Variable Interest Entities - Summary of Assets and Liabilities Related to Consolidated Variable Interest Entities (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Variable interest entities [Member]
Variable Interest Entity [Line Items]
Consolidated Assets	$ 355	$ 380
Consolidated Liabilities	176	167
Other assets [Member] \| Low income housing limited liability partnership [Member]
Variable Interest Entity [Line Items]
Consolidated Assets	355	380
Long-term debt [Member] \| Low income housing limited liability partnership [Member]
Variable Interest Entity [Line Items]
Consolidated Liabilities	92	92
Interest, taxes and other liabilities [Member] \| Low income housing limited liability partnership [Member]
Variable Interest Entity [Line Items]
Consolidated Liabilities	$ 84	$ 75

The carrying amount of the consolidated Variable Interest Entity's assets included in the reporting entity's statement of financial position.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (bb)

-URI http://asc.fasb.org/extlink&oid=52262685&loc=d3e5710-111685

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- Definition

The carrying amount of the consolidated Variable Interest Entity's liabilities included in the reporting entity's statement of financial position.

+ References

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- Definition

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+ References

No definition available.

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