BENEFIT PLANS (Tables)

3 Months Ended

Mar. 31, 2026

Retirement Benefits [Abstract]

Schedule of Components of Net Periodic Benefit Cost

Pension Plans

Three Months Ended March 31, 2026	AEP		AEP Texas		APCo		I&M		OPCo		PSO		SWEPCo
	(in millions)
Service Cost	$	25	$	2	$	2	$	3	$	2	$	2	$	2
Interest Cost	51		4		6		6		5		3		3
Expected Return on Plan Assets	(64)		(5)		(8)		(8)		(7)		(4)		(4)
Amortization of Net Actuarial Loss	11		1		1		1		1		—		1
Net Periodic Benefit Cost	$	23	$	2	$	1	$	2	$	1	$	1	$	2

Three Months Ended March 31, 2025	AEP		AEP Texas		APCo		I&M		OPCo		PSO		SWEPCo
	(in millions)
Service Cost	$	24	$	2	$	2	$	3	$	2	$	1	$	2
Interest Cost	53		5		6		6		5		3		3
Expected Return on Plan Assets	(70)		(6)		(9)		(9)		(7)		(4)		(4)
Amortization of Net Actuarial Loss	4		—		1		—		—		—		—
Net Periodic Benefit Cost	$	11	$	1	$	—	$	—	$	—	$	—	$	1

OPEB

Three Months Ended March 31, 2026	AEP		AEP Texas		APCo		I&M		OPCo		PSO		SWEPCo
	(in millions)
Service Cost	$	1	$	—	$	—	$	—	$	—	$	—	$	—
Interest Cost	8		1		1		1		1		—		1
Expected Return on Plan Assets	(29)		(3)		(4)		(4)		(3)		(1)		(2)
Amortization of Prior Service Credit	(1)		—		—		—		—		—		—
Amortization of Net Actuarial Gain	(1)		—		—		—		—		—		—
Net Periodic Benefit Credit	$	(22)	$	(2)	$	(3)	$	(3)	$	(2)	$	(1)	$	(1)

Three Months Ended March 31, 2025	AEP		AEP Texas		APCo		I&M		OPCo		PSO		SWEPCo
	(in millions)
Service Cost	$	1	$	—	$	—	$	—	$	—	$	—	$	—
Interest Cost	8		1		1		1		1		—		1
Expected Return on Plan Assets	(28)		(3)		(4)		(3)		(3)		(1)		(2)
Amortization of Prior Service Credit	(1)		—		—		—		—		—		—
Net Periodic Benefit Credit	$	(20)	$	(2)	$	(3)	$	(2)	$	(2)	$	(1)	$	(1)