Acquisitions, Discontinued Operations and Dispositions - Direct Energy Purchase Price Allocation (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 05, 2021	Dec. 31, 2021	Dec. 31, 2020
Other Assets
Goodwill		$ 1,795	$ 579
Texas
Other Assets
Goodwill	$ 427	751	324
East
Other Assets
Goodwill	648	$ 853	$ 240
West/Services/Other
Other Assets
Goodwill	175
Customer Relationships
Other Liabilities
Weighted average useful life, years		12 years	5 years
Direct Energy
Current Assets
Cash and cash equivalents	152
Funds deposited by counterparties	21
Restricted cash	9
Account receivable	1,802
Inventory	106
Derivative instruments	1,014
Cash collateral paid in support of energy risk management activities	233
Prepayments and other current assets	173
Total current assets	3,510
Property, plant and equipment, net	151
Other Assets
Goodwill	1,250
Intangible assets	2,321
Derivative instruments	531
Other non-current assets	31
Total other assets	4,133
Total Assets	7,794
Current Liabilities
Accounts payable	1,116
Derivative instruments	1,266
Cash collateral received in support of energy risk management activities	21
Accrued expenses and other current liabilities	670
Total current liabilities	3,073
Other Liabilities
Derivative instruments	562
Deferred income taxes	320
Other non-current liabilities	115
Total other liabilities	997
Total Liabilities	4,070
Purchase Price	3,724
Goodwill, expected to be tax deductible	322
Direct Energy | Customer Relationships
Other Assets
Intangible assets	$ 1,277
Other Liabilities
Weighted average useful life, years	12 years
Direct Energy | Customer and Supply Contracts
Other Assets
Intangible assets	$ 610
Other Liabilities
Weighted average useful life, years	12 years
Direct Energy | Trade Names
Other Assets
Intangible assets	$ 310
Other Liabilities
Weighted average useful life, years	12 years
Direct Energy | Renewable Energy Credits
Other Assets
Intangible assets	$ 124