INVESTMENT OPERATIONS - Schedule of Amortized Cost and Fair Value of the Company's Investments Classified as Available-for-Sale (Details) - Successor - USD ($) $ in Thousands	11 Months Ended	12 Months Ended
Dec. 31, 2015	Dec. 31, 2016
Investments classified as available-for-sale
Amortized Cost	$ 36,724,217	$ 38,233,986
Gross Unrealized Gains	53,419	199,654
Gross Unrealized Losses	(2,930,440)	(1,862,975)
Fair Value	33,847,196	36,570,665
Total OTTI Recognized in OCI	(605)	(11,039)
Fixed maturities
Investments classified as available-for-sale
Amortized Cost	35,793,000	37,192,864
Gross Unrealized Gains	40,164	191,903
Gross Unrealized Losses	(2,923,963)	(1,841,290)
Fair Value	32,909,201	35,543,477
Total OTTI Recognized in OCI	(605)	(11,039)
Residential mortgage-backed securities
Investments classified as available-for-sale
Amortized Cost	1,773,099	1,913,413
Gross Unrealized Gains	9,286	10,737
Gross Unrealized Losses	(17,112)	(25,667)
Fair Value	1,765,273	1,898,483
Total OTTI Recognized in OCI		(9)
Commercial mortgage-backed securities
Investments classified as available-for-sale
Amortized Cost	1,328,317	1,850,620
Gross Unrealized Gains	428	2,528
Gross Unrealized Losses	(41,858)	(41,678)
Fair Value	1,286,887	1,811,470
Other asset-backed securities
Investments classified as available-for-sale
Amortized Cost	813,056	1,210,490
Gross Unrealized Gains	2,758	21,741
Gross Unrealized Losses	(18,763)	(20,698)
Fair Value	797,051	1,211,533
U.S. government-related securities
Investments classified as available-for-sale
Amortized Cost	1,566,260	1,308,192
Gross Unrealized Gains	449	422
Gross Unrealized Losses	(34,532)	(40,455)
Fair Value	1,532,177	1,268,159
Other government-related securities
Investments classified as available-for-sale
Amortized Cost	18,483	253,182
Gross Unrealized Gains	0	1,536
Gross Unrealized Losses	(743)	(14,797)
Fair Value	17,740	239,921
States, municipals, and political subdivisions
Investments classified as available-for-sale
Amortized Cost	1,729,732	1,760,837
Gross Unrealized Gains	682	1,224
Gross Unrealized Losses	(126,814)	(105,558)
Fair Value	1,603,600	1,656,503
Corporate securities
Investments classified as available-for-sale
Amortized Cost	28,499,691	28,801,768
Gross Unrealized Gains	26,369	153,715
Gross Unrealized Losses	(2,682,274)	(1,583,918)
Fair Value	25,843,786	27,371,565
Total OTTI Recognized in OCI		(11,030)
Preferred stock
Investments classified as available-for-sale
Amortized Cost	64,362	94,362
Gross Unrealized Gains	192	0
Gross Unrealized Losses	(1,867)	(8,519)
Fair Value	62,687	85,843
Equity securities
Investments classified as available-for-sale
Amortized Cost	724,226	761,340
Gross Unrealized Gains	13,255	7,751
Gross Unrealized Losses	(6,477)	(21,685)
Fair Value	731,004	747,406
Short-term investments
Investments classified as available-for-sale
Amortized Cost	206,991	279,782
Fair Value	$ 206,991	$ 279,782

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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-Publisher FASB
-Name Accounting Standards Codification
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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount before tax of other than temporary impairment (OTTI) on investment in available-for-sale debt security, recognized in other comprehensive loss.

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