Debt (Senior Notes and Debentures) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Debentures: May 2021
Debt Instrument [Line Items]
Principal	$ 0.0	$ 35.3	$ 35.3
Interest rate	9.25%	9.25%
Senior Notes 2.375% Due March 2033
Debt Instrument [Line Items]
Principal	$ 700.0		$ 0.0
Interest rate	2.375%

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant