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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

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