Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating Activities
Net Income (Loss)	$ 1,007.0	$ 1,062.0
Income (Loss) from Discontinued Operations	(2.5)	10.4
Income (Loss) from Continuing Operations	1,009.5	1,051.6
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	1,010.9	993.1
Deferred Income Taxes	552.3	450.2
Carrying Costs Income	(10.2)	(16.6)
Allowance for Equity Funds Used During Construction	(60.5)	(63.8)
Mark-to-Market of Risk Management Contracts	48.7	(41.1)
Amortization of Nuclear Fuel	73.2	65.5
Pension Contributions to Qualified Plan Trust	(84.8)	(92.5)
Property Taxes	131.3	102.0
Deferred Fuel Over/Under-Recovery, Net	(5.8)	21.5
Deferral of Ohio Capacity Costs, Net	67.4	(1.1)
Change in Other Noncurrent Assets	(191.0)	(78.8)
Change in Other Noncurrent Liabilities	1.8	17.5
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	(166.0)	(34.0)
Fuel, Materials and Supplies	(107.0)	148.0
Accounts Payable	(22.6)	(13.2)
Accrued Taxes, Net	(303.7)	(112.1)
Other Current Assets	26.3	20.2
Other Current Liabilities	(244.0)	(217.5)
Net Cash Flows from (Used for) Operating Activities	1,725.8	2,198.9
Investing Activities
Construction Expenditures	(2,285.8)	(2,181.5)
Change in Other Temporary Investments, Net	80.9	30.7
Purchases of Investment Securities	(1,797.4)	(541.5)
Sales of Investment Securities	1,777.0	515.8
Acquisitions of Nuclear Fuel	(79.2)	(52.2)
Other Investing Activities	4.8	34.2
Net Cash Flows from (Used for) Investing Activities	(2,299.7)	(2,194.5)
Financing Activities
Issuance of Common Stock, Net	30.9	55.8
Issuance of Long-term Debt	743.4	2,603.3
Change in Short-term Debt, Net	1,260.3	(241.0)
Retirement of Long-term Debt	(784.1)	(1,725.7)
Make Whole Premium on Extinguishment of Long-term Debt	0.0	(92.7)
Principal Payments for Capital Lease Obligations	(51.0)	(49.8)
Dividends Paid on Common Stock	(553.1)	(522.1)
Other Financing Activities	0.4	0.1
Net Cash Flows from (Used for) Financing Activities	646.8	27.9
Cash Flows from Discontinued Operations
Operating Activities	(2.5)	4.6
Investing Activities	0.0	4.1
Financing Activities	0.0	(8.3)
Net Increase (Decrease) in Cash and Cash Equivalents	70.4	32.7
Cash and Cash Equivalents at Beginning of Period	176.4	162.5
Cash and Cash Equivalents at End of Period	246.8	195.2
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	425.4	430.6
Net Cash Paid (Received) for Income Taxes	26.2	97.7
Noncash Acquisitions Under Capital Leases	52.7	75.8
Construction Expenditures Included in Current Liabilities as of June 30,	554.2	543.0
Construction Expenditures Included in Noncurrent Liabilities as of June 30,	0.0	66.3
Acquisition of Nuclear Fuel Included in Current Liabilities as of June 30,	41.5	0.0
Appalachian Power Co [Member]
Operating Activities
Net Income (Loss)	199.7	200.8
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	191.9	196.4
Deferred Income Taxes	68.3	122.5
Carrying Costs Income	(0.2)	(0.7)
Allowance for Equity Funds Used During Construction	(4.6)	(6.9)
Mark-to-Market of Risk Management Contracts	24.2	(15.7)
Pension Contributions to Qualified Plan Trust	(8.8)	(10.0)
Deferred Fuel Over/Under-Recovery, Net	3.8	(15.3)
Change in Other Noncurrent Assets	(8.2)	(2.0)
Change in Other Noncurrent Liabilities	(16.3)	(10.2)
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	(16.7)	18.9
Fuel, Materials and Supplies	(31.7)	15.5
Accounts Payable	(13.5)	(20.6)
Accrued Taxes, Net	7.8	(11.4)
Other Current Assets	3.5	(2.2)
Other Current Liabilities	(9.5)	(21.0)
Net Cash Flows from (Used for) Operating Activities	389.7	438.1
Investing Activities
Construction Expenditures	(322.3)	(293.1)
Change in Advances to Affiliates, Net	1.0	24.8
Other Investing Activities	9.5	7.0
Net Cash Flows from (Used for) Investing Activities	(311.8)	(261.3)
Financing Activities
Issuance of Long-term Debt	249.2	726.3
Change in Advances from Affiliates, Net	(35.1)	57.4
Retirement of Long-term Debt	(136.5)	(661.0)
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	(3.1)	(2.5)
Dividends Paid on Common Stock	(150.0)	(118.8)
Other Financing Activities	0.2	0.4
Net Cash Flows from (Used for) Financing Activities	(75.3)	(176.9)
Cash Flows from Discontinued Operations
Net Increase (Decrease) in Cash and Cash Equivalents	2.6	(0.1)
