Fair Value of Assets and Liabilities - Fair Value Measurements (Details) - USD ($)	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Transfers Between Levels Amount	$ 0	$ 0
Fair value liabilities measured on recurring basis
Long-Term Debt, Fair Value	309,500,000		$ 1,819,700,000
Long-Term Debt	2,166,900,000		2,557,600,000
Fair Value, Measurements, Recurring [Member]
Fair value assets measured on recurring basis
Total	14,700,000		29,000,000.0
Fair value liabilities measured on recurring basis
Total	3,700,000		4,400,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value assets measured on recurring basis
Total	14,700,000		29,000,000.0
Fair value liabilities measured on recurring basis
Total	3,700,000		4,400,000
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value assets measured on recurring basis
Total	0		0
Fair value liabilities measured on recurring basis
Total	0		0
Assets held in rabbi trusts [Member]
Fair value assets measured on recurring basis
Fair value of investment assets	3,700,000		4,400,000
Short-term investments | Certificates of deposit | Fair Value, Measurements, Recurring [Member]
Fair value assets measured on recurring basis
Fair value of investment assets	11,000,000.0		24,600,000
Short-term investments | Certificates of deposit | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value assets measured on recurring basis
Fair value of investment assets	11,000,000.0		24,600,000
Short-term investments | Certificates of deposit | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value assets measured on recurring basis
Fair value of investment assets	0		0
Securities and other investments | Assets held in rabbi trusts [Member] | Fair Value, Measurements, Recurring [Member]
Fair value assets measured on recurring basis
Assets held in rabbi trusts	3,700,000		4,400,000
Securities and other investments | Assets held in rabbi trusts [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value assets measured on recurring basis
Assets held in rabbi trusts	3,700,000		4,400,000
Securities and other investments | Assets held in rabbi trusts [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value assets measured on recurring basis
Assets held in rabbi trusts	0		0
Other liabilities | Fair Value, Measurements, Recurring [Member]
Fair value liabilities measured on recurring basis
Deferred compensation	3,700,000		4,400,000
Other liabilities | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value liabilities measured on recurring basis
Deferred compensation	3,700,000		4,400,000
Other liabilities | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value liabilities measured on recurring basis
Deferred compensation	$ 0		$ 0