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Income Taxes (Net Operating and Capital Loss Carryforwards) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Net deferred tax assets
Total net deferred tax assets	$ 88.1	$ 40.4
Tax credit carryforwards, foreign	3.8
Alternative minimum tax credit carryforwards, not subject to expiration	0.4
Operating and Capital Loss Carryforward
Net deferred tax assets
Operating loss carryforwards	598.9
Gross deferred tax asset	129.7
Valuation allowance	(104.9)
Total net deferred tax assets	24.8
Operating and Capital Loss Carryforward | United States
Net deferred tax assets
Operating loss carryforwards	420.1
Gross deferred tax asset	88.0
Valuation allowance	(63.5)
Total net deferred tax assets	24.5
Operating and Capital Loss Carryforward | Luxembourg
Net deferred tax assets
Operating loss carryforwards	86.5
Gross deferred tax asset	21.6
Valuation allowance	(21.5)
Total net deferred tax assets	0.1
Operating and Capital Loss Carryforward | United Kingdom
Net deferred tax assets
Operating loss carryforwards	18.7
Gross deferred tax asset	3.2
Valuation allowance	(3.0)
Total net deferred tax assets	0.2
Operating and Capital Loss Carryforward | Israel
Net deferred tax assets
Operating loss carryforwards	73.6
Gross deferred tax asset	16.9
Valuation allowance	(16.9)
Total net deferred tax assets	0.0
2019-2023 | Operating and Capital Loss Carryforward
Net deferred tax assets
Operating loss carryforwards	0.1
2019-2023 | Operating and Capital Loss Carryforward | United States
Net deferred tax assets
Operating loss carryforwards	0.1
2019-2023 | Operating and Capital Loss Carryforward | Luxembourg
Net deferred tax assets
Operating loss carryforwards	0.0
2019-2023 | Operating and Capital Loss Carryforward | United Kingdom
Net deferred tax assets
Operating loss carryforwards	0.0
2019-2023 | Operating and Capital Loss Carryforward | Israel
Net deferred tax assets
Operating loss carryforwards	0.0
2024-2028 | Operating and Capital Loss Carryforward
Net deferred tax assets
Operating loss carryforwards	0.0
2024-2028 | Operating and Capital Loss Carryforward | United States
Net deferred tax assets
Operating loss carryforwards	0.0
2024-2028 | Operating and Capital Loss Carryforward | Luxembourg
Net deferred tax assets
Operating loss carryforwards	0.0
2024-2028 | Operating and Capital Loss Carryforward | United Kingdom
Net deferred tax assets
Operating loss carryforwards	0.0
2024-2028 | Operating and Capital Loss Carryforward | Israel
Net deferred tax assets
Operating loss carryforwards	0.0
2029-2038 | Operating and Capital Loss Carryforward
Net deferred tax assets
Operating loss carryforwards	360.6
2029-2038 | Operating and Capital Loss Carryforward | United States
Net deferred tax assets
Operating loss carryforwards	302.6
2029-2038 | Operating and Capital Loss Carryforward | Luxembourg
Net deferred tax assets
Operating loss carryforwards	58.0
2029-2038 | Operating and Capital Loss Carryforward | United Kingdom
Net deferred tax assets
Operating loss carryforwards	0.0
2029-2038 | Operating and Capital Loss Carryforward | Israel
Net deferred tax assets
Operating loss carryforwards	0.0
No expiration date | Operating and Capital Loss Carryforward
Net deferred tax assets
Operating loss carryforwards	238.2
No expiration date | Operating and Capital Loss Carryforward | United States
Net deferred tax assets
Operating loss carryforwards	117.4
No expiration date | Operating and Capital Loss Carryforward | Luxembourg
Net deferred tax assets
Operating loss carryforwards	28.5
No expiration date | Operating and Capital Loss Carryforward | United Kingdom
Net deferred tax assets
Operating loss carryforwards	18.7
No expiration date | Operating and Capital Loss Carryforward | Israel
Net deferred tax assets
Operating loss carryforwards	$ 73.6

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