Derivative Assets And Liabilities Outstanding Commodity Derivatives (Details)		Mar. 31, 2020 MMbtu barrels bbl Megawatt bushels	Dec. 31, 2019 MMbtu barrels bbl Megawatt bushels
Fixed Swaps/Futures [Member] | Non Trading [Member] | Mark-To-Market Derivatives [Member] | Short [Member] | Natural Gas [Member]
Notional Volume		(1,425)	(3,085)
Fixed Swaps/Futures [Member] | Non Trading [Member] | Fair Value Hedging Derivatives [Member] | Short [Member] | Natural Gas [Member]
Notional Volume		(32,695)	(31,780)
Fixed Swaps/Futures [Member] | Trading [Member] | Mark-To-Market Derivatives [Member] | Long [Member] | Natural Gas [Member]
Notional Volume		(1,688)	(1,483)
Forward Physical Contracts [Member] | Non Trading [Member] | Mark-To-Market Derivatives [Member] | Short [Member] | Natural Gas [Member]
Notional Volume		(36,691)	(13,364)
Forwards Swaps [Member] | Non Trading [Member] | Mark-To-Market Derivatives [Member] | Short [Member] | Natural Gas Liquids [Member]
Notional Volume | bbl		(2,235)	(1,300)
Forwards Swaps [Member] | Non Trading [Member] | Mark-To-Market Derivatives [Member] | Long [Member] | Crude Oil [Member]
Notional Volume | bbl		(5,260)	(4,465)
Forwards Swaps [Member] | Trading [Member] | Mark-To-Market Derivatives [Member] | Long [Member] | Power [Member]
Notional Volume | Megawatt		(2,125,200)	(3,213,450)
Hedged Item - Inventory (MMBtu) [Member] | Non Trading [Member] | Fair Value Hedging Derivatives [Member] | Long [Member] | Natural Gas [Member]
Notional Volume		(32,695)	(31,780)
Basis Swaps IFERC/NYMEX [Member] | Non Trading [Member] | Mark-To-Market Derivatives [Member] | Short [Member] | Natural Gas [Member]
Notional Volume		(15,860)	(18,923)
Basis Swaps IFERC/NYMEX [Member] | Non Trading [Member] | Fair Value Hedging Derivatives [Member] | Short [Member] | Natural Gas [Member]
Notional Volume		(32,695)	(31,780)
Basis Swaps IFERC/NYMEX [Member] | Trading [Member] | Mark-To-Market Derivatives [Member] | Short [Member] | Natural Gas [Member]
Notional Volume	[1]	(19,673)	(35,208)
Options - Calls [Member] | Trading [Member] | Mark-To-Market Derivatives [Member] | Short [Member] | Power [Member]
Notional Volume | Megawatt			(2,704,330)
Options - Calls [Member] | Trading [Member] | Mark-To-Market Derivatives [Member] | Long [Member] | Power [Member]
Notional Volume | Megawatt		(4,035,972)
Swing Swaps IFERC [Member] | Non Trading [Member] | Mark-To-Market Derivatives [Member] | Short [Member] | Natural Gas [Member]
Notional Volume			(9,265)
Swing Swaps IFERC [Member] | Non Trading [Member] | Mark-To-Market Derivatives [Member] | Long [Member] | Natural Gas [Member]
Notional Volume		(31,505)
Future [Member] | Non Trading [Member] | Mark-To-Market Derivatives [Member] | Short [Member]
Notional Volume | bushels		(140)
Future [Member] | Non Trading [Member] | Mark-To-Market Derivatives [Member] | Short [Member] | Refined Products [Member]
Notional Volume | barrels		(1,779)	(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			(353,527)
Future [Member] | Trading [Member] | Mark-To-Market Derivatives [Member] | Long [Member] | Power [Member]
Notional Volume | Megawatt		(329,896)
Options - Puts [Member] | Trading [Member] | Mark-To-Market Derivatives [Member] | Long [Member] | Power [Member]
Notional Volume | Megawatt		(621,860)
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