Retirement Benefits Funded Status of Plan Assets (Liabilities) (Details 3) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Change in plan assets
Fair value of plan assets at beginning of year	$ 37,824
Fair value of plan assets at end of year	30,146	$ 37,824
Change in projected benefit obligation
Interest cost	1,200
Benefits paid	(2,100)
Amounts Recognized on the Balance Sheet
Non-current liability	(1,188)	(3,269)
Pension Benefits
Change in plan assets
Fair value of plan assets at beginning of year	36,236	34,452
Net (loss) gain on plan assets	(5,422)	3,637
Employer contributions	101	104
Participant contributions	7	8
Benefits paid	1,973	1,964
Other	(29)	(1)
Fair value of plan assets at end of year	28,920	36,236	$ 34,452
Change in projected benefit obligation
Projected benefit obligation at beginning of year	38,888	40,182
Service cost	367	414	409
Interest cost	1,136	1,054	1,226
Participant contributions	7	8
Actuarial loss	(9,325)	(794)
Benefits paid	1,973	1,964
Other	(33)	(12)
Projected benefit obligation at end of year	29,067	38,888	40,182
Funded status	(147)	(2,652)
Amounts Recognized on the Balance Sheet
Non-current assets	982	462
Current liability	(177)	(182)
Non-current liability	(952)	(2,932)
Medical and Life Benefits
Change in plan assets
Fair value of plan assets at beginning of year	1,588	1,515
Net (loss) gain on plan assets	(257)	170
Employer contributions	35	37
Participant contributions	24	23
Benefits paid	164	157
Other	0	0
Fair value of plan assets at end of year	1,226	1,588	1,515
Change in projected benefit obligation
Projected benefit obligation at beginning of year	1,685	2,119
Service cost	9	16	17
Interest cost	47	53	67
Participant contributions	24	23
Actuarial loss	(337)	(369)
Benefits paid	164	157
Other	0	0
Projected benefit obligation at end of year	1,264	1,685	$ 2,119
Funded status	(38)	(97)
Amounts Recognized on the Balance Sheet
Non-current assets	240	285
Current liability	(42)	(45)
Non-current liability	$ (236)	$ (337)