Annual report pursuant to Section 13 and 15(d)

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

v3.10.0.1
Income Taxes - Net Operating Loss and Tax Credit Carryforwards (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Operating Loss Carryforwards [Line Items]    
Deferred Tax Asset $ 7,993 $ 8,506
Tax Credit Carryforward [Line Items]    
Deferred Tax Asset 623 $ 1,793
Net operating losses before benefit of federal deductions 1,900  
Valuation allowance before considering benefit of federal deductions 654  
General business credits    
Tax Credit Carryforward [Line Items]    
Deferred Tax Asset 612  
Valuation Allowance 0  
Net Deferred Tax Asset 612  
Foreign tax credits    
Tax Credit Carryforward [Line Items]    
Deferred Tax Asset 11  
Valuation Allowance (11)  
Net Deferred Tax Asset 0  
Net operating losses - U.S.    
Operating Loss Carryforwards [Line Items]    
Deferred Tax Asset 592  
Valuation Allowance 0  
Net Deferred Tax Asset 592  
Net operating losses – U.K. and Other non-U.S.    
Operating Loss Carryforwards [Line Items]    
Deferred Tax Asset 633  
Valuation Allowance (517)  
Net Deferred Tax Asset 116  
Net operating losses – U.K. and Other non-U.S. | United Kingdom    
Operating Loss Carryforwards [Line Items]    
Deferred Tax Asset 5,294  
Valuation Allowance 0  
Net Deferred Tax Asset 5,294  
Net operating losses – U.S. states    
Operating Loss Carryforwards [Line Items]    
Deferred Tax Asset 1,474  
Valuation Allowance (517)  
Net Deferred Tax Asset $ 957