Annual report pursuant to Section 13 and 15(d)

OTHER COMPREHENSIVE INCOME - AOCI Roll Forward (Details)

v3.8.0.1
OTHER COMPREHENSIVE INCOME - AOCI Roll Forward (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance $ 10,308 $ 6,595 $ 6,328
Other comprehensive income before reclassifications (62) (131)  
Amounts reclassified from accumulated OCI to earnings 28 (44)  
Period change (34) (175)  
Ending balance 10,814 10,308 6,595
Tax Cuts and Job Acts of 2017, Reclassification from AOCI to Retained Earnings 0    
AOCI attributable to parent      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance (401) (226) (222)
Ending balance (528) (401) (226)
Tax Cuts and Job Acts of 2017, Reclassification from AOCI to Retained Earnings (93)    
Unrealized gains and (losses) on securities | Debt securities      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance (193) 8  
Other comprehensive income before reclassifications (54) (132)  
Amounts reclassified from accumulated OCI to earnings 17 (69)  
Period change (37) (201)  
Ending balance (278) (193) 8
Tax Cuts and Job Acts of 2017, Reclassification from AOCI to Retained Earnings (48)    
Unrealized gains and (losses) on securities | Equity Securities [Member]      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance 0 0  
Other comprehensive income before reclassifications 0 0  
Amounts reclassified from accumulated OCI to earnings 0 0  
Period change 0 0  
Ending balance 0 0 0
Unrealized gains (losses) on cash flow hedging derivatives      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance (3) (4)  
Other comprehensive income before reclassifications 2 1  
Amounts reclassified from accumulated OCI to earnings 1 0  
Period change 3 1  
Ending balance 0 (3) (4)
Unrealized gains (losses) for pension and other post-retirement obligations      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance (205) (230)  
Other comprehensive income before reclassifications (10) 0  
Amounts reclassified from accumulated OCI to earnings 10 25  
Period change 0 25  
Ending balance (250) (205) $ (230)
Tax Cuts and Job Acts of 2017, Reclassification from AOCI to Retained Earnings (45)    
Reclassification out of Accumulated Other Comprehensive Income      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Transferred from AFS to HTM (95)    
Reclassification out of Accumulated Other Comprehensive Income | Unrealized gains and (losses) on securities      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Amounts reclassified from accumulated OCI to earnings 17 (69)  
Reclassification out of Accumulated Other Comprehensive Income | Unrealized gains (losses) on cash flow hedging derivatives      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Amounts reclassified from accumulated OCI to earnings 1 0  
Reclassification out of Accumulated Other Comprehensive Income | Unrealized gains (losses) for pension and other post-retirement obligations      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Amounts reclassified from accumulated OCI to earnings $ 10 $ 25