Fair Value - Recurring Fair Value Measures (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022		Dec. 31, 2021
Liabilities [Abstract]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	$ 0.7
Available-for-sale Securities, Debt Maturities, After One Year Through Three Years, Fair Value	2.7
Available-for-sale Securities, Debt Maturities, After Three Years Through Five Years, Fair Value	1.9
Available-for-sale Securities, Debt Maturities, After Five Years, Fair Value	0.4
Recurring Fair Value Measures [Member]
Investments [Abstract]
Available-for-sale – Equity Securities	7.7	[1]	$ 8.9	[2]
Available-for-sale – Corporate and Governmental Debt Securities	5.7	[1],[3]	6.2	[2]
Cash Equivalents	4.2	[1]	2.5	[2]
Total Fair Value of Assets	17.6		17.6
Liabilities [Abstract]
Deferred Compensation	15.0	[4]	18.0	[5]
Total Fair Value of Liabilities	15.0		18.0
Fair Value Hierarchy Transfers, All Levels	0.0		0.0
Recurring Fair Value Measures [Member] | Level 1 [Member]
Investments [Abstract]
Available-for-sale – Equity Securities	7.7	[1]	8.9	[2]
Available-for-sale – Corporate and Governmental Debt Securities	0.0	[1],[3]	0.0	[2]
Cash Equivalents	4.2	[1]	2.5	[2]
Total Fair Value of Assets	11.9		11.4
Liabilities [Abstract]
Deferred Compensation	0.0	[4]	0.0	[5]
Total Fair Value of Liabilities	0.0		0.0
Recurring Fair Value Measures [Member] | Level 2 [Member]
Investments [Abstract]
Available-for-sale – Equity Securities	0.0	[1]	0.0	[2]
Available-for-sale – Corporate and Governmental Debt Securities	5.7	[1],[3]	6.2	[2]
Cash Equivalents	0.0	[1]	0.0	[2]
Total Fair Value of Assets	5.7		6.2
Liabilities [Abstract]
Deferred Compensation	15.0	[4]	18.0	[5]
Total Fair Value of Liabilities	15.0		18.0
Recurring Fair Value Measures [Member] | Level 3 [Member]
Investments [Abstract]
Available-for-sale – Equity Securities	0.0	[1]	0.0	[2]
Available-for-sale – Corporate and Governmental Debt Securities	0.0	[1],[3]	0.0	[2]
Cash Equivalents	0.0	[1]	0.0	[2]
Total Fair Value of Assets	0.0		0.0
Liabilities [Abstract]
Deferred Compensation	0.0	[4]	0.0	[5]
Total Fair Value of Liabilities	$ 0.0		$ 0.0

[1] Included in Other Non-Current Assets on the Consolidated Balance Sheet.

[2] Included in Other Non-Current Assets on the Consolidated Balance Sheet.

[3] As of December 31, 2022, the aggregate amount of available-for-sale corporate and governmental debt securities maturing in one year or less was $0.7 million, in one year to less than three years was $2.7 million, in three years to less than five years was $1.9 million and in five or more years was $0.4 million.

[4] Included in Other Non-Current Liabilities on the Consolidated Balance Sheet.

[5] Included in Other Non-Current Liabilities on the Consolidated Balance Sheet.