Financial Instruments And Fair Value Measurements (Summary Of Carrying Values And Fair Values Of Fixed Rate Debt) (Details) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity investments with readily determinable fair values	$ 13.3		$ 15.4
Equity investment without readily determinable fair value	56.7		56.7
Net losses recognized during the period on equity securities	(2.3)	$ (0.1)
Less: Net losses recognized during the period on equity securities sold during the period	0.0	0.0
Unrealized losses recognized during the reporting period on equity securities still held at the reporting date	(2.3)	$ (0.1)
Carrying value \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed rate debt	3,227.1		3,224.0
Fair value \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed rate debt	2,817.8		$ 2,803.6
Nonrecurring Basis
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment in equity securities without readily determinable fair values, cumulative upward adjustment	$ 3.4

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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