Fair Value Measurements (Fair Value Inputs, Liabilities, Quantitative Information) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Fair Value Inputs, Liabilities, Quantitative Information
Long-term Debt, Gross	$ 1,050.0	$ 1,072.3
Long-term debt	1,037.5	$ 1,066.6
Long-term debt, fair value	$ 1,000.0
Fair Value, Inputs, Level 1
Fair Value Inputs, Liabilities, Quantitative Information
Fair value level 1 inputs	Level 1 inputs