Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Principles (Details)

v3.5.0.2
Summary of Significant Accounting Principles (Details) - Nonrefundable Fees and Other Costs, Prepayment Method - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 6 Months Ended 9 Months Ended
Jun. 30, 2016
Sep. 30, 2015
Jun. 30, 2016
Sep. 30, 2015
Dec. 31, 2014
Change in Accounting Estimate [Line Items]          
Increase (decrease) in net interest income $ 905 $ 429 $ 2,200 $ (71)  
Increase (decrease) in gains on sales of debt securities 18 52 54 65  
Increase (decrease) in net income $ 551 $ 298 $ 1,300 $ 0  
Increase (decrease) in earnings per diluted share $ 0.05 $ 0.03 $ 0.13 $ 0.00  
Cumulative effect of change on retained earnings         $ (293)