Debt and Financing Arrangements - Other Financing Obligations (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Debt Instrument [Line Items]
Long-Term Debt	$ 5,237,114		$ 5,251,799
Long-term debt due within one year	30,530		28,532
Proceeds from other financing obligations	6,047	$ 6,193
Dalton Expansion Project
Debt Instrument [Line Items]
Long-Term Debt	247,600		249,400
Long-term debt due within one year	2,900		2,800
Proceeds from other financing obligations	400
Atlantic Sunrise Project
Debt Instrument [Line Items]
Long-Term Debt	770,200		784,600
Long-term debt due within one year	26,400		24,600
Proceeds from other financing obligations	5,600	1,900
Leidy South Project
Debt Instrument [Line Items]
Long-Term Debt	75,300		76,200
Long-term debt due within one year	$ 1,200		$ 1,100
Proceeds from other financing obligations		$ 4,200