Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating Activities
Net Income (Loss)	$ 242.8	$ 1,581.6
Income (Loss) from Discontinued Operations	(2.5)	18.2
Income (Loss) from Continuing Operations	245.3	1,563.4
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	1,550.2	1,528.0
Deferred Income Taxes	(47.0)	528.6
Asset Impairments and Other Related Charges	2,264.9	0.0
Carrying Costs Income	(11.9)	(18.4)
Allowance for Equity Funds Used During Construction	(86.1)	(96.4)
Mark-to-Market of Risk Management Contracts	56.6	17.7
Amortization of Nuclear Fuel	109.7	101.6
Pension Contributions to Qualified Plan Trust	(84.8)	(91.8)
Property Taxes	288.3	247.1
Deferred Fuel Over/Under-Recovery, Net	(28.5)	93.3
Deferral of Ohio Capacity Costs, Net	108.8	35.0
Change in Other Noncurrent Assets	(231.5)	(114.3)
Change in Other Noncurrent Liabilities	41.3	8.9
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	(240.8)	(17.5)
Fuel, Materials and Supplies	11.6	193.8
Accounts Payable	47.8	(13.3)
Accrued Taxes, Net	(393.0)	(68.3)
Other Current Assets	31.5	10.5
Other Current Liabilities	(211.4)	2.8
Net Cash Flows from (Used for) Operating Activities	3,421.0	3,910.7
Investing Activities
Construction Expenditures	(3,387.0)	(3,282.7)
Change in Other Temporary Investments, Net	109.2	80.8
Purchases of Investment Securities	(2,454.5)	(1,489.4)
Sales of Investment Securities	2,427.0	1,437.3
Acquisitions of Nuclear Fuel	(127.6)	(53.3)
Other Investing Activities	4.2	58.9
Net Cash Flows from (Used for) Investing Activities	(3,428.7)	(3,248.4)
Financing Activities
Issuance of Common Stock	34.2	67.9
Issuance of Long-term Debt	1,559.6	2,931.1
Change in Short-term Debt, Net	678.3	(564.0)
Retirement of Long-term Debt	(1,307.6)	(2,131.4)
Make Whole Premium on Extinguishment of Long-term Debt	0.0	(92.7)
Principal Payments for Capital Lease Obligations	(81.9)	(73.9)
Dividends Paid on Common Stock	(829.8)	(783.4)
Other Financing Activities	(6.8)	(0.9)
Net Cash Flows from (Used for) Financing Activities	46.0	(647.3)
Cash Flows from Discontinued Operations
Operating Activities	(2.5)	10.1
Investing Activities	0.0	2.5
Financing Activities	0.0	(12.3)
Net Increase (Decrease) in Cash and Cash Equivalents	35.8	15.3
Cash and Cash Equivalents at Beginning of Period	176.4	162.5
Cash and Cash Equivalents at End of Period	212.2	177.8
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	637.0	639.1
Net Cash Paid (Received) for Income Taxes	32.2	115.6
Noncash Acquisitions Under Capital Leases	65.8	96.9
Construction Expenditures Included in Current Liabilities as of September 30,	604.8	579.4
Construction Expenditures Included in Noncurrent Liabilities as of September 30,	0.0	66.3
Acquisition of Nuclear Fuel Included in Current Liabilities as of September 30,	0.3	31.1
Appalachian Power Co [Member]
Operating Activities
Net Income (Loss)	303.8	275.4
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	290.0	292.7
Deferred Income Taxes	100.9	179.1
Carrying Costs Income	(0.2)	(0.8)
Allowance for Equity Funds Used During Construction	(9.1)	(10.3)
Mark-to-Market of Risk Management Contracts	18.4	(5.9)
Pension Contributions to Qualified Plan Trust	(8.8)	(10.0)
Property Taxes	29.2	28.0
Deferred Fuel Over/Under-Recovery, Net	19.0	(1.7)
Change in Other Noncurrent Assets	(5.1)	(33.2)
