Share-Based Compensation (Share-Based Compensation Expense) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based compensation expense (benefit)	$ 2.1	$ 6.3	$ 12.8	$ 16.4
Tax benefit	0.0	(0.9)	(0.9)	(2.0)
After-tax expense	2.1	5.4	11.9	14.4
Stock options
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based compensation expense (benefit)	0.5	0.4	3.4	3.2
Restricted Stock Units (RSUs)
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based compensation expense (benefit)	2.2	2.3	9.5	7.9
Performance Share Units (PSUs)
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based compensation expense (benefit)	1.4	2.6	3.0	3.9
Deferred compensation
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based compensation expense (benefit)	$ (2.0)	$ 1.0	$ (3.1)	$ 1.4

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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Amount, after tax, of expense for award under share-based payment arrangement.

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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