CONDENSED STATEMENTS OF CHANGES IN COMMON SHAREHOLDER’S EQUITY - PSO - USD ($) $ in Millions	Total	Accumulated Other Comprehensive Income (Loss)	PUBLIC SERVICE COMPANY OF OKLAHOMA	PUBLIC SERVICE COMPANY OF OKLAHOMA Common Stock	PUBLIC SERVICE COMPANY OF OKLAHOMA Paid-in Capital	PUBLIC SERVICE COMPANY OF OKLAHOMA Retained Earnings	PUBLIC SERVICE COMPANY OF OKLAHOMA Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2024			$ 2,686	$ 157	$ 1,042	$ 1,484	$ 3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income			28			28
Other Comprehensive Loss	$ 24	$ 24	(1)				(1)
Ending balance at Mar. 31, 2025			2,713	157	1,042	1,512	2
Beginning balance at Dec. 31, 2025	31,138		3,613	157	1,718	1,736	2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income			15			15
Other Comprehensive Loss	(14)	$ (14)
Ending balance at Mar. 31, 2026	$ 31,808		$ 3,628	$ 157	$ 1,718	$ 1,751	$ 2