XML 50 R97.htm IDEA: XBRL DOCUMENT v2.4.0.8
Benefit Plans Components of Benefit Plans (Details) (USD $)
 12 Months Ended
Sep. 30, 2014
Number_of_defined_benefit_plan_structures
Years
plans
Dec. 31, 2013
Number_of_defined_benefit_plan_investment_funds
Sep. 30, 2013
Dec. 31, 2012
Sep. 30, 2012
Dec. 31, 2011
Dec. 31, 2010
Sep. 30, 2014
Original benefit structure
Sep. 30, 2014
Cash Balance Benefit Structure
Sep. 30, 2014
Defined Contribution Only
Sep. 30, 2014
Maximum
Original benefit structure
Sep. 30, 2014
Maximum
Cash Balance Benefit Structure
Sep. 30, 2014
Maximum
Defined Contribution Only
Dec. 31, 2014
Scenario, Forecast [Member]
Defined Benefit Plan Disclosure                            
Number of defined benefit plans 1                          
Number of defined contribution plans 1                          
Number of unfunded post-retirement health care plans 2                          
Number of benefit plan structures 2                          
Number of consecutive highest base pay years 3                          
Percentage of straight-time earnings for cash balance benefit credit 6.00%                          
Percentage added to consumer price index for interest credit of cash balance benefit 3.00%                          
Minimum interest credit percentage for cash balance benefit 6.00%                          
Maximum interest credit percentage for cash balance benefit 10.00%                          
Rate of cash balance benefit credit for calendar year   6.00%                       6.00%
Number of defined benefit plan investment funds   2                        
Fixed and variable fund annual maximum contribution $ 10,000                          
Fixed fund balance interest credits after January 1, 2010 6.00%                          
Fixed fund balance credit percentage subtracted from the actuarial rate of return after January 1, 2010 0.50%                          
Fixed fund interest credit rate 6.00%   6.00%                      
Fixed fund interest credit amount 33,000,000   36,000,000                      
Defined contribution plan employer matching contribution rate               0.25 0.75 0.75        
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay                     1.50% 4.50% 4.50%  
Defined Contribution Plan, Automatic Employer Contribution                   4.50%        
Defined contribution plan contribution amount $ 35,000,000   $ 34,000,000   $ 34,000,000                  
Market-related value phase-in period number of years 3                          
Number of years during which cost of living adjustment changed             4 years              
Cost of Living Adjustment Cap   2.30%   0.00%   1.15% 0.00%             1.53%
Cost of living adjustment cap for calendar year 2014 and forward                           5.00%
Retirement age of eligibility for cost of living adjustment after January 1, 2010             60