CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Other comprehensive income (loss), net of tax
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 177.4	$ 250.9	$ (228.5)	$ 398.2
Pension Plan and Restoration of Retirement Income Plan:
Amortization of deferred net loss, net of tax of $0.3, $0.3, $0.9 and $0.8, respectively	0.9	0.9	2.9	2.6
Settlement cost, net of tax of $0.5, $0.3, $0.6 and $2.6, respectively	1.3	0.8	1.5	7.9
Postretirement Benefit Plans:
Amortization of prior service credit, net of tax of ($0.2), ($0.2), ($0.5) and ($0.4), respectively	(0.4)	(0.4)	(1.2)	(1.3)
Amortization of deferred net gain, net of tax of $0.0, $0.0, $0.0 and $0.0, respectively	0.0	0.0	(0.1)	(0.1)
Other comprehensive income (loss) from unconsolidated affiliates, net of tax of $0.1, ($0.2), ($0.3) and ($0.2), respectively	0.4	(0.6)	(0.9)	(0.6)
Other comprehensive income, net of tax	2.2	0.7	2.2	8.5
Comprehensive income (loss)	$ 179.6	$ 251.6	$ (226.3)	$ 406.7