Investment Securities (Impairments) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2012
Pre-tax, Other-Than-Temporary Impairments on Investment Securities
Total pre tax, OTTI recognized	$ 15	$ 7	$ 18	$ 16
Less other-than-temporary impairment recognized in accumulated other comprehensive income	0	0	0	(4)
Net other-than-temporary impairments on investment securities	15	7	18	12
Other Than Temporary Impairment Related To Equity Securities		2		2	$ 0
Changes in Cumulative Credit Loss Impairments Recognized on Debt Securities
Cumulative credit loss impairments recognized, beginning of period	6	255	8	306
Credit loss impairments recognized on securities not previously impaired	0	0	0	0
Incremental credit loss impairments recognized on securities previously impaired	0	1	0	2
Less: credit loss impairments previously recognized on securities sold during the period	0	1	2	53
Cumulative credit loss impairments recognized, end of period	$ 6	$ 255	$ 6	$ 255

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The amount represents the other than temporary impairments recorded through earnings related to equity securities.

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This item represents an increase to the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held for which a previous OTTI was recognized and the investor does not intend to sell the debt security and it is not more likely than not that the investor will be required to sell the debt security before recovery of its amortized cost basis.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph (e)

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- Definition

This item represents an increase to the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held for which no such other than temporary impairment (OTTI) was previously recognized.

+ References

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The cumulative amount of credit losses recognized in earnings related to debt securities held for which a portion of an other than temporary impairment (OTTI) was recognized in other comprehensive income (a component of shareholders' equity).

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- Definition

This item represents reductions in the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security because of the sale of impaired securities during the period.

+ References

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- Definition

The amount by which the fair value of an investment in debt and equity securities categorized as Available-for-sale is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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Amount before tax of other than temporary impairment (OTTI) on investment in available-for-sale debt security, recognized in other comprehensive loss.

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The amount of other than temporary impairment losses on investments in debt and equity securities categorized as Available-for-sale which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis.

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