Acquisitions, Development and Divestitures - Acquisitions (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended	4 Months Ended	6 Months Ended		7 Months Ended	12 Months Ended			25 Months Ended
	May 25, 2022	Jun. 30, 2022	Jun. 30, 2022	Sep. 30, 2022	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Jun. 30, 2024
Disclosure [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-Term Debt		$ 1,500.0	$ 1,500.0		$ 1,500.0
Operating Revenues								$ 7,902.0	$ 5,783.0	$ 5,474.0
Net income (loss)								756.0	(1,480.0)	1,469.0
Business Acquisition, Pro Forma Revenue								8,667.0	7,478.0
Business Acquisition, Pro Forma Net Income (Loss)								790.0	159.0
Business Combination, Integration Related Costs								223.0	38.0
Transition Service Agreement Expense								123.0
Goodwill recognized during the period								1,586.0	0.0
Goodwill							$ 2,248.0	2,248.0	716.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables, Gross	$ 255.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, AR Reserve	60.0
Business Combination, Transaction Costs Expense								18.0
Payments to Acquire Businesses, Gross					5,300.0
Disposal Group [Line Items]
Income (Loss) from Discontinued Operations (net of income taxes)								42.0	(1,498.0)	829.0
Forecast [Member]
Disclosure [Line Items]
Business Combination, Integration Related Costs											$ 408.0
Corporate And Other [Member]
Disclosure [Line Items]
Operating Revenues								23.0	33.0	38.0
Net income (loss)								(274.0)	(895.0)	(275.0)
Goodwill, Purchase Accounting Adjustments								5.0
Goodwill recognized during the period								861.0	0.0
Goodwill							861.0	861.0	53.0	53.0
Rhode Island Energy
Disclosure [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	154.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables	195.0
Business Acquisition, Recognized Identifiable Assets Acquired and Liabilities Assumed, Unbilled Revenues	54.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Regulatory Assets	75.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other	65.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets	642.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	3,988.0
Public Utilities, Customer Bill Credit Agreement, Total	50.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Regulatory Assets	395.0
Goodwill, Business Combination	1,586.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets	166.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets	6,135.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	6,777.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-Term Debt	14.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable	180.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Taxes Accrued	44.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other	198.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities	675.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-Term Debt	1,496.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Regulatory Liabilities	643.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other	143.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities	2,282.0
Business Combination, Consideration Transferred		$ 3,820.0
Operating Revenues							1,038.0
Net income (loss)							(44.0)
Acquisition commitment write off expenses								98.0
RICCREF Contribution Expense			2.5
Accounts Receivable Forgiven, AR Reserve								23.0
Accounts Receivable Forgiven, net				$ 21.0
Accounts Receivable Forgiven, Gross				44.0
Public Utilities, Customer Bill Credit Agreement, Net of Tax	40.0
Business Combination, Regulatory Assets Expensed					20.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Regulatory Liabilities	239.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Price Risk Management Assets	99.0
Rhode Island Energy | Electric Customer
Disclosure [Line Items]
Public Utilities, Customer Bill Credit Agreement, Total	33.0
Rhode Island Energy | Natural Gas Customer
Disclosure [Line Items]
Public Utilities, Customer Bill Credit Agreement, Total	$ 17.0
Rhode Island Energy | Accounts Receivable and Regulatory Asset write off
Disclosure [Line Items]
Acquisition commitment write off expenses								43.0
Rhode Island Energy | Accrued expenditures for the RIAG and decarbonization goals
Disclosure [Line Items]
Acquisition commitment write off expenses								5.0
Rhode Island Energy | RIPUC regulatory liability
Disclosure [Line Items]
Regulatory Liabilities				50.0			$ 50.0	50.0
Rhode Island Energy | Rhode Island Energy TSA
Disclosure [Line Items]
Other Nonrecurring (Income) Expense								181.0
Rhode Island Energy | Accrual for TSA Markup
Disclosure [Line Items]
Other Nonrecurring (Income) Expense								3.0
Rhode Island Energy | Accrual for RIAG Evaluation Fund
Disclosure [Line Items]
Other Nonrecurring (Income) Expense			$ 2.5
WPD [Member]
Disposal Group [Line Items]
Income tax related to Discontinued Operations								(42.0)	759.0	188.0
Transaction Costs | Additional Costs Related to Purchase, Agreed not to seek recovery
Disclosure [Line Items]
Business Combination, Separately Recognized Transactions, Expenses and Losses Recognized								27.0
Transaction Costs | Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses | Additional Costs Related to Purchase, Agreed not to seek recovery
Disclosure [Line Items]
Business Combination, Separately Recognized Transactions, Expenses and Losses Recognized								18.0
Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations | Safari Holdings LLC, Consolidated
Disposal Group [Line Items]
Gain (loss) on disposition of business, net of tax								(46.0)
Goodwill from Disposal Group				$ 53.0
Loss on Sale								60.0
Discontinued Operations, Disposed of by Sale | WPD [Member]
Disposal Group [Line Items]
Income (Loss) from Discontinued Operations (net of income taxes)									(1,498.0)
Discontinued Operations, Held-for-sale | WPD [Member]
Disposal Group [Line Items]
Sale proceeds, net of realized foreign currency hedge losses						$ 10,700.0
Net Proceeds From Divestiture Of Businesses						$ 10,400.0
Operating Revenues related to discontinued operations								0.0	1,344.0	2,133.0
Operating Expense related to discontinued operations								0.0	467.0	916.0
Other Income (Expense) - net related to discontinued operations								0.0	202.0	167.0
Interest Expense related to discontinued operations								0.0	209.0	367.0
Income from Discontinued Operations, before Income Tax								0.0	870.0	1,017.0
Loss on Sale								0.0	(1,609.0)	0.0
Income tax related to Discontinued Operations								(42.0)	759.0	188.0
Income (Loss) from Discontinued Operations (net of income taxes)								$ 42.0	$ (1,498.0)	$ 829.0
Narragansett Electric
Disclosure [Line Items]
Business Combination, Consideration Transferred					$ 3,800.0