Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2013
Comprehensive income:
Net change in unrealized losses on available-for-sale securities, tax benefit	$ 3.8
Net unrealized losses on cash flow hedges, tax benefit	10.9
Postretirement plans and workers' compensation obligations, tax provision	$ (8.3)

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Tax effect of the appreciation (loss) in the value of unsold available-for-sale securities. Excludes amounts related to other than temporary impairment (OTTI) losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 10A

-Subparagraph (e)

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Tax effect, net of reclassification adjustments, of the change in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges. Also includes an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

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-Section 45

-Paragraph 10A

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-URI http://asc.fasb.org/extlink&oid=20435746&loc=SL7669646-108580

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- Definition

Tax effect, net of reclassification adjustments, of pension and other postretirement benefit plans (gain) loss included in accumulated other comprehensive income (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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