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Fair Value Measurements - Schedule of Quantitative Information used in Valuing Level 3 Liabilities (Details) (USD $) In Millions, unless otherwise specified |  |  |  |  | 9 Months Ended | 12 Months Ended | 9 Months Ended | 12 Months Ended |  |  | 9 Months Ended | 12 Months Ended | 9 Months Ended
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Sep. 30, 2014 | Sep. 30, 2013 | Sep. 30, 2014 Discounted Cash Flow Contingent Payment Arrangements | Dec. 31, 2013 Discounted Cash Flow Contingent Payment Arrangements | Sep. 30, 2014 Discounted Cash Flow Contingent Payment Arrangements Minimum | Dec. 31, 2013 Discounted Cash Flow Contingent Payment Arrangements Minimum | Sep. 30, 2014 Discounted Cash Flow Contingent Payment Arrangements Maximum | Dec. 31, 2013 Discounted Cash Flow Contingent Payment Arrangements Maximum | Sep. 30, 2014 Discounted Cash Flow Affiliate Equity Repurchase Obligations | Dec. 31, 2013 Discounted Cash Flow Affiliate Equity Repurchase Obligations | Sep. 30, 2014 Discounted Cash Flow Affiliate Equity Repurchase Obligations Minimum | Dec. 31, 2013 Discounted Cash Flow Affiliate Equity Repurchase Obligations Minimum | Sep. 30, 2014 Discounted Cash Flow Affiliate Equity Repurchase Obligations Maximum
Quantitative information for Level 3 Fair Value Measurements Liabilities |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value Liabilities |  |  | $ 57.0 | $ 50.2 |  |  |  |  | $ 20.5 | $ 4.0 |  |  |
Growth rate (as a percent) |  |  |  |  | 3.00% | 3.00% | 9.00% | 11.00% |  |  | 3.00% | 8.00% | 10.00%
Discount rate (as a percent) |  |  |  |  | 12.00% | 14.00% | 17.00% | 18.00% |  |  | 15.00% | 15.00% | 16.00%
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount | 0 | 0 |  |  |  |  |  |  |  |  |  |  |
Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount | $ 0 | $ 0 |  |  |  |  |  |  |  |  |  |  |

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- Definition Represents percentage of assumed growth rates, used as an input to measure fair value. + 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=25499696&loc=d3e19207-110258 + Details
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- Definition Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt. + 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 (bbb) -URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258 + Details
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- Details
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- Definition Amount of transfers of liabilities 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=25499696&loc=d3e19207-110258 + Details
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- Definition Fair value of financial and nonfinancial obligations. + 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 (a) -URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258 + Details
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