Change in Other Noncurrent Liabilities	(23.0)	(26.7)
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	(20.5)	28.8
Fuel, Materials and Supplies	(1.2)	31.4
Accounts Payable	4.9	2.7
Accrued Taxes, Net	(13.9)	(75.3)
Other Current Assets	(0.2)	(2.6)
Other Current Liabilities	(4.1)	15.4
Net Cash Flows from (Used for) Operating Activities	680.1	687.0
Investing Activities
Construction Expenditures	(472.7)	(456.7)
Change in Restricted Cash for Securitized Funding	7.0	8.2
Change in Advances to Affiliates, Net	1.2	25.0
Other Investing Activities	10.6	10.6
Net Cash Flows from (Used for) Investing Activities	(453.9)	(412.9)
Financing Activities
Issuance of Long-term Debt	314.1	726.3
Change in Advances from Affiliates, Net	(96.9)	35.2
Retirement of Long-term Debt	(213.6)	(672.5)
Repayments of Related Party Debt	0.0	(86.0)
Make Whole Premium on Extinguishment of Long-term Debt	0.0	(92.7)
Principal Payments for Capital Lease Obligations	(4.7)	(3.8)
Dividends Paid on Common Stock	(225.0)	(181.3)
Other Financing Activities	0.4	0.5
Net Cash Flows from (Used for) Financing Activities	(225.7)	(274.3)
Cash Flows from Discontinued Operations
Net Increase (Decrease) in Cash and Cash Equivalents	0.5	(0.2)
Cash and Cash Equivalents at Beginning of Period	2.8	2.6
Cash and Cash Equivalents at End of Period	3.3	2.4
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	113.2	128.4
Net Cash Paid (Received) for Income Taxes	55.8	33.7
Noncash Acquisitions Under Capital Leases	2.1	2.3
Construction Expenditures Included in Current Liabilities as of September 30,	66.8	81.0
Indiana Michigan Power Co [Member]
Operating Activities
Net Income (Loss)	201.4	179.9
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	143.2	150.2
Deferred Income Taxes	116.2	38.3
Asset Impairments and Other Related Charges	10.5	0.0
Amortization (Deferral) of Incremental Nuclear Refueling Outage Expenses, Net	(17.4)	(0.1)
Allowance for Equity Funds Used During Construction	(10.9)	(9.1)
Mark-to-Market of Risk Management Contracts	0.5	12.9
Amortization of Nuclear Fuel	109.7	101.6
Pension Contributions to Qualified Plan Trust	(12.7)	(14.6)
Deferred Fuel Over/Under-Recovery, Net	6.1	(16.1)
Change in Other Noncurrent Assets	0.0	26.4
Change in Other Noncurrent Liabilities	30.0	9.2
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	17.0	5.5
Fuel, Materials and Supplies	(1.1)	29.6
Accounts Payable	(17.9)	(14.0)
Accrued Taxes, Net	(16.5)	4.6
Other Current Assets	6.7	7.0
Other Current Liabilities	(27.8)	(9.3)
Net Cash Flows from (Used for) Operating Activities	537.0	502.0
Investing Activities
Construction Expenditures	(405.1)	(337.0)
Change in Advances to Affiliates, Net	(0.7)	0.0
Purchases of Investment Securities	(2,452.9)	(1,479.1)
Sales of Investment Securities	2,427.0	1,437.3
Acquisitions of Nuclear Fuel	(127.6)	(53.3)
Other Investing Activities	7.8	9.0
Net Cash Flows from (Used for) Investing Activities	(551.5)	(423.1)
Financing Activities
Issuance of Long-term Debt	482.7	210.7
Change in Advances from Affiliates, Net	(268.0)	8.5
Retirement of Long-term Debt	(76.8)	(178.5)
Principal Payments for Capital Lease Obligations	(29.8)	(29.9)
Dividends Paid on Common Stock	(93.8)	(90.0)
Other Financing Activities	0.7	0.6
Net Cash Flows from (Used for) Financing Activities	15.0	(78.6)
Cash Flows from Discontinued Operations
