Employee Benefit Plans (Assumptions Related to Calculation of Domestic Benefit Obligation (End of Period) and Determination of Net Periodic (Benefit) Cost (Beginning of Period)) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	10.00%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	90.00%
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.65%	4.15%	4.50%	4.10%
Rate of increase in compensation levels	4.50%	4.50%	4.50%	4.50%
Expected return on plan assets	6.25%	6.25%	6.25%	6.25%
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.60%	4.05%	4.35%	3.95%
Expected return on plan assets	7.00%	7.00%	7.00%	7.00%
Health care cost trend rates	6.20%	6.60%	7.00%	6.66%
Ultimate health care cost trend rate	5.00%	5.00%	5.00%	5.00%