Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2017

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Regulatory Assets and Liabilities [Table Text Block]

The following table is a summary of OG&E's regulatory assets and liabilities at:

	June 30,		December 31,
(In millions)	2017		2016
Regulatory Assets
Current
Fuel clause under recoveries	$	107.4	$	51.3
Oklahoma demand program rider under recovery (A)	45.1		51.0
SPP cost tracker under recovery (A)	12.7		10.0
Other (A)	5.8		9.5
Total current regulatory assets	$	171.0	$	121.8
Non-current
Benefit obligations regulatory asset	$	225.1	$	232.6
Income taxes recoverable from customers, net	69.8		62.3
Deferred storm expenses	44.6		35.7
Smart Grid	36.4		43.2
Unamortized loss on reacquired debt	12.7		13.4
Other	18.2		17.6
Total non-current regulatory assets	$	406.8	$	404.8
Regulatory Liabilities
Current
Other (B)	$	3.9	$	12.3
Total current regulatory liabilities	$	3.9	$	12.3
Non-current
Accrued removal obligations, net	$	276.5	$	262.8
Pension tracker	35.8		35.5
Other	9.3		1.4
Total non-current regulatory liabilities	$	321.6	$	299.7

(A) Included in Other Current Assets on theCondensedBalance Sheets.

(B) Included in Other Current Liabilities on theCondensedBalance Sheets.

Schedule of Change in Asset Retirement Obligation [Table Text Block]

The following table summarizes changes to OG&E's asset retirement obligations during thesix months endedJune 30, 2017and2016.

	Six Months Ended June 30,
(In millions)	2017		2016
Balance at January 1	$	69.6	$	63.3
Accretion expense	1.5		1.4
Revisions in estimated cash flows	0.8		—
Balance at June 30	$	71.9	$	64.7