Quarterly report pursuant to Section 13 or 15(d)

FAIR VALUE MEASUREMENTS (Fair Value, Assets and Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation) (Details)

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FAIR VALUE MEASUREMENTS (Fair Value, Assets and Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Fair Value, Assets Measured On Recurring Basis, Unobservable Input Reconciliation [Roll Forward]    
Beginning balance $ 91.4 $ 49.5
Total gains    
Included in earnings 15.3 44.3
Settlements 0.0 (0.2)
Ending balance - March 31 106.7 93.6
Total gains for the period included in earnings attributable to the change in unrealized gains on assets still held at the reporting date 15.3 44.5
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]    
Beginning balance 0.0 (1.7)
Total losses    
Included in earnings (9.8) (0.5)
Settlements 0.0 2.2
Ending balance - March 31 (9.8) 0.0
Total losses for the period included in earnings attributable to the change in unrealized losses on liabilities still held at the reporting date $ (9.8) $ 0.0