Quarterly report pursuant to Section 13 or 15(d)

Retirement Benefits - Narrative (Details)

v3.8.0.1
Retirement Benefits - Narrative (Details) - USD ($)
$ in Millions
3 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Sep. 30, 2017
Dec. 19, 2014
Defined Benefit Plan Disclosure [Line Items]        
Pension Contributions   $ 80.0    
Postemployment Benefits, Period Expense $ 0.0 0.1    
Defined Contribution Plan, Cost 2.7 $ 2.6    
$900 revolving credit facility (excluding outstanding letters of credit)        
Defined Benefit Plan Disclosure [Line Items]        
Line of Credit Facility, Maximum Borrowing Capacity $ 569.2     $ 700.0
Term loan        
Defined Benefit Plan Disclosure [Line Items]        
Debt Instrument, Face Amount     $ 180.0 $ 180.0