Retirement Benefits (Unaudited) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Components of Net Periodic Benefit Cost
Net periodic benefit cost (benefit)	$ (76)	$ (298)
Defined contribution plan, employer contributions	215	199
Pension Benefits
Components of Net Periodic Benefit Cost
Service cost	59	92
Interest cost	392	284
Expected return on plan assets	(524)	(660)
Net periodic benefit cost (benefit)	(73)	(284)
Defined benefit plan, contributions by Employer	29	26
OPB
Components of Net Periodic Benefit Cost
Service cost	1	2
Interest cost	17	12
Expected return on plan assets	(21)	(28)
Net periodic benefit cost (benefit)	(3)	(14)
Defined benefit plan, contributions by Employer	$ 11	$ 10