Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2012

Fair Value Disclosures [Abstract]

Fair value of assets and liabilities

The following tables include Great Plains Energy's and KCP&L's balances of financial assets and liabilities measured at fair value on a recurring basis at September 30, 2012, and December 31, 2011.

								Fair Value Measurements Using
Description	September 30 2012			Netting(d)				Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
KCP&L		(millions)
Assets
Nuclear decommissioning trust (b)
Equity securities		$	97.9		$	—			$	97.9		$	—		$	—
Debt securities
U.S. Treasury		18.6			—				18.6			—			—
U.S. Agency		2.8			—				—			2.8			—
State and local obligations		2.7			—				—			2.7			—
Corporate bonds		26.4			—				—			26.4			—
Foreign governments		0.6			—				—			0.6			—
Other		0.2			—				—			0.2			—
Total nuclear decommissioning trust		149.2			—				116.5			32.7			—
Total		149.2			—				116.5			32.7			—
Liabilities
Derivative instruments (a)		—			(0.2		)		0.2			—			—
Total		$	—		$	(0.2	)		$	0.2		$	—		$	—
Other Great Plains Energy
Assets
Derivative instruments (a)		$	6.8		$	(0.4	)		$	0.4		$	4.4		$	2.4
SERP rabbi trust (c)
Equity securities		0.1			—				0.1			—			—
Debt securities		0.1			—				—			0.1			—
Total SERP rabbi trust		0.2			—				0.1			0.1			—
Total		7.0			(0.4		)		0.5			4.5			2.4
Liabilities
Derivative instruments (a)		—			(2.3		)		2.3			—			—
Total		$	—		$	(2.3	)		$	2.3		$	—		$	—
Great Plains Energy
Assets
Derivative instruments (a)		$	6.8		$	(0.4	)		$	0.4		$	4.4		$	2.4
Nuclear decommissioning trust (b)		149.2			—				116.5			32.7			—
SERP rabbi trust (c)		0.2			—				0.1			0.1			—
Total		156.2			(0.4		)		117.0			37.2			2.4
Liabilities
Derivative instruments (a)		—			(2.5		)		2.5			—			—
Total		$	—		$	(2.5	)		$	2.5		$	—		$	—

									Fair Value Measurements Using
Description	December 31 2011				Netting(d)				Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Other Observable Inputs (Level 2)				Significant Unobservable Inputs (Level 3)
KCP&L		(millions)
Assets
Nuclear decommissioning trust (b)
Equity securities		$	84.3			$	—			$	84.3		$	—			$	—
Debt securities
U.S. Treasury		15.3				—				15.3			—				—
U.S. Agency		3.6				—				—			3.6				—
State and local obligations		2.6				—				—			2.6				—
Corporate bonds		26.4				—				—			26.4				—
Foreign governments		0.7				—				—			0.7				—
Other		(0.6		)		—				—			(0.6		)		—
Total nuclear decommissioning trust		132.3				—				99.6			32.7				—
Total		132.3				—				99.6			32.7				—
Liabilities
Derivative instruments (a)		—				(0.5		)		0.5			—				—
Total		$	—			$	(0.5	)		$	0.5		$	—			$	—
Other Great Plains Energy
Assets
Derivative instruments (a)		$	7.8			$	—			$	—		$	4.7			$	3.1
SERP rabbi trust (c)
Equity securities		0.2				—				0.2			—				—
Debt securities		0.1				—				—			0.1				—
Total SERP rabbi trust		0.3				—				0.2			0.1				—
Total		8.1				—				0.2			4.8				3.1
Liabilities
Derivative instruments (a)		—				(5.0		)		5.0			—				—
Total		$	—			$	(5.0	)		$	5.0		$	—			$	—
Great Plains Energy
Assets
Derivative instruments (a)		$	7.8			$	—			$	—		$	4.7			$	3.1
Nuclear decommissioning trust (b)		132.3				—				99.6			32.7				—
SERP rabbi trust (c)		0.3				—				0.2			0.1				—
Total		140.4				—				99.8			37.5				3.1
Liabilities
Derivative instruments (a)		—				(5.5		)		5.5			—				—
Total		$	—			$	(5.5	)		$	5.5		$	—			$	—

(a) The fair value of derivative instruments is estimated using market quotes, over-the-counter forward price and volatility curves and correlations among fuel prices, net of estimated credit risk.

(b) Fair value is based on quoted market prices of the investments held by the fund and/or valuation models.  The total does not include $2.9 million and $3.0 million at September 30, 2012, and December 31, 2011, respectively, of cash and cash equivalents, which are not subject to the fair value requirements.

(c) Fair value is based on quoted market prices of the investments held by the fund and/or valuation models. The total does not include $20.3 million at September 30, 2012, and December 31, 2011, of cash and cash equivalents, which are not subject to the fair value requirements.

(d) Represents the difference between derivative contracts in an asset or liability position presented on a net basis by counterparty on the consolidated balance sheet where a master netting agreement exists between the Company and the counterparty. At September 30, 2012, and December 31, 2011, Great Plains Energy netted $2.1 million and $5.5 million, respectively, of cash collateral posted with counterparties.

Unobservable inputs reconciliation

The following tables reconcile the beginning and ending balances for all Level 3 assets and liabilities, net, measured at fair value on a recurring basis for the three months ended and year to date September 30, 2012 and 2011.

Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
	2012			2011
	Derivative Instruments
	(millions)
Balance at July 1	$	2.2		$	4.9
Total realized/unrealized gains included in non-operating income	3.7			4.0
Settlements	(3.5		)	(4.4		)
Balance at September 30	$	2.4		$	4.5
Total unrealized gains and (losses) included in non-operating income relating to assets
and liabilities still on the consolidated balance sheet at September 30	$	0.3		$	(0.3	)

Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
	2012			2011
	Derivative Instruments
	(millions)
Balance at January 1	$	3.1		$	3.7
Total realized/unrealized gains included in non-operating income	4.8			11.1
Settlements	(5.5		)	(10.3		)
Balance at September 30	$	2.4		$	4.5
Total unrealized gains and (losses) included in non-operating income relating to assets
and liabilities still on the consolidated balance sheet at September 30	$	(0.4	)	$	1.2