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, 2016	Dec. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	$ 193.4	$ 188.1
Actual return on plan assets:
Relating to assets still held at the reporting date	12.3	5.5
Acquired through business combinations	8.0	5.7
Sales	14.6	8.4
Fair value of plan assets — end of year	202.4	193.4
Hedge Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	40.7	41.5
Actual return on plan assets:
Relating to assets still held at the reporting date	(0.1)	(0.8)
Acquired through business combinations	0.0	0.0
Sales	0.0	0.0
Fair value of plan assets — end of year	40.6	40.7
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	33.1	31.2
Actual return on plan assets:
Relating to assets still held at the reporting date	(2.7)	1.5
Acquired through business combinations	8.0	5.7
Sales	6.0	7.8
Fair value of plan assets — end of year	36.1	33.1
Real Estate [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	57.5	50.0
Actual return on plan assets:
Relating to assets still held at the reporting date	5.1	8.1
Acquired through business combinations	0.0	0.0
Sales	0.6	0.6
Fair value of plan assets — end of year	61.9	57.5
Other Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	250.6	269.3
Actual return on plan assets:
Fair value of plan assets — end of year	253.0	250.6
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	11.2
Actual return on plan assets:
Fair value of plan assets — end of year	11.2	11.2
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	5.5
Actual return on plan assets:
Fair value of plan assets — end of year	4.3	5.5
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	5.8
Actual return on plan assets:
Fair value of plan assets — end of year	6.9	5.8
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	10.0
Actual return on plan assets:
Fair value of plan assets — end of year	11.1	10.0
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	32.5
Actual return on plan assets:
Relating to assets still held at the reporting date	1.9	1.0
Acquired through business combinations	0.0	0.1
Sales	1.0	1.5
Fair value of plan assets — end of year	33.5	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	11.2	11.5
Actual return on plan assets:
Relating to assets still held at the reporting date	0.0	(0.3)
Acquired through business combinations	0.0	0.0
Sales	0.0	0.0
Fair value of plan assets — end of year	11.2	11.2
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	5.5	6.2
Actual return on plan assets:
Relating to assets still held at the reporting date	(0.3)	0.3
Acquired through business combinations	0.0	0.1
Sales	1.0	1.5
Fair value of plan assets — end of year	4.3	5.5
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	5.8	6.1
Actual return on plan assets:
Relating to assets still held at the reporting date	1.1	(0.3)
Acquired through business combinations	0.0	0.0
Sales	0.0	0.0
Fair value of plan assets — end of year	6.9	5.8
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	10.0	8.7
Actual return on plan assets:
Relating to assets still held at the reporting date	1.1	1.3
Acquired through business combinations	0.0	0.0
Sales	0.0	0.0
Fair value of plan assets — end of year	$ 11.1	$ 10.0