Retirement Benefits (Unaudited) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Components of Net Periodic Benefit Cost
Net periodic benefit cost (benefit)			$ (226)	$ (154)
Defined contribution plan, employer contributions	$ 151	$ 146	381	361
Pension Benefits
Components of Net Periodic Benefit Cost
Service cost	59	59	119	118
Interest cost	382	392	763	784
Expected return on plan assets	(549)	(525)	(1,098)	(1,049)
Net periodic benefit cost (benefit)	(108)	(74)	(216)	(147)
Defined benefit plan, contributions by Employer	24	25	49	54
OPB
Components of Net Periodic Benefit Cost
Service cost	1	1	2	2
Interest cost	16	16	31	33
Expected return on plan assets	(22)	(21)	(43)	(42)
Net periodic benefit cost (benefit)	(5)	(4)	(10)	(7)
Defined benefit plan, contributions by Employer	$ 9	$ 10	$ 20	$ 21