Annual report pursuant to Section 13 and 15(d)

SHAREHOLDERS' EQUITY - Preferred Stock Issued and Outstanding (Details)

v3.8.0.1
SHAREHOLDERS' EQUITY - Preferred Stock Issued and Outstanding (Details)
$ / shares in Units, $ in Millions
 3 Months Ended 12 Months Ended
Aug. 16, 2016
$ / shares
Mar. 14, 2016
$ / shares
Mar. 31, 2012
Dec. 31, 2017
USD ($)
$ / shares
shares
Dec. 31, 2016
USD ($)
shares
Dec. 31, 2008
$ / shares
shares
Jan. 16, 2012
$ / shares
Class of Stock [Line Items]              
Preferred Stock, Shares Outstanding | shares       1,098,006 1,098,006    
Preferred Stock, Value, Outstanding | $       $ 1,071      
Preferred Stock, Value, Issued | $       $ 1,071 $ 1,071    
Preferred Stock              
Class of Stock [Line Items]              
Preferred stock, liquidation preference per share (in dollars per share)       $ 1,000      
Series A Preferred Stock              
Class of Stock [Line Items]              
Preferred Stock, Shares Outstanding | shares       362,506      
Preferred Stock, Value, Outstanding | $       $ 363      
Preferred stock, dividend percentage       .0850      
Number of shares issued for each share of convertible preferred stock | shares           83.668  
Conversion price (in dollars per share)           $ 11.95  
Convertible preferred stock, threshold percentage of stock price trigger           130.00%  
Convertible preferred stock, threshold consecutive trading days           30 days  
Series B Preferred Stock              
Class of Stock [Line Items]              
Preferred Stock, Shares Outstanding | shares       35,500      
Preferred Stock, Value, Outstanding | $       $ 23      
Preferred stock, dividend percentage       three-month LIBOR plus a spread of 2.70%      
Preferred Stock, Redemption Date       Jan. 15, 2017      
Preferred stock, liquidation preference per share (in dollars per share)             $ 1,000
Depositary Shares, Liquidation Preference Per Share             $ 25
Depository share, percent interest in preferred stock     0.025        
Series D Preferred Stock              
Class of Stock [Line Items]              
Preferred Stock, Shares Outstanding | shares       400,000      
Preferred Stock, Value, Outstanding | $       $ 386      
Preferred stock, dividend percentage       .0625      
Preferred Stock, Redemption Date       Jul. 15, 2021      
Preferred stock, liquidation preference per share (in dollars per share)   $ 1,000          
Depositary Shares, Liquidation Preference Per Share   $ 25          
Preferred Stock, Redemption Period   90 days          
Preferred Stock, Dividend Rate, Percentage         6.25%    
Series D Preferred Stock2              
Class of Stock [Line Items]              
Preferred Stock, Shares Outstanding | shares       200,000      
Preferred Stock, Value, Outstanding | $       $ 199      
Series C Preferred Stock              
Class of Stock [Line Items]              
Preferred Stock, Shares Outstanding | shares       100,000      
Preferred Stock, Value, Outstanding | $       $ 100      
Preferred stock, dividend percentage       .05875      
Preferred Stock, Redemption Date       Jan. 15, 2022      
Preferred stock, liquidation preference per share (in dollars per share) $ 1,000            
Depositary Shares, Liquidation Preference Per Share $ 25            
Preferred Stock, Redemption Period 90 days            
Preferred Stock, Dividend Rate, Percentage         5.875%