PENSIONS AND POSTRETIREMENT BENEFITS (Effect of Fair Value Measurements Using Significant Unobservable Inputs (Level 3) on Changes in Pension Plan Assets) (Details) (USD $)
In Millions, unless otherwise specified

12 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets [Table Text Block]

The following represents the effect of fair value measurements using significant unobservable inputs (Level 3) on changes in plan assets for the years ended December 31, 2014 and 2013:



	(In Millions)
	Year Ended December 31, 2014
	Hedge Funds			Private Equity Funds			Structured Credit Fund		Real Estate			Total
Beginning balance — January 1, 2014	$	57.6		$	29.1		$	61.0	$	40.9		$	188.6
Actual return on plan assets:
Relating to assets still held at the reporting date	3.1			3.2			4.4		5.2			15.9
Relating to assets sold during the period	(1.5		)	3.0			—		—			1.5
Purchases	—			1.4			—		5.4			6.8
Sales	—			(5.5		)	—		(1.5		)	(7.0		)
Ending balance — December 31, 2014	$	59.2		$	31.2		$	65.4	$	50.0		$	205.8



	(In Millions)
	Year Ended December 31, 2013
	Hedge Funds			Private Equity Funds			Structured Credit Fund			Real Estate			Total
Beginning balance — January 1, 2013	$	85.6		$	29.3		$	56.2		$	29.4		$	200.5
Actual return on plan assets:
Relating to assets still held at the reporting date	4.5			(2.1		)	33.5			5.1			41.0
Relating to assets sold during the period	(1.2		)	5.2			(28.7		)	(0.4		)	(25.1		)
Purchases	66.0			14.7			27.5			36.8			145.0
Sales	(97.3		)	(18.0		)	(27.5		)	(30.0		)	(172.8		)
Ending balance — December 31, 2013	$	57.6		$	29.1		$	61.0		$	40.9		$	188.6

Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Roll Forward]

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

Relating to assets sold during the period

Fair value of plan assets — end of year

205.8

188.6

Hedge Funds [Member]

Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Roll Forward]

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

Relating to assets sold during the period

Fair value of plan assets — end of year

59.2

57.6

Private Equity Funds [Member]

Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Roll Forward]

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)

Relating to assets sold during the period

Fair value of plan assets — end of year

31.2

29.1

Structured Finance [Member]

Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Roll Forward]

Fair value of plan assets — beginning of year

61.0

56.2

Actual return on plan assets:

Relating to assets still held at the reporting date

4.4

33.5

Relating to assets sold during the period

Fair value of plan assets — end of year

65.4

61.0

Real Estate [Member]

Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Roll Forward]

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

Relating to assets sold during the period

Fair value of plan assets — end of year

$ 50.0

$ 40.9

Veba Trust [Member]

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets [Table Text Block]

The following represents the effect of fair value measurements using significant unobservable inputs (Level 3) on changes in plan assets for the year ended December 31, 2014 and 2013:



	(In Millions)
	Year Ended December 31, 2014
	Hedge Funds			Private Equity Funds			Structured Credit Fund			Real Estate			Total
Beginning balance — January 1, 2014	$	24.6		$	6.0		$	13.5		$	13.2		$	57.3
Actual return on plan assets:
Relating to assets still held at the reporting date	0.5			1.0			0.4			0.9			2.8
Relating to assets sold during the period	0.6			0.4			0.4			0.5			1.9
Purchases	—			0.1			—			—			0.1
Sales	(14.2		)	(1.3		)	(8.2		)	(5.9		)	(29.6		)
Ending balance — December 31, 2014	$	11.5		$	6.2		$	6.1		$	8.7		$	32.5



	(In Millions)
	Year Ended December 31, 2013
	Hedge Funds			Private Equity Funds			Structured Credit Fund			Real Estate			Total
Beginning balance — January 1, 2014	$	23.2		$	6.2		$	12.5		$	15.9		$	57.8
Actual return on plan assets:
Relating to assets still held at the reporting date	2.1			0.2			2.4			2.8			7.5
Relating to assets sold during the period	(0.7		)	0.4			(1.4		)	(0.7		)	(2.4		)
Purchases	22.5			0.3			11.0			14.2			48.0
Sales	(22.5		)	(1.1		)	(11		)	(19.0		)	(53.6		)
Ending balance — December 31, 2014	$	24.6		$	6.0		$	13.5		$	13.2		$	57.3