Retirement Benefits (Fair Value Of Plan Assets Utilizing Fair Value Hierarchy) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 4,027	$ 5,745	$ 5,510
Pension Benefits | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	584	947
Pension Benefits | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,304	2,056
Pension Benefits | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,271	2,905
Pension Benefits | Includes Medical Benefit Component Under Section401 H And Excludes Receivables Related To Pending Security Sales [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,159	5,908
Pension Benefits | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	172	116
Pension Benefits | Cash and cash equivalents | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Cash and cash equivalents | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Cash and cash equivalents | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	172	116
Pension Benefits | U.S. large-capitalization
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	658	1,381
Pension Benefits | U.S. large-capitalization | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | U.S. large-capitalization | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | U.S. large-capitalization | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	658	1,381
Pension Benefits | U.S. small- and mid-capitalization
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	321	558
Pension Benefits | U.S. small- and mid-capitalization | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	321	558
Pension Benefits | U.S. small- and mid-capitalization | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | U.S. small- and mid-capitalization | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | International
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	661	903
Pension Benefits | International | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	266	372
Pension Benefits | International | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | International | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	395	531
Pension Benefits | Global
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	493	621
Pension Benefits | Global | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Global | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Global | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	493	621
Pension Benefits | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	397	572
Pension Benefits | Corporate bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Corporate bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	397	545
Pension Benefits | Corporate bonds | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	27
Pension Benefits | Municipal bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	41	50
Pension Benefits | Municipal bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Municipal bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	41	50
Pension Benefits | Municipal bonds | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | U.S. Treasury and agency securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	859	1,450
Pension Benefits | U.S. Treasury and agency securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | U.S. Treasury and agency securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	859	1,450
Pension Benefits | U.S. Treasury and agency securities | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Diversified Credit
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	281	0
Pension Benefits | Diversified Credit | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Diversified Credit | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Diversified Credit | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	281	0
Pension Benefits | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4	28
Pension Benefits | Other | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(3)	17
Pension Benefits | Other | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7	11
Pension Benefits | Other | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	271	228
Pension Benefits | Real estate | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Real estate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Real estate | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	271	228
Pension Benefits | Private equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	1
Pension Benefits | Private equity | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Private equity | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Private equity | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	1
Pension Benefits | Medical benefit assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(172)	(234)
Pension Benefits | Net receivables
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	40	71
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,249	1,558	$ 1,453
Postretirement Benefits | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	370	480
Postretirement Benefits | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	123	133
Postretirement Benefits | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	582	699
Postretirement Benefits | Includes Medical Benefit Component Under Section401 H And Excludes Receivables Related To Pending Security Sales [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,075	1,312
Postretirement Benefits | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14	24
Postretirement Benefits | Cash and cash equivalents | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14	24
Postretirement Benefits | Cash and cash equivalents | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Postretirement Benefits | Cash and cash equivalents | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Postretirement Benefits | U.S. large-capitalization
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	308	398
Postretirement Benefits | U.S. large-capitalization | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	221	283
Postretirement Benefits | U.S. large-capitalization | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Postretirement Benefits | U.S. large-capitalization | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	87	115
Postretirement Benefits | U.S. small- and mid-capitalization
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	92	113
Postretirement Benefits | U.S. small- and mid-capitalization | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	92	113
Postretirement Benefits | U.S. small- and mid-capitalization | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Postretirement Benefits | U.S. small- and mid-capitalization | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Postretirement Benefits | International
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	141	177
Postretirement Benefits | International | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	43	60
Postretirement Benefits | International | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Postretirement Benefits | International | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	98	117
Postretirement Benefits | Global
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	110	132
Postretirement Benefits | Global | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Postretirement Benefits | Global | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Postretirement Benefits | Global | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	110	132
Postretirement Benefits | Municipal bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	123	133
Postretirement Benefits | Municipal bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Postretirement Benefits | Municipal bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	123	133
Postretirement Benefits | Municipal bonds | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Postretirement Benefits | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	287	335
Postretirement Benefits | Other | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Postretirement Benefits | Other | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Postretirement Benefits | Other | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	287	335
Postretirement Benefits | Medical benefit assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	172	234
Postretirement Benefits | Net receivables
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 2	$ 12