v3.8.0.1
Derivatives (AOCL Related to Cash Flow Hedges) (Details) - Cash Flow Hedge [Member] - USD ($)
$ in Millions
9 Months Ended
Sep. 30, 2017
Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]    
Unrealized gains on unsettled contracts $ (9.9) $ (8.9)
Income tax expense 3.6 3.3
Losses included in AOCL, net of tax (6.3) $ (5.6)
Cash flow hedge derivative losses expected to be reclassified into earnings within the next 12 months $ 6.1