RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES, Part 2 (Details) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2021 USD ($) MMBbls Bcf	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($) Bcf MMBbls
Derivative [Line Items]
Realized Loss on Settled Interest Rate Swaps Recorded in AOCI		$ 48.3
Notional Amount Of Cash Flow Hedge Instruments Settled		$ 1,300.0
Derivatives designated as Hedging Instrument | Futures | - Natural gas (Bcf) | Fixed price | Sold/ Receiver
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume | Bcf	38.1		43.3
Derivatives designated as Hedging Instrument | Futures | - Natural gas (Bcf) | Basis | Sold/ Receiver
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume | Bcf	35.8		43.3
Derivatives designated as Hedging Instrument | Futures | - Crude oil and NGLs (MMBbl) | Fixed price | Sold/ Receiver
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume | MMBbls	9.1		4.6
Derivatives designated as Hedging Instrument | Interest Rate Contracts | Purchased/ Payor
Derivative [Line Items]
Derivative, Notional Amount	$ 1,100.0		$ 1,100.0
Derivatives not designated as hedging instruments | Futures | - Crude oil and NGLs (MMBbl) | Fixed price | Purchased/ Payor
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume | MMBbls	0.2		0.8
Derivatives not designated as hedging instruments | Futures | - Crude oil and NGLs (MMBbl) | Fixed price | Sold/ Receiver
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume | MMBbls	0.2		0.8
Forecasted Debt Issuances [Member] | Cash Flow Hedging [Member] | Forward contracts | Interest Rate Contracts
Derivative [Line Items]
Derivative, Notional Amount	$ 1,100.0		$ 1,100.0