Special Cash Dividend (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended	0 Months Ended	24 Months Ended
Mar. 31, 2014	Mar. 31, 2013	Apr. 03, 2012 2012 Special Cash Dividend [Member]	Mar. 23, 2012 2012 Special Cash Dividend [Member]	Mar. 31, 2014 2012 Special Cash Dividend [Member]
Special Cash Dividend And Stock Option Adjustments [Line Items]
Dividend declared, per share				$ 8.55
Dividend declared				$ 508.0
Dividends paid	$ 1.2	$ 0.7	$ 502.9		$ 3.7

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Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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- Definition

Amount of paid and unpaid common stock dividends declared with the form of settlement in cash.

+ References

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- Definition

Cash outflow in the form of capital distributions and dividends to common shareholders, preferred shareholders and noncontrolling interests.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 15

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585

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