Condensed Statements of Consolidated Changes in Equity (Unaudited) - CERC - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	AOCI Attributable to Parent	CERC	CERC Common Stock	CERC Additional Paid-in Capital	CERC Retained Earnings	CERC AOCI Attributable to Parent
Balance, beginning of period (in shares) at Dec. 31, 2020		551,000,000					1,000
Balance, beginning of period at Dec. 31, 2020		$ 6	$ 6,914	$ (845)	$ (90)		$ 0	$ 3,966	$ 644	$ 10
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Non-cash contribution from parent						$ 0		0
Contribution from parent								0
Contribution to parent for sale of Arkansas and Oklahoma Natural Gas businesses						0		0
Other								(1)
Net income	$ 614			614		295			295
Dividend to parent									0
Balance, end of period (in shares) at Jun. 30, 2021		593,000,000					1,000
Balance, end of period at Jun. 30, 2021	8,870	$ 6	7,553	(343)	(85)	4,914	$ 0	3,965	939	10
Balance, beginning of period (in shares) at Mar. 31, 2021		552,000,000					1,000
Balance, beginning of period at Mar. 31, 2021		$ 6	6,916	(482)	(87)		$ 0	3,965	866	10
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Non-cash contribution from parent						0		0
Contribution from parent								0
Contribution to parent for sale of Arkansas and Oklahoma Natural Gas businesses						0		0
Other								0
Net income	251			251		73			73
Dividend to parent									0
Balance, end of period (in shares) at Jun. 30, 2021		593,000,000					1,000
Balance, end of period at Jun. 30, 2021	$ 8,870	$ 6	7,553	(343)	(85)	4,914	$ 0	3,965	939	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)	5,133	$ 0	4,106	1,017	10
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Non-cash contribution from parent						54		54
Contribution from parent								125
Contribution to parent for sale of Arkansas and Oklahoma Natural Gas businesses						720		(720)
Other								0
Net income	$ 721			721		663			663
Dividend to parent									(111)
Balance, end of period (in shares) at Jun. 30, 2022	629,490,422	629,000,000					1,000
Balance, end of period at Jun. 30, 2022	$ 10,023	$ 6	8,544	768	(85)	5,144	$ 0	3,565	1,569	10
Balance, beginning of period (in shares) at Mar. 31, 2022		629,000,000					1,000
Balance, beginning of period at Mar. 31, 2022		$ 6	8,532	685	(62)		$ 0	3,440	1,614	10
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Non-cash contribution from parent						0		0
Contribution from parent								125
Contribution to parent for sale of Arkansas and Oklahoma Natural Gas businesses						0		0
Other								0
Net income	$ 190			190		27			27
Dividend to parent									(72)
Balance, end of period (in shares) at Jun. 30, 2022	629,490,422	629,000,000					1,000
Balance, end of period at Jun. 30, 2022	$ 10,023	$ 6	$ 8,544	$ 768	$ (85)	$ 5,144	$ 0	$ 3,565	$ 1,569	$ 10