Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Assets
Property, plant and equipment, at cost	$ 14,344,435	$ 13,737,387
Less: accumulated depreciation	2,753,586	2,606,441
Net property, plant and equipment	11,590,849	11,130,946
Current assets:
Cash and cash equivalents	11,642	11,398
Accounts receivable, net	149,942	206,324
Unbilled revenues	75,737	170,504
Inventory - materials and supplies	45,300	46,592
Inventory - gas stored	63,216	153,143
Current assets held for sale	7,378	11,167
Prepayments and other current assets	36,557	39,759
Regulatory assets	16,938	19,272
Total current assets	406,710	658,159
Regulatory assets	1,518,079	1,342,753
Deferred charges and other assets, net	166,391	166,653
Funds restricted for construction activity	1,360	1,342
Goodwill	2,340,755	2,340,792
Non-current assets held for sale	34,419	32,124
Operating lease right-of-use assets	39,151	41,734
Intangible assets	4,221	4,604
Total assets	16,101,935	15,719,107
Stockholders' equity:
Common stock at $0.50 par value, authorized 600,000,000 shares, issued 267,818,219 and 266,973,321 as of June 30, 2023 and December 31, 2022	133,909	133,486
Capital in excess of par value	3,827,199	3,793,262
Retained earnings	1,740,682	1,534,331
Treasury stock, at cost, 3,312,850 and 3,236,237 shares as of June 30, 2023 and December 31, 2022	(87,092)	(83,693)
Total stockholders' equity	5,614,698	5,377,386
Long-term debt, excluding current portion	6,661,014	6,418,039
Less: debt issuance costs	45,498	46,982
Long-term debt, excluding current portion, net of debt issuance costs	6,615,516	6,371,057
Commitments and contingencies (See Note 14)
Current liabilities:
Current portion of long-term debt	198,749	199,356
Loans payable	48,043	228,500
Accounts payable	178,902	238,843
Book overdraft	32,490	28,694
Accrued interest	50,625	47,063
Accrued taxes	26,232	34,393
Liabilities related to assets held for sale	3,081	3,263
Regulatory liabilities	96,669	35,276
Dividends payable		75,808
Other accrued liabilities	130,344	130,673
Total current liabilities	765,135	1,021,869
Deferred credits and other liabilities:
Deferred income taxes and investment tax credits	1,459,002	1,345,766
Customers' advances for construction	125,362	114,732
Regulatory liabilities	807,240	778,754
Asset retirement obligations	842	843
Operating lease liabilities	36,387	37,666
Non-current liabilities related to assets held for sale	803	974
Pension and other postretirement benefit liabilities	31,196	31,244
Other	24,648	28,562
Total deferred credits and other liabilities	2,485,480	2,338,541
Contributions in aid of construction	621,106	610,254
Total liabilities and equity	$ 16,101,935	$ 15,719,107