XML 175 R127.htm IDEA: XBRL DOCUMENT v3.3.1.900
Benefit Plans (Narrative) (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2015
USD ($)
plan
Dec. 31, 2014
USD ($)
Dec. 31, 2013
USD ($)
Defined Benefit Plan Disclosure [Line Items]      
Defined contribution plan, number of plans 4    
Defined contribution plan, award vesting period 5 years    
Defined contribution plan contributions | $ $ 18 $ 22 $ 23
Defined benefit plan, number of plans disclosure 33    
U.S. Non-Union Number of Defined Contribution Plans 2    
Parent Company Number of Defined Contribution Plans 1    
IPL Number of Non-Union and Union Defined Contribution Plans 1    
DPL Number of Non-Union Defined Contribution Plans 1    
DPL Number of Union Defined Contribution Plans 1    
U.S. Defined Benefit Plans      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan, number of plans disclosure 5