Accounts Receivable (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recoveries of accounts written off and other	$ 10,369	$ 13,034	$ 1,113
Pennsylvania [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
utility customers by geographic operating segment, percentage	66.00%
Ohio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
utility customers by geographic operating segment, percentage	9.00%
North Carolina [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
utility customers by geographic operating segment, percentage	6.00%
Texas [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
utility customers by geographic operating segment, percentage	5.00%
Illinois [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
utility customers by geographic operating segment, percentage	5.00%
Peoples Gas Acquisition [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recoveries of accounts written off and other	$ 12,851	$ 10,962