Business Segments (Details) - USD ($) $ in Millions |
3 Months Ended |
12 Months Ended |
Dec. 31, 2017 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Mar. 31, 2017 |
Dec. 31, 2016 |
Sep. 30, 2016 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Reportable Segment Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Vertically Integrated Utilities |
|
|
|
|
|
|
|
|
|
|
|
|
$ 9,095.1
|
$ 9,012.4
|
|
$ 9,069.9
|
Transmission and Distribution Utilities |
|
|
|
|
|
|
|
|
|
|
|
|
4,328.9
|
4,328.3
|
|
4,392.0
|
Generation and Marketing Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
1,771.4
|
2,858.7
|
|
2,866.7
|
Corporate and Other Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
229.5
|
180.7
|
|
124.6
|
Sales to AEP Affiliates |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Total Revenues |
|
$ 3,810.4
|
$ 4,104.7
|
$ 3,576.5
|
$ 3,933.3
|
$ 3,790.1
|
|
$ 4,652.2
|
|
$ 3,892.9
|
|
$ 4,044.9
|
15,424.9
|
16,380.1
|
|
16,453.2
|
Asset Impairments and Other Related Charges |
|
|
|
|
|
|
|
|
|
|
|
|
87.1
|
2,267.8
|
|
0.0
|
Depreciation and Amortization |
|
|
|
|
|
|
|
|
|
|
|
|
1,997.2
|
1,962.3
|
|
2,009.7
|
Interest and Investment Income |
|
|
|
|
|
|
|
|
|
|
|
|
16.0
|
16.3
|
|
7.9
|
Carrying Costs Income |
|
|
|
|
|
|
|
|
|
|
|
|
18.6
|
16.2
|
|
23.5
|
Allowance for Equity Funds Used During Construction |
|
|
|
|
|
|
|
|
|
|
|
|
93.7
|
113.2
|
|
131.9
|
Interest Expense |
|
|
|
|
|
|
|
|
|
|
|
|
895.0
|
877.2
|
|
873.9
|
Income Tax Expense (Credit) |
|
|
|
|
|
|
|
|
|
|
|
|
969.7
|
(73.7)
|
|
919.6
|
Income from Continuing Operations |
|
|
|
|
|
375.2
|
|
(764.2)
|
[1] |
506.4
|
|
503.1
|
1,928.9
|
620.5
|
|
1,768.6
|
Income (Loss) from Discontinued Operations, Net of Tax |
|
|
|
|
|
0.0
|
|
0.0
|
|
(2.5)
|
[2] |
0.0
|
0.0
|
(2.5)
|
|
283.7
|
NET INCOME (LOSS) |
|
401.8
|
556.7
|
376.2
|
594.2
|
375.2
|
|
(764.2)
|
[1] |
503.9
|
|
503.1
|
1,928.9
|
618.0
|
|
2,052.3
|
Gross Property Additions |
|
|
|
|
|
|
|
|
|
|
|
|
5,698.1
|
4,889.0
|
|
4,513.3
|
Balance Sheet Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Property, Plant and Equipment, Gross, Period Increase (Decrease) |
|
67,428.5
|
|
|
|
62,036.6
|
|
|
|
|
|
|
67,428.5
|
62,036.6
|
|
|
Accumulated Depreciation and Amortization |
|
17,167.0
|
|
|
|
16,397.3
|
|
|
|
|
|
|
17,167.0
|
16,397.3
|
|
|
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET |
|
50,261.5
|
|
|
|
45,639.3
|
[3] |
|
|
|
|
|
50,261.5
|
45,639.3
|
[3] |
|
Assets Held for Sale |
|
|
|
|
|
1,951.2
|
|
|
|
|
|
|
|
1,951.2
|
|
|
Total Assets |
|
64,729.1
|
|
|
|
63,467.7
|
|
|
|
|
|
|
64,729.1
|
63,467.7
|
|
61,683.1
|
Investments in Equity Method Investees |
|
812.3
|
|
|
|
809.4
|
|
|
|
|
|
|
812.3
|
809.4
|
|
|
Long-term Debt Due Within One Year |
|
1,753.7
|
|
|
|
2,878.0
|
|
|
|
|
|
|
1,753.7
|
2,878.0
|
|
|
Long-term Debt - Affiliated |
|
0.0
|
|
|
|
0.0
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Long-term Debt |
|
19,419.6
|
|
|
|
17,378.4
|
|
|
|
|
|
|
19,419.6
|
17,378.4
|
|
|
Total Long-term Debt Outstanding |
|
21,173.3
|
|
|
|
20,256.4
|
|
|
|
|
|
|
21,173.3
|
20,256.4
|
|
|
