Fair Value of Assets and Liabilities (Changes in Level 3 Assets and Liabilities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Included in earnings:
Realized investment gains (losses), net	$ 0
Cash Equivalents
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	225	$ 0
Included in earnings:
Realized investment gains (losses), net	0	0
Asset management fees and other income	0	0
Included in other comprehensive income (loss)	0	0
Net investment income	0	0
Purchases	0	400
Sales	0	(175)
Issuances	0	0
Settlements	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair Value, end of period	225	225	$ 0
Included in earnings:
Realized investment gains (losses), net	0	0
Asset management fees and other income	0	0
Other Long-term Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	633	486	1,054
Included in earnings:
Realized investment gains (losses), net	1,405	0	(739)
Asset management fees and other income	(17)	(14)	60
Included in other comprehensive income (loss)	0	0	0
Net investment income	22	0	0
Purchases	179	166	111
Sales	0	0	0
Issuances	0	0	0
Settlements	(103)	(5)	0
Transfers into Level 3	0	0	0
Transfers out of Level 3	0	0	0
Other			0
Fair Value, end of period	2,119	633	486
Included in earnings:
Realized investment gains (losses), net	1,405	0	0
Asset management fees and other income	(17)	(14)	51
Reinsurance Recoverables
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	2,996,154	748,005	1,732,094
Included in earnings:
Realized investment gains (losses), net	(212,035)	2,013,931	(1,220,073)
Asset management fees and other income	0	0	0
Included in other comprehensive income (loss)	0	0	0
Net investment income	0	0	0
Purchases	228,534	234,218	235,984
Sales	0	0	0
Issuances	0	0	0
Settlements	0	0	0
Transfers into Level 3	0	0	0
Transfers out of Level 3	0	0	0
Other			0
Fair Value, end of period	3,012,653	2,996,154	748,005
Included in earnings:
Realized investment gains (losses), net	(117,840)	2,040,048	(1,166,676)
Asset management fees and other income	0	0	0
Receivables from Parent and Affiliates
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	22,320	6,347	1,995
Included in earnings:
Realized investment gains (losses), net	0	0	0
Asset management fees and other income	0	0	0
Included in other comprehensive income (loss)	(264)	(420)	99
Net investment income	1	0	0
Purchases	0	19,351	6,250
Sales	0	0	(2,996)
Issuances	0	0	0
Settlements	0	0	0
Transfers into Level 3	6,941	1,985	0
Transfers out of Level 3	(21,334)	(4,943)	(1,997)
Other			2,996
Fair Value, end of period	7,664	22,320	6,347
Included in earnings:
Realized investment gains (losses), net	0	0	0
Asset management fees and other income	0	0	0
Future Policy Benefits
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	(3,112,411)	(778,226)	(1,793,137)
Included in earnings:
Realized investment gains (losses), net	217,101	(2,088,505)	1,262,310
Asset management fees and other income	0	0	0
Included in other comprehensive income (loss)	0	0	0
Net investment income	0	0	0
Purchases	0	0	0
Sales	0	0	0
Issuances	(238,767)	(245,680)	(247,399)
Settlements	0	0	0
Transfers into Level 3	0	0	0
Transfers out of Level 3	0	0	0
Other			0
Fair Value, end of period	(3,134,077)	(3,112,411)	(778,226)
Included in earnings:
Realized investment gains (losses), net	119,609	(2,115,680)	1,207,600
Asset management fees and other income	0	0	0
U.S. Corporate Public Securities | Fixed Maturities Available-For-Sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	16,860	2,065	3,292
Included in earnings:
Realized investment gains (losses), net	0	0	0
Asset management fees and other income	0	0	0
Included in other comprehensive income (loss)	(23)	(42)	(551)
Net investment income	9	37	41
Purchases	0	14,999	0
Sales	0	0	0
Issuances	0	0	0
Settlements	(119)	(199)	(1,171)
Transfers into Level 3	0	0	4,976
Transfers out of Level 3	(1,727)	0	(4,522)
Other			0
Fair Value, end of period	15,000	16,860	2,065
Included in earnings:
Realized investment gains (losses), net		0	0
Asset management fees and other income	0	0	0
U.S. Corporate Private Securities | Fixed Maturities Available-For-Sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	98,544	93,841	91,088
Included in earnings:
