Derivative Financial Instruments (Offsetting Derivatives) (Details) - USD ($)
$ in Millions |
Jun. 30, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
| Liabilities |
|
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral |
$ 116
|
$ 41
|
|
| Assets |
|
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral |
19
|
14
|
|
| Mortgage backed securities forwards |
|
|
|
| Liabilities |
|
|
|
| Gross Amount |
|
6
|
|
| Gross Amounts Offset in the Statement of Financial Position |
|
0
|
|
| Net Amount Presented in the Statement of Financial Position |
|
6
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments |
|
0
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral |
|
8
|
|
| Designated as Hedging Instrument | Interest rate swaps on FHLB advances |
|
|
|
| Liabilities |
|
|
|
| Gross Amount |
56
|
4
|
|
| Gross Amounts Offset in the Statement of Financial Position |
2
|
0
|
|
| Net Amount Presented in the Statement of Financial Position |
54
|
4
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments |
0
|
0
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral |
35
|
19
|
|
| Assets |
|
|
|
| Gross Amount |
2
|
|
|
| Gross Amounts Offset in the Statement of Financial Position |
2
|
|
|
| Net Amount Presented in the Statement of Financial Position |
0
|
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments |
0
|
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral |
0
|
|
|
| Not Designated as Hedging Instrument |
|
|
|
| Liabilities |
|
|
|
| Gross Amount |
79
|
14
|
|
| Gross Amounts Offset in the Statement of Financial Position |
3
|
0
|
|
| Net Amount Presented in the Statement of Financial Position |
76
|
14
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments |
0
|
0
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral |
81
|
22
|
|
| Assets |
|
|
|
| Gross Amount |
95
|
32
|
$ 52
|
| Gross Amounts Offset in the Statement of Financial Position |
3
|
0
|
1
|
| Net Amount Presented in the Statement of Financial Position |
92
|
32
|
51
|
| Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments |
0
|
0
|
0
|
| Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral |
19
|
14
|
36
|
| Net Amount |
|
|
15
|
| Not Designated as Hedging Instrument | U.S. Treasury and euro dollar futures |
|
|
|
| Liabilities |
|
|
|
| Gross Amount |
3
|
1
|
|
| Gross Amounts Offset in the Statement of Financial Position |
3
|
0
|
|
| Net Amount Presented in the Statement of Financial Position |
0
|
1
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments |
0
|
0
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral |
5
|
2
|
|
| Assets |
|
|
|
| Gross Amount |
3
|
|
18
|
| Gross Amounts Offset in the Statement of Financial Position |
3
|
|
1
|
| Net Amount Presented in the Statement of Financial Position |
0
|
|
17
|
| Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments |
0
|
|
0
|
| Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral |
0
|
|
10
|
| Net Amount |
|
|
7
|
| Not Designated as Hedging Instrument | Mortgage backed securities forwards |
|
|
|
| Liabilities |
|
|
|
| Gross Amount |
58
|
6
|
|
| Gross Amounts Offset in the Statement of Financial Position |
0
|
0
|
|
| Net Amount Presented in the Statement of Financial Position |
58
|
6
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments |
0
|
0
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral |
62
|
8
|
|
| Assets |
|
|
|
| Gross Amount |
4
|
7
|
26
|
| Gross Amounts Offset in the Statement of Financial Position |
0
|
0
|
0
|
| Net Amount Presented in the Statement of Financial Position |
4
|
7
|
26
|
| Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments |
0
|
0
|
0
|
| Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral |
0
|
4
|
24
|
| Net Amount |
|
|
2
|
| Not Designated as Hedging Instrument | Interest rate swaps and swaptions |
|
|
|
| Liabilities |
|
|
|
| Gross Amount |
|
7
|
6
|
| Gross Amounts Offset in the Statement of Financial Position |
|
0
|
0
|
| Net Amount Presented in the Statement of Financial Position |
|
7
|
6
|
| Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments |
|
0
|
0
|
| Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral |
|
12
|
0
|
| Net Amount |
|
|
6
|
| Assets |
|
|
|
| Gross Amount |
|
25
|
8
|
| Gross Amounts Offset in the Statement of Financial Position |
|
0
|
0
|
| Net Amount Presented in the Statement of Financial Position |
|
25
|
8
|
| Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments |
|
0
|
0
|
| Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral |
|
10
|
2
|
| Net Amount |
|
|
$ 6
|
| Not Designated as Hedging Instrument | Interest Rate Swaps and Swaptions |
|
|
|
| Liabilities |
|
|
|
| Gross Amount |
18
|
7
|
|
| Gross Amounts Offset in the Statement of Financial Position |
0
|
0
|
|
| Net Amount Presented in the Statement of Financial Position |
18
|
7
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments |
0
|
0
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral |
14
|
12
|
|
| Assets |
|
|
|
| Gross Amount |
88
|
25
|
|
| Gross Amounts Offset in the Statement of Financial Position |
0
|
0
|
|
| Net Amount Presented in the Statement of Financial Position |
88
|
25
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments |
0
|
0
|
|
| Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral |
$ 19
|
$ 10
|
|