Disposal Group, Including Discontinued Operation, Liabilities, Current |
|
0.0
|
|
|
|
235.9
|
|
|
|
|
|
|
0.0
|
235.9
|
|
|
Vertically Integrated Utilities [Member] |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Reportable Segment Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Vertically Integrated Utilities |
|
|
|
|
|
|
|
|
|
|
|
|
9,095.1
|
9,012.4
|
|
9,069.9
|
Sales to AEP Affiliates |
|
|
|
|
|
|
|
|
|
|
|
|
96.9
|
79.5
|
|
102.3
|
Total Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
9,192.0
|
9,091.9
|
|
9,172.2
|
Asset Impairments and Other Related Charges |
|
|
|
|
|
|
|
|
|
|
|
|
33.6
|
10.5
|
|
|
Depreciation and Amortization |
|
|
|
|
|
|
|
|
|
|
|
|
1,142.5
|
1,073.8
|
|
1,062.6
|
Interest and Investment Income |
|
|
|
|
|
|
|
|
|
|
|
|
6.8
|
4.8
|
|
4.6
|
Carrying Costs Income |
|
|
|
|
|
|
|
|
|
|
|
|
15.2
|
10.5
|
|
11.8
|
Interest Expense |
|
|
|
|
|
|
|
|
|
|
|
|
540.0
|
522.1
|
|
517.4
|
Income Tax Expense (Credit) |
|
|
|
|
|
|
|
|
|
|
|
|
425.6
|
397.3
|
|
449.3
|
Income from Continuing Operations |
|
|
|
|
|
|
|
|
|
|
|
|
803.3
|
984.0
|
|
900.2
|
Income (Loss) from Discontinued Operations, Net of Tax |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
NET INCOME (LOSS) |
|
|
|
|
|
|
|
|
|
|
|
|
803.3
|
984.0
|
|
900.2
|
Gross Property Additions |
|
|
|
|
|
|
|
|
|
|
|
|
2,343.2
|
2,237.0
|
|
2,222.3
|
Balance Sheet Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Property, Plant and Equipment, Gross, Period Increase (Decrease) |
|
43,294.4
|
|
|
|
41,552.6
|
|
|
|
|
|
|
43,294.4
|
41,552.6
|
|
|
Accumulated Depreciation and Amortization |
|
13,153.4
|
|
|
|
12,596.7
|
|
|
|
|
|
|
13,153.4
|
12,596.7
|
|
|
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET |
|
30,141.0
|
|
|
|
28,955.9
|
|
|
|
|
|
|
30,141.0
|
28,955.9
|
|
|
Assets Held for Sale |
|
|
|
|
|
0.0
|
|
|
|
|
|
|
|
0.0
|
|
|
Total Assets |
|
37,579.7
|
|
|
|
37,428.3
|
|
|
|
|
|
|
37,579.7
|
37,428.3
|
|
35,792.3
|
Investments in Equity Method Investees |
|
37.1
|
|
|
|
41.2
|
|
|
|
|
|
|
37.1
|
41.2
|
|
|
Long-term Debt Due Within One Year |
|
1,038.1
|
|
|
|
1,519.9
|
|
|
|
|
|
|
1,038.1
|
1,519.9
|
|
|
Long-term Debt - Affiliated |
|
50.0
|
|
|
|
20.0
|
|
|
|
|
|
|
50.0
|
20.0
|
|
|
Long-term Debt |
|
10,801.4
|
|
|
|
10,353.3
|
|
|
|
|
|
|
10,801.4
|
10,353.3
|
|
|
Total Long-term Debt Outstanding |
|
11,889.5
|
|
|
|
11,893.2
|
|
|
|
|
|
|
11,889.5
|
11,893.2
|
|
|
Disposal Group, Including Discontinued Operation, Liabilities, Current |
|
|
|
|
|
0.0
|
|
|
|
|
|
|
|
0.0
|
|
|
Transmission and Distribution Companies [Member] |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Reportable Segment Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Transmission and Distribution Utilities |
|
|
|
|
|
|
|
|
|
|
|
|
4,328.9
|
4,328.3
|
|
4,392.0
|
Sales to AEP Affiliates |
|
|
|
|
|
|
|
|
|
|
|
|
90.4
|
94.1
|
|
164.6
|
Total Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
4,419.3
|
4,422.4
|
|
4,556.6
|
Asset Impairments and Other Related Charges |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Depreciation and Amortization |
|
|
|
|
|
|
|
|
|
|
|
|
667.5
|
649.9
|
|
686.4
|
