Annual report pursuant to Section 13 and 15(d)

PENSION AND OTHER POSTRETIREMENT BENEFITS (Effect of Fair Value Measurements Using Significant Unobservable Inputs (Level 3) on Changes in Other Benefit Plan Assets) (Details)

v3.3.1.900
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