COMPREHENSIVE INCOME - Schedule of Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 26,986	$ 25,286	$ 24,123
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)	39	52	(139)
Ending balance	32,218	26,986	25,286
Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(3)	(55)	84
Change in Fair Value Recognized in AOCI, Net of Tax	53	50	(198)
Amount of (Gain) Loss Reclassified from AOCI	(18)	2	53
Income Tax (Expense) Benefit	(4)	0	11
Reclassifications from AOCI, Net of Income Tax (Expense) Benefit	(14)	2	42
Reclassifications of KPCo Pension and OPEB Regulatory Assets to AOCI, before Income Tax (Expense) Benefit			21
Income Tax (Expense) Benefit			4
Reclassifications of KPCo Pension and OPEB Regulatory Assets to AOCI, Net of Income Tax (Expense) Benefit			17
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)	39	52	(139)
Ending balance	36	(3)	(55)
Pension and OPEB Amortization of Deferred Costs
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	99	93	106
Change in Fair Value Recognized in AOCI, Net of Tax	0	0	0
Amount of (Gain) Loss Reclassified from AOCI	1	7	(16)
Income Tax (Expense) Benefit	0	1	(3)
Reclassifications from AOCI, Net of Income Tax (Expense) Benefit	1	6	(13)
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)	1	6	(13)
Ending balance	100	99	93
Amortization of Prior Service Cost (Credit)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amount of (Gain) Loss Reclassified from AOCI	(1)	(5)	(21)
Amortization of Actuarial (Gains) Losses
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amount of (Gain) Loss Reclassified from AOCI	2	1	5
Recognition of Pension Settlement Costs
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amount of (Gain) Loss Reclassified from AOCI		11
Pension and OPEB Changes in Funded Status
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(204)	(245)	(246)
Change in Fair Value Recognized in AOCI, Net of Tax	63	41	(16)
Reclassifications of KPCo Pension and OPEB Regulatory Assets to AOCI, before Income Tax (Expense) Benefit			21
Income Tax (Expense) Benefit			4
Reclassifications of KPCo Pension and OPEB Regulatory Assets to AOCI, Net of Income Tax (Expense) Benefit			17
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)	63	41	1
Ending balance	(141)	(204)	(245)
Commodity | Cash Flow Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	99	105	224
Change in Fair Value Recognized in AOCI, Net of Tax	(9)	3	(176)
Amount of (Gain) Loss Reclassified from AOCI	(15)	(11)	72
Income Tax (Expense) Benefit	(3)	(2)	15
Reclassifications from AOCI, Net of Income Tax (Expense) Benefit	(12)	(9)	57
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)	(21)	(6)	(119)
Ending balance	78	99	105
Interest Rate (USD) | Cash Flow Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	3	(8)	0
Change in Fair Value Recognized in AOCI, Net of Tax	(1)	6	(6)
Amount of (Gain) Loss Reclassified from AOCI	(4)	6	(3)
Income Tax (Expense) Benefit	(1)	1	(1)
Reclassifications from AOCI, Net of Income Tax (Expense) Benefit	(3)	5	(2)
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)	(4)	11	(8)
Ending balance	$ (1)	$ 3	$ (8)