Interest and Investment Income |
|
|
|
|
|
|
|
|
|
|
|
|
7.7
|
14.8
|
|
6.4
|
Carrying Costs Income |
|
|
|
|
|
|
|
|
|
|
|
|
3.6
|
20.0
|
|
11.8
|
Interest Expense |
|
|
|
|
|
|
|
|
|
|
|
|
244.1
|
256.9
|
|
276.2
|
Income Tax Expense (Credit) |
|
|
|
|
|
|
|
|
|
|
|
|
127.2
|
205.1
|
|
185.5
|
Income from Continuing Operations |
|
|
|
|
|
|
|
|
|
|
|
|
636.4
|
482.1
|
|
352.4
|
Income (Loss) from Discontinued Operations, Net of Tax |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
NET INCOME (LOSS) |
|
|
|
|
|
|
|
|
|
|
|
|
636.4
|
482.1
|
|
352.4
|
Gross Property Additions |
|
|
|
|
|
|
|
|
|
|
|
|
1,558.4
|
1,058.3
|
|
1,048.4
|
Balance Sheet Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Property, Plant and Equipment, Gross, Period Increase (Decrease) |
|
16,371.2
|
|
|
|
14,762.2
|
|
|
|
|
|
|
16,371.2
|
14,762.2
|
|
|
Accumulated Depreciation and Amortization |
|
3,768.3
|
|
|
|
3,655.0
|
|
|
|
|
|
|
3,768.3
|
3,655.0
|
|
|
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET |
|
12,602.9
|
|
|
|
11,107.2
|
|
|
|
|
|
|
12,602.9
|
11,107.2
|
|
|
Assets Held for Sale |
|
|
|
|
|
0.0
|
|
|
|
|
|
|
|
0.0
|
|
|
Total Assets |
|
16,060.7
|
|
|
|
14,802.4
|
|
|
|
|
|
|
16,060.7
|
14,802.4
|
|
14,795.0
|
Investments in Equity Method Investees |
|
1.5
|
|
|
|
1.2
|
|
|
|
|
|
|
1.5
|
1.2
|
|
|
Long-term Debt Due Within One Year |
|
663.1
|
|
|
|
309.4
|
|
|
|
|
|
|
663.1
|
309.4
|
|
|
Long-term Debt - Affiliated |
|
0.0
|
|
|
|
0.0
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Long-term Debt |
|
4,705.4
|
|
|
|
4,672.2
|
|
|
|
|
|
|
4,705.4
|
4,672.2
|
|
|
Total Long-term Debt Outstanding |
|
5,368.5
|
|
|
|
4,981.6
|
|
|
|
|
|
|
5,368.5
|
4,981.6
|
|
|
Disposal Group, Including Discontinued Operation, Liabilities, Current |
|
|
|
|
|
0.0
|
|
|
|
|
|
|
|
0.0
|
|
|
AEP Transmission Holdco |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Reportable Segment Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Transmission Revenue |
|
|
|
|
|
|
|
|
|
|
|
|
178.4
|
145.9
|
|
100.6
|
Sales to AEP Affiliates |
|
|
|
|
|
|
|
|
|
|
|
|
588.3
|
366.9
|
|
228.6
|
Total Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
766.7
|
512.8
|
|
329.2
|
Asset Impairments and Other Related Charges |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Depreciation and Amortization |
|
|
|
|
|
|
|
|
|
|
|
|
102.2
|
67.1
|
|
43.0
|
Interest and Investment Income |
|
|
|
|
|
|
|
|
|
|
|
|
1.2
|
0.4
|
|
0.2
|
Carrying Costs Income |
|
|
|
|
|
|
|
|
|
|
|
|
(0.2)
|
(0.3)
|
|
(0.2)
|
Interest Expense |
|
|
|
|
|
|
|
|
|
|
|
|
72.8
|
50.3
|
|
37.2
|
Income Tax Expense (Credit) |
|
|
|
|
|
|
|
|
|
|
|
|
189.8
|
134.1
|
|
91.3
|
Income from Continuing Operations |
|
|
|
|
|
|
|
|
|
|
|
|
355.6
|
269.3
|
|
192.7
|
Income (Loss) from Discontinued Operations, Net of Tax |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
NET INCOME (LOSS) |
|
|
|
|
|
|
|
|
|
|
|
|
355.6
|
269.3
|
|
192.7
|
Gross Property Additions |
|
|
|
|
|
|
|
|
|
|
|
|
1,542.8
|
1,265.8
|
|
1,121.3
|
Balance Sheet Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Property, Plant and Equipment, Gross, Period Increase (Decrease) |
