Retirement Benefits (Unaudited) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Components of Net Periodic Benefit Cost
Net periodic benefit cost (benefit)			$ (256)	$ (339)
Defined contribution plan, employer contributions	$ 133	$ 136	517	517
Pension Benefits
Components of Net Periodic Benefit Cost
Service cost	55	60	163	179
Interest cost	404	381	1,209	1,144
Expected return on plan assets	(540)	(549)	(1,619)	(1,647)
Amortization of prior service credit	0	0	0	0
Other	0	0	7	0
Net periodic benefit cost (benefit)	(81)	(108)	(240)	(324)
Defined benefit plan, contributions by Employer	25	17	67	66
OPB
Components of Net Periodic Benefit Cost
Service cost	1	1	3	3
Interest cost	16	15	47	46
Expected return on plan assets	(22)	(21)	(64)	(64)
Amortization of prior service credit	(1)	0	(2)	0
Other	0	0	0	0
Net periodic benefit cost (benefit)	(6)	(5)	(16)	(15)
Defined benefit plan, contributions by Employer	$ 7	$ 7	$ 27	$ 27