Net Increase (Decrease) in Cash and Cash Equivalents	0.5	0.3
Cash and Cash Equivalents at Beginning of Period	1.1	1.0
Cash and Cash Equivalents at End of Period	1.6	1.3
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	85.6	77.5
Net Cash Paid (Received) for Income Taxes	(36.0)	17.2
Noncash Acquisitions Under Capital Leases	16.8	2.0
Construction Expenditures Included in Current Liabilities as of September 30,	83.4	51.6
Acquisition of Nuclear Fuel Included in Current Liabilities as of September 30,	0.3	31.1
Expected Reimbursement for Spent Nuclear Fuel Dry Cask Storage	0.1	2.1
Ohio Power Co [Member]
Operating Activities
Net Income (Loss)	244.7	184.7
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	189.0	178.6
Amortization Of Generation Deferrals	173.0	122.2
Deferred Income Taxes	28.6	28.1
Carrying Costs Income	(4.0)	(10.0)
Allowance for Equity Funds Used During Construction	(3.7)	(7.0)
Mark-to-Market of Risk Management Contracts	124.7	31.8
Pension Contributions to Qualified Plan Trust	(7.1)	(7.7)
Property Taxes	169.1	148.4
Purchased Electricity Over Under Recovery Net	(21.1)	(15.7)
Deferral of Ohio Capacity Costs, Net	0.0	(30.7)
Change in Other Noncurrent Assets	(124.9)	27.8
Change in Other Noncurrent Liabilities	17.2	32.3
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	8.8	41.2
Fuel, Materials and Supplies	0.5	(15.0)
Accounts Payable	2.0	(78.8)
Accrued Taxes, Net	(291.1)	(134.7)
Other Current Assets	(4.5)	(3.2)
Other Current Liabilities	(26.9)	1.7
Net Cash Flows from (Used for) Operating Activities	474.3	494.0
Investing Activities
Construction Expenditures	(276.4)	(346.8)
Change in Restricted Cash for Securitized Funding	11.6	12.5
Change in Advances to Affiliates, Net	330.9	33.3
Proceeds from Notes Receivable Affiliated	0.0	86.0
Other Investing Activities	9.0	10.9
Net Cash Flows from (Used for) Investing Activities	75.1	(204.1)
Financing Activities
Retirement of Long-term Debt	(395.9)	(131.5)
Principal Payments for Capital Lease Obligations	(3.1)	(2.9)
Dividends Paid on Common Stock	(150.0)	(156.3)
Other Financing Activities	0.5	1.2
Net Cash Flows from (Used for) Financing Activities	(548.5)	(289.5)
Cash Flows from Discontinued Operations
Net Increase (Decrease) in Cash and Cash Equivalents	0.9	0.4
Cash and Cash Equivalents at Beginning of Period	3.1	2.9
Cash and Cash Equivalents at End of Period	4.0	3.3
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	78.2	79.0
Net Cash Paid (Received) for Income Taxes	178.0	24.1
Noncash Acquisitions Under Capital Leases	2.4	2.1
Construction Expenditures Included in Current Liabilities as of September 30,	30.0	30.2
Public Service Co Of Oklahoma [Member]
Operating Activities
Net Income (Loss)	97.4	85.5
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	109.9	90.2
Deferred Income Taxes	79.5	40.1
Allowance for Equity Funds Used During Construction	(4.9)	(6.0)
Mark-to-Market of Risk Management Contracts	(0.7)	(1.9)
Pension Contributions to Qualified Plan Trust	(5.6)	(5.8)
Property Taxes	(8.0)	(8.0)
Deferred Fuel Over/Under-Recovery, Net	(80.2)	76.9
Change in Other Noncurrent Assets	(18.8)	(13.6)
Change in Other Noncurrent Liabilities	(3.7)	8.2
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	4.4	(2.6)
Fuel, Materials and Supplies	(2.4)	(1.1)
Accounts Payable	23.1	(9.3)
