Pension and Other Postretirement Benefits - Schedule of Weighted Average Assumptions Used to Determine Benefit Obligations (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate		3.30%	4.35%
Rate of compensation increase		0.00%	3.50%
Cash balance plan interest crediting rate		3.00%	3.00%
Average duration for plans' projected cash flows		10 years
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate to calculate service cost		4.35%	3.75%	4.20%
Discount rate to calculate interest cost		4.00%	3.30%	3.60%
Expected long-term rate of return on plan assets		7.00%	7.00%	7.75%
Rate of compensation increase		3.50%	3.50%	3.50%
Cash balance plan interest crediting rate		0.0300	0.0300	0.0300
Period expected long-term rate of return is applied		5 years
Number of years over actual annual healthcare cost trend experience		20 years
Basis point of decrease identified In long term rate of return		0.75%
Other postretirement benefits
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Number of years over actual annual healthcare cost trend experience		3 years
Scenario, Forecast
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Expected long-term rate of return on plan assets	7.00%