Available-For-Sale Securities (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Available-For-Sale Securities [Abstract]
Number of securities in an unrealized loss position, percentage of total	31.00%		31.00%		34.00%
Net unrealized gains on available-for-sale securities included in accumulated other comprehensive income	$ 24.8	$ 9.7	$ 24.1	$ 18.4
Amounts reclassified out of accumulated OCI into interest and other income, net	$ 2.6	$ 1.0	$ 7.2	$ 5.0

Reclassification adjustment for unrealized gains or losses realized upon the sale of securities, after tax.

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- Definition

Appreciation or loss in value (before reclassification adjustment) of the total of unsold securities during the period being reported on, net of tax. Reclassification adjustments include: (1) the unrealized holding gain (loss), net of tax, at the date of the transfer for a debt security from the held-to-maturity category transferred into the available-for-sale category. Also includes the unrealized gain (loss) at the date of transfer for a debt security from the available-for-sale category transferred into the held-to-maturity category; (2) the unrealized gains (losses) realized upon the sale of securities, after tax; and (3) the unrealized gains (losses) realized upon the write-down of securities, after tax.

+ References

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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