MONY CLOSED BLOCK OF BUSINESS - Summary of Financial Information of the Policyholder Dividend Obligation (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Closed block liabilities
Future policy benefits, policyholders’ account balances and other policyholder liabilities	$ 5,593,437	$ 5,836,815
Policyholder dividend obligation	73,930	278,505	$ 11,803	$ 0
Other liabilities	17,732	11,247
Total closed block liabilities	5,685,099	6,126,567
Closed block assets
Fixed maturities, available-for-sale, at fair value	4,453,685	4,682,731
Mortgage loans on real estate	70,789	72,829
Policy loans	632,318	640,134
Cash and other invested assets	57,031	44,877
Other assets	100,885	107,177
Total closed block assets	5,314,708	5,547,748
Excess of reported closed block liabilities over closed block assets	370,391	578,819
Portion of above representing accumulated other comprehensive income:
Net unrealized gains (losses) - investments/derivatives net of policyholder dividend obligation: $— and $167,285; and net of income tax: $— and $(35,130)	0	0
Future earnings to be recognized from closed block assets and closed block liabilities	370,391	578,819
Policyholder dividend obligations	0	167,285
Deferred income tax expense (benefit)	$ 0	$ (35,130)