Pensions and Other Postretirement Benefits (Net Periodic Benefit Costs) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2	$ 3
Interest cost	19	16
Expected return on plan assets	(36)	(38)
Amortization of actuarial losses	8	10
Amortization of prior service credit	0	0
Net periodic benefit (income)/cost	(7)	(9)
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	3
Interest cost	4	3
Expected return on plan assets	0	0
Amortization of actuarial losses	4	6
Amortization of prior service credit	(3)	(14)
Net periodic benefit (income)/cost	$ 8	$ (2)