Derivative Assets And Liabilities Table - Outstanding Commodity-Related Derivatives (Details)		Sep. 30, 2020 Megawatt MMbtu bushels bbl barrels	Dec. 31, 2019 MMbtu Megawatt bushels barrels bbl
Mark-To-Market Derivatives [Member] | Non Trading [Member] | Future [Member]
Derivative, Nonmonetary Notional Amount | bushels		0
Natural Gas Liquids [Member] | Mark-To-Market Derivatives [Member] | Non Trading [Member] | Forwards Swaps [Member] | Short [Member]
Derivative, Nonmonetary Notional Amount | bbl		(14,743)	(1,300)
Natural Gas [Member] | Mark-To-Market Derivatives [Member] | Non Trading [Member] | Basis Swaps IFERC/NYMEX [Member] | Short [Member]
Derivative, Nonmonetary Notional Amount		(20,800)	(18,923)
Natural Gas [Member] | Mark-To-Market Derivatives [Member] | Non Trading [Member] | Swing Swaps IFERC [Member] | Short [Member]
Derivative, Nonmonetary Notional Amount		(7,480)	(9,265)
Natural Gas [Member] | Mark-To-Market Derivatives [Member] | Non Trading [Member] | Fixed Swaps/Futures [Member] | Short [Member]
Derivative, Nonmonetary Notional Amount		(43,708)	(3,085)
Natural Gas [Member] | Mark-To-Market Derivatives [Member] | Non Trading [Member] | Forward Physical Contracts [Member] | Short [Member]
Derivative, Nonmonetary Notional Amount		(15,281)	(13,364)
Natural Gas [Member] | Mark-To-Market Derivatives [Member] | Trading [Member] | Basis Swaps IFERC/NYMEX [Member] | Short [Member]
Derivative, Nonmonetary Notional Amount	[1]	(91,365)	(35,208)
Natural Gas [Member] | Mark-To-Market Derivatives [Member] | Trading [Member] | Fixed Swaps/Futures [Member] | Long [Member]
Derivative, Nonmonetary Notional Amount		(4,965)	(1,483)
Natural Gas [Member] | Fair Value Hedging [Member] | Non Trading [Member] | Basis Swaps IFERC/NYMEX [Member] | Short [Member]
Derivative, Nonmonetary Notional Amount		(38,490)	(31,780)
Natural Gas [Member] | Fair Value Hedging [Member] | Non Trading [Member] | Fixed Swaps/Futures [Member] | Short [Member]
Derivative, Nonmonetary Notional Amount		(38,490)	(31,780)
Natural Gas [Member] | Fair Value Hedging [Member] | Non Trading [Member] | Hedged Item - Inventory (MMBtu) [Member] | Long [Member]
Derivative, Nonmonetary Notional Amount		(38,490)	(31,780)
Power [Member] | Mark-To-Market Derivatives [Member] | Trading [Member] | Options - Puts [Member] | Short [Member]
Derivative, Nonmonetary Notional Amount | Megawatt		(15)
Power [Member] | Mark-To-Market Derivatives [Member] | Trading [Member] | Call Option [Member] | Short [Member]
Derivative, Nonmonetary Notional Amount | Megawatt		(6,323,560)	(2,704,330)
Power [Member] | Mark-To-Market Derivatives [Member] | Trading [Member] | Forwards Swaps [Member] | Long [Member]
Derivative, Nonmonetary Notional Amount | Megawatt		(1,714,800)	(3,213,450)
Power [Member] | Mark-To-Market Derivatives [Member] | Trading [Member] | Future [Member] | Short [Member]
Derivative, Nonmonetary Notional Amount | Megawatt		(35,313)	(353,527)
Power [Member] | Mark-To-Market Derivatives [Member] | Trading [Member] | Put Option [Member] | Long [Member]
Derivative, Nonmonetary Notional Amount | Megawatt			(51,615)
Crude Oil [Member] | Mark-To-Market Derivatives [Member] | Non Trading [Member] | Forwards Swaps [Member] | Long [Member]
Derivative, Nonmonetary Notional Amount | bbl		(1,929)	(4,465)
Refined product sales | Mark-To-Market Derivatives [Member] | Non Trading [Member] | Future [Member] | Short [Member]
Derivative, Nonmonetary Notional Amount | barrels		(3,391)	(2,473)
Corn [Member] | Mark-To-Market Derivatives [Member] | Non Trading [Member] | Future [Member] | Short [Member]
Derivative, Nonmonetary Notional Amount | bushels			(1,210)

[1] Includes aggregate amounts for open positions related to Houston Ship Channel, Waha Hub, NGPL TexOk, West Louisiana Zone and Henry Hub locations