v3.7.0.1
Stockholders' Equity Preferred and Common Stock (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Dec. 31, 2016
Stockholders' Equity Note [Abstract]      
Preferred stock shares authorized (in shares) 2,000,000,000.0   2,000,000,000.0
Common stock shares authorized (in shares) 5,000,000,000.0   5,000,000,000.0
Common stock shares issued (in shares) 1,500,000,000   1,500,000,000
Common stock shares outstanding (in shares) 1,500,000,000   1,500,000,000
Common stock shares purchased (in shares) 0 10,000,000  
Common stock shares purchased amount   $ 300  
Total dividends paid on common stock $ 573 $ 587