Income Taxes - Unrecognized tax benefits (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Beginning Balance	$ 49.9	$ 46.0
Increase based on tax positions taken in a prior year	25.8	8.5
Decrease based on tax positions taken in a prior year	(1.6)	(4.8)
Increase based on tax positions taken in the current year	9.3	6.0
Decrease resulting from the lapse of statutes of limitations	(8.9)	(5.8)
Ending Balance	$ 74.5	$ 49.9

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Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Unrecognized Tax Benefit

-URI http://asc.fasb.org/extlink&oid=6527854

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-Publisher FASB

-Name Accounting Standards Codification

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

+ References

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-Publisher FASB

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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