Derivative Instruments and Hedging Activities Interest Rate Sensitive Assets/Liabilities (Details) (USD $) In Thousands, unless otherwise specified
|
Jun. 30, 2013
|
Dec. 31, 2012
|
Derivatives, Fair Value [Line Items] |
|
|
Available-for-sale Securities, Interest-only |
$ 95,039
|
$ 77,342
|
Derivative Financial Instruments, Assets [Member]
|
|
|
Derivatives, Fair Value [Line Items] |
|
|
Derivative, Fair Value, Net |
699,351
|
462,080
|
Derivative, Notional Amount |
29,556,972
|
9,768,656
|
Derivative Financial Instruments, Liabilities [Member]
|
|
|
Derivatives, Fair Value [Line Items] |
|
|
Derivative, Fair Value, Net |
(46,028)
|
(129,294)
|
Derivative, Notional Amount |
23,551,633
|
14,209,000
|
Forward Contracts [Member] | Derivative Financial Instruments, Assets [Member]
|
|
|
Derivatives, Fair Value [Line Items] |
|
|
Derivative, Fair Value, Net |
61,156
|
1,917
|
Derivative, Notional Amount |
2,813,000
|
2,414,000
|
Forward Contracts [Member] | Derivative Financial Instruments, Liabilities [Member]
|
|
|
Derivatives, Fair Value [Line Items] |
|
|
Derivative, Fair Value, Net |
(22,568)
|
(239)
|
Derivative, Notional Amount |
2,892,000
|
139,000
|
Options Held [Member] | Derivative Financial Instruments, Assets [Member]
|
|
|
Derivatives, Fair Value [Line Items] |
|
|
Derivative, Fair Value, Net |
24,873
|
|
Derivative, Notional Amount |
210,000
|
|
Options Held [Member] | Derivative Financial Instruments, Liabilities [Member]
|
|
|
Derivatives, Fair Value [Line Items] |
|
|
Derivative, Fair Value, Net |
0
|
|
Derivative, Notional Amount |
0
|
|
Forward Purchase Commitment [Member] | Derivative Financial Instruments, Assets [Member]
|
|
|
Derivatives, Fair Value [Line Items] |
|
|
Derivative, Fair Value, Net |
0
|
234
|
Derivative, Notional Amount |
0
|
56,865
|
Forward Purchase Commitment [Member] | Derivative Financial Instruments, Liabilities [Member]
|
|
|
Derivatives, Fair Value [Line Items] |
|
|
Derivative, Fair Value, Net |
(1,204)
|
0
|
Derivative, Notional Amount |
29,229
|
0
|
Long [Member]
|
|
|
Derivatives, Fair Value [Line Items] |
|
|
Agency To-be-Announced Securities, Notional Amount, Mitigate Prepayment Exposure |
92,000
|
|
Long [Member] | Forward Contracts [Member]
|
|
|
Derivatives, Fair Value [Line Items] |
|
|
Agency To-be-Announced Securities, Notional Amount, Non-Risk Management |
1,400,000
|
|
Derivative, Notional Amount |
1,492,000
|
1,753,000
|
Long [Member] | Options Held [Member]
|
|
|
Derivatives, Fair Value [Line Items] |
|
|
Derivative, Notional Amount |
1,315,000
|
|
Derivative, Cost |
(9,992)
|
|
Short [Member]
|
|
|
Derivatives, Fair Value [Line Items] |
|
|
Agency To-be-Announced Securities, Notional Amount, Mitigate Prepayment Exposure |
4,213,000
|
|
Short [Member] | Forward Contracts [Member]
|
|
|
Derivatives, Fair Value [Line Items] |
|
|
Derivative, Notional Amount |
4,213,000
|
800,000
|
Short [Member] | Options Held [Member]
|
|
|
Derivatives, Fair Value [Line Items] |
|
|
Derivative, Notional Amount |
(1,525,000)
|
|
Derivative, Cost |
$ 8,348
|
|