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, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	$ 188.6	$ 200.5
Actual return on plan assets:
Relating to assets still held at the reporting date	15.9	41.0
Acquired through business combinations	6.8	145.0
Sales	(7.0)	(172.8)
Fair value of plan assets — end of year	205.8	188.6
Hedge Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	57.6	85.6
Actual return on plan assets:
Relating to assets still held at the reporting date	3.1	4.5
Acquired through business combinations	0	66.0
Sales	0	(97.3)
Fair value of plan assets — end of year	59.2	57.6
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	29.1	29.3
Actual return on plan assets:
Relating to assets still held at the reporting date	3.2	(2.1)
Acquired through business combinations	1.4	14.7
Sales	(5.5)	(18.0)
Fair value of plan assets — end of year	31.2	29.1
Real Estate [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year	40.9	29.4
Actual return on plan assets:
Relating to assets still held at the reporting date	5.2	5.1
Acquired through business combinations	5.4	36.8
Sales	(1.5)	(30.0)
Fair value of plan assets — end of year	50.0	40.9
Other Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets — beginning of year			237.0
Actual return on plan assets:
Fair value of plan assets — end of year	269.3	251.8	237.0
Other Benefits [Member] | Hedge Funds [Member]
Actual return on plan assets:
Fair value of plan assets — end of year	11.5	24.6
Other Benefits [Member] | Private Equity Funds [Member]
Actual return on plan assets:
Fair value of plan assets — end of year	6.2	6.0
Other Benefits [Member] | Structured Credit [Member]
Actual return on plan assets:
Fair value of plan assets — end of year	6.1	13.5
Other Benefits [Member] | Real Estate [Member]
Actual return on plan assets:
Fair value of plan assets — end of year	8.7	13.2
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	57.3	57.8
Actual return on plan assets:
Relating to assets still held at the reporting date	2.8	7.5
Acquired through business combinations	0.1	48.0
Sales	(29.6)	(53.6)
Fair value of plan assets — end of year	32.5	57.3
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	24.6	23.2
Actual return on plan assets:
Relating to assets still held at the reporting date	0.5	2.1
Acquired through business combinations	0	22.5
Sales	(14.2)	(22.5)
Fair value of plan assets — end of year	11.5	24.6
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	6.0	6.2
Actual return on plan assets:
Relating to assets still held at the reporting date	1.0	0.2
Acquired through business combinations	0.1	0.3
Sales	(1.3)	(1.1)
Fair value of plan assets — end of year	6.2	6.0
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	13.5	12.5
Actual return on plan assets:
Relating to assets still held at the reporting date	0.4	2.4
Acquired through business combinations	0	11.0
Sales	(8.2)	(11.0)
Fair value of plan assets — end of year	6.1	13.5
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	13.2	15.9
Actual return on plan assets:
Relating to assets still held at the reporting date	0.9	2.8
Acquired through business combinations	0	14.2
Sales	(5.9)	(19.0)
Fair value of plan assets — end of year	$ 8.7	$ 13.2