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, 2018
Mar. 31, 2017
Fair Value, Assets Measured On Recurring Basis, Unobservable Input Reconciliation [Roll Forward]    
Beginning balance1 $ 51.0 $ 31.6
Total gains (losses)    
Included in earnings 49.1 42.1
Settlements (6.5) (14.3)
Ending balance - March 31 93.6 59.4
Total gains for the period included in earnings attributable to the change in unrealized gains on assets still held at the reporting date 44.5 33.2
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]    
Beginning balance (2.4) (0.5)
Total gains (losses)    
Included in earnings (4.0) (8.6)
Settlements 2.2 0.0
Ending balance - March 31 (4.2) (9.1)
Total losses for the period included in earnings attributable to the change in unrealized losses on liabilities still held at the reporting date $ (4.2) $ (9.1)