QuickLinks -- Click here to rapidly navigate through this document

EXHIBIT 12

PSI ENERGY INC.

COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES AND
RATIO OF EARNINGS TO FIXED CHARGES AND PREFERRED STOCK DIVIDENDS

						Year Ended December 31
				Nine Months Ended September 30, 2003
						2002		2001		2000		1999		1998
				(Thousands, except ratios)
Earnings Available
	Net Income			$	94,892	$	214,249	$	162,333	$	135,398	$	117,199	$	52,038
	Plus:
		Income Taxes			64,107		114,709		106,086		88,547		69,215		23,147
		Interest on Long-Term Debt			72,813		98,903		95,364		93,640		80,536		80,259
		Other Interest			17,653		4,429		14,110		8,463		11,425		11,060
		Interest Component of Rents (a)			4,259		5,679		5,042		5,396		5,394		5,351
			Total Available	$	253,724	$	437,969	$	382,935	$	331,444	$	283,769	$	171,855
Fixed Charges
	Interest Charges			$	90,466	$	103,332	$	109,474	$	102,103	$	91,961	$	91,319
	Interest Component of Rents (a)				4,259		5,679		5,042		5,396		5,394		5,351
			Total Fixed Charges	$	94,725	$	109,011	$	114,516	$	107,499	$	97,355	$	96,670
Ratio of Earnings to Fixed Charges					2.68		4.02		3.34		3.08		2.91		1.78
Fixed Charges and Preferred Stock Dividends
	Interest Charges			$	90,466	$	103,332	$	109,474	$	102,103	$	91,961	$	91,319
	Interest Component of Rents (a)				4,259		5,679		5,042		5,396		5,394		5,351
	Preferred dividends (pre-income tax basis)				4,335		3,972		4,278		6,182		7,318		8,176
Total Fixed Charges and Preferred Stock Dividends				$	99,060	$	112,983	$	118,794	$	113,681	$	104,673	$	104,846
Ratio of Earnings to Fixed Charges and Preferred Stock Dividends					2.56		3.88		3.22		2.92		2.71		1.64

(a)

Estimated interest component of rentals (1/3 of rentals was used where no readily defined interest element could be determined).

(b)

Before cumulative effect of a change in accounting principle, net of tax.

QuickLinks

EXHIBIT 12