SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Reclassifications Out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 21,223	$ 21,253
Net current period other comprehensive gain (loss)	15	7
Ending balance	23,075	21,223
Pension Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net current period other comprehensive gain (loss)	21	6
Other Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net current period other comprehensive gain (loss)	0	1
Customer Credit Trust
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net current period other comprehensive gain (loss)	(6)
Accumulated Other Comprehensive Income (Loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(15)	(22)
Ending balance	0	(15)
Accumulated Other Comprehensive Income (Loss) | Pension Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(33)	(39)
Ending balance	(12)	(33)
Accumulated Other Comprehensive Income (Loss) | Other Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	18	17
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	0
Ending balance	(6)	0
Amortization of net actuarial gain (loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Loss on investments	(6)
Other comprehensive income before reclassifications:	8	1,144
Amounts reclassified from other comprehensive income	28	20
Amortization of net actuarial gain (loss) | Pension Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amount attributable to tax, before reclassification	0
Loss on investments	0
Other comprehensive income before reclassifications, tax	102	391
Other comprehensive income before reclassifications:	263	1,007
Amount attributable to tax, reclassification	1	2
Amounts reclassified from other comprehensive income	(1)	(4)
Amortization of net actuarial gain (loss) | Other Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amount attributable to tax, before reclassification	0
Loss on investments	0
Other comprehensive income before reclassifications, tax	99	53
Other comprehensive income before reclassifications:	(255)	137
Amount attributable to tax, reclassification	11	9
Amounts reclassified from other comprehensive income	29	24
Amortization of net actuarial gain (loss) | Customer Credit Trust
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amount attributable to tax, before reclassification	3
Loss on investments	(6)
Other comprehensive income before reclassifications, tax	0
Other comprehensive income before reclassifications:	0
Amount attributable to tax, reclassification	0
Amounts reclassified from other comprehensive income	0
Regulatory account transfer
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive income before reclassifications:	13	(1,139)
Amounts reclassified from other comprehensive income	(26)	(16)
Regulatory account transfer | Pension Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive income before reclassifications, tax	94	390
Other comprehensive income before reclassifications:	(242)	(1,003)
Amount attributable to tax, reclassification	0	1
Amounts reclassified from other comprehensive income	(2)	(2)
Regulatory account transfer | Other Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive income before reclassifications, tax	99	53
Other comprehensive income before reclassifications:	255	(136)
Amount attributable to tax, reclassification	9	5
Amounts reclassified from other comprehensive income	(24)	(14)
Regulatory account transfer | Customer Credit Trust
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive income before reclassifications, tax	0
Other comprehensive income before reclassifications:	0
Amount attributable to tax, reclassification	0
Amounts reclassified from other comprehensive income	0
Amortization of prior service cost
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amounts reclassified from other comprehensive income	(2)	(6)
Amortization of prior service cost | Pension Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amount attributable to tax, reclassification	1	2
Amounts reclassified from other comprehensive income	3	4
Amortization of prior service cost | Other Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amount attributable to tax, reclassification	2	4
Amounts reclassified from other comprehensive income	(5)	$ (10)
Amortization of prior service cost | Customer Credit Trust
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amount attributable to tax, reclassification	0
Amounts reclassified from other comprehensive income	$ 0