Defined Benefit and Postretirement Benefits Contributions by Plan Type (Details) $ in Millions	6 Months Ended
	Jun. 30, 2021 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	$ 20.7
Defined Benefit Plan, Plan Assets, Contributions by Employer	16.9
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	2.6
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 0.3