Fair Value of Assets and Liabilities (Balances of Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	$ 2,524,272	$ 2,800,593
Trading account assets	5,653	6,131
Equity securities, available-for-sale, at fair value (cost, 2015: $14; 2014: $14)	17	17
Separate account assets	39,250,159	44,101,699
Margin Deposit Assets	(3,800)	3,000
Embedded Derivative, Fair Value of Embedded Derivative Asset (Liability)	(3,134,000)	(3,112,000)
Embedded Derivative Gross Asset	34,000	55,000
Embedded Derivative Gross Liability	3,168,000	3,167,000
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	2,524,272	2,800,593
Trading account assets	5,653	6,131
Equity securities, available-for-sale, at fair value (cost, 2015: $14; 2014: $14)	17	17
Short-term investments	158,227	57,185
Cash equivalents	225	225
Other long-term investments	115,820	95,191
Reinsurance recoverables	3,012,653	2,996,154
Receivables from parent and affiliates	37,340	41,068
Subtotal excluding separate account assets	5,854,207	5,996,564
Separate account assets	39,250,159	44,101,699
Total assets	45,104,366	50,098,263
Future policy benefits	3,134,077	3,112,411
Payables to parent and affiliates	0	0
Total liabilities	3,134,077	3,112,411
Assets, Netting	(21,508)	(24,288)
Liabilities, Netting	(25,277)	(21,249)
Fair Value, Measurements, Recurring | Other long-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Netting	(21,508)	(24,288)
Fair Value, Measurements, Recurring | Payables to parent and affiliates
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Netting	(25,277)	(21,249)
Level 1 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
Trading account assets	5,653	6,131
Equity securities, available-for-sale, at fair value (cost, 2015: $14; 2014: $14)	0	0
Short-term investments	157,257	57,185
Cash equivalents	0	0
Other long-term investments	0	0
Reinsurance recoverables	0	0
Receivables from parent and affiliates	0	0
Subtotal excluding separate account assets	162,910	63,316
Separate account assets	0	0
Total assets	162,910	63,316
Future policy benefits	0	0
Payables to parent and affiliates	0	0
Total liabilities	0	0
Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	2,350,471	2,643,999
Trading account assets	0	0
Equity securities, available-for-sale, at fair value (cost, 2015: $14; 2014: $14)	17	17
Short-term investments	520	0
Cash equivalents	0	0
Other long-term investments	135,209	118,846
Reinsurance recoverables	0	0
Receivables from parent and affiliates	29,676	18,748
Subtotal excluding separate account assets	2,515,893	2,781,610
Separate account assets	39,250,159	44,101,699
Total assets	41,766,052	46,883,309
Future policy benefits	0	0
Payables to parent and affiliates	25,277	21,249
Total liabilities	25,277	21,249
Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	173,801	156,594
Trading account assets	0	0
Equity securities, available-for-sale, at fair value (cost, 2015: $14; 2014: $14)	0	0
Short-term investments	450	0
Cash equivalents	225	225
Other long-term investments	2,119	633
Reinsurance recoverables	3,012,653	2,996,154
Receivables from parent and affiliates	7,664	22,320
Subtotal excluding separate account assets	3,196,912	3,175,926
Separate account assets	0	0
Total assets	3,196,912	3,175,926
Future policy benefits	3,134,077	3,112,411
Payables to parent and affiliates	0	0
Total liabilities	3,134,077	3,112,411
U.S. Treasury securities and obligations of U.S. government authorities and agencies | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	12,154	6,336
U.S. Treasury securities and obligations of U.S. government authorities and agencies | Level 1 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
U.S. Treasury securities and obligations of U.S. government authorities and agencies | Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	12,154	6,336
U.S. Treasury securities and obligations of U.S. government authorities and agencies | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
Obligations of U.S. states and their political subdivisions | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	20,212	70,789
Obligations of U.S. states and their political subdivisions | Level 1 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
Obligations of U.S. states and their political subdivisions | Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	20,212	70,789
Obligations of U.S. states and their political subdivisions | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
Foreign government bonds | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	49,283	37,355
Foreign government bonds | Level 1 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
Foreign government bonds | Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	49,283	37,355
Foreign government bonds | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
All other U.S. public corporate securities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	949,109	1,089,118
All other U.S. public corporate securities | Level 1 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
All other U.S. public corporate securities | Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	934,109	1,072,258
All other U.S. public corporate securities | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	15,000	16,860
All other U.S. private corporate securities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	631,075	658,657
All other U.S. private corporate securities | Level 1 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
All other U.S. private corporate securities | Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	523,298	560,113
All other U.S. private corporate securities | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	107,777	98,544
All other foreign public corporate securities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	136,222	123,860
All other foreign public corporate securities | Level 1 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
All other foreign public corporate securities | Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	136,222	123,860
All other foreign public corporate securities | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
All other foreign private corporate securities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	225,349	230,049
All other foreign private corporate securities | Level 1 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
All other foreign private corporate securities | Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	220,818	229,383
All other foreign private corporate securities | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	4,531	666
Asset-backed securities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	151,290	149,011
Asset-backed securities | Level 1 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
Asset-backed securities | Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	104,797	108,487
Asset-backed securities | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	46,493	40,524
Commercial mortgage-backed securities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	215,740	302,185
Commercial mortgage-backed securities | Level 1 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
Commercial mortgage-backed securities | Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	215,740	302,185
Commercial mortgage-backed securities | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
Residential mortgage-backed securities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	133,838	133,233
Residential mortgage-backed securities | Level 1 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
Residential mortgage-backed securities | Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	133,838	133,233
Residential mortgage-backed securities | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale, at fair value (amortized cost, 2015: $2,433,626; 2014: $2,609,253)	0	0
Equity securities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	5,653	6,131
Equity securities | Level 1 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	5,653	6,131
Equity securities | Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	0	0
Equity securities | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	$ 0	$ 0