Cost [Member]	Dec. 31, 2013 Available For Sale Securities Amortized Cost [Member]	Jun. 30, 2014 Available For Sale Securities Fair Value Disclosure [Member]	Dec. 31, 2013 Available For Sale Securities Fair Value Disclosure [Member]	Jun. 30, 2013 Collateral Received Fixed Maturity Securities [Member]	Dec. 31, 2012 Collateral Received Fixed Maturity Securities [Member]	Jun. 30, 2014 Investment in mortgage loans	Dec. 31, 2013 Investment in mortgage loans	Jun. 30, 2014 Fixed maturity securities	Dec. 31, 2013 Fixed maturity securities	Jun. 30, 2014 Fixed maturity securities Non-investment grade securities	Dec. 31, 2013 Fixed maturity securities Non-investment grade securities	Jun. 30, 2014 Fixed maturity securities Corporate securities Non-investment grade securities	Dec. 31, 2013 Fixed maturity securities Corporate securities Non-investment grade securities
Investment Narrative [Line Items]
Transfer to Investments			$ 1,580,100,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss																				109,745,000	314,899,000	11,279,000	28,642,000	3,540,000	13,343,000
Available-for-sale Securities, Amortized Cost Basis	13,280,721,000		13,280,721,000		11,697,394,000	70,000,000	57,200,000
Securities held in trust												9,600,700,000	7,842,900,000	10,188,100,000	8,125,400,000
Proceeds From Sale Of Available For Sale Securities Sold At Loss	222,800,000	257,600,000	457,900,000	461,900,000
Available-for-sale Securities	14,151,411,000		14,151,411,000		12,110,755,000	71,800,000	58,000,000	1,336,500,000	1,222,300,000	1,553,800,000	1,389,100,000					111,800,000	94,100,000
Securities as a percentage of consolidated stockholder equity	10.00%		10.00%		10.00%
Number of fixed maturity and equity securities in an unrealized loss position	939		939		1,396
Gross Unrealized Losses - 12 months or greater																				78,536,000	80,715,000	8,777,000	17,580,000	1,359,000	3,892,000
Net other-than-temporary impairment losses on fixed maturities recognized in earnings	(870,000)	(10,109,000)	(1,173,000)	(10,311,000)
Realized losses on fixed maturity and equity securities sold	(6,877,000)	(6,760,000)	(13,460,000)	(17,972,000)
Minimum percentage of fair value			100.00%
Securities Borrowed												187,700,000	93,000,000	191,100,000	93,000,000
Collateral Obtained Percent Of Fair Value Reverse Repurchase Agreements			100.00%
Securities pledged or received	300,700,000		300,700,000		300,300,000
Securities Sold under Agreements to Repurchase, Fair Value of Collateral	315,200,000		315,200,000		310,800,000
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	354,900,000		354,900,000		344,200,000
Mortgage loans percentage of total investments	7.20%		7.20%		7.70%
Maximum loan to value ratio on mortgage loan approval			75.00%
Mortgage loans on nonaccrual status																		7,087,000	0
Policy loans, percentage of total investments	3.50%		3.50%		3.80%
Funds withheld at interest, percentage of total investments	16.80%		16.80%		17.80%
Funds withheld at interest	5,940,521,000		5,940,521,000		5,771,467,000
Funds withheld at interest, percentage attibutable to one client	$ 4,200,000,000		$ 4,200,000,000
Other invested assets, percentage of total investments	3.20%		3.20%		4.10%