Schedule I - Condensed Financial Information - Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Current Assets
Cash and temporary cash investments	$ 1,629	$ 1,324
Tax receivable	11	145
Accounts receivable from affiliated companies	2,583	2,440
Accrued unbilled revenue	821	848
Prepayments	381	445
Other current assets	161	194
TOTAL CURRENT ASSETS	6,750	6,664
Investments in subsidiaries and others	1,213	1,126
Goodwill	406	408
Pension and retiree benefits - asset	4,227	3,791
Other deferred charges and noncurrent assets	11,237	10,607
TOTAL ASSETS	74,603	70,562	$ 66,331
Current Liabilities
Notes payable	1,575	2,170
Accounts payable	1,947	1,676
Accrued taxes	104	70
Other current liabilities	544	481
TOTAL CURRENT LIABILITIES	6,614	6,433
Shareholders’ Equity
Retained earnings	14,857	14,048
Total Shareholders’ Equity	24,190	21,962
TOTAL LIABILITIES AND EQUITY	74,603	70,562
Parent Company
Current Assets
Cash and temporary cash investments	1	1
Other receivables, net allowance for uncollectible accounts	0	64
Tax receivable	11	145
Accounts receivable from affiliated companies	48	24
Accrued unbilled revenue	4	3
Prepayments	12	13
Other current assets	4	1
TOTAL CURRENT ASSETS	80	251
Investments in subsidiaries and others	23,869	21,706
Goodwill	406	406
Pension and retiree benefits - asset	8	6
Other deferred charges and noncurrent assets	204	356
TOTAL ASSETS	24,567	22,725
Current Liabilities
Notes payable	315	348
Other current liabilities	8	9
TOTAL CURRENT LIABILITIES	371	760
Other noncurrent liabilities	6	4
Total Liabilities	377	764
Shareholders’ Equity
Common stock, including additional paid-in capital	11,475	10,024
Retained earnings	12,715	11,937
Total Shareholders’ Equity	24,190	21,961
TOTAL LIABILITIES AND EQUITY	24,567	22,725
Parent Company | Nonrelated Party
Current Liabilities
Accounts payable	5	17
Accrued taxes	2	2
Parent Company | Related Party
Current Liabilities
Accounts payable	15	14
Accrued taxes	$ 26	$ 370