Cash and Cash Equivalents at Beginning of Period	2.8	2.6
Cash and Cash Equivalents at End of Period	5.4	2.5
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	90.9	105.6
Net Cash Paid (Received) for Income Taxes	28.3	5.2
Noncash Acquisitions Under Capital Leases	0.8	1.9
Construction Expenditures Included in Current Liabilities as of June 30,	69.1	81.6
Indiana Michigan Power Co [Member]
Operating Activities
Net Income (Loss)	126.0	123.3
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	94.1	100.9
Deferred Income Taxes	86.8	48.0
Amortization (Deferral) of Incremental Nuclear Refueling Outage Expenses, Net	(20.6)	(11.6)
Allowance for Equity Funds Used During Construction	(6.8)	(7.0)
Mark-to-Market of Risk Management Contracts	3.1	6.0
Amortization of Nuclear Fuel	73.2	65.5
Pension Contributions to Qualified Plan Trust	(12.7)	(14.6)
Deferred Fuel Over/Under-Recovery, Net	4.9	(15.1)
Change in Other Noncurrent Assets	(1.9)	31.0
Change in Other Noncurrent Liabilities	17.9	(9.8)
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	(6.0)	(2.3)
Fuel, Materials and Supplies	(19.3)	31.1
Accounts Payable	(26.8)	6.8
Accrued Taxes, Net	(9.2)	(7.8)
Other Current Assets	8.0	5.2
Other Current Liabilities	(19.7)	(37.1)
Net Cash Flows from (Used for) Operating Activities	291.0	312.5
Investing Activities
Construction Expenditures	(258.9)	(221.6)
Change in Advances to Affiliates, Net	(0.7)	0.0
Purchases of Investment Securities	(1,796.4)	(540.7)
Sales of Investment Securities	1,777.0	515.8
Acquisitions of Nuclear Fuel	(79.2)	(52.2)
Other Investing Activities	4.0	7.4
Net Cash Flows from (Used for) Investing Activities	(354.2)	(291.3)
Financing Activities
Issuance of Long-term Debt	482.7	210.7
Change in Advances from Affiliates, Net	(282.9)	(1.8)
Retirement of Long-term Debt	(53.5)	(150.1)
Principal Payments for Capital Lease Obligations	(19.8)	(20.2)
Dividends Paid on Common Stock	(62.5)	(60.0)
Other Financing Activities	0.6	0.5
Net Cash Flows from (Used for) Financing Activities	64.6	(20.9)
Cash Flows from Discontinued Operations
Net Increase (Decrease) in Cash and Cash Equivalents	1.4	0.3
Cash and Cash Equivalents at Beginning of Period	1.1	1.0
Cash and Cash Equivalents at End of Period	2.5	1.3
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	40.3	42.3
Net Cash Paid (Received) for Income Taxes	(23.6)	17.1
Noncash Acquisitions Under Capital Leases	16.5	1.4
Construction Expenditures Included in Current Liabilities as of June 30,	89.8	53.1
Acquisition of Nuclear Fuel Included in Current Liabilities as of June 30,	41.5	0.0
Expected Reimbursement for Spent Nuclear Fuel Dry Cask Storage	0.1	0.4
Ohio Power Co [Member]
Operating Activities
Net Income (Loss)	144.8	113.1
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	119.6	114.9
Amortization Of Generation Deferrals	106.9	66.8
Deferred Income Taxes	20.6	15.5
Carrying Costs Income	(3.1)	(11.6)
Allowance for Equity Funds Used During Construction	(3.4)	(4.8)
Mark-to-Market of Risk Management Contracts	30.2	9.9
Pension Contributions to Qualified Plan Trust	(7.1)	(7.7)
Property Taxes	113.2	96.3
Purchased Electricity Over Under Recovery Net	(21.1)	(22.9)
Deferral of Ohio Capacity Costs, Net	0.0	(30.7)
Change in Other Noncurrent Assets	(36.2)	22.9
Change in Other Noncurrent Liabilities	8.6	23.5
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	8.6	38.2
Fuel, Materials and Supplies	(3.0)	(14.7)
Accounts Payable	(4.8)	(68.1)
Accrued Taxes, Net	(226.8)	(99.7)
Other Current Assets	(2.2)	(0.8)
Other Current Liabilities	(39.0)	(24.1)
Net Cash Flows from (Used for) Operating Activities	205.8	216.0
Investing Activities
Construction Expenditures	(193.2)	(236.0)
Change in Restricted Cash for Securitized Funding	0.5	0.0
Change in Advances to Affiliates, Net	331.1	124.7
Proceeds from Notes Receivable Affiliated	0.0	86.0
Other Investing Activities	6.2	6.3
Net Cash Flows from (Used for) Investing Activities	144.6	(19.0)
Financing Activities
Change in Advances from Affiliates, Net	177.1	0.0
Retirement of Long-term Debt	(372.8)	(108.2)
Principal Payments for Capital Lease Obligations	(2.0)	(1.9)
Dividends Paid on Common Stock	(150.0)	(87.5)
Other Financing Activities	0.5	1.1
Net Cash Flows from (Used for) Financing Activities	(347.2)	(196.5)
