Retirement Benefits Net Periodic Benefit Cost (Benefit) (Details 1) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Components of Net Periodic Benefit Cost (Table Amounts) [Abstract]
Interest cost	$ 1,600
Mark-to-market pension and OPB (expense) benefit	(422)	$ 1,232	$ 2,355
Net periodic benefit cost (benefit)	(308)	(1,193)	(1,091)
Pension Benefits
Components of Net Periodic Benefit Cost (Table Amounts) [Abstract]
Service cost	236	367	414
Interest cost	1,568	1,136	1,054
Expected return on plan assets	(2,098)	(2,641)	(2,512)
Amortization of prior service credit	0	0	(9)
Mark-to-market pension and OPB (expense) benefit	(442)	1,262	1,921
Other	0	0	(1)
Net periodic benefit cost (benefit)	148	(2,400)	(2,975)
Medical and Life Benefits
Components of Net Periodic Benefit Cost (Table Amounts) [Abstract]
Service cost	5	9	16
Interest cost	67	47	53
Expected return on plan assets	(85)	(110)	(105)
Amortization of prior service credit	(1)	(1)	(1)
Mark-to-market pension and OPB (expense) benefit	20	(30)	434
Other	0	0	0
Net periodic benefit cost (benefit)	$ (34)	$ (25)	$ (471)