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Affiliate Equity - Effect of Changes in the Company's Ownership Interest in its Affiliates on the Controlling Interest's Equity (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended
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Dec. 31, 2019 | [1] | Sep. 30, 2019 | [1] | Jun. 30, 2019 | Mar. 31, 2019 | [1] | Dec. 31, 2018 | [2] | Sep. 30, 2018 | Jun. 30, 2018 | [2] | Mar. 31, 2018 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Affiliate Equity [Abstract] |  |  |  |  |  |  |  |  |  |  |
Net income (controlling interest) | $ 22.5 | $ 86.3 | $ 107.7 | $ (200.8) | $ (151.3) | $ 124.9 | $ 117.0 | $ 153.0 | $ 15.7 | $ 243.6 | $ 689.5
Decrease in controlling interest paid-in capital from Affiliate equity issuances |  |  |  |  |  |  |  |  | (3.1) | (5.0) | (1.0)
Decrease in controlling interest paid-in capital from Affiliate equity repurchases |  |  |  |  |  |  |  |  | (50.8) | (67.9) | (116.2)
Net income (loss) (controlling interest) including the net impact of Affiliate equity transactions |  |  |  |  |  |  |  |  | $ (38.2) | $ 170.7 | $ 572.3
[1] | In the first, third and fourth quarters of 2019, the Company recorded $415.0 million, $10.0 million and $60.0 million of expenses, respectively, to reduce the carrying value to fair value of certain of its Affiliates. In the fourth quarter of 2019, the Company recorded $35.0 million of expenses to reduce the carrying value to fair value of certain of its indefinite-lived
[2] | In the second and fourth quarter of 2018, the Company recorded $33.3 million and $240.0 million of expenses, respectively, to reduce the carrying value to fair value of certain of its Affiliates.

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- Definition The increase (decrease) in additional paid-in capital of the reporting entity from purchases and sales of Affiliate equity. + References No definition available. + Details
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- Definition Adjustments to Additional Paid in Capital Decrease in Carrying Amount of Redeemable Noncontrolling Interests + References No definition available. + Details
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- Definition Affiliate Equity [Abstract] + References No definition available. + Details
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- Definition Increase (decrease) in equity during the period due to net income attributable to the parent company and net transfers with non-controlling interests. + References No definition available. + Details
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- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 1A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669619-108580 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04(22)) -URI http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 1B -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669625-108580 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(18)) -URI http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(20)) -URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227 Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585 Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 + Details
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