Retirement Plans and Postretirement Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2021

Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]

Schedule of Capitalized Pension and Postretirement Cost [Table Text Block]

	OGE Energy								OG&E
	Three Months Ended				Six Months Ended				Three Months Ended				Six Months Ended
	June 30,				June 30,				June 30,				June 30,
(In millions)	2021		2020		2021		2020		2021		2020		2021		2020
Capitalized portion of net periodic pension benefit cost	$	0.8	$	0.8	$	1.6	$	1.8	$	0.7	$	0.6	$	1.4	$	1.5
Capitalized portion of net periodic postretirement benefit cost	$	—	$	0.1	$	0.1	$	0.1	$	0.1	$	0.1	$	0.1	$	0.1