SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Reclassifications Out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 25,292	$ 23,075
Unrealized gain on investments	1	8
Net current period other comprehensive income (loss)	(6)	(8)
Ending balance	30,401	25,292
Pension Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Unrealized gain on investments	0	0
Amount attributable to tax, before reclassification	0	0
Net current period other comprehensive income (loss)	(7)	(16)
Other Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Unrealized gain on investments	0	0
Amount attributable to tax, before reclassification	0	0
Net current period other comprehensive income (loss)	0	0
Customer Credit Trust
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Unrealized gain on investments	1	8
Amount attributable to tax, before reclassification	0	3
Net current period other comprehensive income (loss)	1	8
Accumulated Other Comprehensive Income (Loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(8)	0
Ending balance	(14)	(8)
Accumulated Other Comprehensive Income (Loss) | Pension Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(28)	(12)
Ending balance	(35)	(28)
Accumulated Other Comprehensive Income (Loss) | Other Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	18	18
Ending balance	18	18
Accumulated Other Comprehensive Income (Loss) | Customer Credit Trust
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	2	(6)
Ending balance	3	2
Amortization of prior service cost
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amounts reclassified from other comprehensive income	0	(1)
Amortization of prior service cost | Pension Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amounts reclassified from other comprehensive income	(2)	(3)
Amount attributable to tax, reclassification	1	1
Amortization of prior service cost | Other Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amounts reclassified from other comprehensive income	2	2
Amount attributable to tax, reclassification	1	1
Amortization of prior service cost | Customer Credit Trust
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amounts reclassified from other comprehensive income	0	0
Amount attributable to tax, reclassification	0	0
Amortization of net actuarial gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive income before reclassifications:	(239)	(123)
Amounts reclassified from other comprehensive income	(15)	(13)
Amortization of net actuarial gain | Pension Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive income before reclassifications:	(268)	(196)
Other comprehensive income before reclassifications, tax	104	76
Amounts reclassified from other comprehensive income	1	1
Amount attributable to tax, reclassification	0	0
Amortization of net actuarial gain | Other Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive income before reclassifications:	29	73
Other comprehensive income before reclassifications, tax	11	28
Amounts reclassified from other comprehensive income	(16)	(14)
Amount attributable to tax, reclassification	6	5
Amortization of net actuarial gain | Customer Credit Trust
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive income before reclassifications:	0	0
Other comprehensive income before reclassifications, tax	0	0
Amounts reclassified from other comprehensive income	0	0
Amount attributable to tax, reclassification	0	0
Regulatory account transfer
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive income before reclassifications:	231	107
Amounts reclassified from other comprehensive income	16	14
Regulatory account transfer | Pension Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive income before reclassifications:	260	180
Other comprehensive income before reclassifications, tax	101	70
Amounts reclassified from other comprehensive income	2	2
Amount attributable to tax, reclassification	1	1
Regulatory account transfer | Other Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive income before reclassifications:	(29)	(73)
Other comprehensive income before reclassifications, tax	11	28
Amounts reclassified from other comprehensive income	14	12
Amount attributable to tax, reclassification	5	4
Regulatory account transfer | Customer Credit Trust
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive income before reclassifications:	0	0
Other comprehensive income before reclassifications, tax	0	0
Amounts reclassified from other comprehensive income	0	0
Amount attributable to tax, reclassification	$ 0	$ 0