Retirement Benefits (Fair Values Of Pension Benefit Assets And Other Benefit Assets By Asset Category And Level Inputs) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension benefit assets	$ 424	$ 517	$ 512	$ 469
Insurance Company Contracts [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension benefit assets	154	179	189	175
Life Insurance Contracts [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension benefit assets	270	338	323	$ 294
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension benefit assets	1,734	2,216	2,186
Pension Benefits [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension benefit assets	673	935
Pension Benefits [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension benefit assets	800	978
Pension Benefits [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension benefit assets	154	179
Pension Benefits [Member] | U.S. Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	489	682
Pension Benefits [Member] | U.S. Securities [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	489	682
Pension Benefits [Member] | U.S. Securities [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Pension Benefits [Member] | U.S. Securities [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Pension Benefits [Member] | Foreign Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	145	204
Pension Benefits [Member] | Foreign Securities [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	145	204
Pension Benefits [Member] | Foreign Securities [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Pension Benefits [Member] | Foreign Securities [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Pension Benefits [Member] | Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	39	49
Pension Benefits [Member] | Mutual Funds [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	39	49
Pension Benefits [Member] | Mutual Funds [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Pension Benefits [Member] | Mutual Funds [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Pension Benefits [Member] | Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	247	395
Pension Benefits [Member] | Government Securities [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Pension Benefits [Member] | Government Securities [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	247	395
Pension Benefits [Member] | Government Securities [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Pension Benefits [Member] | Corporate Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	275	379
Pension Benefits [Member] | Corporate Securities [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Pension Benefits [Member] | Corporate Securities [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	275	379
Pension Benefits [Member] | Corporate Securities [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Pension Benefits [Member] | Asset-Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	185	98
Pension Benefits [Member] | Asset-Backed Securities [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Pension Benefits [Member] | Asset-Backed Securities [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	185	98
Pension Benefits [Member] | Asset-Backed Securities [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Pension Benefits [Member] | Commingled fund
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	93	106
Pension Benefits [Member] | Commingled fund | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension benefit assets		0
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0
Pension Benefits [Member] | Commingled fund | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	93	106
Pension Benefits [Member] | Commingled fund | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension benefit assets		0
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0
Pension Benefits [Member] | Insurance Company Contracts [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	154	179
Pension Benefits [Member] | Insurance Company Contracts [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Pension Benefits [Member] | Insurance Company Contracts [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Pension Benefits [Member] | Insurance Company Contracts [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	154	179
Pension Benefits [Member] | Total Plan Assets Excluding Partnership Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	1,627	2,092
Pension Benefits [Member] | Partnership investments [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	71	78
Pension Benefits [Member] | Total Plan Assets Excluding Cash, Investment Income Receivable And Amounts Due (To) From Brokers [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	1,698	2,170
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension benefit assets	299	371	$ 391
Other Benefits [Member] | U.S. Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	7	10
Other Benefits [Member] | U.S. Securities [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	7	10
Other Benefits [Member] | U.S. Securities [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | U.S. Securities [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Foreign Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	1	2
Other Benefits [Member] | Foreign Securities [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	1	2
Other Benefits [Member] | Foreign Securities [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Foreign Securities [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	17	24
Other Benefits [Member] | Mutual Funds [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	17	24
Other Benefits [Member] | Mutual Funds [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Mutual Funds [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	3	4
Other Benefits [Member] | Government Securities [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Government Securities [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	3	4
Other Benefits [Member] | Government Securities [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Corporate Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	3	4
Other Benefits [Member] | Corporate Securities [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Corporate Securities [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	3	4
Other Benefits [Member] | Corporate Securities [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Asset-Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	3	3
Other Benefits [Member] | Asset-Backed Securities [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Asset-Backed Securities [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	3	3
Other Benefits [Member] | Asset-Backed Securities [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Commingled fund
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	2	2
Other Benefits [Member] | Commingled fund | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Commingled fund | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	2	2
Other Benefits [Member] | Commingled fund | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Life Insurance Contracts [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	270	338
Other Benefits [Member] | Life Insurance Contracts [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Life Insurance Contracts [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Life Insurance Contracts [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	270	338
Other Benefits [Member] | Investment In DOL 103-12 Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	10	11
Other Benefits [Member] | Investment In DOL 103-12 Trust [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Investment In DOL 103-12 Trust [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	10	11
Other Benefits [Member] | Investment In DOL 103-12 Trust [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Other Benefits [Member] | Total Plan Assets Excluding Cash, Investment Income Receivable And Amounts Due (To) From Brokers [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	316	398
Other Benefits [Member] | Total Plan Assets Excluding Cash, Investment Income Receivable And Amounts Due (To) From Brokers [Member] | Level I [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension benefit assets	25	36
Other Benefits [Member] | Total Plan Assets Excluding Cash, Investment Income Receivable And Amounts Due (To) From Brokers [Member] | Level II [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension benefit assets	21	24
Other Benefits [Member] | Total Plan Assets Excluding Cash, Investment Income Receivable And Amounts Due (To) From Brokers [Member] | Level III [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension benefit assets	$ 270	$ 338