Fair Value Measurements (Assets Measured on a Nonrecurring Basis, Level 3 Quantitative Information) (Details) - Nonrecurring - Level 3 - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2015	Dec. 31, 2014
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Repossessed assets	$ 18	$ 19
Residential first mortgage loans
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired loans held-for-investment	$ 42	$ 74
Residential first mortgage loans \| Fair value of underlying collateral \| Lower range
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Loss severity (as a percent)	35.00%	35.00%
Residential first mortgage loans \| Fair value of underlying collateral \| Upper range
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Loss severity (as a percent)	45.00%	47.00%
Residential first mortgage loans \| Fair value of underlying collateral \| Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Loss severity (as a percent)	44.20%	36.90%
Repossessed assets \| Fair value of underlying collateral \| Lower range
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Loss severity (as a percent)	0.00%	7.00%
Repossessed assets \| Fair value of underlying collateral \| Upper range
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Loss severity (as a percent)	99.00%	100.00%
Repossessed assets \| Fair value of underlying collateral \| Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Loss severity (as a percent)	50.50%	45.40%

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents impaired financing receivable which may include impaired mortgage loans held for investment, impaired finance receivables held for investment, or any other impaired loans which are due the Company as of the balance sheet date.

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Loss, including interest and principal, incurred on a defaulted security, expressed as a percentage of the original principal balance, used as an input to measure fair value.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bbb)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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- Definition

Carrying amount as of the balance sheet date of land and buildings obtained through foreclosure proceedings or defeasance in full or partial satisfaction of a debt arrangement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4437-111522

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 28

-Article 12

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph c

-Subparagraph Schedule III

-Article 5

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