Shareholders' Equity (Schedule Of Accumulated Other Comprehensive Income Activity) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	$ 364.9	$ 226.0
Impact of ASU 2017-12 adoption	869.8	1,008.2
Other comprehensive income (loss) income before reclassifications, net of tax benefit (expense)	(0.2)	(9.7)
Amounts reclassified from accumulated other comprehensive (loss)	267.0	93.1
Net current period other comprehensive (loss) income	266.8	83.4
Balance	450.9	364.9
ASU 2017-12 [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Impact of ASU 2017-12 adoption		0.1
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	9.4	(74.7)
Other comprehensive income (loss) income before reclassifications, net of tax benefit (expense)	(0.2)	3.9
Amounts reclassified from accumulated other comprehensive (loss)	(6.9)	80.2
Net current period other comprehensive (loss) income	(7.1)	84.1
Balance	2.3	9.4
Derivative Gain (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(8.5)	5.3
Other comprehensive income (loss) income before reclassifications, net of tax benefit (expense)	(6.1)	(15.0)
Amounts reclassified from accumulated other comprehensive (loss)	(4.4)	1.1
Net current period other comprehensive (loss) income	(10.5)	(13.9)
Balance	(19.0)	(8.5)
Derivative Gain (Loss) [Member] | ASU 2017-12 [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Impact of ASU 2017-12 adoption		0.1
Pension And Postretirement Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(377.0)	(390.2)
Other comprehensive income (loss) income before reclassifications, net of tax benefit (expense)	6.1	1.4
Amounts reclassified from accumulated other comprehensive (loss)	278.3	11.8
Net current period other comprehensive (loss) income	284.4	13.2
Balance	(92.6)	(377.0)
Accumulated Other Comprehensive (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(376.1)	(459.6)
Balance	$ (109.3)	(376.1)
Accumulated Other Comprehensive (Loss) [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance		$ 0.1