|
7,110.2
|
|
|
|
5,354.0
|
|
|
|
|
|
|
7,110.2
|
5,354.0
|
|
|
Accumulated Depreciation and Amortization |
|
176.6
|
|
|
|
101.4
|
|
|
|
|
|
|
176.6
|
101.4
|
|
|
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET |
|
6,933.6
|
|
|
|
5,252.6
|
|
|
|
|
|
|
6,933.6
|
5,252.6
|
|
|
Assets Held for Sale |
|
|
|
|
|
0.0
|
|
|
|
|
|
|
|
0.0
|
|
|
Total Assets |
|
8,141.8
|
|
|
|
6,384.8
|
|
|
|
|
|
|
8,141.8
|
6,384.8
|
|
5,012.1
|
Investments in Equity Method Investees |
|
742.9
|
|
|
|
742.0
|
|
|
|
|
|
|
742.9
|
742.0
|
|
|
Long-term Debt Due Within One Year |
|
50.0
|
|
|
|
0.0
|
|
|
|
|
|
|
50.0
|
0.0
|
|
|
Long-term Debt - Affiliated |
|
0.0
|
|
|
|
0.0
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Long-term Debt |
|
2,631.3
|
|
|
|
2,055.7
|
|
|
|
|
|
|
2,631.3
|
2,055.7
|
|
|
Total Long-term Debt Outstanding |
|
2,681.3
|
|
|
|
2,055.7
|
|
|
|
|
|
|
2,681.3
|
2,055.7
|
|
|
Disposal Group, Including Discontinued Operation, Liabilities, Current |
|
|
|
|
|
0.0
|
|
|
|
|
|
|
|
0.0
|
|
|
Generation and Marketing [Member] |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Reportable Segment Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Generation and Marketing Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
1,771.4
|
2,858.7
|
|
2,866.7
|
Sales to AEP Affiliates |
|
|
|
|
|
|
|
|
|
|
|
|
103.7
|
127.3
|
|
546.0
|
Total Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
1,875.1
|
2,986.0
|
|
3,412.7
|
Asset Impairments and Other Related Charges |
|
|
|
|
|
|
|
|
|
|
|
|
53.5
|
2,257.3
|
|
|
Depreciation and Amortization |
|
|
|
|
|
|
|
|
|
|
|
|
24.2
|
154.6
|
|
201.4
|
Interest and Investment Income |
|
|
|
|
|
|
|
|
|
|
|
|
10.3
|
1.4
|
|
2.8
|
Carrying Costs Income |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Interest Expense |
|
|
|
|
|
|
|
|
|
|
|
|
18.5
|
35.8
|
|
40.0
|
Income Tax Expense (Credit) |
|
|
|
|
|
|
|
|
|
|
|
|
189.7
|
(666.5)
|
|
194.6
|
Income from Continuing Operations |
|
|
|
|
|
|
|
|
|
|
|
|
166.0
|
(1,198.0)
|
|
366.0
|
Income (Loss) from Discontinued Operations, Net of Tax |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
NET INCOME (LOSS) |
|
|
|
|
|
|
|
|
|
|
|
|
166.0
|
(1,198.0)
|
|
366.0
|
Gross Property Additions |
|
|
|
|
|
|
|
|
|
|
|
|
328.5
|
336.2
|
|
134.3
|
Balance Sheet Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Property, Plant and Equipment, Gross, Period Increase (Decrease) |
|
644.6
|
|
|
|
364.7
|
|
|
|
|
|
|
644.6
|
364.7
|
|
|
Accumulated Depreciation and Amortization |
|
75.0
|
|
|
|
42.2
|
|
|
|
|
|
|
75.0
|
42.2
|
|
|
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET |
|
569.6
|
|
|
|
322.5
|
|
|
|
|
|
|
569.6
|
322.5
|
|
|
Assets Held for Sale |
|
|
|
|
|
1,951.2
|
|
|
|
|
|
|
|
1,951.2
|
|
|
Total Assets |
|
2,009.8
|
|
|
|
3,386.1
|
|
|
|
|
|
|
2,009.8
|
3,386.1
|
|
5,414.5
|
Investments in Equity Method Investees |
|
16.6
|
|
|
|
0.1
|
|
|
|
|
|
|
16.6
|
0.1
|
|
|
Long-term Debt Due Within One Year |
|
0.0
|
|
|
|
500.1
|
|
|
|
|
|
|
0.0
|
500.1
|
|
|
Long-term Debt - Affiliated |
|
32.2
|
|
|
|
32.2
|
|
|
|
|
|
|
32.2
|
32.2
|
|
|
Long-term Debt |
|
(0.3)
|
|
|
