CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating Activities:
Net income	$ 70,753	$ 145,987
Non-cash items included in net income:
Depreciation and amortization	169,851	154,943
Deferred income tax provision and investment tax credits	(2,200)	10,219
Power and natural gas cost amortizations (deferrals), net	(6,470)	(45,835)
Amortization of debt expense	2,329	2,008
Amortization of investment in exchange power		1,633
Stock-based compensation expense	3,705	8,951
Equity-related AFUDC	(5,030)	(5,021)
Pension and other postretirement benefit expense	25,010	27,139
Other regulatory assets and liabilities and deferred debits and credits	12,456	1,871
Change in decoupling regulatory deferral	3,340	(11,540)
Gain on sale of METALfx (before payment of transaction costs)		(6,477)
Gain on sale of investments	(3,914)
Other	12,807	(5,095)
Contributions to defined benefit pension plan	(22,000)	(22,000)
Cash paid for settlement of interest rate swap agreements	(33,499)	(13,325)
Changes in certain current assets and liabilities:
Accounts and notes receivable	45,552	54,554
Materials and supplies, fuel stock and stored natural gas	(2,444)	(7,298)
Collateral posted for derivative instruments	10,105	64,770
Income taxes receivable	3,549	(9,116)
Other current assets	6,352	(2,307)
Accounts payable	(23,328)	(8,366)
Other current liabilities	15,604	4,796
Net cash provided by operating activities	282,528	340,491
Investing Activities:
Utility property capital expenditures (excluding equity-related AFUDC)	(297,834)	(320,964)
Issuance of notes receivable by subsidiaries	(4,343)	(6,036)
Equity and property investments	(3,994)	(10,031)
Proceeds from sale of METALfx (net of cash sold)		16,407
Proceeds from sale of investments	6,644
Other	(1,478)	309
Net cash used in investing activities	(301,005)	(320,315)
Financing Activities:
Net increase (decrease) in short-term borrowings	(35,800)	17,000
Proceeds from issuance of long-term debt	165,000
Maturity of long-term debt and finance leases	(2,129)	(1,995)
Issuance of common stock, net of issuance costs	53,356	42,899
Cash dividends paid	(82,281)	(76,772)
Other	(4,818)	(1,510)
Net cash provided by (used in) financing activities	93,328	(20,378)
Net increase (decrease) in cash and cash equivalents	74,851	(202)
Cash and cash equivalents at beginning of period	9,896	14,656
Cash and cash equivalents at end of period	$ 84,747	$ 14,454