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

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