Retirement Benefits (Components Of Net Periodic Benefit Cost) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total non-service cost components	$ (47)	$ (34)	$ (93)	$ (68)
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	31	34	64	67
Interest cost	41	38	81	76
Expected return on plan assets	(80)	(74)	(160)	(149)
Prior service benefit	0	0	0	0
Actuarial loss (gain)	6	20	12	37
Total non-service cost components	(33)	(16)	(67)	(36)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total	(2)	18	(3)	31
Other Postretirement Benefit Plan, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	5	6	10	12
Interest cost	9	8	17	16
Expected return on plan assets	(22)	(20)	(43)	(40)
Prior service benefit	(1)	(1)	(2)	(2)
Actuarial loss (gain)	(5)	(2)	(9)	(3)
Total non-service cost components	(19)	(15)	(37)	(29)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total	$ (14)	$ (9)	$ (27)	$ (17)