Pension and Other Benefit Programs - Weighted Average Assumptions (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Weighted-average discount rate for determining interest costs (pension/SERP plans)	3.00%	3.20%
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets (pension/SERP plans)	3.50%	6.50%	6.50%
Maximum | Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate (pension/SERP plans)	4.00%	3.40%	3.90%
Weighted-average discount rate for determining interest costs (pension/SERP plans)	3.00%	3.20%	3.30%
Minimum | Supplemental Employee Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate (pension/SERP plans)	3.80%	3.10%	3.40%
Weighted-average discount rate for determining interest costs (pension/SERP plans)	2.70%	2.60%	2.50%