OPERATING SEGMENTS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Summarized financial information for the company's segments
Revenues	$ 1,105,392	$ 1,053,788	$ 3,216,211	$ 3,388,532
Pre-tax Adjusted Operating Income (Loss)	120,582	84,968	350,499	302,919
Realized (losses) gains on investments and derivatives	45,400	9,299	35,413	286,907
Income before income tax	165,982	94,267	385,912	589,826
Income tax expense	(49,016)	(20,965)	(120,975)	(185,114)
Net income	116,966	73,302	264,937	404,712
Adjusted operating income tax (expense) benefit	(33,126)	(17,710)	(108,580)	(84,697)
After-tax adjusted operating income	87,456	67,258	241,919	218,222
Income tax benefit (expense) on adjustments	(15,890)	(3,255)	(12,395)	(100,417)
Realized investment (losses) gains:
Derivative financial instruments	5,302	532	(119,392)	75,988
All other investments	18,150	24,152	94,526	194,644
Net impairment losses recognized in earnings	(273)	(3,308)	(8,259)	(6,892)
Less: related amortization	(12,123)	21,532	(38,570)	4,409
Less: VA GLWB economic cost	(10,098)	(9,455)	(29,968)	(27,576)
Operating Segment Assets
Investments and other assets	74,815,547		74,815,547		$ 70,959,790
DAC and VOBA	2,164,450		2,164,450		2,024,524
Other intangibles	672,912		672,912		687,348
Goodwill	793,470		793,470		793,470
Total assets	78,446,379		78,446,379		74,465,132
Life Marketing
Summarized financial information for the company's segments
Revenues	397,096	382,224	1,174,048	1,148,121
Pre-tax Adjusted Operating Income (Loss)	10,798	(512)	55,217	37,712
Operating Segment Assets
Investments and other assets	14,700,306		14,700,306		14,050,905
DAC and VOBA	1,295,708		1,295,708		1,218,944
Other intangibles	286,444		286,444		300,664
Goodwill	200,274		200,274		200,274
Total assets	16,482,732		16,482,732		15,770,787
Acquisitions
Summarized financial information for the company's segments
Revenues	375,819	391,017	1,164,650	1,269,672
Pre-tax Adjusted Operating Income (Loss)	62,880	70,157	184,825	184,095
Operating Segment Assets
Investments and other assets	19,681,306		19,681,306		19,679,690
DAC and VOBA	77,157		77,157		106,532
Other intangibles	35,187		35,187		37,103
Goodwill	14,524		14,524		14,524
Total assets	19,808,174		19,808,174		19,837,849
Annuities
Summarized financial information for the company's segments
Revenues	110,870	139,265	357,589	546,378
Pre-tax Adjusted Operating Income (Loss)	51,779	43,033	130,128	135,789
Operating Segment Assets
Investments and other assets	20,442,345		20,442,345		20,076,818
DAC and VOBA	752,540		752,540		655,618
Other intangibles	173,450		173,450		183,449
Goodwill	336,677		336,677		336,677
Total assets	21,705,012		21,705,012		21,252,562
Stable Value Products
Summarized financial information for the company's segments
Revenues	49,933	27,380	132,863	83,519
Pre-tax Adjusted Operating Income (Loss)	27,992	14,700	74,258	44,326
Operating Segment Assets
Investments and other assets	4,664,251		4,664,251		3,373,646
DAC and VOBA	7,605		7,605		5,455
Other intangibles	8,222		8,222		8,722
Goodwill	113,813		113,813		113,813
Total assets	4,793,891		4,793,891		3,501,636
Asset Protection
Summarized financial information for the company's segments
Revenues	93,799	79,030	277,433	229,128
Pre-tax Adjusted Operating Income (Loss)	5,187	4,099	13,812	12,496
Operating Segment Assets
Investments and other assets	735,538		735,538		858,648
DAC and VOBA	31,440		31,440		37,975
Other intangibles	135,895		135,895		143,865
Goodwill	128,182		128,182		128,182
Total assets	1,031,055		1,031,055		1,168,670
Corporate and Other
Summarized financial information for the company's segments
Revenues	77,875	34,872	109,628	111,714
Pre-tax Adjusted Operating Income (Loss)	(38,054)	$ (46,509)	(107,741)	$ (111,499)
Operating Segment Assets
Investments and other assets	14,591,801		14,591,801		12,920,083
DAC and VOBA	0		0		0
Other intangibles	33,714		33,714		13,545
Goodwill	0		0		0
Total assets	$ 14,625,515		$ 14,625,515		$ 12,933,628