Cumulative Preferred Stock of Subsidiaries (Narrative) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Temporary Equity [Line Items]
Cumulative preferred stock of subsidiaries	$ 78	$ 78
IPL Subsidiary
Temporary Equity [Line Items]
Temporary equity carrying amount	60	60
Number of preferred stock series	5
Temporary equity annual dividend requirement	3	3
Number of consecutive quarters without paid dividends to invoke board of directors election rule	4
IPL Subsidiary | Minimum
Temporary Equity [Line Items]
Temporary equity, redemption price per share	$ 100
IPL Subsidiary | Maximum
Temporary Equity [Line Items]
Temporary equity, redemption price per share	$ 118
DPL Subsidiary
Temporary Equity [Line Items]
Temporary equity carrying amount	18	18
Number of preferred stock series	3
Temporary equity annual dividend requirement	$ 1
Number of quarters cumulative dividends in arrears to invoke board of directors election rule	4
DPL Subsidiary | Minimum
Temporary Equity [Line Items]
Temporary equity, redemption price per share	$ 101
DPL Subsidiary | Maximum
Temporary Equity [Line Items]
Temporary equity, redemption price per share	$ 103