Goodwill and Other Intangible Assets - Estimated Amortization Expense for Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011
2012	$ 34
2013	24
2014	13
2015	8
2016	5
Thereafter	12
Total	96
Core Deposits [Member]
2012	21
2013	13
2014	4
2015	0
2016	0
Thereafter	0
Total	38
Other [Member]
2012	13
2013	11
2014	9
2015	8
2016	5
Thereafter	12
Total	$ 58

Future Amortization Expense, Thereafter

No definition available.

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- Definition

Future Amortization Expense, Total

+ References

No definition available.

+ Details

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- Definition

The amount of amortization expense expected to be recognized during year five of the five succeeding fiscal years.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph a(3)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=6905858&loc=d3e16323-109275

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- Definition

The amount of amortization expense expected to be recognized during year four of the five succeeding fiscal years.

+ References

+ Details

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- Definition

The amount of amortization expense expected to be recognized during year one of the five succeeding fiscal years.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

The amount of amortization expense expected to be recognized during year three of the five succeeding fiscal years.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

The amount of amortization expense expected to be recognized during year two of the five succeeding fiscal years.

+ References

+ Details

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