Pensions and Other Postretirement Benefits (Net Periodic Benefit Costs) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Pension settlement charge	$ 0		$ 0	$ 190	$ 0
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	2		3	6	7
Interest cost	28		18	83	55
Expected return on plan assets	(28)		(35)	(83)	(106)
Amortization of actuarial losses	6		8	16	25
Pension settlement charge	0	$ 190	0	191	0
Net periodic benefit cost/(income)	8		(6)	213	(19)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1		2	3	6
Interest cost	7		4	20	12
Amortization of actuarial losses	0		3	(1)	9
Amortization of prior service credit	(2)		(3)	(5)	(8)
Net periodic benefit cost/(income)	$ 6		$ 6	$ 17	$ 19