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Fair Value Measurements (Details 3) (USD $) In Millions, unless otherwise specified | 3 Months Ended
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Mar. 31, 2013 | Mar. 31, 2012
Changes in level 3 assets and liabilities |  |
Transfers of financial assets | $ 0 |
Transfers of financial liabilities | 0 |
Transfers of financial assets from level 1 to level 2 |  | 2.0
Other investments |  |
Changes in level 3 assets and liabilities |  |
Balance at the beginning of the period | 118.9 | 103.4
Net realized gains/losses | (0.5) | (0.8)
Net unrealized gains/losses relating to instruments still held at the reporting date | 2.5 | 2.5
Purchases and issuances | 4.9 | 4.8
Settlements and reductions | (3.9) | (2.4)
Balance at the end of period | 121.9 | 107.5
Contingent payment arrangements |  |
Changes in level 3 assets and liabilities |  |
Balance at the beginning of the period | 31.0 | 87.1
Net unrealized gains/losses relating to instruments still held at the reporting date | 9.5 | (4.0)
Balance at the end of period | 40.5 | 83.1
Obligations to related parties |  |
Changes in level 3 assets and liabilities |  |
Balance at the beginning of the period | 77.8 | 92.0
Net realized gains/losses | 1.3 | (0.3)
Net unrealized gains/losses relating to instruments still held at the reporting date | (0.5) | 1.0
Purchases and issuances | 15.2 | 14.4
Settlements and reductions | (3.1) | (29.5)
Balance at the end of period | $ 90.7 | $ 77.6

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- Definition Represents assets and liabilities measured at fair value using significant unobservable inputs (Level 3) which are required for reconciliation purposes of beginning and ending balances. + References No definition available. + Details
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- Definition Represents purchases, sales, issuances, and settlements (net) which have taken place during the period in relation to assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3). + References No definition available. + Details
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- Definition Represents settlements and reductions which have taken place during the period in relation to assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3). + References No definition available. + Details
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- Definition Represents total unrealized gains or losses for the period, arising from assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in earnings or other comprehensive income. + References No definition available. + Details
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- Definition Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bb) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258 + Details
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