Defined Benefit and Postretirement Benefits Contributions by Plan Type (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019 USD ($)
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year	$ 3.1
Defined Benefit Plan, Plan Assets, Contributions by Employer	2.4
Other Postretirement Benefits Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year	2.5
Defined Benefit Plan, Plan Assets, Contributions by Employer	1.4
Supplemental Employee Retirement Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year	2.2
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 2.2