Income Taxes (Earnings (Loss) Before Income Tax) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Examination [Line Items]
Earnings (loss) from continuing operations before income taxes	$ (3,724.2)	$ 1,424.2	$ 14,000.8
Continuing Operations | Domestic tax authority | U.K.
Income Tax Examination [Line Items]
Earnings (loss) from continuing operations before income taxes	(2,899.5)	(516.2)	12,922.0
Continuing Operations | Foreign tax authority | The Netherlands
Income Tax Examination [Line Items]
Earnings (loss) from continuing operations before income taxes	(805.4)	742.3	644.5
Continuing Operations | Foreign tax authority | Belgium
Income Tax Examination [Line Items]
Earnings (loss) from continuing operations before income taxes	653.9	1,000.4	404.7
Continuing Operations | Foreign tax authority | Switzerland
Income Tax Examination [Line Items]
Earnings (loss) from continuing operations before income taxes	(446.7)	(470.5)	(308.3)
Continuing Operations | Foreign tax authority | Luxembourg
Income Tax Examination [Line Items]
Earnings (loss) from continuing operations before income taxes	(195.6)	505.4	373.2
Continuing Operations | Foreign tax authority | Ireland
Income Tax Examination [Line Items]
Earnings (loss) from continuing operations before income taxes	(16.6)	178.3	39.5
Continuing Operations | Foreign tax authority | U.S.
Income Tax Examination [Line Items]
Earnings (loss) from continuing operations before income taxes	(4.7)	5.9	(3.7)
Continuing Operations | Foreign tax authority | Other
Income Tax Examination [Line Items]
Earnings (loss) from continuing operations before income taxes	(9.6)	(5.8)	(16.9)
Discontinued Operations
Income Tax Examination [Line Items]
Earnings (loss) from continuing operations before income taxes	$ 0.0	$ (15.6)	$ (54.2)