Derivative Instruments (Tables)

9 Months Ended

Sep. 30, 2020

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]

The table below summarizes the Registrants’ outstanding interest rate hedging activity:

	September 30, 2020		December 31, 2019
Hedging Classification	Notional Principal
	(in millions)
Economic hedge (1)	$	84	$	84

(1)Relates to interest rate derivative instruments at SIGECO.

Fair Value of Derivative Instruments [Table Text Block]

The following tables present information about derivative instruments and hedging activities. The first table provides a balance sheet overview of Derivative Assets and Liabilities, while the last table provides a breakdown of the related income statement impacts.

Fair Value of Derivative Instruments and Hedged Items (CenterPoint Energy)

		September 30, 2020				December 31, 2019
	Balance Sheet Location	Derivative Assets Fair Value		Derivative Liabilities Fair Value		Derivative Assets Fair Value		Derivative Liabilities Fair Value
		(in millions)
Derivatives not designated as hedging instruments:
Natural gas derivatives (1)	Current Liabilities: Non-trading derivative liabilities	$	—	$	1	$	—	$	7
Natural gas derivatives (1)	Other Liabilities: Non-trading derivative liabilities	—		6		—		15
Interest rate derivatives	Other Liabilities	—		24		—		10
Indexed debt securities derivative (2)	Current Liabilities	—		918		—		893
Total		$	—	$	949	$	—	$	925

(1)Natural gas contracts are subject to master netting arrangements. This netting applies to all undisputed amounts due or past due. However, the mark-to-market fair value of each natural gas contract is in a liability position with no offsetting amounts.

(2)Derivative component of the ZENS obligation that represents the ZENS holder’s option to receive the appreciated value of the reference shares at maturity. See Note 11 for further information.

Income Statement Impact of Derivative Activity [Table Text Block]

Income Statement Impact of Hedge Accounting Activity (CenterPoint Energy)

		Three Months Ended September 30,				Nine Months Ended September 30,
	Income Statement Location	2020		2019		2020		2019
		(in millions)
Effects of derivatives not designated as hedging instruments on the income statement:
Indexed debt securities derivative	Gain (loss) on indexed debt securities	$	(84)	$	(62)	$	(25)	$	(216)
Total		$	(84)	$	(62)	$	(25)	$	(216)