CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Statement [Abstract]
Operating Revenues	$ 12,289,336	$ 9,863,085	$ 8,904,430
Operating Expenses:
Purchased Power, Purchased Natural Gas and Transmission	5,014,074	3,372,344	2,987,840
Operations and Maintenance	1,865,328	1,739,685	1,480,252
Depreciation	1,194,246	1,103,008	981,380
Amortization	448,892	231,965	177,679
Energy Efficiency Programs	658,051	592,775	535,760
Taxes Other Than Income Taxes	910,591	829,987	752,785
Total Operating Expenses	10,091,182	7,869,764	6,915,696
Operating Income	2,198,154	1,993,321	1,988,734
Interest Expense	678,274	582,334	538,452
Other Income, Net	346,088	161,282	108,590
Income Before Income Tax Expense	1,865,968	1,572,269	1,558,872
Income Tax Expense	453,574	344,223	346,186
Net Income	1,412,394	1,228,046	1,212,686
Net Income Attributable to Noncontrolling Interests	7,519	7,519	7,519
Net Income Attributable to Common Shareholders	$ 1,404,875	$ 1,220,527	$ 1,205,167
Basic Earnings Per Common Share (in dollars per share)	$ 4.05	$ 3.55	$ 3.56
Diluted Earnings Per Common Share (in dollars per share)	$ 4.05	$ 3.54	$ 3.55
Weighted Average Common Shares Outstanding:
Basic (in shares)	346,783,444	343,972,926	338,836,147
Diluted (in shares)	347,246,768	344,631,056	339,847,062