Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2014

Commitments and Contingencies Disclosure [Abstract]

Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]

Operating Lease Obligations

OG&E has operating lease obligations expiring at various dates, primarily forrailcar leases and wind farm land leases. Future minimum payments for noncancellable operating leasesare as follows:

Year ended December 31 (In millions)	2015		2016		2017		2018		2019		After 2019		Total
Operating lease obligations
Railcars	$	4.5	$	28.7	$	1.0	$	—	$	—	$	—	$	34.2
Wind farm land leases	2.1		2.1		2.4		2.4		2.4		46.4		57.8
Total operating lease obligations	$	6.6	$	30.8	$	3.4	$	2.4	$	2.4	$	46.4	$	92.0

Unrecorded Unconditional Purchase Obligations Disclosure [Table Text Block]

Other Purchase Obligations and Commitments

OG&E's other future purchase obligations and commitments estimated for the next five years are as follows:

(In millions)	2015		2016		2017		2018		2019		Total
Other purchase obligations and commitments
Cogeneration capacity and fixed operation and maintenance payments	$	85.2	$	83.3	$	80.7	$	77.8	$	70.6	$	397.6
Expected cogeneration energy payments	74.4		78.5		81.2		89.7		85.1		408.9
Minimum fuel purchase commitments	389.3		246.6		43.6		—		—		679.5
Expected wind purchase commitments	58.4		59.3		60.3		59.1		58.4		295.5
Long-term service agreement commitments	2.5		2.6		2.7		19.4		27.5		54.7
Environmental compliance plan expenditures	66.5		138.1		117.6		50.1		3.9		376.2
Total other purchase obligations and commitments	$	676.3	$	608.4	$	386.1	$	296.1	$	245.5	$	2,212.4

Schedule of Wind Power Purchases [Table Text Block]

The following table summarizes OG&E's wind power purchases for the years endedDecember 31, 2014, 2013and2012. 

Year ended December 31 (In millions)	2014		2013		2012
CPV Keenan	$	28.1	$	30.9	$	25.1
Edison Mission Energy	21.3		20.6		20.2
FPL Energy	3.6		3.3		3.4
NextEra Energy	7.8		7.2		0.8
Total wind power purchased	$	60.8	$	62.0	$	49.5