AGENT DEFERRED COMPENSATION PLAN (NARRATIVE) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Cost recognized for defined contribution plan		$ 5.3	$ 5.0	$ 5.1
Agent Deferred Compensation Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Recognized pre-tax gain related to settlement distributions	$ 6.1
Pension and other postretirement defined benefit plans, liabilities		156.3	170.8
Net periodic benefit cost		8.1	2.2	36.3
Actuarial net gains (losses)		3.1	15.2	(24.3)
Company-owned life insurance		165.0	158.1
Change in value of corporate or bank owned life insurance		$ 6.9	$ 0.5	$ 5.7