Income Taxes (Notes)	12 Months Ended
Income Taxes (Notes)	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	As of December 31, 2020, there were $1,188.8 of loss carryforwards. These loss carryforwards were all non-U.S. tax loss carryforwards, of which $1,035.3 have unlimited carryforward periods and $153.5 have expiration periods from 2021 to 2041. As of December 31, 2020, the Company also had $31.4 in deferred tax assets for state net operating loss carryforwards and tax credit carryforwards, which will expire between 2021 and 2041. As of December 31, 2020 and 2019, we had $1,080.2 and $1,199.7, respectively, of undistributed earnings attributable to foreign subsidiaries. The Company has historically asserted that its unremitted foreign earnings are permanently reinvested, and therefore has not recorded any deferred taxes on such amounts. It is not practicable to determine the deferred tax on these undistributed earnings because such liability, if any, is dependent on circumstances that exist if and when a remittance occurs, including the source location and amount of the distribution and foreign withholding taxes. In the second quarter of 2020, in response to changes in non-US tax law, a decision was made to change our indefinite reinvestment assertion on a $120.0 of undistributed foreign earnings of specific subsidiaries. We recorded $10.4 of income tax costs associated with this change to our assertion. In the third quarter of 2020, in response to restructuring actions taken within foreign subsidiaries, a decision was made to change our indefinite reinvestment assertion on a $46.0 of undistributed foreign earnings of specific subsidiaries. We recorded $3.2 of income tax costs associated with this change to our assertion. During the third quarter ended September 30, 2018, as a result of our increased debt and associated servicing commitments in connection with the Acxiom acquisition that was consummated on October 1, 2018, the Company re-evaluated its global cash needs and as a result determined that approximately $435.0 of undistributed foreign earnings from certain international entities were no longer subject to the permanent reinvestment assertion. We recorded a tax expense of $10.8 in 2018 representing our estimate of the tax costs associated with this change to our assertion. We have not changed our permanent reinvestment assertion with respect to any other international entities as we intend to use the related historical earnings and profits to fund international operations and investments.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.