Pensions and Postretirement Benefits Other Than Pensions (Schedule of Pretax Amounts Recognized in Accumulated Other Comprehensive Income (Loss) Other Than Pension) (Details) - Other Postretirement Benefits Plan [Member] $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Balance at December 31, 2013	$ 90.7
Current year changes recorded to Accumulated other comprehensive income (loss)	(6.7)
Amortization reclassified to earnings	(11.2)
Balance at December 31, 2014	72.8
Net Actuarial Losses [Member]
Balance at December 31, 2013	90.4
Current year changes recorded to Accumulated other comprehensive income (loss)	(6.7)
Amortization reclassified to earnings	(10.9)
Balance at December 31, 2014	72.8
prior service gains [Member]
Balance at December 31, 2013	0.3
Current year changes recorded to Accumulated other comprehensive income (loss)	0.0
Amortization reclassified to earnings	(0.3)
Balance at December 31, 2014	$ 0.0