Employee Benefits - Components of Net Periodic Benefit Cost (Credit) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Retirement Benefits [Abstract]
Service cost	$ 1	$ 1
Interest cost	12	10
Expected return on assets	(22)	(26)
Amortization of prior service credit / actuarial loss	3	4
Net periodic benefit cost	$ (6)	$ (11)