Employer Sponsored Benefit Plans - Assumptions Used in Determining the Year-End Benefit Obligation and Annual Net Cost (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Benefit Obligation
Discount rate (as a percent)	3.99%	3.71%
Expected return on plan assets (as a percent)	4.08%	5.80%
Net Cost
Discount rate (as a percent)	3.75%	4.21%	4.56%
Expected return on plan assets (as a percent)	5.79%	6.30%	7.00%