Pension and Other Postretirement Benefit Plans - Weighted-Average Assumptions Used to Determine Projected Benefit Obligations and Net Periodic Benefit Cost (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Plans
Benefit obligations:
Discount rate (as a percent)	2.80%	2.50%	3.00%
Rate of compensation increase (as a percent)	2.10%	2.10%	2.10%
Net periodic benefit cost (credit):
Discount rate (as a percent)	2.50%	3.00%	3.80%
Expected return on assets (as a percent)	5.70%	6.00%	6.50%
Rate of compensation increase (as a percent)	2.10%	2.10%	2.10%
OPEB Plans
Benefit obligations:
Discount rate (as a percent)	2.90%	2.50%	3.10%
Net periodic benefit cost (credit):
Discount rate (as a percent)	2.50%	3.10%	3.90%