Common and Preferred Stock, Preferred Stock (Details) (Cumulative Preferred Stock, $100 Par Value, Not Subject to Mandatory Redemption 4.5% [Member], USD $)	12 Months Ended
	Dec. 31, 2011	Jun. 24, 2011
Cumulative Preferred Stock, $100 Par Value, Not Subject to Mandatory Redemption 4.5% [Member]
Preferred Stock [Abstract]
Redemption date	Jun. 24, 2011
Preferred stock redeemed (in shares)	10,288
Preferred stock not subject to mandatory redemption, dividend rate (in hundredths)	4.50%
Redemption price (in dollars per share)		$ 101
Redemption price, plus accrued and unpaid dividends to the redemption date (in dollars per share)		$ 101.296