XML 36 R27.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Fair Value Measurements (Tables) | 6 Months Ended
--- | ---
Jun. 30, 2018
Fair Value Disclosures [Abstract] |
Schedule of Fair Value and Carrying Amount of PRM Financial Instruments [Table Text Block] | The following table summarizes the fair value and carrying amount of the Company's financial instruments at June 30, 2018 and December 31, 2017.
| June 30, | December 31,
| 2018 | 2017
(In millions) | Carrying Amount | Fair Value | Carrying Amount | Fair Value
Long-term Debt (including Long-term Debt due within one year): |  |  |  |
Senior Notes | $ | 2,855.2 |  | $ | 3,101.4 |  | $ | 2,854.3 |  | $ | 3,242.8 |
OG&E Industrial Authority Bonds | $ | 135.4 |  | $ | 135.4 |  | $ | 135.4 |  | $ | 135.4 |
Tinker Debt | $ | 9.7 |  | $ | 9.1 |  | $ | 9.7 |  | $ | 9.8 |

X
- Definition Tabular disclosure of the fair value of financial instruments, including financial assets and financial liabilities, and the measurements of those instruments, assets, and liabilities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13467-108611 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueByBalanceSheetGroupingTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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