Loans with Government Guarantees (Details) - USD ($) $ in Millions |
6 Months Ended | 12 Months Ended | |
|---|---|---|---|
Jun. 30, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Accounts, Notes, Loans and Financing Receivable [Line Items] | |||
| Debt instrument, term (in years) | 10 years | 10 years | |
| Loans with government guarantees | $ 485 | $ 1,128 | |
| Loans with Government Guarantees (EBO) | $ 435 | 485 | |
| Loans Repurchased With Government Guarantees | 485 | 1,128 | |
| Other assets | |||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | |||
| Non-cash reclassification of loans with government guarantees to other assets | $ 178 | 210 | |
| Accounting Standards Update 2014-14 | |||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | |||
| New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets | $ 210 | $ 373 |