NSTAR ELECTRIC COMPANY AND SUBSIDIARY CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Revenues	$ 12,289,336	$ 9,863,085	$ 8,904,430
Operating Expenses:
Purchased Power 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
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
NSTAR Electric Company
Operating Revenues	3,583,070	3,056,350	2,941,148
Operating Expenses:
Purchased Power and Transmission	1,264,824	932,530	879,244
Operations and Maintenance	640,834	563,172	534,118
Depreciation	361,969	337,451	319,468
Amortization of Regulatory Assets, Net	83,855	55,774	83,248
Energy Efficiency Programs	332,247	288,612	263,986
Taxes Other Than Income Taxes	246,705	216,703	206,764
Total Operating Expenses	2,930,434	2,394,242	2,286,828
Operating Income	652,636	662,108	654,320
Interest Expense	162,892	146,048	130,508
Other Income, Net	142,661	74,844	52,017
Income Before Income Tax Expense	632,405	590,904	575,829
Income Tax Expense	139,977	114,335	130,828
Net Income	$ 492,428	$ 476,569	$ 445,001