Income Taxes - PAC - Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current:
Federal	$ (1,650)	$ (1,463)	$ (1,701)
State	118	(65)	(177)
Total current	(1,442)	(1,449)	(1,778)
Deferred:
Federal	(114)	(408)	1,037
State	(275)	(49)	(476)
Total deferred	(356)	(462)	650
Investment tax credits	99	(5)	(4)
Total	(1,699)	(1,916)	(1,132)
PAC
Current:
Federal	(324)	(216)	(150)
State	(5)	(3)	7
Total current	(329)	(219)	(143)
Deferred:
Federal	(172)	90	26
State	(51)	71	40
Total deferred	(223)	161	66
Investment tax credits	(1)	(4)	(2)
Total	$ (553)	$ (62)	$ (79)