Accumulated change, net of tax, in other comprehensive income (loss) attributable to equity method investments.

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Amount of unrealized gain (loss) related to interest rate derivatives designated as cash flow hedging instruments recorded in accumulated other comprehensive income.

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Amount of unrealized gain (loss) related to interest rate derivatives designated as cash flow hedging instruments recorded in accumulated other comprehensive income.

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The estimated net amount of unrealized gains or losses on commodity cash flow hedges as of the balance sheet date expected to be reclassified to earnings after the next twelve months.

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Amount after tax, before reclassification adjustments, of other comprehensive income (loss) attributable to equity method investments.

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Other comprehensive income (loss) before reclassifications

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Amount after tax of other comprehensive income attributable to equity method investments.

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Net of tax effect of the total reclassification adjustment for accumulated gains and losses included in accumulated comprehensive income that was realized in net income during the period.

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Amount after tax of reclassification adjustment from accumulated other comprehensive income for comprehensive income attributable to equity method investments.

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Amount of unrealized gain (loss) related to the increase or decrease in fair value of derivatives designated as cash flow hedging instruments, which was recorded in accumulated other comprehensive income to the extent that the cash flow hedge was determined to be effective, net of tax.

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Accumulated change, net of tax, in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges. Includes an entity's share of an equity investee's Increase or Decrease in deferred hedging gains or losses.

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Amount, after tax, of accumulated other comprehensive (income) loss for defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months.

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Amount after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Amount, after tax, before reclassification adjustment, of (increase) decrease in accumulated other comprehensive income of defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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Amount after tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

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ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Risk management assets/liabilities - January 1		$ (233,520)			$ (233,520)
Retirement and other postretirement benefit plan obligations - January 1		(131,481)			(131,481)
Risk-management assets/liabilities of unconsolidated affiliates - January 1		(8,999)			(8,999)
Accumulated other comprehensive loss - January 1		(374,000)			(374,000)
Other comprehensive income (loss) before reclassification, risk-management assets/liabilities	$ (46,530)		$ (57,029)		(152,671)	$ (125,973)
Other comprehensive (income) loss before reclassification, retirement and postretirement benefit plan obligations					39
Other comprehensive income (loss) before reclassification, risk-management assets/liabilities of unconsolidated affiliates					(11,567)
Other comprehensive income (loss) before reclassifications					(164,199)
Other comprehensive income (loss) reclassification adjustment from AOCI for risk-management assets/liabilities, net of tax	21,013		(8,625)		5,849	(20,796)
Other comprehensive (income) loss, retirement and other postretirement benefit plans, reclassification adjustment from AOCI, net of tax					7,084
Other comprehensive income (loss), reclassification adjustment from AOCI for other comprehensive income attributable to unconsolidated affiliates, net of tax					363
Other comprehensive income (loss), reclassification adjustment included in net income, net of tax					13,296
Other comprehensive income (loss), risk-management assets/liabilities, after reclassification adjustment, net of tax					(146,822)
Other comprehensive (income) loss, retirement and other postretirement benefit plans, after reclassification adjustment, net of tax	3,561		2,465		7,123	4,806
Other comprehensive income (loss), risk-management assets/liabilities of unconsolidated affiliates, net of tax	(3,561)		(3,683)		(11,204)	(6,194)
Other comprehensive income (loss), net of tax	(25,517)	$ (125,386)	$ (66,872)	$ (81,285)	(150,903)	$ (148,157)
Risk management assets/liabilities - June 30	(380,342)				(380,342)
Retirement and other postretirement benefit plan obligations - June 30	(124,358)				(124,358)
Risk-management assets/liabilities of unconsolidated affiliates - June 30	(20,203)				(20,203)
Accumulated other comprehensive loss - June 30	(524,903)				(524,903)
Cash Flow Hedging [Member] \| Commodity contracts
Unrealized gain loss on cash flow hedges net of tax accumulated other comprehensive income loss	12,317				12,317
Price risk cash flow hedge unrealized gain (loss) to be reclassified during next 12 months	12,600				12,600
Commodity cash flow hedge gain (loss) to be reclassified after next 12 months net	(300)				(300)
Cash Flow Hedging [Member] \| Interest-rate contracts
Amount of accumulated other comprehensive income (loss) attributable primarily to settled interest-rate swaps.	(206,931)				(206,931)
Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, net	(30,000)				(30,000)
Cash Flow Hedging [Member] \| Forward contracts
Amount of accumulated other comprehensive income (loss) attributable primarily to forward starting interest-rate swaps.	$ (185,728)				$ (185,728)