Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | 12 Months Ended | ||||
|---|---|---|---|---|---|---|---|
Jun. 30, 2016 |
Jun. 30, 2015 |
Jun. 30, 2016 |
Jun. 30, 2015 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Statement of Comprehensive Income [Abstract] | |||||||
| Unrealized Holding Gain (Loss) on Securities, Tax | $ 1 | $ 9 | $ 10 | $ 1 | $ (2) | $ 8 | $ 1 |
| Reclassification Adjustment from AOCI for Securities, Tax | 1 | (1) | 1 | ||||
| Unrealized Gain (Loss) on Derivatives, Tax | $ 3 | $ 0 | $ 19 | $ 0 | $ (1) | $ 0 | $ 0 |