Benefit Plans - Summary of Weighted Average Assumptions (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Discount rate for obligations			8.50%
Rate of compensation increases			4.50%
Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate for obligations	5.25%	5.25%
Discount rate for net periodic benefit costs	5.25%	4.75%	0.75%
Rate of compensation increases	3.00%	4.50%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate for obligations	10.00%	9.25%
Discount rate for net periodic benefit costs	9.25%	8.50%	7.50%
Rate of compensation increases	4.50%	5.00%