v3.19.3.a.u2
Income Taxes (Narrative) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Operating Loss Carryforwards [Line Items]      
Net operating and capital loss carryforwards (tax effected) for federal income tax purposes $ 693    
Net operating and capital loss carryforwards (tax effected) for state income tax purposes 970    
Net operating and capital loss carryforwards (tax effected) for foreign income tax purposes $ 2,948    
Expiration year of operating and capital loss carryforwards 2039    
Expiration year for credit carryforwards Dec. 31, 2039    
Income Tax Contingency [Line Items]      
IRS field examination of tax returns complete through year 2010    
All audit periods prior to this year are closed for federal examination purposes 2003    
Enactment of the Tax Cuts and Jobs Act, Total   $ (22,211)  
Enactment date and measurement period adjustments from the Act $ 0 (718) $ (20,271)
Net deposits to various taxing jurisdictions 2,584 2,115  
Accrued interest and penalties included in unrecognized tax benefits balance at year end 2,708 2,588  
Net interest and penalty expense (benefit) included in income tax expense 267 $ 1,290 $ 107
Federal [Member]      
Operating Loss Carryforwards [Line Items]      
Tax credit carryforwards 664    
State [Member]      
Operating Loss Carryforwards [Line Items]      
Tax credit carryforwards $ 2,025    
Period Start [Member]      
Income Tax Contingency [Line Items]      
Tax return year(s) subject to resolution with IRS Appeals Division 2003    
Period End [Member]      
Income Tax Contingency [Line Items]      
Tax return year(s) subject to resolution with IRS Appeals Division 2010