Borrowings (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
Jun. 30, 2011	Dec. 31, 2010
Borrowings (Textuals) [Abstract]
Junior subordinated debentures	$ 1,200	$ 1,200
Rate on related enhanced trust preferred securities	8.50%
Junior Subordinated Debentures Maturity Date	Jan. 31, 2068
Debt Maturity, Start Date	2027
Debt Maturity, End Date	2068
Period of days prior to redemption or repurchase of enhanced trust preferred securities applicable to provisions of the replacement capital covenant		180 days
End date of restrictions included in the replacement capital covenant	Jan. 31, 2048
Junior Subordinated Debenture due January 31, 2068 [Member]
Borrowings (Textuals) [Abstract]
Junior subordinated debentures	$ 350

Borrowings.

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- Definition

End date of restrictions included in the replacement capital covenant.

+ Details

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- Definition

Enhanced trust preferred securities rate.

+ Details

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- Definition

Period of days prior to redemption or repurchase of enhanced trust preferred securities applicable to provisions of the replacement capital covenant.

+ Details

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- Definition

Date when the debt instrument is scheduled to be fully repaid, which may be presented in a variety of ways (year, month and year, day, month and year, quarter, etc.).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 129
-Paragraph 2, 4

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- Definition

When presenting a range of maturity dates, the latest date when the outstanding debt instruments are required to be repaid. May be presented in a variety of ways (for example: year only, month and year, day, month and year, and number of years).

+ References

+ Details

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- Definition

When presenting a range of maturity dates, the earliest date when the outstanding debt instruments are required to be repaid. May be presented in a variety of ways (for example: year only, month and year, day, month and year, and number of years).

+ References

+ Details

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- Definition

Including the current and noncurrent portions, the carrying value of junior subordinated long-term debt owed to unconsolidated subsidiary trusts as of the balance sheet date. Such debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets and was initially scheduled to be repaid after one year or beyond the normal operating cycle if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 16
-Article 9

+ Details

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