Redeemable Preferred Stock (Narrative) (Details) - IPL [Member]	12 Months Ended
	Dec. 31, 2016 Q board_member $ / shares shares
Temporary Equity [Line Items]
Number of board members to be elected (in members) | board_member	2
Number of quarterly dividend requirements (in quarters) | Q	6
Redeemable Preferred Stock [Member]
Temporary Equity [Line Items]
Shares Authorized (in shares)	16,000,000
Redeemable Preferred Stock [Member] | 5.1% [Member]
Temporary Equity [Line Items]
Shares Authorized (in shares)	8,000,000
Cumulative preferred stock rate	5.10%
Preferred stock redemption price per share (in dollars per share) | $ / shares	$ 25