Derivative Instruments (Narrative) (Details)
$ in Millions |
3 Months Ended |
12 Months Ended |
|
|
Sep. 30, 2019
USD ($)
tranche
shares
|
Dec. 31, 2019
USD ($)
shares
|
Dec. 31, 2018
USD ($)
|
Dec. 31, 2017
USD ($)
|
May 22, 2018
USD ($)
|
| Derivative [Line Items] |
|
|
|
|
|
| Gain (loss) on change in credit risk valuation included in realized and unrealized gains (losses) on derivative instruments, net |
|
$ 16.6
|
$ (71.1)
|
$ 168.4
|
|
| Assets - derivative instruments |
|
1,827.5
|
2,496.7
|
|
|
| Principal borrowing outstanding |
|
1,582.7
|
$ 1,370.7
|
|
|
| Virgin Media |
|
|
|
|
|
| Derivative [Line Items] |
|
|
|
|
|
| Notional amount of derivative instruments without exchange of notional amounts at inception and maturity |
|
3,400.0
|
|
|
|
| Sumitomo Collar |
|
|
|
|
|
| Derivative [Line Items] |
|
|
|
|
|
| Aggregate market value of borrowed shares |
|
|
|
|
$ 159.3
|
| Counterparty Credit Risk |
|
|
|
|
|
| Derivative [Line Items] |
|
|
|
|
|
| Assets - derivative instruments |
|
$ 253.2
|
|
|
|
| ITV Collar |
|
|
|
|
|
| Derivative [Line Items] |
|
|
|
|
|
| Number of common stock shares owned (in shares) | shares |
|
398,515,510
|
|
|
|
| Shares needed to borrow from custody account to hedge exposure (in shares) | shares |
|
390,000,000
|
|
|
|
| Derivative asset fair value |
|
$ 619.6
|
|
|
|
| Principal borrowing outstanding |
|
1,435.5
|
|
|
|
| Lionsgate Loan |
|
|
|
|
|
| Derivative [Line Items] |
|
|
|
|
|
| Principal borrowing outstanding |
$ 27.6
|
$ 55.3
|
|
|
|
| Lionsgate Loan | Common Stock |
|
|
|
|
|
| Derivative [Line Items] |
|
|
|
|
|
| Number of common stock shares owned (in shares) | shares |
833,334
|
1,250,000
|
|
|
|
| Derivative asset fair value |
|
$ 37.2
|
|
|
|
| Lionsgate Loan | Nonvoting Common Stock |
|
|
|
|
|
| Derivative [Line Items] |
|
|
|
|
|
| Number of common stock shares owned (in shares) | shares |
833,333
|
1,250,000
|
|
|
|
| Lionsgate Forward |
|
|
|
|
|
| Derivative [Line Items] |
|
|
|
|
|
| Derivative asset fair value |
$ 18.1
|
|
|
|
|
| Number of tranches settled | tranche |
25
|
|
|
|
|