Retirement Benefits (Reconciliation Of The Beginning And Ending Balances Of Plan Assets Measured At Fair Value Using Level III Inputs) (Details) - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Change in Fair Value of Plan Assets, Level III Reconciliation
Beginning balance	$ 517	$ 512	$ 469
Actual return on plan assets, relating to assets still held at the reporting date	(75)	20	36
Purchases	9	5	15
Sales	(27)	(20)	(8)
Ending balance	424	517	512
Insurance Company Contracts [Member]
Change in Fair Value of Plan Assets, Level III Reconciliation
Beginning balance	179	189	175
Actual return on plan assets, relating to assets still held at the reporting date	(22)	(6)	7
Purchases	9	5	15
Sales	(12)	(9)	(8)
Ending balance	154	179	189
Life Insurance Contracts [Member]
Change in Fair Value of Plan Assets, Level III Reconciliation
Beginning balance	338	323	294
Actual return on plan assets, relating to assets still held at the reporting date	(53)	26	29
Purchases	0	0	0
Sales	(15)	(11)	0
Ending balance	$ 270	$ 338	$ 323