DERIVATIVE INSTRUMENTS - BALANCE SHEET RELATED DISCLOSURES (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Sep. 30, 2019
Fair Value
Derivative assets, current	$ 35,428	$ 25,103
Derivative liabilities, current	51,686	57,623
Derivative assets, noncurrent	8,654	7,426
Derivative liabilities, noncurrent	12,028	18,821
Not Designated as Hedging Instrument
Fair Value
Derivative assets	44,082	32,529
Derivative liabilities	63,714	76,444
Home Services and Other \| Designated as Hedging Instrument [Member] \| Interest rate contracts
Fair Value
Derivative assets, current	0	0
Derivative liabilities, current	12,492	0
Natural Gas Distribution \| Not Designated as Hedging Instrument \| Physical commodity contracts
Fair Value
Derivative assets, current	131	67
Derivative liabilities, current	175	245
Natural Gas Distribution \| Not Designated as Hedging Instrument \| Financial commodity contracts
Fair Value
Derivative assets, current	0	382
Derivative liabilities, current	24	570
Natural Gas Distribution \| Not Designated as Hedging Instrument \| Interest rate contracts
Fair Value
Derivative assets, current	0	0
Derivative liabilities, current	6,692	0
Energy Services \| Not Designated as Hedging Instrument \| Physical commodity contracts
Fair Value
Derivative assets, current	7,712	6,847
Derivative liabilities, current	16,239	27,540
Derivative assets, noncurrent	3,366	1,710
Derivative liabilities, noncurrent	10,568	12,641
Energy Services \| Not Designated as Hedging Instrument \| Financial commodity contracts
Fair Value
Derivative assets, current	27,585	17,806
Derivative liabilities, current	15,641	29,057
Derivative assets, noncurrent	5,288	5,716
Derivative liabilities, noncurrent	1,391	6,105
Energy Services \| Not Designated as Hedging Instrument \| Foreign currency contracts
Fair Value
Derivative assets, current	0	1
Derivative liabilities, current	423	211
Derivative assets, noncurrent	0	0
Derivative liabilities, noncurrent	$ 69	$ 75

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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