Annual report pursuant to Section 13 and 15(d)

Assets and Liabilities Measured at Fair Value (Details)

v3.20.4
Assets and Liabilities Measured at Fair Value (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Nov. 19, 2020
Aug. 27, 2020
1.75% Exchangeable Senior Debentures due 2046      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Interest rate (as a percent) 1.75%    
1.25% Exchangeable Senior Debentures due 2050      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Interest rate (as a percent) 1.25% 1.25%  
2.75% Exchangeable Senior Debentures due 2050      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Interest rate (as a percent) 2.75%   2.75%
Exchangeable senior debentures      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Change in fair value $ 7.3    
Cumulative change 7.3    
Exchangeable senior debentures | 1.75% Exchangeable Senior Debentures due 2046 | Indemnification obligation      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Indemnity obligation recorded $ 336.1    
Exchangeable senior debentures | 1.75% Exchangeable Senior Debentures due 2046 | Indemnification obligation | LI LLC      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Interest rate (as a percent) 1.75%