Income Taxes (Details of Income Tax Expense for Continuing Operations Including Noncontrolling Interests) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Current:
Federal	$ (69)	$ (52)	$ (139)
State	(3)	(39)	3
Total current benefit	(72)	(91)	(136)
Deferred:
Taxes before operating loss carryforwards and investment tax credits	135	61	158
Tax utilization expense of operating loss carryforwards	33	34	33
State	36	7	17
Total deferred expense	204	102	208
Investment tax credit-amortization	(1)	(2)	(1)
Total income tax expense	$ 131	$ 9	$ 71