Summary of Significant Accounting Policies - Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Fair Values of Financial Instruments
Total debt	$ 1,659.6	$ 1,662.4
Senior Unsecured Notes - Publicly Traded
Fair Values of Financial Instruments
Carrying value, before deducting unamortized discount or premiums	1,650.0	1,650.0
Carrying value	1,640.0	1,640.0
Senior Unsecured Notes - Publicly Traded \| Level 2
Fair Values of Financial Instruments
Fair value	$ 1,530.0	$ 1,750.0

Amount, excluding unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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