v3.19.3.a.u2
New Accounting Standards (Details) - USD ($)
$ in Millions
3 Months Ended
Jan. 01, 2019
Dec. 31, 2018
Dec. 31, 2019
Jan. 01, 2018
Recently Adopted Accounting Standards        
Lease, Practical Expedients, Package [true false] true      
Operating Lease - ROU Asset     $ 934  
Lease liabilities     960  
Retained earnings   $ 24,560 $ 25,847  
ASU 2018-02        
Recently Adopted Accounting Standards        
Accumulated other comprehensive income (loss) to retained earnings stranded tax effects   $ 337    
ASU 2014-09 | Cumulative Effect        
Recently Adopted Accounting Standards        
Retained earnings       $ 23
ASU 2016-02 | Restatement Adjustment        
Recently Adopted Accounting Standards        
Operating Lease - ROU Asset $ 850      
Lease liabilities $ 850