|
0.0
|
|
|
|
|
|
|
(0.3)
|
0.0
|
|
|
Total Long-term Debt Outstanding |
|
31.9
|
|
|
|
532.3
|
|
|
|
|
|
|
31.9
|
532.3
|
|
|
Disposal Group, Including Discontinued Operation, Liabilities, Current |
|
|
|
|
|
235.9
|
|
|
|
|
|
|
|
235.9
|
|
|
All Other [Member] |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Reportable Segment Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Corporate and Other Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
51.1
|
34.8
|
|
24.0
|
Sales to AEP Affiliates |
|
|
|
|
|
|
|
|
|
|
|
|
69.7
|
70.3
|
|
75.0
|
Total Revenues |
[4] |
|
|
|
|
|
|
|
|
|
|
|
120.8
|
105.1
|
|
99.0
|
Asset Impairments and Other Related Charges |
[4] |
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Depreciation and Amortization |
[4] |
|
|
|
|
|
|
|
|
|
|
|
0.3
|
0.2
|
|
0.8
|
Interest and Investment Income |
[4] |
|
|
|
|
|
|
|
|
|
|
|
23.3
|
11.8
|
|
9.2
|
Carrying Costs Income |
[4] |
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Interest Expense |
[4] |
|
|
|
|
|
|
|
|
|
|
|
63.9
|
40.5
|
|
30.3
|
Income Tax Expense (Credit) |
[4] |
|
|
|
|
|
|
|
|
|
|
|
37.4
|
(143.7)
|
|
(1.1)
|
Income from Continuing Operations |
[4] |
|
|
|
|
|
|
|
|
|
|
|
(32.4)
|
83.1
|
|
(42.7)
|
Income (Loss) from Discontinued Operations, Net of Tax |
[4] |
|
|
|
|
|
|
|
|
|
|
|
0.0
|
(2.5)
|
|
283.7
|
NET INCOME (LOSS) |
[4] |
|
|
|
|
|
|
|
|
|
|
|
(32.4)
|
80.6
|
|
241.0
|
Gross Property Additions |
[4] |
|
|
|
|
|
|
|
|
|
|
|
15.6
|
9.8
|
|
4.8
|
Balance Sheet Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Property, Plant and Equipment, Gross, Period Increase (Decrease) |
[4] |
374.5
|
|
|
|
356.6
|
|
|
|
|
|
|
374.5
|
356.6
|
|
|
Accumulated Depreciation and Amortization |
[4] |
180.6
|
|
|
|
186.0
|
|
|
|
|
|
|
180.6
|
186.0
|
|
|
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET |
[4] |
193.9
|
|
|
|
170.6
|
|
|
|
|
|
|
193.9
|
170.6
|
|
|
Assets Held for Sale |
[4] |
|
|
|
|
0.0
|
|
|
|
|
|
|
|
0.0
|
|
|
Total Assets |
[4],[5] |
3,959.1
|
|
|
|
3,883.4
|
|
|
|
|
|
|
3,959.1
|
3,883.4
|
|
3,628.5
|
Investments in Equity Method Investees |
[4] |
14.2
|
|
|
|
24.9
|
|
|
|
|
|
|
14.2
|
24.9
|
|
|
Long-term Debt Due Within One Year |
[4] |
2.5
|
|
|
|
548.6
|
|
|
|
|
|
|
2.5
|
548.6
|
|
|
Long-term Debt - Affiliated |
[4] |
0.0
|
|
|
|
0.0
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Long-term Debt |
[4] |
1,281.8
|
|
|
|
297.2
|
|
|
|
|
|
|
1,281.8
|
297.2
|
|
|
Total Long-term Debt Outstanding |
[4] |
1,284.3
|
|
|
|
845.8
|
|
|
|
|
|
|
1,284.3
|
845.8
|
|
|
Disposal Group, Including Discontinued Operation, Liabilities, Current |
|
|
|
|
|
0.0
|
|
|
|
|
|
|
|
0.0
|
|
|
Reconciling Adjustments [Member] |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Reportable Segment Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Corporate and Other Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Sales to AEP Affiliates |
|
|
|
|
|
|
|
|
|
|
|
|
(949.0)
|
(738.1)
|
|
(1,116.5)
|
Total Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
(949.0)
|
(738.1)
|
|
(1,116.5)
|
Asset Impairments and Other Related Charges |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Depreciation and Amortization |
