Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2024

Components of Net Periodic Benefit Cost

Pension Plans

Three Months Ended March 31, 2024	AEP		AEP Texas		APCo		I&M		OPCo		PSO		SWEPCo
	(in millions)
Service Cost	$	25.6	$	2.2	$	2.4	$	3.3	$	2.4	$	1.5	$	1.9
Interest Cost	51.9		4.3		6.2		6.0		4.7		2.5		3.1
Expected Return on Plan Assets	(80.2)		(6.4)		(10.7)		(10.8)		(8.2)		(4.3)		(4.4)
Amortization of Net Actuarial Loss	1.1		0.1		0.1		0.1		0.1		—		0.1
Net Periodic Benefit Cost (Credit)	$	(1.6)	$	0.2	$	(2.0)	$	(1.4)	$	(1.0)	$	(0.3)	$	0.7

Three Months Ended March 31, 2023	AEP		AEP Texas		APCo		I&M		OPCo		PSO		SWEPCo
	(in millions)
Service Cost	$	23.6	$	2.0	$	2.3	$	3.0	$	2.1	$	1.4	$	1.9
Interest Cost	54.8		4.6		6.6		6.2		4.9		2.7		3.5
Expected Return on Plan Assets	(84.8)		(7.0)		(11.2)		(11.0)		(8.5)		(4.6)		(4.8)
Amortization of Net Actuarial Loss	0.3		—		—		—		—		—		—
Net Periodic Benefit Cost (Credit)	$	(6.1)	$	(0.4)	$	(2.3)	$	(1.8)	$	(1.5)	$	(0.5)	$	0.6

OPEB

Three Months Ended March 31, 2024	AEP		AEP Texas		APCo		I&M		OPCo		PSO		SWEPCo
	(in millions)
Service Cost	$	1.1	$	0.1	$	0.1	$	0.1	$	0.1	$	0.1	$	0.1
Interest Cost	10.5		0.8		1.7		1.2		1.1		0.5		0.7
Expected Return on Plan Assets	(27.8)		(2.3)		(4.0)		(3.4)		(3.0)		(1.4)		(1.9)
Amortization of Prior Service Credit	(3.2)		(0.3)		(0.5)		(0.4)		(0.3)		(0.2)		(0.3)
Amortization of Net Actuarial Loss	0.8		0.1		0.1		0.1		0.1		—		0.1
Net Periodic Benefit Credit	$	(18.6)	$	(1.6)	$	(2.6)	$	(2.4)	$	(2.0)	$	(1.0)	$	(1.3)

Three Months Ended March 31, 2023	AEP		AEP Texas		APCo		I&M		OPCo		PSO		SWEPCo
	(in millions)
Service Cost	$	1.1	$	0.1	$	0.1	$	0.2	$	0.1	$	0.1	$	0.1
Interest Cost	11.6		0.9		1.8		1.3		1.2		0.6		0.7
Expected Return on Plan Assets	(27.4)		(2.3)		(4.0)		(3.4)		(2.9)		(1.5)		(1.8)
Amortization of Prior Service Credit	(15.8)		(1.3)		(2.3)		(2.2)		(1.6)		(1.0)		(1.2)
Amortization of Net Actuarial Loss	3.7		0.3		0.6		0.5		0.4		0.2		0.2
Net Periodic Benefit Credit	$	(26.8)	$	(2.3)	$	(3.8)	$	(3.6)	$	(2.8)	$	(1.6)	$	(2.0)