PENSION AND OTHER POSTRETIREMENT BENEFITS (Effect of Fair Value Measurements Using Significant Unobservable Inputs (Level 3) on Changes in Other Benefit Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	$ 188.1	$ 169.8
Actual return on plan assets:
Relating to assets still held at the reporting date	5.5	15.5
Acquired through business combinations	5.7	6.8
Sales	(8.4)	(7.0)
Fair value of plan assets — end of year	193.4	188.1
Hedge Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	41.5	38.8
Actual return on plan assets:
Relating to assets still held at the reporting date	(0.8)	2.7
Acquired through business combinations	0.0	0.0
Sales	0.0	0.0
Fair value of plan assets — end of year	40.7	41.5
Private Equity Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	31.2	29.1
Actual return on plan assets:
Relating to assets still held at the reporting date	1.5	3.2
Acquired through business combinations	5.7	1.4
Sales	(7.8)	(5.5)
Fair value of plan assets — end of year	33.1	31.2
Real Estate [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	50.0	40.9
Actual return on plan assets:
Relating to assets still held at the reporting date	8.1	5.2
Acquired through business combinations	0.0	5.4
Sales	(0.6)	(1.5)
Fair value of plan assets — end of year	57.5	50.0
Other Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	269.3	251.8
Actual return on plan assets:
Fair value of plan assets — end of year	250.6	269.3
Other Benefits [Member] | Hedge Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	11.5
Actual return on plan assets:
Fair value of plan assets — end of year	11.2	11.5
Other Benefits [Member] | Private Equity Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	6.2
Actual return on plan assets:
Fair value of plan assets — end of year	5.5	6.2
Other Benefits [Member] | Structured Credit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	6.1
Actual return on plan assets:
Fair value of plan assets — end of year	5.8	6.1
Other Benefits [Member] | Real Estate [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	8.7
Actual return on plan assets:
Fair value of plan assets — end of year	10.0	8.7
Significant Unobservable Inputs (Level 3) [Member] | Other Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	32.5	57.3
Actual return on plan assets:
Relating to assets still held at the reporting date	1.0	2.8
Acquired through business combinations	0.1	0.1
Sales	(1.5)	(29.6)
Fair value of plan assets — end of year	32.5	32.5
Significant Unobservable Inputs (Level 3) [Member] | Other Benefits [Member] | Hedge Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	11.5	24.6
Actual return on plan assets:
Relating to assets still held at the reporting date	(0.3)	0.5
Acquired through business combinations	0.0	0.0
Sales	0.0	(14.2)
Fair value of plan assets — end of year	11.2	11.5
Significant Unobservable Inputs (Level 3) [Member] | Other Benefits [Member] | Private Equity Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	6.2	6.0
Actual return on plan assets:
Relating to assets still held at the reporting date	0.3	1.0
Acquired through business combinations	0.1	0.1
Sales	(1.5)	(1.3)
Fair value of plan assets — end of year	5.5	6.2
Significant Unobservable Inputs (Level 3) [Member] | Other Benefits [Member] | Structured Credit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	6.1	13.5
Actual return on plan assets:
Relating to assets still held at the reporting date	(0.3)	0.4
Acquired through business combinations	0.0	0.0
Sales	0.0	(8.2)
Fair value of plan assets — end of year	5.8	6.1
Significant Unobservable Inputs (Level 3) [Member] | Other Benefits [Member] | Real Estate [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	8.7	13.2
Actual return on plan assets:
Relating to assets still held at the reporting date	1.3	0.9
Acquired through business combinations	0.0	0.0
Sales	0.0	(5.9)
Fair value of plan assets — end of year	$ 10.0	$ 8.7