Redeemable Stock of Subsidiaries (Narrative) (Details)			1 Months Ended			9 Months Ended	12 Months Ended
		Feb. 11, 2015 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Feb. 28, 2015 USD ($)	Sep. 30, 2016 USD ($) quarter	Dec. 31, 2016 USD ($) quarter series $ / shares	Dec. 31, 2015 USD ($) quarter series $ / shares		Dec. 31, 2014 USD ($)		Apr. 01, 2015 USD ($)
Temporary Equity [Line Items]
Gain (Loss) on Disposition of Stock in Subsidiary								$ 0
Redeemable Noncontrolling Interest, Equity, Carrying Amount							$ 782,000,000	538,000,000
Temporary equity carrying amount							782,000,000	538,000,000		$ 78,000,000
Temporary Equity, Stock Issued During Period, Value, New Issues							134,000,000	460,000,000
Temporary Equity, Other Changes							130,000,000	0
Temporary Equity, Net Income							(11,000,000)	0		0
Temporary Equity, Accretion to Redemption Value							$ 4,000,000	0
Colon [Domain]
Temporary Equity [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners						49.90%	25.00%
Temporary equity carrying amount	[1]						$ 100,000,000	0
Temporary Equity, Other Changes						$ 106,000,000
Temporary Equity, Accretion to Redemption Value							1,000,000
IPALCO Enterprises, Inc. [Member]
Temporary Equity [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners						30.00%
Temporary equity carrying amount							618,000,000	460,000,000
Temporary Equity, Stock Issued During Period, Value, New Issues				$ 134,000,000
Temporary Equity, Other Changes			$ 24,000,000
IPL Subsidiary
Temporary Equity [Line Items]
Temporary equity carrying amount							$ 60,000,000	60,000,000
Number of preferred stock series | series							5
Temporary equity annual dividend requirement							$ 3,000,000	$ 3,000,000
Number of consecutive quarters without paid dividends to invoke board of directors election rule | quarter							4	4
IPL Subsidiary | Minimum
Temporary Equity [Line Items]
Temporary equity, redemption price per share | $ / shares							$ 100	$ 100
IPL Subsidiary | Maximum
Temporary Equity [Line Items]
Temporary equity, redemption price per share | $ / shares							$ 118	$ 118
DPL Subsidiary
Temporary Equity [Line Items]
Temporary equity carrying amount							$ 0	$ 18,000,000
Number of preferred stock series | series								3
Temporary equity annual dividend requirement
Number of quarters cumulative dividends in arrears to invoke board of directors election rule | quarter						4		4
Temporary Equity, Accretion to Redemption Value							$ 5,000,000
DPL Subsidiary | Minimum
Temporary Equity [Line Items]
Temporary equity, redemption price per share | $ / shares							$ 101	$ 101
DPL Subsidiary | Maximum
Temporary Equity [Line Items]
Temporary equity, redemption price per share | $ / shares							$ 103	$ 103
AES US Investment, Inc. [Member]
Temporary Equity [Line Items]
Sale of Stock, Consideration Received Per Transaction		$ 247,000,000
Investment In Affiliate Ownership Percentage Sold		15.00%
IPALCO Enterprises, Inc. [Member]
Temporary Equity [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners												24.90%
Noncontrolling Interest, Ownership Percentage by Parent		100.00%
sales agreement, Buyer option to purchase ownership interest, exercised												$ 214,000,000
Other Comprehensive Income (Loss) [Member]
Temporary Equity [Line Items]
Temporary Equity, Other Changes							$ 6,000,000	$ 0
Additional Paid-in Capital [Member]
Temporary Equity [Line Items]
Sale of subsidiary shares to noncontrolling interests							84,000,000	323,000,000		29,000,000
Additional Paid-in Capital [Member] | IPALCO Enterprises, Inc. [Member]
Temporary Equity [Line Items]
Business Combination, Separately Recognized Transactions, Additional Disclosures, Issuance Costs Not Expensed								84,000,000
Retained Earnings [Member]
Temporary Equity [Line Items]
Sale of subsidiary shares to noncontrolling interests							(84,000,000)	(377,000,000)		0
Retained Earnings [Member] | IPALCO Enterprises, Inc. [Member]
Temporary Equity [Line Items]
Sale of subsidiary shares to noncontrolling interests							(84,000,000)	$ (377,000,000)	[2]	$ 0	[2]
Redeemable Preferred Stock [Member]
Temporary Equity [Line Items]
Temporary Equity Reclassification						$ 0	$ (19,000,000)
Redeemable Preferred Stock [Member] | DPL Subsidiary
Temporary Equity [Line Items]
Redeemable Noncontrolling Interest, Equity, Preferred, Redemption Value						$ 23,000,000
Acquire additional shares through 2016 [Member]
Temporary Equity [Line Items]
Investment Options, acquisition percentage					17.65%
Acquire additional shares through 2016 [Member] | IPALCO Enterprises, Inc. [Member]
Temporary Equity [Line Items]
Sale Agreement, Buyer Option To Purchase Ownership Interest, Sales Price					$ 349,000,000

[1] Characteristics of quotas are similar to common stock.

[2] See Note 18—Redeemable stock of subsidiaries for further information on increase in paid-in capital transferred to redeemable stock of subsidiaries.