Realized investment gains (losses), net	(16)	1,423	48
Asset management fees and other income	0	0	0
Included in other comprehensive income (loss)	(2,992)	(763)	(3,490)
Net investment income	5,264	4,953	4,658
Purchases	6,233	5,712	4,817
Sales	(1,548)	0	0
Issuances	0	0	0
Settlements	(1,863)	(6,622)	(3,280)
Transfers into Level 3	4,155	0	0
Transfers out of Level 3	0	0	0
Other			0
Fair Value, end of period	107,777	98,544	93,841
Included in earnings:
Realized investment gains (losses), net		0	0
Asset management fees and other income	0	0	0
Foreign Corporate Private Securities | Fixed Maturities Available-For-Sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	666	890	1,175
Included in earnings:
Realized investment gains (losses), net	62	169	1
Asset management fees and other income	0	0	0
Included in other comprehensive income (loss)	(24)	(41)	(138)
Net investment income	1	34	30
Purchases	0	9	0
Sales	0	(202)	0
Issuances	0	0	0
Settlements	(678)	(193)	(178)
Transfers into Level 3	4,504	0	0
Transfers out of Level 3	0	0	0
Other			0
Fair Value, end of period	4,531	666	890
Included in earnings:
Realized investment gains (losses), net	0	0	0
Asset management fees and other income	0	0	0
Asset-Backed Securities | Fixed Maturities Available-For-Sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	40,524	63,789	69,298
Included in earnings:
Realized investment gains (losses), net	9	0	0
Asset management fees and other income	0	0	0
Included in other comprehensive income (loss)	(170)	196	(470)
Net investment income	49	120	454
Purchases	20,053	14,933	40,868
Sales	(15,878)	0	0
Issuances	0	0	0
Settlements	(3,704)	(40,337)	(13,924)
Transfers into Level 3	34,921	28,152	0
Transfers out of Level 3	(29,311)	(26,329)	(29,441)
Other			(2,996)
Fair Value, end of period	46,493	40,524	63,789
Included in earnings:
Realized investment gains (losses), net	0	0	0
Asset management fees and other income	0	0	0
Commercial Mortgage-Backed Securities | Fixed Maturities Available-For-Sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	0	0	0
Included in earnings:
Realized investment gains (losses), net	0	0	0
Asset management fees and other income	0	0	0
Included in other comprehensive income (loss)	0	(83)	18
Net investment income	0	0	0
Purchases	1,565	52,518	17,169
Sales	0	0	0
Issuances	0	0	0
Settlements	0	0	0
Transfers into Level 3	0	0	0
Transfers out of Level 3	(1,565)	(52,435)	(17,187)
Other			0
Fair Value, end of period	0	0	0
Included in earnings:
Realized investment gains (losses), net	0	0	0
Asset management fees and other income	0	0	0
Short-term Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	0
Included in earnings:
Realized investment gains (losses), net	0
Asset management fees and other income	0
Included in other comprehensive income (loss)	0
Net investment income	0
Purchases	450
Sales	0
Issuances	0
Settlements	0
Transfers into Level 3	0
Transfers out of Level 3	0
Fair Value, end of period	450	0
Included in earnings:
Realized investment gains (losses), net	0
Asset management fees and other income	0
Equity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	0	192	0
Included in earnings:
Realized investment gains (losses), net		0	0
Asset management fees and other income		0	0
Included in other comprehensive income (loss)		0	0
Net investment income		0	0
Purchases		0	192
Sales		(192)	0
Issuances		0	0
Settlements		0	0
Transfers into Level 3		0	0
Transfers out of Level 3		0	0
Other			0
Fair Value, end of period		0	192
Included in earnings:
Realized investment gains (losses), net		0	0
Asset management fees and other income		0	0
Equity Securities | Trading Account Assets - Equity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	$ 0	313	207
Included in earnings:
Realized investment gains (losses), net		0	0
Asset management fees and other income		15	106
Included in other comprehensive income (loss)		0	0
Net investment income		0	0
Purchases		0	0
Sales		0	0
Issuances		0	0
Settlements		(328)	0
Transfers into Level 3		0	0
Transfers out of Level 3		0	0
Other			0
Fair Value, end of period		0	313
Included in earnings:
Realized investment gains (losses), net		0	0
Asset management fees and other income		$ 15	$ 107