[6] |
|
|
|
|
|
|
|
|
|
|
|
60.5
|
16.7
|
|
15.5
|
Interest and Investment Income |
|
|
|
|
|
|
|
|
|
|
|
|
(33.3)
|
(16.9)
|
|
(15.3)
|
Carrying Costs Income |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
(14.0)
|
|
0.1
|
Interest Expense |
[6] |
|
|
|
|
|
|
|
|
|
|
|
(44.3)
|
(28.4)
|
|
(27.2)
|
Income Tax Expense (Credit) |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Income from Continuing Operations |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Income (Loss) from Discontinued Operations, Net of Tax |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
NET INCOME (LOSS) |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Gross Property Additions |
|
|
|
|
|
|
|
|
|
|
|
|
(90.4)
|
(18.1)
|
|
(17.8)
|
Balance Sheet Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Property, Plant and Equipment, Gross, Period Increase (Decrease) |
[6] |
(366.4)
|
|
|
|
(353.5)
|
|
|
|
|
|
|
(366.4)
|
(353.5)
|
|
|
Accumulated Depreciation and Amortization |
[6] |
(186.9)
|
|
|
|
(184.0)
|
|
|
|
|
|
|
(186.9)
|
(184.0)
|
|
|
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET |
[6] |
(179.5)
|
|
|
|
(169.5)
|
|
|
|
|
|
|
(179.5)
|
(169.5)
|
|
|
Assets Held for Sale |
|
|
|
|
|
0.0
|
|
|
|
|
|
|
|
0.0
|
|
|
Total Assets |
[6],[7] |
(3,022.0)
|
|
|
|
(2,417.3)
|
|
|
|
|
|
|
(3,022.0)
|
(2,417.3)
|
|
(2,959.3)
|
Investments in Equity Method Investees |
|
0.0
|
|
|
|
0.0
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Long-term Debt Due Within One Year |
|
0.0
|
|
|
|
0.0
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Long-term Debt - Affiliated |
|
(82.2)
|
|
|
|
(52.2)
|
|
|
|
|
|
|
(82.2)
|
(52.2)
|
|
|
Long-term Debt |
|
0.0
|
|
|
|
0.0
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Total Long-term Debt Outstanding |
|
(82.2)
|
|
|
|
(52.2)
|
|
|
|
|
|
|
(82.2)
|
(52.2)
|
|
|
Disposal Group, Including Discontinued Operation, Liabilities, Current |
|
|
|
|
|
0.0
|
|
|
|
|
|
|
|
0.0
|
|
|
AEP Transmission Co [Member] |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Reportable Segment Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Transmission Revenue |
|
|
|
|
|
|
|
|
|
|
|
|
141.9
|
110.4
|
|
84.3
|
Corporate and Other Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
0.8
|
0.1
|
|
0.3
|
Sales to AEP Affiliates |
|
|
|
|
|
|
|
|
|
|
|
|
580.5
|
367.5
|
|
225.6
|
Total Revenues |
|
173.8
|
167.3
|
229.4
|
152.7
|
120.0
|
|
125.3
|
|
153.1
|
|
79.6
|
723.2
|
478.0
|
|
310.2
|
Depreciation and Amortization |
|
|
|
|
|
|
|
|
|
|
|
|
97.1
|
65.9
|
|
42.4
|
Interest Income |
|
|
|
|
|
|
|
|
|
|
|
|
1.2
|
0.4
|
|
0.1
|
Allowance for Equity Funds Used During Construction |
|
|
|
|
|
|
|
|
|
|
|
|
52.3
|
52.3
|
|
53.0
|
Interest Expense |
|
|
|
|
|
|
|
|
|
|
|
|
68.0
|
46.0
|
|
34.6
|
Income Tax Expense (Credit) |
|
|
|
|
|
|
|
|
|
|
|
|
147.2
|
94.1
|
|
60.0
|
Income from Continuing Operations |
|
|
|
|
|
0.0
|
|
0.0
|
|
0.0
|
|
0.0
|
|
|
|
|
Income (Loss) from Discontinued Operations, Net of Tax |
|
|
|
|
|
0.0
|
|
0.0
|
|
0.0
|
|
0.0
|
|
|
|
|
NET INCOME (LOSS) |
|
61.8
|
$ 59.9
|
$ 107.4
