Federal Home Loan Bank Advances (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Federal Home Loan Bank, Advances [Line Items]
Federal Home Loan Bank advances (includes both short-term and long-term)	$ 2,198	$ 514
Weighted average interest rate (as a percent)	0.76%	0.90%
Short-term fixed rate term advances
Federal Home Loan Bank, Advances [Line Items]
Federal Home Loan Bank advances (includes both short-term and long-term)	$ 1,323	$ 214
Weighted average interest rate (as a percent)	0.18%	0.26%
Long-term fixed rate term advances
Federal Home Loan Bank, Advances [Line Items]
Federal Home Loan Bank advances (includes both short-term and long-term)	$ 875	$ 300
Weighted average interest rate (as a percent)	1.64%	1.36%

Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 470

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822

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- Definition

States the weighted average interest rate applicable to the advances from the Federal Home Loan Bank outstanding as of the Balance Sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.13(3)(a))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Industry Guide

-Number 3

-Section VII

-Subsection 1

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