v3.7.0.1
Recent Accounting Pronouncements (Narrative) (Details) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Net cash provided by operating activities $ 5,656 $ 5,399
Net cash provided by (used in) financing activities (1,141) 643
Financial Assets and Financial Liabilities New Accounting Pronouncement [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
New Accounting Pronouncement impact on net income if adopted 104  
Share Based Compensation New Accounting Pronouncement [Member] | Effect of Adoption [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Decrease in income tax expense $ 139  
Increase in diluted earnings per share (in dollars per share) $ 0.03  
Net cash provided by operating activities $ 385 289
Net cash provided by (used in) financing activities $ (385) $ (289)