XML 62 R52.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Retirement Plans and Postretirement Benefit Plans (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2018 | Mar. 31, 2017
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost, Net of Unconsolidated Affiliates |  | $ 2.3 | $ 5.5
Pension Plan [Member] |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] |  |  |
Service cost |  | 4.1 | 4.2
Interest cost |  | 5.9 | 6.5
Expected return on plan assets |  | 11.3 | 10.7
Defined Benefit Plan, Amortization of Gain (Loss) |  | 3.9 | 4.0
Amortization of unrecognized prior service cost | [1] | 0.0 | 0.0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) |  | 2.6 | 4.0
Less: Amount paid by unconsolidated affiliates |  | 0.5 | 0.8
Capitalized Portion of Net Periodic Benefit Cost |  | 1.0 | 1.0
Defined Benefit Plan, Net Periodic Benefit Cost, Net of Unconsolidated Affiliates | [2] | 2.1 | 3.2
Other Pension Plan [Member] |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] |  |  |
Service cost |  | 0.1 | 0.1
Interest cost |  | 0.1 | 0.1
Expected return on plan assets |  | 0.0 | 0.0
Defined Benefit Plan, Amortization of Gain (Loss) |  | 0.1 | 0.1
Amortization of unrecognized prior service cost | [1] | 0.0 | 0.0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) |  | 0.3 | 0.3
Less: Amount paid by unconsolidated affiliates |  | 0.0 | 0.0
Defined Benefit Plan, Net Periodic Benefit Cost, Net of Unconsolidated Affiliates | [2] | 0.3 | 0.3
Postretirement Benefit Plan [Member] |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] |  |  |
Service cost |  | 0.1 | 0.2
Interest cost |  | 1.3 | 2.2
Expected return on plan assets |  | 0.5 | 0.6
Defined Benefit Plan, Amortization of Gain (Loss) |  | 1.0 | 0.6
Amortization of unrecognized prior service cost | [1] | (2.1) | 0.0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) |  | (0.2) | 2.4
Less: Amount paid by unconsolidated affiliates |  | (0.1) | 0.4
Capitalized Portion of Net Periodic Benefit Cost |  | 0.0 | 0.7
Defined Benefit Plan, Net Periodic Benefit Cost, Net of Unconsolidated Affiliates | [2] | (0.1) | 2.0
OKLAHOMA |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] |  |  |
Additional Pension Expense to Meet State Requirements |  | 4.0 | 2.9
OKLAHOMA | Postretirement Benefit Plan [Member] |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] |  |  |
Additional Pension Expense to Meet State Requirements |  | $ 2.1 | $ 1.1
[1] | Unamortized prior service cost is amortized on a straight-line basis over the average remaining service period to the first eligibility age of participants who are expected to receive a benefit and are active at the date of the plan amendment.
[2] | In addition to the $2.3 million and $5.5 million of net periodic benefit cost recognized during the three months ended March 31, 2018 and 2017, respectively, OG&E recognized the following:•an increase in pension expense during the three months ended March 31, 2018 and 2017 of $4.0 million and $2.9 million, respectively, to maintain the allowable amount to be recovered for pension expense in the Oklahoma jurisdiction, which are included in the Pension tracker regulatory liability (see Note 1); and•an increase in postretirement medical expense in the three months ended March 31, 2018 and 2017 of $2.1 million and $1.1 million, respectively, to maintain the allowable amount to be recovered for postretirement medical expense in the Oklahoma jurisdiction, which are included in the Pension tracker regulatory liability (see Note 1).

X
- Definition Additional Pension Expense to Meet State Requirements + References No definition available. + Details
Name: | oge_AdditionalPensionExpenseToMeetStateRequirements
Namespace Prefix: | oge_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount Attributable to Unconsolidated Affiliates + References No definition available. + Details
Name: | oge_AmountAttributabletoUnconsolidatedAffiliates
Namespace Prefix: | oge_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Capitalized Portion of Net Periodic Benefit Cost + References No definition available. + Details
Name: | oge_CapitalizedPortionOfNetPeriodicBenefitCost
Namespace Prefix: | oge_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Defined Benefit Plan, Net Periodic Benefit Cost, Net of Unconsolidated Affiliates + References No definition available. + Details
Name: | oge_DefinedBenefitPlanNetPeriodicBenefitCostNetOfUnconsolidatedAffiliates
Namespace Prefix: | oge_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(4) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of prior service cost (credit) recognized in net periodic benefit cost (credit) of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(5) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(3) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of cost recognized for passage of time related to defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(2) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanInterestCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of net periodic benefit cost (credit) for defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(1) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanServiceCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_EntityByLocationAxis=stpr_OK
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |