Retirement Benefits (Unaudited) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Components of Net Periodic Benefit Cost
Net periodic benefit cost (benefit)			$ (230)	$ (895)
Defined contribution plan, employer contributions	$ 126	$ 108	487	429
Pension Benefits
Components of Net Periodic Benefit Cost
Service cost	59	92	177	276
Interest cost	392	285	1,176	853
Expected return on plan assets	(524)	(661)	(1,573)	(1,982)
Amortization of prior service credit	0	0	0	0
Net periodic benefit cost (benefit)	(73)	(284)	(220)	(853)
Defined benefit plan, contributions by Employer	26	26	80	77
OPB
Components of Net Periodic Benefit Cost
Service cost	2	2	4	6
Interest cost	17	12	50	36
Expected return on plan assets	(22)	(28)	(64)	(83)
Amortization of prior service credit	0	0	0	(1)
Net periodic benefit cost (benefit)	(3)	(14)	(10)	(42)
Defined benefit plan, contributions by Employer	$ 7	$ 9	$ 28	$ 29