Employee and Retiree Benefit Plans (Weighted-Average Assumptions used in Measurement of Benefit Obligations and Net Periodic Benefit Expense) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Benefit Obligations, Expected return on plan assets	5.62%
Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets	5.62%
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit Obligations, Discount rate	3.94%	4.37%
Benefit Obligations, Expected return on plan assets	5.62%	6.00%
Benefit Obligation, Rate of compensation increase	3.52%	3.74%
Net Periodic Benefit Expense, Discount rate	3.84%	4.04%
Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets	5.62%	6.00%
Net Periodic Benefit Expense, Rate of compensation increase	3.52%	3.74%
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit Obligations, Discount rate	4.41%	4.61%
Net Periodic Benefit Expense, Discount rate	4.24%	4.12%