Recent Accounting Pronouncements (Details) (USD $)	1 Months Ended
Jan. 31, 2010
Recent Accounting Pronouncements
Cumulative effect increase in assets	$ 5,500,000,000
Cumulative effect increase in liabilities	5,100,000,000
Cumulative effect increase in appropriated retained earnings	$ 473,000,000

Amount of the cumulative effect of the change in accounting principle on retained earnings or other components of equity or net assets in the statement of financial position as of the beginning of the earliest period presented.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 154
-Paragraph 2, 17, 18

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration