Consolidated Entities and Equity Method Investments - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2022 USD ($) investor	Dec. 31, 2021 USD ($)
Schedule of Equity Method Investments [Line Items]
Assets	$ 128,639	$ 127,534
Liabilities	95,719	94,967
Equity investments in unconsolidated subsidiaries	1,293	1,282
Southern Power
Schedule of Equity Method Investments [Line Items]
Assets	13,766	13,390
Liabilities	7,210	6,792
Equity investments in unconsolidated subsidiaries	56	86
Proceeds from sale of equity method investments	$ 31
SP Solar Holdings I, LP | Southern Power
Schedule of Equity Method Investments [Line Items]
Distribution made to limited partner, cash distributions paid, percentage	67.00%
SP Solar Holdings I, LP | Global Atlantic
Schedule of Equity Method Investments [Line Items]
Distribution made to limited partner, cash distributions paid, percentage	33.00%
Variable Interest Entity, Primary Beneficiary | SP Solar Holdings I, LP | Southern Power
Schedule of Equity Method Investments [Line Items]
Assets	$ 6,000	6,100
Liabilities	407	408
Noncontrolling interests related to other partners' interests	1,100	1,100
Variable Interest Entity, Primary Beneficiary | SP Wind | Southern Power
Schedule of Equity Method Investments [Line Items]
Assets	2,300	2,300
Liabilities	180	130
Noncontrolling interests related to other partners' interests	$ 41	41
Distribution made to limited partner, cash distributions paid, percentage	60.00%
Number of financial investors | investor	3
Variable Interest Entity, Primary Beneficiary | SP Wind | Financial Investors
Schedule of Equity Method Investments [Line Items]
Distribution made to limited partner, cash distributions paid, percentage	40.00%
Variable Interest Entity, Primary Beneficiary | Other Variable Interest Entities | Southern Power
Schedule of Equity Method Investments [Line Items]
Assets	$ 1,800	1,900
Liabilities	248	263
Noncontrolling interests related to other partners' interests	$ 876	$ 886