Retirement and Postretirement Benefit Plans - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Postretirement and Other Benefit Plans Disclosure
Contributions to defined benefit plans	$ 1	$ 147
Pension Benefit
Postretirement and Other Benefit Plans Disclosure
Net periodic benefit costs (gains)	0	(11)
Postretirement Benefit
Postretirement and Other Benefit Plans Disclosure
Net periodic benefit costs (gains)	$ 19	$ 20