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Number of Provinces in which Entity Operates

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Acquisitions and Dispositions - Acquisitions (Details) customer in Millions, $ in Millions		1 Months Ended	3 Months Ended
	Jan. 05, 2021 USD ($) customer state counterparty	Dec. 31, 2020 USD ($)	Mar. 31, 2021 USD ($)	Jan. 05, 2021 province
Business Acquisition [Line Items]
Customers added (over) \| counterparty	3,000,000
Acquisition costs			$ 22
Direct Energy
Business Acquisition [Line Items]
Customers added (over) \| customer	3
Purchase price	$ 3,625
Purchase price adjustment	77		$ (38)
Cash paid to acquire business	715
Borrowings on credit facility	166
Acquisition costs	107
Proceeds from issuance of secured and unsecured debt		$ 2,900
Increase in collective collateral facilities	3,400
Business acquisition, revenue	4,161
Business acquisition, net income	$ 134
Direct Energy \| U.S.
Business Acquisition [Line Items]
States in which entity operates \| state	50
Direct Energy \| Canada
Business Acquisition [Line Items]
Provinces in which entity operates	8			8