Accrued Taxes, Net	45.4	21.0
Other Current Assets	(2.2)	(1.9)
Other Current Liabilities	(1.1)	8.0
Net Cash Flows from (Used for) Operating Activities	232.1	279.7
Investing Activities
Construction Expenditures	(266.8)	(262.9)
Change in Advances to Affiliates, Net	29.5	(116.3)
Other Investing Activities	8.7	7.6
Net Cash Flows from (Used for) Investing Activities	(228.6)	(371.6)
Financing Activities
Issuance of Long-term Debt	150.0	248.8
Change in Advances from Affiliates, Net	0.0	(154.2)
Retirement of Long-term Debt	(150.3)	(0.3)
Principal Payments for Capital Lease Obligations	(3.0)	(2.8)
Other Financing Activities	0.4	0.7
Net Cash Flows from (Used for) Financing Activities	(2.9)	92.2
Cash Flows from Discontinued Operations
Net Increase (Decrease) in Cash and Cash Equivalents	0.6	0.3
Cash and Cash Equivalents at Beginning of Period	1.4	1.4
Cash and Cash Equivalents at End of Period	2.0	1.7
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	45.0	40.6
Net Cash Paid (Received) for Income Taxes	(50.3)	12.8
Noncash Acquisitions Under Capital Leases	2.2	1.5
Construction Expenditures Included in Current Liabilities as of September 30,	20.2	37.3
Southwestern Electric Power Co [Member]
Operating Activities
Net Income (Loss)	153.2	188.3
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	148.1	143.8
Deferred Income Taxes	141.9	45.7
Allowance for Equity Funds Used During Construction	(9.5)	(18.2)
Mark-to-Market of Risk Management Contracts	(5.8)	(0.3)
Pension Contributions to Qualified Plan Trust	(8.3)	(8.1)
Property Taxes	(13.7)	(13.0)
Deferred Fuel Over/Under-Recovery, Net	1.2	11.7
Change in Other Noncurrent Assets	18.4	2.0
Change in Other Noncurrent Liabilities	(25.8)	(1.1)
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	12.2	2.8
Fuel, Materials and Supplies	33.4	24.8
Accounts Payable	(17.2)	(17.1)
Accrued Taxes, Net	14.1	53.1
Accrued Interest	(20.0)	(21.2)
Other Current Assets	(2.4)	2.8
Other Current Liabilities	(24.8)	(23.7)
Net Cash Flows from (Used for) Operating Activities	395.0	372.3
Investing Activities
Construction Expenditures	(315.3)	(408.3)
Change in Advances to Affiliates, Net	(297.4)	(2.0)
Other Investing Activities	(1.9)	4.4
Net Cash Flows from (Used for) Investing Activities	(614.6)	(405.9)
Financing Activities
Issuance of Long-term Debt	402.2	446.0
Change in Advances from Affiliates, Net	(58.3)	0.0
Retirement of Long-term Debt	(3.3)	(306.8)
Principal Payments for Capital Lease Obligations	(18.6)	(13.4)
Dividends Paid on Common Stock	(90.0)	(90.0)
Dividends Paid on Common Stock	(3.5)	(3.1)
Other Financing Activities	1.1	0.8
Net Cash Flows from (Used for) Financing Activities	229.6	33.5
Cash Flows from Discontinued Operations
Net Increase (Decrease) in Cash and Cash Equivalents	10.0	(0.1)
Cash and Cash Equivalents at Beginning of Period	5.2	14.4
Cash and Cash Equivalents at End of Period	15.2	14.3
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	107.6	106.1
Net Cash Paid (Received) for Income Taxes	(66.6)	12.3
Noncash Acquisitions Under Capital Leases	5.5	1.5
Construction Expenditures Included in Current Liabilities as of September 30,	54.3	85.3
Noncash Contribution of Mutual Energy SWEPCo, LLC from Parent	0.0	(2.0)
Noncash Increase in Advances to Affiliates, Net due to Contribution of Mutual Energy SWEPCo, LLC	$ 0.0	$ 2.0