Retirement Benefits Funded Status of Plan Assets (Liabilities) (Details 3) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Change in plan assets
Fair value of plan assets at beginning of year	$ 31,006
Fair value of plan assets at end of year	32,413	$ 31,006
Change in projected benefit obligation
Interest cost	1,700
Benefits paid	(2,100)
Amounts Recognized on the Balance Sheet
Non-current assets	3,167	2,184
Non-current liability	(1,110)	(1,120)
Pension Benefits
Change in plan assets
Fair value of plan assets at beginning of year	29,769	30,251
Net gain on plan assets	3,244	1,358
Employer contributions	99	96
Participant contributions	9	6
Benefits paid	2,000	1,942
Other	10	0
Fair value of plan assets at end of year	31,131	29,769	$ 30,251
Change in projected benefit obligation
Projected benefit obligation at beginning of year	28,992	30,443
Service cost	217	239	236
Interest cost	1,612	1,526	1,568
Participant contributions	9	6
Actuarial loss (gain)	578	(1,295)
Benefits paid	2,000	1,942
Other	20	15
Projected benefit obligation at end of year	29,428	28,992	30,443
Funded status	1,703	777
Amounts Recognized on the Balance Sheet
Non-current assets	2,774	1,851
Current liability	(181)	(177)
Non-current liability	(890)	(897)
Medical and Life Benefits
Change in plan assets
Fair value of plan assets at beginning of year	1,237	1,274
Net gain on plan assets	129	61
Employer contributions	31	33
Participant contributions	2	26
Benefits paid	117	157
Other	0	0
Fair value of plan assets at end of year	1,282	1,237	1,274
Change in projected benefit obligation
Projected benefit obligation at beginning of year	1,150	1,246
Service cost	4	4	5
Interest cost	62	62	67
Participant contributions	2	26
Actuarial loss (gain)	31	(19)
Benefits paid	117	157
Other	0	(12)
Projected benefit obligation at end of year	1,132	1,150	$ 1,246
Funded status	150	87
Amounts Recognized on the Balance Sheet
Non-current assets	393	333
Current liability	(23)	(23)
Non-current liability	$ (220)	$ (223)