Income Taxes - Operating Loss Carryforwards (Details) $ in Millions	Dec. 31, 2020 USD ($)
Operating Loss Carryforwards
Recognized valuation allowance relating to NOL carryforwards	$ 3,400.0
U.S. Federal
Operating Loss Carryforwards
Net operating loss carryforwards	670.3
U.S. Federal | Between 2021 and 2040
Operating Loss Carryforwards
Net operating loss carryforwards	6,400.0
State
Operating Loss Carryforwards
Net operating loss carryforwards	1,200.0
Foreign
Operating Loss Carryforwards
Net operating loss carryforwards	$ 13,800.0