OPERATING SEGMENTS (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Summarized financial information for the company's segments
Revenues	$ 1,087,067	$ 1,116,401	$ 2,192,364	$ 2,243,314
Pre-tax Adjusted Operating Income (Loss)	146,134	130,651	281,523	272,661
Realized (losses) gains on investments and derivatives	(20,366)	38,010	(43,406)	67,842
Income before income tax	125,768	168,661	238,117	340,503
Income tax (expense) benefit	(41,500)	(56,541)	(78,435)	(113,035)
Net income	84,268	112,120	159,682	227,468
Adjusted operating income tax (expense) benefit	(48,628)	(43,237)	(93,627)	(89,290)
After-tax adjusted operating income	97,506	87,414	187,896	183,371
Income tax benefit (expense) on adjustments	7,128	(13,304)	15,192	(23,745)
Realized investment (losses) gains:
Derivative financial instruments	(108,188)	(83,366)	(178,066)	(156,865)
All other investments	53,717	88,783	76,558	170,511
Net impairment losses recognized in earnings	(2,785)	(967)	(10,616)	(3,584)
Less: related amortization	(15,703)	(13,073)	(26,447)	(17,123)
Less: VA GLWB economic cost	(21,187)	(20,487)	(42,271)	(40,657)
Operating Segment Assets
Investments and other assets	73,495,052		73,495,052		$ 71,501,997
Deferred policy acquisition costs and value of business acquired	2,094,497		2,094,497		2,019,829
Other intangibles	665,907		665,907		688,083
Goodwill	793,470		793,470		793,470
Total assets	77,048,926		77,048,926		75,003,379
Life Marketing
Summarized financial information for the company's segments
Revenues	407,046	412,892	828,438	821,974
Pre-tax Adjusted Operating Income (Loss)	23,243	24,562	42,188	38,263
Operating Segment Assets
Investments and other assets	14,507,558		14,507,558		14,050,170
Deferred policy acquisition costs and value of business acquired	1,265,342		1,265,342		1,218,944
Other intangibles	291,880		291,880		301,399
Goodwill	200,274		200,274		200,274
Total assets	16,265,054		16,265,054		15,770,787
Acquisitions
Summarized financial information for the company's segments
Revenues	387,464	453,848	788,831	878,655
Pre-tax Adjusted Operating Income (Loss)	68,278	45,285	121,945	113,938
Operating Segment Assets
Investments and other assets	19,543,986		19,543,986		19,679,690
Deferred policy acquisition costs and value of business acquired	91,168		91,168		106,532
Other intangibles	35,825		35,825		37,103
Goodwill	14,524		14,524		14,524
Total assets	19,685,503		19,685,503		19,837,849
Annuities
Summarized financial information for the company's segments
Revenues	112,322	97,243	220,964	235,657
Pre-tax Adjusted Operating Income (Loss)	46,578	56,901	99,585	110,530
Operating Segment Assets
Investments and other assets	20,775,682		20,775,682		20,243,333
Deferred policy acquisition costs and value of business acquired	704,256		704,256		655,618
Other intangibles	176,782		176,782		183,449
Goodwill	336,677		336,677		336,677
Total assets	21,993,397		21,993,397		21,419,077
Stable Value Products
Summarized financial information for the company's segments
Revenues	42,087	26,237	82,930	56,139
Pre-tax Adjusted Operating Income (Loss)	22,367	15,178	46,266	29,626
Operating Segment Assets
Investments and other assets	3,896,076		3,896,076		3,373,646
Deferred policy acquisition costs and value of business acquired	5,512		5,512		5,455
Other intangibles	8,389		8,389		8,722
Goodwill	113,813		113,813		113,813
Total assets	4,023,790		4,023,790		3,501,636
Asset Protection
Summarized financial information for the company's segments
Revenues	82,462	67,487	162,545	131,735
Pre-tax Adjusted Operating Income (Loss)	6,536	5,462	12,135	10,761
Operating Segment Assets
Investments and other assets	1,050,098		1,050,098		1,013,399
Deferred policy acquisition costs and value of business acquired	28,219		28,219		33,280
Other intangibles	138,557		138,557		143,865
Goodwill	128,182		128,182		128,182
Total assets	1,345,056		1,345,056		1,318,726
Corporate and Other
Summarized financial information for the company's segments
Revenues	55,686	58,694	108,656	119,154
Pre-tax Adjusted Operating Income (Loss)	(20,868)	$ (16,737)	(40,596)	$ (30,457)
Operating Segment Assets
Investments and other assets	13,721,652		13,721,652		13,141,759
Deferred policy acquisition costs and value of business acquired	0		0		0
Other intangibles	14,474		14,474		13,545
Goodwill	0		0		0
Total assets	$ 13,736,126		$ 13,736,126		$ 13,155,304