Earnings Per Share Basic to Diluted EPS Reconciliation (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income (loss) from continuing operations, after Adjustment to Retained Earnings, Diluted Earnings		$ 171		$ 203
Income (loss) from continuing operations, after Adjustment to Retained Earnings, Basic Earnings		171		203
Income from continuing operations, net of tax		176	$ 175	208	$ 403
Temporary Equity, Accretion to Redemption Value	[1]			4	$ 0
DPL Subsidiary [Member]
Temporary Equity, Accretion to Redemption Value		$ 5		$ 5

[1] (1) $5 million increase in fair value of DP&L preferred shares offset by $1 million decrease in fair value of Colon common stock.