Financing (Components Of Debt) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2013	Nov. 30, 2006
Debt Instrument [Line Items]
Short-term borrowings	$ 699.3	$ 0.0
Long-term debt	(543.7)	(842.4)
Debt discounts and debt issuance costs	5.6	5.7
4.45% notes due December 2023
Debt Instrument [Line Items]
Long-term debt	$ 0.0	$ (299.4)
Debt instrument interest rate	4.45%	4.45%	4.45%
6.55% notes due November 2036
Debt Instrument [Line Items]
Long-term debt	$ (198.6)	$ (198.5)
Debt instrument interest rate	6.55%	6.55%		6.55%
4.20% notes due March 2048
Debt Instrument [Line Items]
Long-term debt	$ (346.5)	$ (346.3)
Debt instrument interest rate	4.20%	4.20%
Other deferred financing costs associated with credit facilities
Debt Instrument [Line Items]
Long-term debt	$ (1.4)	$ (1.8)
Four Point Four Five Percent Notes Due Two Thousand And Twenty Three
Debt Instrument [Line Items]
Short-term borrowings	299.7
Line of Credit | 364-Day Credit Agreement
Debt Instrument [Line Items]
Short-term borrowings	$ 399.6	$ 0.0
Notes Payable to Banks
Debt Instrument [Line Items]
Debt instrument, term	364 days	364 days