Acquisitions, Development and Divestitures - Development (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Business Acquisition [Line Items]
Goodwill, Acquired During Period				$ 1,585
Transition Service Agreement Cost	$ 63		$ 120
Goodwill	2,247		2,247		$ 2,248
Operating Revenues from external customers	1,823	$ 1,696	4,238	3,478
Net income (loss)	112	119	397	392
Indemnification for Safari sale/leaseback			25
Narragansett Electric
Business Acquisition [Line Items]
Total cash consideration				3,800
Rhode Island Regulated
Business Acquisition [Line Items]
Goodwill	725		725
Operating Revenues from external customers	377	128	942	128
Net income (loss)	10	(29)	64	(29)
Corporate and Other [Member]
Business Acquisition [Line Items]
Goodwill, Acquired During Period				860
Goodwill, Purchase Accounting Adjustments	1
Operating Revenues from external customers	1	9	0	12
Net income (loss)	(99)	$ (88)	(172)	$ (147)
Rhode Island Energy | Rhode Island Energy TSA
Business Acquisition [Line Items]
Other Nonrecurring (Income) Expense	70		124
Rhode Island Energy | Accrual for TSA Markup
Business Acquisition [Line Items]
Other Nonrecurring (Income) Expense	$ 2		$ 4