Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Assets
Property, plant and equipment, at cost	$ 15,891,451	$ 14,977,021
Less: accumulated depreciation	3,075,589	2,879,949
Net property, plant and equipment	12,815,862	12,097,072
Current assets:
Cash and cash equivalents	8,436	4,612
Accounts receivable, net	124,767	144,300
Unbilled revenues	79,095	101,436
Inventory - materials and supplies	51,216	47,494
Inventory - gas stored	54,014	65,173
Prepayments and other current assets	25,746	99,884
Regulatory assets	30,659	29,080
Total current assets	373,933	491,979
Regulatory assets	1,897,883	1,766,892
Deferred charges and other assets, net	98,996	102,388
Funds restricted for construction activity	1,412	1,381
Goodwill	2,340,719	2,340,738
Operating lease right-of-use assets	32,470	37,416
Intangible assets	3,351	3,593
Total assets	17,564,626	16,841,459
Stockholders' equity:
Common stock at $0.50 par value, authorized 600,000,000 shares, issued 277,950,436 and 276,595,228 as of September 30, 2024 and December 31, 2023	138,975	138,297
Capital in excess of par value	4,186,048	4,137,696
Retained earnings	1,943,876	1,706,675
Treasury stock, at cost, 3,341,458 and 3,299,191 shares as of September 30, 2024 and December 31, 2023	(87,965)	(86,485)
Total stockholders' equity	6,180,934	5,896,183
Long-term debt, excluding current portion	7,279,048	6,870,593
Less: debt issuance costs	48,880	44,508
Long-term debt, excluding current portion, net of debt issuance costs	7,230,168	6,826,085
Commitments and contingencies (See Note 14)
Current liabilities:
Current portion of long-term debt	29,218	67,415
Loans payable	143,017	160,123
Accounts payable	231,443	221,191
Book overdraft	16,795	13,358
Accrued interest	87,519	53,084
Accrued taxes	33,143	40,641
Regulatory liabilities	683	31,270
Dividends payable		83,929
Other accrued liabilities	141,325	126,916
Total current liabilities	683,143	797,927
Deferred credits and other liabilities:
Deferred income taxes and investment tax credits	1,788,225	1,628,324
Customers' advances for construction	120,154	128,755
Regulatory liabilities	804,323	820,910
Asset retirement obligations	857	848
Operating lease liabilities	29,153	34,425
Pension and other postretirement benefit liabilities	28,386	38,850
Other	23,859	24,086
Total deferred credits and other liabilities	2,794,957	2,676,198
Contributions in aid of construction	675,424	645,066
Total liabilities and equity	$ 17,564,626	$ 16,841,459