Amount of receivables arising from transactions with related parties due within one year or the normal operating cycle, if longer.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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Investment in Unconsolidated Affiliates Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Enable Midstream Partners [Member] \| OG&E [Member]
Related Party Transaction [Line Items]
Revenue from Related Parties	$ 3.8	$ 4.0
Operating Costs Charged [Member] \| Enable Midstream Partners [Member] \| OGE Energy [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party	0.1
Employment Costs [Member] \| Enable Midstream Partners [Member] \| OGE Energy [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party	12.4	11.6
Natural Gas Transportation [Member] \| Enable Midstream Partners [Member] \| OG&E [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Purchases from Related Party	14.8	8.8
Natural Gas Purchases [Member] \| Enable Midstream Partners [Member] \| OG&E [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Purchases from Related Party	(1.0)	$ 0.3
Excluding Fuel Purchases [Member]
Related Party Transaction [Line Items]
Accounts receivable - unconsolidated affiliates	$ 9.4		$ 1.7