v3.10.0.1
Derivative Instruments (Narrative) (Details) - USD ($)
shares in Thousands, $ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
May 22, 2018
Dec. 31, 2017
Derivative [Line Items]            
Derivative assets $ 2,221.3   $ 2,221.3     $ 2,127.7
Cross-currency and interest rate derivative contracts            
Derivative [Line Items]            
Gain (loss) in changes in the credit risk valuation adjustments associated with our cross-currency and interest rate derivative contracts (65.6) $ 59.6 (27.9) $ 109.0    
Derivative assets 1,715.7   1,715.7     $ 1,548.9
Counterparty Credit Risk            
Derivative [Line Items]            
Derivative assets $ 456.1   $ 456.1      
Sumitomo Share Loan            
Derivative [Line Items]            
Aggregate market value of borrowed shares         $ 159.3  
Ordinary shares | Lionsgate Loan            
Derivative [Line Items]            
Number of common stock shares owned (in shares) 1,250   1,250      
Nonvoting Common Stock | Lionsgate Loan            
Derivative [Line Items]            
Number of common stock shares owned (in shares) 1,250   1,250