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Fair Value - Recurring Fair Value Measures (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Liabilities
Aggregate amount of available-for-sale corporate and governmental debt securities maturing in one year	$ 1.6
Aggregate amount of available-for-sale corporate and governmental debt securities maturing after one year through three years	2.9
Aggregate amount of available-for-sale corporate and governmental debt securities maturing after one year through three years after three years through five years	0.9
Aggregate amount of available-for-sale corporate and governmental debt securities maturing after one year through three years after three years through five years after five years	0.4
Recurring Fair Value Measures
Investments [Abstract]
Available-for-sale – Equity Securities	8.1	$ 7.7
Available-for-sale – Corporate and Governmental Debt Securities	5.8	5.7
Cash Equivalents	5.8	4.2
Total Fair Value of Assets	19.7	17.6
Liabilities
Deferred compensation	15.9	15.0
Total Fair Value of Liabilities	15.9	15.0
Recurring Fair Value Measures | Level 1
Investments [Abstract]
Available-for-sale – Equity Securities	8.1	7.7
Available-for-sale – Corporate and Governmental Debt Securities	0.0	0.0
Cash Equivalents	5.8	4.2
Total Fair Value of Assets	13.9	11.9
Liabilities
Deferred compensation	0.0	0.0
Total Fair Value of Liabilities	0.0	0.0
Recurring Fair Value Measures | Level 2
Investments [Abstract]
Available-for-sale – Equity Securities	0.0	0.0
Available-for-sale – Corporate and Governmental Debt Securities	5.8	5.7
Cash Equivalents	0.0	0.0
Total Fair Value of Assets	5.8	5.7
Liabilities
Deferred compensation	15.9	15.0
Total Fair Value of Liabilities	15.9	15.0
Recurring Fair Value Measures | Level 3
Investments [Abstract]
Available-for-sale – Equity Securities	0.0	0.0
Available-for-sale – Corporate and Governmental Debt Securities	0.0	0.0
Cash Equivalents	0.0	0.0
Total Fair Value of Assets	0.0	0.0
Liabilities
Deferred compensation	0.0	0.0
Total Fair Value of Liabilities	$ 0.0	$ 0.0

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Amount of available-for-sale debt securities at fair value maturing in after the fifth fiscal year following the latest fiscal year (maturing in five years or more).

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Amount of available-for-sale debt securities at fair value maturing after the first fiscal year through the third fiscal year following the latest fiscal year (maturing in more than one year to less than three years).

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Amount of noncurrent assets that are pledged or subject to withdrawal restrictions, classified as other.

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