Fair Value Disclosure (Tables)

12 Months Ended

Dec. 31, 2011

Fair Value Disclosures [Abstract]

Financial Assets And Liabilities Measured At Fair Value On A Recurring Basis

Financial assets and liabilities measured at fair value on a recurring basis are summarized below:

	Fair Value Measurement
	December 31, 2011									December 31, 2010
(in millions)	Level 1			Level 2		Level 3		Fair Value		Level 1		Level 2		Level 3		Fair Value
Assets:
Derivative assets	$	—	—	$	10.7	$	—	$	10.7	$	—	$	36.5	$	—	$	36.5
Equity securities	15.2		—	—		—		15.2		16.0		—		—		16.0
Total Assets	$	15.2		$	10.7	$	—	$	25.9	$	16.0	$	36.5	$	—	$	52.5
Liabilities:
Derivative liabilities	$	—		$	36.2	$	—	$	36.2	$	—	$	16.2	$	—	$	16.2
Total liabilities	$	—		$	36.2	$	—	$	36.2	$	—	$	16.2	$	—	$	16.2