Annual report pursuant to Section 13 and 15(d)

Income Taxes - Net Operating Loss and Tax Credit Carryforwards (Details)

v3.20.4
Income Taxes - Net Operating Loss and Tax Credit Carryforwards (Details) - USD ($)
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Tax Credit Carryforward [Line Items]    
Deferred Tax Asset $ 7,717,000,000 $ 7,417,000,000
Deferred Tax Asset 484,000,000 $ 183,000,000
Net operating losses before benefit of federal deductions 1,600,000,000  
Valuation allowance before considering benefit of federal deductions 733,000,000  
Foreign tax credits    
Tax Credit Carryforward [Line Items]    
Deferred Tax Asset 484,000,000  
Valuation Allowance (484,000,000)  
Net Deferred Tax Asset 0  
Net operating losses - U.S.     
Tax Credit Carryforward [Line Items]    
Deferred Tax Asset 36,000,000  
Valuation Allowance 0  
Net Deferred Tax Asset 36,000,000  
Net operating losses – non-U.S.    
Tax Credit Carryforward [Line Items]    
Deferred Tax Asset 506,000,000  
Valuation Allowance (441,000,000)  
Net Deferred Tax Asset 65,000,000  
Net operating losses – non-U.S. | United Kingdom    
Tax Credit Carryforward [Line Items]    
Deferred Tax Asset 5,896,000,000  
Valuation Allowance 0  
Net Deferred Tax Asset 5,896,000,000  
Net operating losses – U.S. states    
Tax Credit Carryforward [Line Items]    
Deferred Tax Asset 1,279,000,000  
Valuation Allowance (579,000,000)  
Net Deferred Tax Asset $ 700,000,000