MORTGAGE LOANS (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014 item	Sep. 30, 2013	Sep. 30, 2014 item	Sep. 30, 2013	Dec. 31, 2013
Mortgage loans
Mortgage loan holdings	$ 5,232,463,000		$ 5,232,463,000		$ 5,493,492,000
Amount that would become due for the remainder of 2014, if loans are called at their next call dates	29,900,000		29,900,000
Amount that would become due in 2015 through 2019, if loans are called at their next call dates	1,100,000,000		1,100,000,000
Amount that would become due in 2020 through 2024, if loans are called at their next call dates	510,000,000		510,000,000
Amount that would become due after 2024, if loans are called at their next call dates	129,300,000		129,300,000
Commercial mortgage loans
Mortgage loans
Mortgage loan holdings	5,200,000,000		5,200,000,000
Mortgage loans having participation feature	583,400,000		583,400,000		666,600,000
Income recognized on participating mortgage loans	8,000,000	3,700,000	13,800,000	12,900,000
Nonperforming mortgage loans, foreclosed properties and restructured loans pursuant to pooling and servicing agreement	34,000,000		34,000,000
Nonperforming mortgage loans, foreclosed properties and restructured loans to invested assets (as a percent)	0.07%		0.07%
Number of mortgage loans permanently impaired	1		1
Mortgage loans accounted for as troubled debt restructurings	11,200,000		26,300,000
Principal amount accounted for as troubled debt restructurings	14,600,000		30,600,000
Principal amount of impaired loans accounted for as troubled debt restructurings	12,600,000		12,600,000
Impaired mortgage loans accounted for as troubled debt restructurings	7,300,000		7,300,000
Reduction in the entity's investment in mortgage loans, net of existing allowances for mortgage loan losses	5,300,000		6,200,000
Remaining mortgage loan transactions accounted for as troubled debt restructurings			21,848,000
Number of loan categories			2
Nonperforming or restructured loans not subject to a pooling and servicing agreement	34,000,000		34,000,000
Loans subject to a pooling and servicing agreement which are nonperforming	21,800,000		21,800,000
Number of nonperforming loans subject to a pooling and servicing agreement which have been restructured			0
Change in the allowance for credit losses
Beginning balance			3,130,000	2,875,000	2,875,000
Charge offs			(416,000)		(6,838,000)
Recoveries			(2,600,000)		(1,016,000)
Provision			3,536,000		8,109,000
Ending balance	$ 3,650,000		$ 3,650,000		$ 3,130,000
Commercial mortgage loans | Minimum
Mortgage loans
Period for exercise of call options or interest rate reset options			3 years
Commercial mortgage loans | Maximum
Mortgage loans
Period for exercise of call options or interest rate reset options			10 years
Loan-to-value ratio with participating interest (as a percent)	85.00%		85.00%