Debt and Financing Arrangements - Other Financing Obligations (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Debt Instrument [Line Items]
Long-Term Debt	$ 5,242,688		$ 5,251,799
Long-term debt due within one year	29,849		28,532
Proceeds from other financing obligations	4,547	$ 5,148
Dalton Expansion Project
Debt Instrument [Line Items]
Long-Term Debt	248,200		249,400
Long-term debt due within one year	2,900		2,800
Proceeds from other financing obligations	300
Atlantic Sunrise Project
Debt Instrument [Line Items]
Long-Term Debt	775,700		784,600
Long-term debt due within one year	25,800		24,600
Proceeds from other financing obligations	4,300	1,300
Leidy South Project
Debt Instrument [Line Items]
Long-Term Debt	75,600		76,200
Long-term debt due within one year	$ 1,100		$ 1,100
Proceeds from other financing obligations		$ 3,900