Income Taxes (Tax Loss Carryforwards and Related Tax Assets) (Details)
$ in Millions |
Dec. 31, 2019
USD ($)
|
| Operating Loss Carryforwards [Line Items] |
|
| Tax loss carryforward |
$ 24,049.1
|
| Related tax asset |
4,367.5
|
| U.K. |
|
| Operating Loss Carryforwards [Line Items] |
|
| Tax loss carryforward |
1,222.4
|
| Related tax asset |
207.8
|
| U.K. | Amount attributable to capital losses |
|
| Operating Loss Carryforwards [Line Items] |
|
| Tax loss carryforward |
16,052.0
|
| Related tax asset |
2,728.8
|
| The Netherlands |
|
| Operating Loss Carryforwards [Line Items] |
|
| Tax loss carryforward |
3,204.0
|
| Related tax asset |
696.2
|
| Belgium |
|
| Operating Loss Carryforwards [Line Items] |
|
| Tax loss carryforward |
1,320.4
|
| Related tax asset |
330.1
|
| Ireland |
|
| Operating Loss Carryforwards [Line Items] |
|
| Tax loss carryforward |
713.8
|
| Related tax asset |
89.4
|
| Luxembourg |
|
| Operating Loss Carryforwards [Line Items] |
|
| Tax loss carryforward |
586.4
|
| Related tax asset |
159.4
|
| France |
|
| Operating Loss Carryforwards [Line Items] |
|
| Tax loss carryforward |
533.3
|
| Related tax asset |
137.8
|
| Other |
|
| Operating Loss Carryforwards [Line Items] |
|
| Tax loss carryforward |
416.8
|
| Related tax asset |
$ 18.0
|