Retirement Benefits (Unaudited) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Components of Net Periodic Benefit Cost
Net periodic benefit cost (benefit)			$ (339)	$ (230)
Defined contribution plan, employer contributions	$ 136	$ 126	517	487
Pension Benefits
Components of Net Periodic Benefit Cost
Service cost	60	59	179	177
Interest cost	381	392	1,144	1,176
Expected return on plan assets	(549)	(524)	(1,647)	(1,573)
Net periodic benefit cost (benefit)	(108)	(73)	(324)	(220)
Defined benefit plan, contributions by Employer	17	26	66	80
OPB
Components of Net Periodic Benefit Cost
Service cost	1	2	3	4
Interest cost	15	17	46	50
Expected return on plan assets	(21)	(22)	(64)	(64)
Net periodic benefit cost (benefit)	(5)	(3)	(15)	(10)
Defined benefit plan, contributions by Employer	$ 7	$ 7	$ 27	$ 28