Income Taxes (Tax Loss Carryforwards and Related Tax Assets) (Details) - Capital Loss Carryforward $ in Millions	Dec. 31, 2023 USD ($)
Operating Loss Carryforwards [Line Items]
Tax loss carryforward	$ 5,646.1
Related tax asset	1,372.1
The Netherlands
Operating Loss Carryforwards [Line Items]
Tax loss carryforward	2,599.3
Related tax asset	670.6
Belgium
Operating Loss Carryforwards [Line Items]
Tax loss carryforward	1,145.5
Related tax asset	286.4
U.K.
Operating Loss Carryforwards [Line Items]
Tax loss carryforward	767.7
Related tax asset	191.9
Luxembourg
Operating Loss Carryforwards [Line Items]
Tax loss carryforward	441.1
Related tax asset	119.9
Ireland
Operating Loss Carryforwards [Line Items]
Tax loss carryforward	387.1
Related tax asset	48.7
Switzerland
Operating Loss Carryforwards [Line Items]
Tax loss carryforward	295.5
Related tax asset	51.1
Other
Operating Loss Carryforwards [Line Items]
Tax loss carryforward	9.9
Related tax asset	$ 3.5