ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		8 Months Ended	9 Months Ended	12 Months Ended
	Jan. 31, 2015	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance				$ 6,509,213
Other comprehensive income relating to other-than-temporary impaired investments for which a portion has been recognized in earnings		$ 1,451		(3,115)
Total other comprehensive income (loss)		(38,151)		(935,647)
Balance	$ 6,509,213	5,447,989		5,447,989
Accumulated Other Comprehensive Income (Loss).
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Other comprehensive income (loss) before reclassifications				(941,282)
Other comprehensive income relating to other-than-temporary impaired investments for which a portion has been recognized in earnings				(3,115)
Amounts reclassified from accumulated other comprehensive income (loss)				8,750
Total other comprehensive income (loss)				(935,647)
Balance		(935,647)		(935,647)
Unrealized gains and losses on available-for-sale securities
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Other comprehensive income (loss) before reclassifications				(941,196)
Other comprehensive income relating to other-than-temporary impaired investments for which a portion has been recognized in earnings				(3,115)
Amounts reclassified from accumulated other comprehensive income (loss)				8,664
Total other comprehensive income (loss)				(935,647)
Balance		(935,647)		(935,647)
Impact of DAC and VOBA		$ 506,900		506,900
Gains and losses on derivative instruments
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Other comprehensive income (loss) before reclassifications				(86)
Amounts reclassified from accumulated other comprehensive income (loss)				86
Predecessor
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance	5,831,151			6,397,439
Other comprehensive income relating to other-than-temporary impaired investments for which a portion has been recognized in earnings	(243)		$ 1,044		$ 4,494
Total other comprehensive income (loss)	477,766		$ (97,309)		774,522
Balance	6,397,439					$ 5,831,151
Predecessor | Accumulated Other Comprehensive Income (Loss).
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance	1,483,211			1,960,977	538,966	538,966
Other comprehensive income (loss) before reclassifications	482,152					983,983
Other comprehensive income relating to other-than-temporary impaired investments for which a portion has been recognized in earnings	(243)					3,498
Amounts reclassified from accumulated other comprehensive income (loss)	(4,143)					(43,236)
Total other comprehensive income (loss)	477,766					944,245
Balance	1,960,977					1,483,211
Predecessor | Unrealized gains and losses on available-for-sale securities
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance	1,483,293			1,961,027	540,201	540,201
Other comprehensive income (loss) before reclassifications	482,143					983,985
Other comprehensive income relating to other-than-temporary impaired investments for which a portion has been recognized in earnings	(243)					3,498
Amounts reclassified from accumulated other comprehensive income (loss)	(4,166)					(44,391)
Total other comprehensive income (loss)	477,734					943,092
Balance	1,961,027					1,483,293
Impact of DAC and VOBA	(492,600)					(504,400)	$ (189,800)
Predecessor | Gains and losses on derivative instruments
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance	(82)			$ (50)	$ (1,235)	(1,235)
Other comprehensive income (loss) before reclassifications	9					(2)
Amounts reclassified from accumulated other comprehensive income (loss)	23					1,155
Total other comprehensive income (loss)	32					1,153
Balance	$ (50)					$ (82)