Cash Flows from Discontinued Operations
Net Increase (Decrease) in Cash and Cash Equivalents	3.2	0.5
Cash and Cash Equivalents at Beginning of Period	3.1	2.9
Cash and Cash Equivalents at End of Period	6.3	3.4
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	60.0	61.3
Net Cash Paid (Received) for Income Taxes	132.3	20.5
Noncash Acquisitions Under Capital Leases	1.7	1.7
Construction Expenditures Included in Current Liabilities as of June 30,	23.1	42.2
Public Service Co Of Oklahoma [Member]
Operating Activities
Net Income (Loss)	44.6	40.8
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	72.7	59.3
Deferred Income Taxes	62.6	24.7
Allowance for Equity Funds Used During Construction	(3.8)	(3.6)
Mark-to-Market of Risk Management Contracts	(0.7)	(2.5)
Pension Contributions to Qualified Plan Trust	(5.6)	(5.8)
Property Taxes	(16.0)	(16.1)
Deferred Fuel Over/Under-Recovery, Net	(33.5)	51.6
Change in Other Noncurrent Assets	(14.2)	(14.3)
Change in Other Noncurrent Liabilities	(3.4)	4.8
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	(3.8)	(6.0)
Fuel, Materials and Supplies	(5.6)	(0.5)
Accounts Payable	27.0	5.5
Accrued Taxes, Net	21.6	12.5
Other Current Assets	(1.1)	0.6
Other Current Liabilities	4.6	(3.6)
Net Cash Flows from (Used for) Operating Activities	145.4	147.4
Investing Activities
Construction Expenditures	(194.0)	(180.2)
Change in Advances to Affiliates, Net	47.1	(64.2)
Other Investing Activities	5.1	3.6
Net Cash Flows from (Used for) Investing Activities	(141.8)	(240.8)
Financing Activities
Issuance of Long-term Debt	0.0	248.8
Change in Advances from Affiliates, Net	0.0	(154.2)
Retirement of Long-term Debt	(0.2)	(0.2)
Principal Payments for Capital Lease Obligations	(1.8)	(1.8)
Other Financing Activities	0.3	0.7
Net Cash Flows from (Used for) Financing Activities	(1.7)	93.3
Cash Flows from Discontinued Operations
Net Increase (Decrease) in Cash and Cash Equivalents	1.9	(0.1)
Cash and Cash Equivalents at Beginning of Period	1.4	1.4
Cash and Cash Equivalents at End of Period	3.3	1.3
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	30.2	25.4
Net Cash Paid (Received) for Income Taxes	(42.0)	4.2
Noncash Acquisitions Under Capital Leases	1.6	1.4
Construction Expenditures Included in Current Liabilities as of June 30,	24.3	30.9
Southwestern Electric Power Co [Member]
Operating Activities
Net Income (Loss)	68.8	106.2
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	96.9	94.9
Deferred Income Taxes	96.6	31.5
Allowance for Equity Funds Used During Construction	(9.4)	(11.1)
Mark-to-Market of Risk Management Contracts	(3.2)	(0.6)
Pension Contributions to Qualified Plan Trust	(8.3)	(8.1)
Property Taxes	(27.4)	(26.1)
Deferred Fuel Over/Under-Recovery, Net	5.4	4.9
Change in Other Noncurrent Assets	11.8	(5.0)
Change in Other Noncurrent Liabilities	(11.0)	0.1
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	2.5	(14.7)
Fuel, Materials and Supplies	16.8	12.1
Accounts Payable	(1.0)	(3.2)
Accrued Taxes, Net	(7.5)	36.6
Other Current Assets	(2.7)	1.4
Other Current Liabilities	(21.2)	(40.6)
Net Cash Flows from (Used for) Operating Activities	207.1	178.3
Investing Activities
Construction Expenditures	(220.7)	(268.4)
Change in Advances to Affiliates, Net	0.0	(138.7)
Other Investing Activities	(2.2)	2.1
Net Cash Flows from (Used for) Investing Activities	(222.9)	(405.0)
Financing Activities
Issuance of Long-term Debt	0.0	445.9
Change in Advances from Affiliates, Net	96.8	0.0
Retirement of Long-term Debt	(1.6)	(155.1)
Principal Payments for Capital Lease Obligations	(9.3)	(9.1)
Dividends Paid on Common Stock	(60.0)	(60.0)
Dividends Paid on Common Stock	(2.3)	(2.1)
Other Financing Activities	1.0	0.7
Net Cash Flows from (Used for) Financing Activities	24.6	220.3
Cash Flows from Discontinued Operations
Net Increase (Decrease) in Cash and Cash Equivalents	8.8	(6.4)
Cash and Cash Equivalents at Beginning of Period	5.2	14.4
Cash and Cash Equivalents at End of Period	14.0	8.0
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	57.5	55.8
Net Cash Paid (Received) for Income Taxes	(29.4)	9.6
Noncash Acquisitions Under Capital Leases	5.3	1.2
Construction Expenditures Included in Current Liabilities as of June 30,	$ 68.9	$ 73.6