DEBT AND OTHER OBLIGATIONS - Non-Recourse Funding Obligations (Details)			3 Months Ended		12 Months Ended
	Jan. 15, 2016 USD ($)	Oct. 10, 2012 USD ($)	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)	Jan. 14, 2016 USD ($) reinsurer
Debt Instrument [Line Items]
Outstanding non-recourse funding obligations repurchased at a discount			$ 0	$ 11,300,000
Outstanding Principal			2,950,040,000		$ 2,961,040,000
Carrying Value			2,962,601,000		2,973,829,000
Financing Arrangement with Golden Gate and Syndicate if Risk Takers
Debt Instrument [Line Items]
Term of financing agreement	18 years
Financing capacity under the arrangement	$ 2,188,000,000.000
Golden Gate
Debt Instrument [Line Items]
Payments made under the agreements			0
Golden Gate | Steel City Notes
Debt Instrument [Line Items]
Outstanding non-recourse funding obligations			$ 2,090,000,000
Fixed interest rate (as a percent)			4.75%
Golden Gate | Non-recourse Funding Obligations Series
Debt Instrument [Line Items]
Outstanding non-recourse funding obligations	800,000,000					$ 800,000,000
Golden Gate | Series A1 Non-recourse Funding Obligation
Debt Instrument [Line Items]
Outstanding non-recourse funding obligations						$ 400,000,000
Fixed interest rate (as a percent)						7.375%
Golden Gate | Series A2 Non-recourse Funding Obligation
Debt Instrument [Line Items]
Outstanding non-recourse funding obligations						$ 100,000,000
Fixed interest rate (as a percent)						8.00%
Golden Gate | Series A3 Non-recourse Funding Obligation
Debt Instrument [Line Items]
Outstanding non-recourse funding obligations						$ 300,000,000
Fixed interest rate (as a percent)						8.45%
Golden Gate | Surplus Notes | Steel City Notes
Debt Instrument [Line Items]
Amount of debt issued	2,188,000,000.000
Long-term Debt			$ 2,090,000,000
Steel City | Surplus Notes | Golden Gate Surplus Notes
Debt Instrument [Line Items]
Amount of debt issued	$ 2,188,000,000.000
Golden Gate Captive Insurance Company
Debt Instrument [Line Items]
Outstanding Principal			2,090,000,000		2,116,000,000
Carrying Value			$ 2,090,000,000		$ 2,116,000,000
Year-to-Date Weighted-Avg Interest Rate			4.75%		4.75%
Golden Gate Captive Insurance Company | Non Recourse Funding Obligations
Debt Instrument [Line Items]
Number of series of non-recourse funding obligations | reinsurer						3
Golden Gate I I
Debt Instrument [Line Items]
Payments made under the agreements			$ 0
Outstanding non-recourse funding obligations			575,000,000
Non-recourse funding obligations held by external parties			58,600,000
Non-recourse funding obligations held by nonconsolidated affiliates			220,300,000
Non-recourse funding obligations held by consolidated subsidiaries of the Company			296,100,000
Amount of collateralized support agreement obligations by PLC			2,800,000
Outstanding Principal			278,949,000		$ 278,949,000
Carrying Value			$ 227,551,000		$ 227,338,000
Year-to-Date Weighted-Avg Interest Rate			1.57%		1.30%
Golden Gate V and Red Mountain
Debt Instrument [Line Items]
Payments made under the agreements			$ 0
Transaction period of financing for reserves related to a block of universal life insurance policies with secondary guarantees		20 years
Maximum amount to be financed for reserves related to a block of universal life insurance policies with secondary guarantees		$ 945,000,000
Red Mountain
Debt Instrument [Line Items]
Maximum amount to be financed for reserves related to a block of universal life insurance policies with secondary guarantees		945,000,000
Initial principal amount of note for deposit to a reinsurance trust		$ 275,000,000	580,000,000
Future scheduled capital contributions to prefund credit enhancements fees amount			128,300,000
Golden Gate V
Debt Instrument [Line Items]
Outstanding non-recourse funding obligations			$ 580,000,000
Fixed interest rate (as a percent)			6.25%
Maximum amount to be financed for reserves related to a block of universal life insurance policies with secondary guarantees			$ 945,000,000
Outstanding Principal			580,000,000		$ 565,000,000
Carrying Value			$ 642,599,000		$ 628,025,000
Year-to-Date Weighted-Avg Interest Rate			5.12%		5.12%
MONY
Debt Instrument [Line Items]
Outstanding Principal			$ 1,091,000		$ 1,091,000
Carrying Value			$ 2,451,000		$ 2,466,000
Year-to-Date Weighted-Avg Interest Rate			6.19%		6.19%