Derivative Financial Instruments - Summary of Economic Hedges (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Derivative [Line Items]
Total			$ (31)	$ 490
Not Designated as Hedging Instrument, Economic Hedge | Commodity Contract
Derivative [Line Items]
Total	$ 45	$ 312	(48)	494
Not Designated as Hedging Instrument, Economic Hedge | Commodity Contract | Operating revenues
Derivative [Line Items]
Total	(303)	(240)	(1,222)	(323)
Not Designated as Hedging Instrument, Economic Hedge | Commodity Contract | Purchased power and fuel
Derivative [Line Items]
Total	$ 348	$ 552	$ 1,174	$ 817