Derivative Instruments (Tables)

12 Months Ended

Dec. 31, 2013

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Values of open positions for derivative instruments [Table Text Block]

	December 31
	2013					2012
	Notional Contract Amount		Fair Value			Notional Contract Amount		Fair Value
Great Plains Energy	(millions)
Futures contracts
Cash flow hedges	$	—	$	—		$	1.0	$	(0.2	)
Non-hedging derivatives	19.3		(0.6		)	17.9		(2.8		)
Forward contracts
Non-hedging derivatives	47.7		5.2			65.5		6.5
Transmission congestion rights
Non-hedging derivatives	22.9		1.7			—		—
Option contracts
Non-hedging derivatives	4.8		1.2			—		—
KCP&L
Futures contracts
Cash flow hedges	$	—	$	—		$	1.0	$	(0.2	)
Non-hedging derivatives	7.7		(0.2		)	—		—
Transmission congestion rights
Non-hedging derivatives	18.0		1.1			—		—

Fair value of open derivative positions, gross values before netting agreements and netting of cash collatral [Table Text Block]

Great Plains Energy
	Balance Sheet	Asset Derivatives			Liability Derivatives
December 31, 2013	Classification	Fair Value			Fair Value
Derivatives Not Designated as Hedging Instruments			(millions)
Commodity contracts	Other		8.5			1.0
December 31, 2012
Derivatives Designated as Hedging Instruments
Commodity contracts	Other		$	—		$	0.2
Derivatives Not Designated as Hedging Instruments
Commodity contracts	Other		6.5			2.8
Total Derivatives			$	6.5		$	3.0

KCP&L
	Balance Sheet	Asset Derivatives			Liability Derivatives
December 31, 2013	Classification	Fair Value			Fair Value
Derivatives Not Designated as Hedging Instruments			(millions)
Commodity contracts	Other		$	1.2		$	0.3
December 31, 2012
Derivatives Designated as Hedging Instruments
Commodity contracts	Other		$	—		$	0.2

Offsetting Derivative Assets and Liabilities [Table Text Block]

Great Plains Energy
											Gross Amounts Not Offset in the Statement of Financial Position
Description	Gross Amounts Recognized			Gross Amounts Offset in the Statement of Financial Position				Net Amounts Presented in the Statement of Financial Position			Financial Instruments			Cash Collateral Received			Net Amount
December 31, 2013	(millions)
Derivative assets		$	8.5		$	(0.7	)		$	7.8		$	—		$	—		$	7.8
Derivative liabilities		1.0			(0.9		)		0.1			—			—			0.1
December 31, 2012
Derivative assets		$	6.5		$	—			$	6.5		$	—		$	—		$	6.5
Derivative liabilities		3.0			(3.0		)		—			—			—			—

KCP&L
											Gross Amounts Not Offset in the Statement of Financial Position
Description	Gross Amounts Recognized			Gross Amounts Offset in the Statement of Financial Position				Net Amounts Presented in the Statement of Financial Position			Financial Instruments			Cash Collateral Received			Net Amount
December 31, 2013	(millions)
Derivative assets		$	1.2		$	(0.1	)		$	1.1		$	—		$	—		$	1.1
Derivative liabilities		0.3			(0.3		)		—			—			—			—
December 31, 2012
Derivative liabilities		$	0.2		$	(0.2	)		$	—		$	—		$	—		$	—

Gain (loss) recognized in other comprehensive income or earnings for interest rate and commodity hedges [Table Text Block]

Great Plains Energy
Derivatives in Cash Flow Hedging Relationship
					Gain (Loss) Reclassified from
					Accumulated OCI into Income
					(Effective Portion)
	Amount of Gain  (Loss) Recognized in OCI on Derivatives  (Effective Portion)				Income Statement Classification	Amount
2013	(millions)					(millions)
Interest rate contracts		$	—		Interest charges	$	(18.6	)
Commodity contracts		—			Fuel	(0.3		)
Income tax benefit		—			Income tax benefit	7.3
Total		$	—		Total	$	(11.6	)
2012
Interest rate contracts		$	—		Interest charges	$	(20.2	)
Commodity contracts		(0.1		)	Fuel	(0.5		)
Income tax benefit		—			Income tax benefit	8.1
Total		$	(0.1	)	Total	$	(12.6	)

KCP&L
Derivatives in Cash Flow Hedging Relationship
					Gain (Loss) Reclassified from
					Accumulated OCI into Income
					(Effective Portion)
	Amount of Gain (Loss) Recognized in OCI on Derivatives (Effective Portion)				Income Statement Classification	Amount
2013	(millions)					(millions)
Interest rate contracts		$	—		Interest charges	$	(8.8	)
Commodity contracts		—			Fuel	(0.3		)
Income tax benefit		—			Income tax benefit	3.5
Total		$	—		Total	$	(5.6	)
2012
Interest rate contracts		$	—		Interest charges	$	(8.7	)
Commodity contracts		(0.1		)	Fuel	(0.5		)
Income tax benefit		—			Income tax benefit	3.5
Total		$	(0.1	)	Total	$	(5.7	)

Gain (loss) recognized in a regulatory balance sheet account or earnings for utility commodity hedges [Table Text Block]

Great Plains Energy
Derivatives in Regulatory Account Relationship
					Gain (Loss) Reclassified from
					Regulatory Account
	Amount of Gain (Loss) Recognized in Regulatory Asset on Derivatives				Income Statement  Classification	Amount
2013	(millions)					(millions)
Commodity contracts		$	2.0		Fuel	$	(1.9	)
Total		$	2.0		Total	$	(1.9	)
2012
Commodity contracts		$	(2.7	)	Fuel	$	(6.6	)
Total		$	(2.7	)	Total	$	(6.6	)

Accumulated other comprehensive income related to cash flow hedges [Table Text Block]

	Great Plains Energy								KCP&L
	December 31								December 31
	2013				2012				2013				2012
		(millions)
Current assets		$	9.9			$	10.6			$	9.9			$	10.6
Current liabilities		(48.9		)		(68.4		)		(43.1		)		(52.8		)
Noncurrent liabilities		—				(0.1		)		—				(0.1		)
Deferred income taxes		15.2				22.5				13.0				16.5
Total		$	(23.8	)		$	(35.4	)		$	(20.2	)		$	(25.8	)