STATEMENTS OF CONSOLIDATED CHANGES IN EQUITY - CERC - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in-Capital	Retained Earnings (Accumulated Deficit)	Retained Earnings (Accumulated Deficit) Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss	CERC Corp	CERC Corp Common Stock	CERC Corp Additional Paid-in-Capital	CERC Corp Additional Paid-in-Capital Discontinued Operations	CERC Corp Retained Earnings (Accumulated Deficit)	CERC Corp Retained Earnings (Accumulated Deficit) Cumulative Effect, Period of Adoption, Adjustment	CERC Corp Accumulated Other Comprehensive Loss
Balance, beginning of year (in shares) at Dec. 31, 2018		501,000,000						1,000
Balance, end of year (in shares) at Dec. 31, 2019		502,000,000						1,000
Balance, beginning of year at Dec. 31, 2018		$ 5	$ 6,072	$ 349	$ 0	$ (108)		$ 0	$ 2,015		$ 423		$ 5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash contribution from parent									129
Other									0	$ 0
Capital distribution to parent associated with Internal Spin									(28)
Net income (loss)	$ 791			791			$ 212				212
Dividend to parent											(120)
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2016-13 [Member]
Other comprehensive income						10							5
Balance, end of year at Dec. 31, 2019	$ 8,359	$ 5	6,080	632	(7)	(98)	2,641	$ 0	2,116		515	$ (5)	10
Balance, end of year (in shares) at Dec. 31, 2020	551,355,861	551,000,000						1,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash contribution from parent									217
Other									(1)	(286)
Capital distribution to parent associated with Internal Spin									0
Net income (loss)	$ (773)			(773)			81				81
Dividend to parent											(80)
Other comprehensive income						8							0
Balance, end of year at Dec. 31, 2020	$ 8,348	$ 6	6,914	(845)	$ 0	(90)	2,567	$ 0	2,046		511		10
Balance, end of year (in shares) at Dec. 31, 2021	628,923,534	629,000,000						1,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash contribution from parent									180
Other									0	$ 0
Capital distribution to parent associated with Internal Spin									0
Net income (loss)	$ 1,486			1,486			254				254
Dividend to parent											0
Other comprehensive income						26							0
Balance, end of year at Dec. 31, 2021	$ 9,415	$ 6	$ 8,529	$ 154		$ (64)	$ 3,001	$ 0	$ 2,226		$ 765		$ 10