Condensed Statements of Consolidated Changes in Equity - CERC - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	AOCI Attributable to Parent	CERC Corp	CERC Corp Common Stock	CERC Corp Additional Paid-in Capital	CERC Corp Retained Earnings	CERC Corp AOCI Attributable to Parent
Balance, beginning of period (in shares) at Dec. 31, 2020		551,000,000					1,000,000,000
Balance, beginning of period at Dec. 31, 2020		$ 6	$ 6,914	$ (845)	$ (90)		$ 0	$ 2,046	$ 511	$ 10
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Contribution from parent						$ 0		0
Contribution to parent for sale of Arkansas and Oklahoma Natural Gas businesses						0		0
Other								0
Net income	$ 363			363		151			151
Dividend to parent									0
Balance, end of period (in shares) at Mar. 31, 2021		552,000,000					1,000,000,000
Balance, end of period at Mar. 31, 2021	$ 8,716	$ 6	6,916	(482)	(87)	2,718	$ 0	2,046	662	10
Balance, beginning of period (in shares) at Dec. 31, 2021	628,923,534	629,000,000					1,000
Balance, beginning of period at Dec. 31, 2021	$ 9,415	$ 6	8,529	154	(64)	3,001	$ 0	2,226	765	10
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Contribution from parent						0		46
Contribution to parent for sale of Arkansas and Oklahoma Natural Gas businesses						720		(720)
Other								1
Net income	$ 531			531		554			554
Dividend to parent									(23)
Balance, end of period (in shares) at Mar. 31, 2022	629,432,406	629,000,000					1,000
Balance, end of period at Mar. 31, 2022	$ 9,951	$ 6	$ 8,532	$ 685	$ (62)	$ 2,859	$ 0	$ 1,553	$ 1,296	$ 10