Pension and Postretirement Benefit Plans (Narrative) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2020 USD ($)
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 17.1
Estimated minimum contributions	32.2
Postretirement Health Coverage
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	0.7
Estimated minimum contributions	$ 1.6