Shareholders' Equity and Stock-Based Compensation Plans Equity (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Sep. 08, 2010 Series A Preferred Stock [Member] Repurchase Agreements [Member]	Jul. 14, 2010 Series A Preferred Stock [Member] Repurchase Agreements [Member]	Dec. 23, 2008 Series A Preferred Stock [Member] Repurchase Agreements [Member]	Jul. 14, 2010 Series A Preferred Stock [Member] Dividends [Member] Repurchase Agreements [Member]	Jul. 14, 2010 Series A Preferred Stock [Member] Principle [Member] Repurchase Agreements [Member]	May 05, 2010 Common Stock [Member]	Dec. 23, 2008 Common Stock [Member] Repurchase Agreements [Member]
Class of Stock [Line Items]
Proceeds from Issuance of Preferred Stock and Preference Stock						$ 376,500,000
Preferred Shares Issued In Connection With Repurchase Agreement						376,500
Preferred Stock, Par or Stated Value Per Share						$ 1,000
Common Stock Shares Issued In Connection With Warrent										5,500,000
Common stock, par value	$ 2.50	$ 2.50								$ 2.50
Preferred Stock, Dividend Rate, Percentage										5.00%
Common stock, shares issued	216,200,000	215,400,000							21,800,000
Proceeds from Issuance of Common Stock	6,835,000	231,510,000	7,419,000						226,300,000
Stock Redeemed or Called During Period, Shares					376,500
Payments for Repurchase of Preferred Stock and Preference Stock	0	387,300,000	0		379,600,000		3,100,000	376,500,000
Preferred Stock Carrying Value					371,000,000
Preferred Stock Redemption Discount					5,500,000
Repurchase Of Common Stock Shares				5,500,000
Payments for Repurchase of Common Stock				10,800,000
Common Stock Warrant Carrying Value				$ 7,600,000