Retirement Benefits (Components Of Net Periodic Benefit Cost) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total non-service cost components	$ (45)	$ (34)	$ (138)	$ (102)
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	31	33	95	100
Interest cost	42	38	123	114
Expected return on plan assets	(80)	(74)	(240)	(223)
Prior service benefit	0	0	0	0
Actuarial loss (gain)	7	18	19	55
Total non-service cost components	(31)	(18)	(98)	(54)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total	0	15	(3)	46
Other Postretirement Benefit Plan, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	5	5	15	17
Interest cost	8	9	25	25
Expected return on plan assets	(21)	(20)	(64)	(60)
Prior service benefit	(1)	(1)	(3)	(3)
Actuarial loss (gain)	(5)	(1)	(14)	(4)
Total non-service cost components	(19)	(13)	(56)	(42)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total	$ (14)	$ (8)	$ (41)	$ (25)