OFFSETTING OF ASSETS AND LIABILITIES - Schedule of Derivative Instruments by Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Derivative instruments by assets
Fair value of non-cash collateral	$ 30,400	$ 45,000
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives Not Subject to a master netting arrangement	676,456	414,827
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	676,456	414,827
Derivative Asset, Not Offset, Policy Election Deduction	210,744	70,322
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received	214,952	99,199
Net Amount	250,760	245,306
Free-Standing derivatives
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives	532,700	263,349
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	532,700	263,349
Derivative Asset, Not Subject to Master Netting Arrangement Deduction	210,744	70,322
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received	214,952	99,199
Net Amount	107,004	93,828
Total derivatives, subject to a master netting arrangement or similar arrangement
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives	532,700	263,349
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	532,700	263,349
Derivative Asset, Not Subject to Master Netting Arrangement Deduction	210,744	70,322
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received	214,952	99,199
Net Amount	107,004	93,828
Embedded derivative - Modco reinsurance treaties
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives Not Subject to a master netting arrangement	13,738	7,072
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	13,738	7,072
Derivative Asset, Not Offset, Policy Election Deduction	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received	0	0
Net Amount	13,738	7,072
Embedded derivative - GLWB
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives Not Subject to a master netting arrangement	34,235	54,221
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	34,235	54,221
Derivative Asset, Not Offset, Policy Election Deduction	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received	0	0
Net Amount	34,235	54,221
Derivatives with PLC
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives Not Subject to a master netting arrangement	95,610	90,049
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	95,610	90,049
Derivative Asset, Not Offset, Policy Election Deduction	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received	0	0
Net Amount	95,610	90,049
Other
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives Not Subject to a master netting arrangement	173	136
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	173	136
Derivative Asset, Not Offset, Policy Election Deduction	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received	0	0
Net Amount	173	136
Total derivatives, not subject to a master netting arrangement or similar arrangement
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives Not Subject to a master netting arrangement	143,756	151,478
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	143,756	151,478
Derivative Asset, Not Offset, Policy Election Deduction	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received	0	0
Net Amount	$ 143,756	$ 151,478

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and elected not to be offset.

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