Nuclear Plant (Tables)

12 Months Ended

Dec. 31, 2011

Nuclear Plant [Abstract]

Changes in nuclear decommissioning trust fund

December 31	2011			2010
Decommissioning Trust	(millions)
Beginning balance January 1	$	129.2		$	112.5
Contributions		3.4			3.7
Earned income, net of fees		4.8			2.0
Net realized gains		0.3			6.7
Net unrealized gains (losses)		(2.4	)		4.3
Ending balance	$	135.3		$	129.2

Detail of assets held in nuclear decommissioning trust fund

	December 31
	2011									2010
	Cost		Unrealized		Unrealized			Fair		Cost		Unrealized		Unrealized			Fair
	Basis		Gains		Losses			Value		Basis		Gains		Losses			Value
	(millions)
Equity securities	$	76.5	$	12.3	$	(4.5	)	$	84.3	$	73.4	$	13.1	$	(1.0	)	$	85.5
Debt securities		44.2		4.5		(0.1	)		48.6		38.1		2.6		(0.1	)		40.6
Other		2.4		-		-			2.4		3.1		-		-			3.1
Total	$	123.1	$	16.8	$	(4.6	)	$	135.3	$	114.6	$	15.7	$	(1.1	)	$	129.2

Gains and losses from the sale of securities by the nuclear decommissioning trust fund

	2011			2010			2009
	(millions)
Realized gains	$	1.0		$	7.3		$	2.8
Realized losses		(0.7	)		(0.6	)		(8.3	)

Nuclear Plant Decommissioning Costs

		Total		KCP&L's
		Station		47% Share
		(millions)
Current cost of decommissioning (in 2011 dollars)		$	630	$	296
Future cost of decommissioning (in 2045-2053 dollars) (a)			2,455		1,154
Annual escalation factor		3.73%
Annual return on trust assets (b)		6.89%
(a)	Total future cost over an eight year decommissioning period.
(b)	The 6.89% rate of return is through 2025. The rate then systematically decreases
	through 2053 to 1.81% based on the assumption that the fund's investment mix
	will become increasingly more conservative as the decommissioning period
	approaches.