Divestitures (CenterPoint Energy and CERC) - Discontinued Operations (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 02, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Common and preferred units acquired (as a percent)				100.00%
Equity in earnings (loss) of unconsolidated affiliates, net	$ 0	$ 108
Income tax expense (benefit) from discontinued operations	0	25
Income from Discontinued Operations (net of tax expense of $—, $25, respectively)	0	83
Distributions from unconsolidated affiliates	0	39
Current assets	0		$ 2,338
Current liabilities	0		562
Operating revenues	2,763	2,547
Depreciation and amortization	318	307
Operating income	477	453
Income available to common shareholders - basic and diluted	518	334
CERC Corp
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Current assets	0		2,084
Current liabilities	0		$ 562
Operating revenues	1,385	1,177
Depreciation and amortization	72	80
Operating income	$ 212	218
Discontinued Operations | Enable Midstream Partners
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Equity in earnings (loss) of unconsolidated affiliates, net		108
Income from discontinued operations before income taxes		108
Income tax expense (benefit) from discontinued operations		25
Income from Discontinued Operations (net of tax expense of $—, $25, respectively)		83
Distributions from unconsolidated affiliates		39
Cash distribution received		48
Natural gas expense		32
Current assets				$ 594
Non-current assets				11,227
Current liabilities				1,254
Non-current liabilities				3,281
Non-controlling interest				26
Preferred equity				362
Accumulated other comprehensive loss				(1)
Enable partners’ equity				6,899
CenterPoint Energy’s ownership interest in Enable partners’ equity				3,701
CenterPoint Energy’s basis difference				(2,732)
CenterPoint Energy’s equity method investment in Enable				$ 969
Operating revenues		970
Cost of sales, excluding depreciation and amortization		519
Depreciation and amortization		106
Operating income		206
Income available to common shareholders - basic and diluted		155
CenterPoint Energy’s interest		83
Basis difference amortization		25
Discontinued Operations | Enable Midstream Partners | CERC Corp
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Natural gas expense		$ 32
Discontinued Operations | Enable Midstream Partners | Common Units
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Distribution received (in dollars per unit)		$ 0.16525
Cash distribution received		$ 39
Discontinued Operations | Enable Midstream Partners | Series A Preferred Units
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Distribution received (in dollars per unit)		$ 0.62500
Cash distribution received		$ 9