|
$ 57.0
|
39.7
|
|
$ 52.4
|
|
$ 74.8
|
|
$ 25.8
|
286.1
|
192.7
|
|
132.9
|
Gross Property Additions |
|
|
|
|
|
|
|
|
|
|
|
|
1,522.5
|
1,166.0
|
|
1,008.9
|
Balance Sheet Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Property, Plant and Equipment, Gross, Period Increase (Decrease) |
|
6,780.2
|
|
|
|
5,054.2
|
|
|
|
|
|
|
6,780.2
|
5,054.2
|
|
|
Accumulated Depreciation and Amortization |
|
170.4
|
|
|
|
99.6
|
|
|
|
|
|
|
170.4
|
99.6
|
|
|
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET |
|
6,609.8
|
|
|
|
4,954.6
|
|
|
|
|
|
|
6,609.8
|
4,954.6
|
|
|
Notes Receivable, Related Parties |
|
0.0
|
|
|
|
0.0
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Total Assets |
|
7,068.1
|
|
|
|
5,349.8
|
|
|
|
|
|
|
7,068.1
|
5,349.8
|
|
4,156.5
|
Long-term Debt Due Within One Year |
|
50.0
|
|
|
|
0.0
|
|
|
|
|
|
|
50.0
|
0.0
|
|
|
Long-term Debt |
|
2,500.4
|
|
|
|
1,932.0
|
|
|
|
|
|
|
2,500.4
|
1,932.0
|
|
|
Total Long-term Debt Outstanding |
|
2,550.4
|
|
|
|
1,932.0
|
|
|
|
|
|
|
2,550.4
|
1,932.0
|
|
|
AEP Transmission Co [Member] | State Transcos [Member] |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Reportable Segment Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Transmission Revenue |
|
|
|
|
|
|
|
|
|
|
|
|
141.9
|
110.4
|
|
84.3
|
Corporate and Other Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
0.8
|
0.1
|
|
0.3
|
Sales to AEP Affiliates |
|
|
|
|
|
|
|
|
|
|
|
|
580.5
|
367.5
|
|
225.6
|
Total Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
723.2
|
478.0
|
|
310.2
|
Depreciation and Amortization |
|
|
|
|
|
|
|
|
|
|
|
|
97.1
|
65.9
|
|
42.4
|
Interest Income |
|
|
|
|
|
|
|
|
|
|
|
|
0.7
|
0.1
|
|
0.1
|
Allowance for Equity Funds Used During Construction |
|
|
|
|
|
|
|
|
|
|
|
|
52.3
|
52.3
|
|
53.0
|
Interest Expense |
|
|
|
|
|
|
|
|
|
|
|
|
68.0
|
45.6
|
|
34.4
|
Income Tax Expense (Credit) |
|
|
|
|
|
|
|
|
|
|
|
|
147.0
|
94.4
|
|
60.1
|
NET INCOME (LOSS) |
|
|
|
|
|
|
|
|
|
|
|
|
285.8
|
193.3
|
|
133.2
|
Gross Property Additions |
|
|
|
|
|
|
|
|
|
|
|
|
1,522.5
|
1,166.0
|
|
1,008.9
|
Balance Sheet Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Property, Plant and Equipment, Gross, Period Increase (Decrease) |
|
6,780.2
|
|
|
|
5,054.2
|
|
|
|
|
|
|
6,780.2
|
5,054.2
|
|
|
Accumulated Depreciation and Amortization |
|
170.4
|
|
|
|
99.6
|
|
|
|
|
|
|
170.4
|
99.6
|
|
|
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET |
|
6,609.8
|
|
|
|
4,954.6
|
|
|
|
|
|
|
6,609.8
|
4,954.6
|
|
|
Notes Receivable, Related Parties |
|
0.0
|
|
|
|
0.0
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Total Assets |
|
7,072.9
|
|
|
|
5,337.5
|
|
|
|
|
|
|
7,072.9
|
5,337.5
|
|
4,143.6
|
Total Long-term Debt Outstanding |
|
2,575.0
|
|
|
|
1,932.0
|
|
|
|
|
|
|
2,575.0
|
1,932.0
|
|
|
AEP Transmission Co [Member] | AEPTCo Parent [Member] |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Reportable Segment Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Transmission Revenue |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Corporate and Other Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Sales to AEP Affiliates |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Total Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Depreciation and Amortization |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Interest Income |
