Equity and Financing Arrangements (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Oct. 25, 2012
Common Stock Disclosures [Abstract]
Common stock issued during period	0	0
Preferred Stock, Shares Authorized	1,175,000
Preferred Stock, Par or Stated Value Per Share	$ 25
Preferred Stock, Shares Issued			0
Preferred Stock, Shares Outstanding			0
Dilutive Securities [Abstract]
Dilutive Securities	$ 0
Issuance of Debt [Member]
Debt Instruments [Line Items]
Unsecured debt	28.0
Interest rate	4.38%
Repayment of Debt [Member]
Debt Instruments [Line Items]
Interest rate	5.875%
Redeemed and retired debt	28.0
Extinguishment of debt at principal percent	100.00%
Remarketing of debt [Abstract]
Extinguishment of debt at principal percent	100.00%
Debt Conversion [Member]
Debt Instruments [Line Items]
Extinguishment of debt at principal percent	100.00%
Remarketing of debt [Abstract]
Tax exempt debt	$ 19.3
Interest rate before remarketing	4.875%
Interest rate after remarketing	3.45%
Extinguishment of debt at principal percent	100.00%