Financing Activities and Stock Transactions (Details) (USD $)	3 Months Ended	6 Months Ended
Mar. 31, 2011	Jun. 30, 2011
Financing Activities and Stock Transactions [Line Items]
Number Of Common Shares Issued		5,500,000
Loss On Unamortized Issuance Costs	$ 4,400,000
Treasury Stock Shares Acquired		3,000,000
Treasury Stock Value Acquired Cost Method		61.14
Debt Instrument Issuance Date		May 27, 2011
Debt Instrument Interest Rate Stated Percentage		5.00%
Debt Instrument Maturity Date		Jun. 01, 2021
Debt Instrument Face Amount		400,000,000
Proceeds From Issuance Of Senior Long Term Debt		394,400,000
Debt Issuance Costs Incurred And Capitalized		3,400,000
Remarketed On March 4 2011 Member
Financing Activities and Stock Transactions [Line Items]
Number Of Trust Preferred Securites		4,500,000
Aggregate Value Of Trust Preferred Securites		158,200,000
Trust Preferred Security Value		35.44
Warrants Excercised		4,400,000
Price Per Warrant		35.44
Number Of Common Shares Issued		5,500,000
Trust Preferred Securities Fixed Annual Distribution Rate		2.375%
Warrant Conversion Value In Common Shares		1.2508
Unexercised Warrant Cash Redemption Value		14.56
Issued December 18 2001 Original Maturity Date March 18 2051 Member
Financing Activities and Stock Transactions [Line Items]
Trust Preferred Securities Fixed Annual Distribution Rate		5.75%
Warrant Conversion Value In Common Shares		1.2508
ASR March 7 2011 Member
Financing Activities and Stock Transactions [Line Items]
Treasury Stock Shares Acquired ASR		2,500,000
Accelerated Share Repurchases Initial Price Paid Per Share		$ 59.76
Accelerated Share Repurchases Settlement Payment Or Receipt		149,400,000
Accelerated Share Repurchases Adjustment To Recorded Amount		$ 4,300,000
Accelerated Share Repurchases Final Price Paid Per Share		$ 61.47

The adjustment needed to reconcile previously recorded amounts to the actual aggregate amount paid, whether in cash or other consideration, to acquire all of the shares purchased under an Accelerated Share Repurchase arrangement.

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Aggregate accreted value of remarketed trust preferred securities.

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The amount of issuance costs that were incurred and capitalized for a debt transaction.

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Represents unamortized debt issue costs related to the original issuance of Trust Preferred Income Equity Redeemable Preferred Securities which were expensed due to the remarketing of the securites.

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- Definition

Number of common shares issued upon exercise of warrants.

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Number of remarketed trust preferred securities.

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- Definition

Number of shares that have been repurchased during the period under an accererated stock repurchase agreement and are being held in treasury.

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Annual distribution rate on remarketed trust preferred securities.

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- Definition

Value of each remarketed trust preferred security.

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Amount paid by the company for each unexercised warrant.

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Number of common shares to be issued upon conversion of original Trust Preferred Income Equity Redeemable Preferred Securities.

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Represents the number of warrants exercised.

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Final price paid for the purchase of the targeted number of shares, determined by an average market price over a fixed period of time.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 99-7
-Paragraph 1

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The price paid to immediately purchase the targeted number of shares on the date of executing the accelerated share repurchase agreement.

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-Name Emerging Issues Task Force (EITF)
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- Definition

Dollar amount of the cash payment to (cash received from) the bank; or the stock issuance to (stock received from) the bank in the settlement of the accelerated share repurchase agreement.

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The stated principal amount of the debt instrument at time of issuance, which may vary from the carrying amount because of unamortized premium or discount.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 21
-Paragraph 16, 20

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- Definition

Interest rate stated in the contractual debt agreement.

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-Publisher SEC
-Name Regulation S-X (SX)
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-Section 02
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Date when the debt instrument was issued, which may be presented in a variety of ways (year, month and year, day, month and year, quarter, etc.).

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-Publisher SEC
-Name Regulation S-X (SX)
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Date when the debt instrument is scheduled to be fully repaid, which may be presented in a variety of ways (year, month and year, day, month and year, quarter, etc.).

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The cash inflow from a borrowing with the highest claim on the assets of the entity in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle, if longer).

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Number of shares that have been repurchased during the period and are being held in treasury.

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Cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

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-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
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-Paragraph 7
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