|
|
|
|
|
|
|
|
|
|
|
|
82.9
|
57.8
|
|
49.6
|
Allowance for Equity Funds Used During Construction |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Interest Expense |
|
|
|
|
|
|
|
|
|
|
|
|
82.4
|
57.9
|
|
49.8
|
Income Tax Expense (Credit) |
|
|
|
|
|
|
|
|
|
|
|
|
0.2
|
(0.3)
|
|
(0.1)
|
NET INCOME (LOSS) |
[8] |
|
|
|
|
|
|
|
|
|
|
|
0.3
|
(0.6)
|
|
(0.3)
|
Gross Property Additions |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Balance Sheet Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Property, Plant and Equipment, Gross, Period Increase (Decrease) |
|
0.0
|
|
|
|
0.0
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Accumulated Depreciation and Amortization |
|
0.0
|
|
|
|
0.0
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET |
|
0.0
|
|
|
|
0.0
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Notes Receivable, Related Parties |
|
2,550.4
|
|
|
|
1,950.0
|
|
|
|
|
|
|
2,550.4
|
1,950.0
|
|
|
Total Assets |
[9] |
2,590.1
|
|
|
|
1,987.7
|
|
|
|
|
|
|
2,590.1
|
1,987.7
|
|
1,588.4
|
Total Long-term Debt Outstanding |
|
2,550.4
|
|
|
|
1,950.0
|
|
|
|
|
|
|
2,550.4
|
1,950.0
|
|
|
AEP Transmission Co [Member] | Reconciling Adjustments [Member] |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Reportable Segment Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Transmission Revenue |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Corporate and Other Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Sales to AEP Affiliates |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Total Revenues |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Depreciation and Amortization |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Interest Income |
[10] |
|
|
|
|
|
|
|
|
|
|
|
(82.4)
|
(57.5)
|
|
(49.6)
|
Allowance for Equity Funds Used During Construction |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Interest Expense |
[10] |
|
|
|
|
|
|
|
|
|
|
|
(82.4)
|
(57.5)
|
|
(49.6)
|
Income Tax Expense (Credit) |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
NET INCOME (LOSS) |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Gross Property Additions |
|
|
|
|
|
|
|
|
|
|
|
|
0.0
|
0.0
|
|
0.0
|
Balance Sheet Information |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Property, Plant and Equipment, Gross, Period Increase (Decrease) |
|
0.0
|
|
|
|
0.0
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Accumulated Depreciation and Amortization |
|
0.0
|
|
|
|
0.0
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET |
|
0.0
|
|
|
|
0.0
|
|
|
|
|
|
|
0.0
|
0.0
|
|
|
Notes Receivable, Related Parties |
[11] |
(2,550.4)
|
|
|
|
(1,950.0)
|
|
|
|
|
|
|
(2,550.4)
|
(1,950.0)
|
|
|
Total Assets |
[12] |
(2,594.9)
|
|
|
|
(1,975.4)
|
|
|
|
|
|
|
(2,594.9)
|
(1,975.4)
|
|
$ (1,575.5)
|
Total Long-term Debt Outstanding |
[11] |
$ (2,575.0)
|
|
|
|
$ (1,950.0)
|
|
|
|
|
|
|
$ (2,575.0)
|
$ (1,950.0)
|
|
|
|
|