Pension and Other Post Retirement Benefit Plans - Schedule of Plan Assets by Category (Details)	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Actual (as a percent)	100.00%	100.00%
Target (as a percent)	100.00%	100.00%
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Actual (as a percent)	3.90%	6.00%
Target (as a percent)	3.00%	3.00%
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual (as a percent)	48.40%	52.40%
Target (as a percent)	50.00%	55.00%
Debt securities
Defined Benefit Plan Disclosure [Line Items]
Actual (as a percent)	45.60%	39.60%
Target (as a percent)	45.00%	40.00%
Alternative investments
Defined Benefit Plan Disclosure [Line Items]
Actual (as a percent)	2.10%	2.00%
Target (as a percent)	2.00%	2.00%