Related Party Transactions (Tables)

12 Months Ended

Dec. 31, 2017

Affiliated Revenues

Related Party Revenues	AEP Texas		AEPTCo		APCo		I&M			OPCo		PSO		SWEPCo
	(in millions)
Year Ended December 31, 2017
Direct Sales to East Affiliates	$	—	$	—	$	130.4	$	—		$	—	$	—	$	—
Direct Sales to West Affiliates	—		—		—		3.8			—		—		—
Auction Sales to OPCo (a)	—		—		1.0		—			—		—		—
Direct Sales to AEPEP	63.6		—		—		—			—		—		(0.2		)
Transmission Agreement and Transmission Coordination Agreement Sales	—		572.0		34.1		(4.4		)	6.2		—		24.2
Other Revenues	2.1		8.5		6.5		2.4			18.2		4.3		1.9
Total Affiliated Revenues	$	65.7	$	580.5	$	172.0	$	1.8		$	24.4	$	4.3	$	25.9

Related Party Revenues	AEP Texas		AEPTCo		APCo		I&M		OPCo			PSO			SWEPCo
	(in millions)
Year Ended December 31, 2016
Direct Sales to East Affiliates	$	—	$	—	$	126.0	$	—	$	—		$	—		$	—
Direct Sales to West Affiliates	—		—		—		—		—			—			3.7
Auction Sales to OPCo (a)	—		—		9.2		12.0		—			—			—
Direct Sales to AEPEP	73.9		—		—		—		—			—			(0.2		)
Transmission Agreement and Transmission Coordination Agreement Sales	—		366.1		1.3		12.2		(2.0		)	(1.7		)	19.4
Other Revenues	1.8		—		5.6		2.0		19.3			4.3			1.6
Total Affiliated Revenues	$	75.7	$	366.1	$	142.1	$	26.2	$	17.3		$	2.6		$	24.5

Related Party Revenues	AEP Texas		AEPTCo		APCo		I&M		OPCo		PSO		SWEPCo
	(in millions)
Year Ended December 31, 2015
Direct Sales to East Affiliates	$	—	$	—	$	132.1	$	—	$	—	$	—	$	—
Auction Sales to OPCo (a)	—		—		10.6		17.1		—		—		—
Direct Sales to AEPEP	76.9		—		—		—		29.7		—		(0.2		)
Transmission Agreement and Transmission Coordination Agreement Sales	—		225.6		0.7		8.4		35.5		0.2		15.2
Other Revenues	1.6		—		4.4		1.9		18.9		4.4		1.6
Total Affiliated Revenues	$	78.5	$	225.6	$	147.8	$	27.4	$	84.1	$	4.6	$	16.6

(a)    Refer to the Ohio Auctions section below for further information regarding these amounts.

Affiliated Purchases

Related Party Purchases	I&M		OPCo		PSO
	(in millions)
Year Ended December 31, 2017
Auction Purchases from AEPEP (a)	$	—	$	96.5	$	—
Auction Purchases from AEP Energy (a)	—		5.5		—
Auction Purchases from AEPSC (a)	—		6.5		—
Direct Purchases from AEGCo	223.9		—		—
Total Affiliated Purchases	$	223.9	$	108.5	$	—

Related Party Purchases	I&M		OPCo		PSO
	(in millions)
Year Ended December 31, 2016
Direct Purchases from West Affiliates	$	—	$	—	$	3.7
Auction Purchases from AEPEP (a)	—		110.1		—
Auction Purchases from AEP Energy (a)	—		7.7		—
Auction Purchases from AEPSC (a)	—		24.1		—
Direct Purchases from AEGCo	228.6		—		—
Total Affiliated Purchases	$	228.6	$	141.9	$	3.7

Related Party Purchases	I&M		OPCo		PSO
	(in millions)
Year Ended December 31, 2015
Direct Purchases from AGR (b)	$	—	$	269.2	$	—
Auction Purchases from AEPEP (a)	—		225.2		—
Auction Purchases from AEPSC (a)	—		32.7		—
Direct Purchases from AEGCo	232.1		—		—
Total Affiliated Purchases	$	232.1	$	527.1	$	—

(a) Refer to the Ohio Auctions section below for further information regarding this amount.

(b) Amount excludes $31 million in 2015 which is now presented as Generation Deferrals on the Statement of Income.

Transmission Agreement

	Years Ended December 31,
Company	2017		2016		2015
	(in millions)
APCo	$	158.2	$	103.2	$	92.7
I&M	103.8		53.0		38.0
OPCo	248.6		143.6		81.0

Transmission Coordination Agreement

	Years Ended December 31,
Company	2017		2016			2015
	(in millions)
PSO	$	56.0	$	19.6		$	15.0
SWEPCo	6.6		(19.6		)	(15.0		)

Joint License Agreement [Table Text Block]

	Years Ended December 31,
Billing Company	2017		2016		2015
	(in millions)
I&M	$	1.4	$	0.8	$	0.6
KPCo	0.2		0.1		—
OPCo	2.4		2.3		2.0
PSO	0.3		0.2		0.3

Coal Transloading

	Years Ended December 31,
Company	2017		2016		2015
	(in millions)
I&M	$	10.2	$	12.8	$	15.8

Railcar Maintenance

	Years Ended December 31,
Company	2017		2016		2015
	(in millions)
I&M	$	1.3	$	1.7	$	2.0
PSO	0.5		0.6		0.2
SWEPCo	3.5		3.3		2.8

Barging, Urea Transloading and Other Services

	Years Ended December 31,
Company	2017		2016		2015
	(in millions)
AEGCo	$	15.3	$	14.8	$	16.1
AGR	0.1		0.3		4.9
APCo	37.2		36.9		37.7
KPCo	5.0		5.3		4.6
WPCo	5.0		4.8		—
AEP River Operations LLC – (Nonutility Subsidiary of AEP)	—		—		15.5

Central Machine Shop

	Years Ended December 31,
Company	2017		2016		2015
	(in millions)
AEGCo	$	—	$	—	$	0.1
AGR	1.2		2.0		2.7
I&M	2.7		2.9		2.5
KPCo	1.8		1.5		1.3
PSO	1.1		0.5		0.2
SWEPCo	0.8		0.9		0.8

Related Party Sales of Property

Sales

	Years Ended December 31,
Company	2017		2016		2015
	(in millions)
AEP Texas	$	0.2	$	0.3	$	0.6
AEPTCo	—		—		0.2
APCo	3.5		4.5		9.4
I&M	5.0		5.2		3.0
OPCo	2.9		1.9		2.4
PSO	1.5		7.5		7.1
SWEPCo	0.5		1.0		0.8

Related Party Purchases of Property

Purchases

	Years Ended December 31,
Company	2017		2016		2015
	(in millions)
AEP Texas	$	0.4	$	0.7	$	0.9
AEPTCo	9.1		6.5		0.4
APCo	0.9		1.5		8.6
I&M	3.5		2.7		8.1
OPCo	1.6		1.7		2.1
PSO	0.2		3.2		0.6
SWEPCo	0.4		6.5		7.4