Retirement Benefits (Funded Status Of Benefit Plans And Amounts Included In Regulatory Assets And OCI) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Change in plan assets:
Funded status – deficiency (surplus)	$ (551)	$ (377)
Accrued benefit cost (asset) at December 31	(551)	(377)
Amounts recognized in the balance sheet consist of:
Noncurrent asset	(581)	(411)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation at end of year	4,102	3,911
Change in benefit obligation:
Net benefit obligation at beginning of year	4,061	5,457
Service cost	79	128	$ 134
Interest cost	221	163	152
Participant contributions	0	0
Actuarial (gain) loss	170	(1,425)
Benefits paid	(273)	(262)
Net benefit obligation at end of year	4,258	4,061	5,457
Change in plan assets:
Fair value of plan assets at beginning of year	4,027	5,745
Actual return on plan assets	514	(1,461)
Employer contributions	4	5	60
Participant contributions	0	0
Benefits paid	(273)	(262)
Fair value of plan assets at end of year	4,272	4,027	5,745
Funded status – deficiency (surplus)	(14)	34
Accrued benefit cost (asset) at December 31	(14)	34
Amounts recognized in the balance sheet consist of:
Noncurrent asset	(44)	0
Liability, Defined Benefit Plan, Current	2	3
Liability, Defined Benefit Plan, Noncurrent	28	31
Amounts recognized in regulatory assets or liabilities consist of:
Net actuarial gain	(10)	(107)
Prior service credit	0	0
Amounts recognized in accumulated OCI (pretax) consist of:
Net actuarial (gain) loss	22	15
Total	12	(92)
Postretirement Benefits
Change in benefit obligation:
Net benefit obligation at beginning of year	838	1,129
Service cost	12	20	23
Interest cost	45	34	33
Participant contributions	7	8
Actuarial (gain) loss	17	(289)
Benefits paid	(63)	(64)
Net benefit obligation at end of year	856	838	1,129
Change in plan assets:
Fair value of plan assets at beginning of year	1,249	1,558
Actual return on plan assets	197	(255)
Employer contributions	3	2	2
Participant contributions	7	8
Benefits paid	(63)	(64)
Fair value of plan assets at end of year	1,393	1,249	$ 1,558
Funded status – deficiency (surplus)	(537)	(411)
Accrued benefit cost (asset) at December 31	(537)	(411)
Amounts recognized in the balance sheet consist of:
Noncurrent asset	(537)	(411)
Liability, Defined Benefit Plan, Current	0	0
Liability, Defined Benefit Plan, Noncurrent	0	0
Amounts recognized in regulatory assets or liabilities consist of:
Net actuarial gain	(311)	(268)
Prior service credit	(25)	(29)
Amounts recognized in accumulated OCI (pretax) consist of:
Net actuarial (gain) loss	(4)	(4)
Total	$ (340)	$ (301)