Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Net operating losses, credits and other carryforwards	$ 1,520.2	$ 1,414.9
Unrealized gains and losses	64.9	68.8
Accrued expenses	23.7	41.9
Other future deductible amounts	2.3	5.7
Deferred tax assets	1,611.1	1,531.3
Valuation allowance	(1,402.8)	(1,308.9)	$ (1,282.2)	$ (1,328.4)
Deferred tax assets, net of valuation allowance	208.3	222.4
Deferred tax liabilities:
Investments	(224.1)	(231.6)
Intangible assets	(168.6)	(197.5)
Property and equipment, net	(158.1)	(173.5)
Un-remitted foreign earnings	(3.1)	(18.1)
Other future taxable amounts	(0.5)	0.0
Deferred tax liabilities	(554.4)	(620.7)
Net deferred tax liability	$ (346.1)	$ (398.3)