CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - SPC Noncontrolling Interests and VIEs Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) investor	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Redeemable Noncontrolling Interest [Line Items]
Total assets	$ 139,331	$ 134,891	$ 127,534
Liabilities	104,106	100,359
Equity investments in unconsolidated subsidiaries	1,368	1,443
Southern Power
Redeemable Noncontrolling Interest [Line Items]
Total assets	12,761	13,081
Liabilities	6,063	6,165
Proceeds from sale of equity method investments	50	38
Equity investments in unconsolidated subsidiaries	$ 0	49
Southern Power | SP Solar Holdings I, LP
Redeemable Noncontrolling Interest [Line Items]
Sale of equity interest in limited partnership	33.00%
Wholly Owned Subsidiary Of Southern Power | Southern Power | SP Solar Holdings I, LP
Redeemable Noncontrolling Interest [Line Items]
Ownership interest	66.00%
Wholly Owned Subsidiary Of Southern Power | Southern Power | SP Wind
Redeemable Noncontrolling Interest [Line Items]
Ownership interest	100.00%
SP Solar Holdings I, LP | Southern Power
Redeemable Noncontrolling Interest [Line Items]
Distribution made to limited partner, cash distributions paid, percentage	67.00%
SP Solar Holdings I, LP | Global Atlantic
Redeemable Noncontrolling Interest [Line Items]
Distribution made to limited partner, cash distributions paid, percentage	33.00%
SP Wind | Southern Power
Redeemable Noncontrolling Interest [Line Items]
Distribution made to limited partner, cash distributions paid, percentage	60.00%
Number of financial investors | investor	3
SP Wind | Financial Investors
Redeemable Noncontrolling Interest [Line Items]
Distribution made to limited partner, cash distributions paid, percentage	40.00%
General Partner | Wholly Owned Subsidiary Of Southern Power | Southern Power | SP Solar Holdings I, LP
Redeemable Noncontrolling Interest [Line Items]
Ownership interest	1.00%
Variable Interest Entity, Primary Beneficiary | SP Solar Holdings I, LP | Southern Power
Redeemable Noncontrolling Interest [Line Items]
Total assets	$ 5,600	5,900
Liabilities	400
Noncontrolling interests related to other partners' interest	1,000	1,100
Variable Interest Entity, Primary Beneficiary | SP Wind | Southern Power
Redeemable Noncontrolling Interest [Line Items]
Total assets	2,100	2,200
Liabilities	187	169
Noncontrolling interests related to other partners' interest	38	39
Variable Interest Entity, Primary Beneficiary | Other Variable Interest Entities | Southern Power
Redeemable Noncontrolling Interest [Line Items]
Total assets	1,700	$ 1,800
Liabilities	200
Noncontrolling interests related to other partners' interest	$ 800