Regulatory Matters - GPC Deferral of Incremental COVID-19 Costs (Details) - GEORGIA POWER CO $ in Millions	4 Months Ended
Sep. 30, 2021 USD ($)
Public Utilities, General Disclosures [Line Items]
Decrease in incremental COVID-19 costs deferred	$ 23
Incremental COVID-19 costs deferred	20
Incremental COVID-19 costs deferred, bad debt costs	1
Incremental COVID-19 costs deferred, other	$ 19

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