Investment in Unconsolidated Affiliate and Related Party Transactions Related Party Transactions (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Expected Settlement Charge	$ 21.4
Accounts receivable - unconsolidated affiliates	2.5	$ 1.7
Og and E [Member] \| Enable Midstream Partners [Member]
Related Party Transaction [Line Items]
Revenue from Related Parties	11.5	13.8	$ 13.3
Operating Costs Charged [Member] \| OGE Energy [Member] \| Enable Midstream Partners [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party	4.7	12.4	16.8
Natural Gas Transportation [Member] \| Og and E [Member] \| Enable Midstream Partners [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Purchases from Related Party	35.0	35.0	34.9
Natural Gas Storage [Member] \| Og and E [Member] \| Enable Midstream Partners [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Purchases from Related Party	0.0	0.0	4.4
Natural Gas Purchases [Member] \| Og and E [Member] \| Enable Midstream Partners [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Purchases from Related Party	11.2	7.6	8.7
Employment Costs [Member] \| OGE Energy [Member] \| Enable Midstream Partners [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party	28.6	32.7	$ 104.8
Excluding Fuel Purchases [Member]
Related Party Transaction [Line Items]
Accounts receivable - unconsolidated affiliates	$ 2.7	$ 3.4

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
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-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=16382449

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-Publisher FASB
-Name Accounting Standards Codification
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