Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Nonrecurring Fair Value Inputs (Details)

v3.8.0.1
Fair Value Measurements - Nonrecurring Fair Value Inputs (Details) - Nonrecurring - Level 3 - USD ($)
$ in Millions
9 Months Ended 12 Months Ended
Sep. 30, 2017
Dec. 31, 2016
Market Comparables | Minimum    
Fair Value Inputs [Abstract]    
OREO discount 8.00% 8.00%
Costs to sell 7.00% 7.00%
Market Comparables | Maximum    
Fair Value Inputs [Abstract]    
OREO discount 54.00% 56.00%
Costs to sell 45.00% 45.00%
Instruments backed by residential real estate assets    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Assets, fair value $ 813 $ 1,416
Instruments backed by residential real estate assets | Market Comparables | Weighted Average    
Fair Value Inputs [Abstract]    
OREO discount 21.00% 21.00%
Costs to sell 9.00% 9.00%