INVESTMENT OPERATIONS - Schedule of Investments' Gross Unrealized Losses and Fair Value of the Company's Investments that are Not Deemed to be Other-than-Temporarily Impaired (Details) - Successor - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value
Less Than 12 Months	$ 3,621,753	$ 30,286,819
12 Months or More	12,271,598	0
Total	15,893,351	30,286,819
Unrealized Loss
Less Than 12 Months	(54,354)	(2,930,440)
12 Months or More	(733,640)	0
Total	(787,994)	(2,930,440)
Residential mortgage-backed securities
Fair Value
Less Than 12 Months	86,908	977,433
12 Months or More	180,768	0
Total	267,676	977,433
Unrealized Loss
Less Than 12 Months	(433)	(17,112)
12 Months or More	(4,125)	0
Total	(4,558)	(17,112)
Commercial mortgage-backed securities
Fair Value
Less Than 12 Months	187,164	1,233,518
12 Months or More	104,931	0
Total	292,095	1,233,518
Unrealized Loss
Less Than 12 Months	(1,223)	(41,858)
12 Months or More	(1,470)	0
Total	(2,693)	(41,858)
Other asset-backed securities
Fair Value
Less Than 12 Months	68,039	633,274
12 Months or More	465,787	0
Total	533,826	633,274
Unrealized Loss
Less Than 12 Months	(268)	(18,763)
12 Months or More	(15,423)	0
Total	(15,691)	(18,763)
U.S. government-related securities
Fair Value
Less Than 12 Months	128,224	1,291,476
12 Months or More	3	0
Total	128,227	1,291,476
Unrealized Loss
Less Than 12 Months	(1,789)	(34,532)
12 Months or More	0	0
Total	(1,789)	(34,532)
Other government-related securities
Fair Value
Less Than 12 Months	1,927	17,740
12 Months or More	0	0
Total	1,927	17,740
Unrealized Loss
Less Than 12 Months	(2)	(743)
12 Months or More	0	0
Total	(2)	(743)
States, municipals, and political subdivisions
Fair Value
Less Than 12 Months	239,380	1,566,752
12 Months or More	561,253	0
Total	800,633	1,566,752
Unrealized Loss
Less Than 12 Months	(2,842)	(126,814)
12 Months or More	(20,487)	0
Total	(23,329)	(126,814)
Corporate securities
Fair Value
Less Than 12 Months	2,772,883	24,283,448
12 Months or More	10,879,675	0
Total	13,652,558	24,283,448
Unrealized Loss
Less Than 12 Months	(46,680)	(2,682,274)
12 Months or More	(684,682)	0
Total	(731,362)	(2,682,274)
Preferred stock
Fair Value
Less Than 12 Months	53,040	34,685
12 Months or More	19,251	0
Total	72,291	34,685
Unrealized Loss
Less Than 12 Months	(128)	(1,867)
12 Months or More	(1,687)	0
Total	(1,815)	(1,867)
Equity securities
Fair Value
Less Than 12 Months	84,188	248,493
12 Months or More	59,930	0
Total	144,118	248,493
Unrealized Loss
Less Than 12 Months	(989)	(6,477)
12 Months or More	(5,766)	0
Total	$ (6,755)	$ (6,477)