INVESTMENTS IN VARIABLE INTEREST ENTITIES (SCHEDULE OF IMPACT ON BALANCE SHEET OF CONSOLIDATING VARIABLE INTEREST ENTITIES) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Assets [Abstract]
Investments held by variable interest entities	$ 1,724.3	$ 1,633.6
Cash and cash equivalents held by variable interest entities	189.3	364.4
Liabilities:
Borrowings related to variable interest entities	1,662.8	1,676.4
VIEs [Member]
Assets [Abstract]
Investments held by variable interest entities	1,724.3	1,633.6
Notes receivable of VIEs held by insurance subsidiaries	0.0	0.0
Cash and cash equivalents held by variable interest entities	189.3	364.4
Accrued investment income	3.0	3.3
Income tax assets, net	6.4	26.0
Other assets	13.1	1.4
Total assets	1,936.1	2,028.7
Liabilities:
Other liabilities	81.8	196.6
Borrowings related to variable interest entities	1,662.8	1,676.4
Notes payable of VIEs held by insurance subsidiaries	203.3	204.0
Total liabilities	1,947.9	2,077.0
Eliminations [Member]
Assets [Abstract]
Investments held by variable interest entities	0.0	0.0
Notes receivable of VIEs held by insurance subsidiaries	(204.2)	(204.3)
Cash and cash equivalents held by variable interest entities	0.0	0.0
Accrued investment income	(0.1)	0.0
Income tax assets, net	(1.3)	(1.9)
Other assets	(1.8)	(1.5)
Total assets	(207.4)	(207.7)
Liabilities:
Other liabilities	(6.4)	(7.2)
Borrowings related to variable interest entities	0.0	0.0
Notes payable of VIEs held by insurance subsidiaries	(203.3)	(204.0)
Total liabilities	(209.7)	(211.2)
Net Effect of Consolidating VIEs on the Balance Sheet [Member]
Assets [Abstract]
Investments held by variable interest entities	1,724.3	1,633.6
Notes receivable of VIEs held by insurance subsidiaries	(204.2)	(204.3)
Cash and cash equivalents held by variable interest entities	189.3	364.4
Accrued investment income	2.9	3.3
Income tax assets, net	5.1	24.1
Other assets	11.3	(0.1)
Total assets	1,728.7	1,821.0
Liabilities:
Other liabilities	75.4	189.4
Borrowings related to variable interest entities	1,662.8	1,676.4
Notes payable of VIEs held by insurance subsidiaries	0.0	0.0
Total liabilities	$ 1,738.2	$ 1,865.8