Business Changes and Developments (Details) (USD $) In Billions, except Per Share data	6 Months Ended	12 Months Ended
Jun. 30, 2011 Approved Repurchase Program Period Start in 2011 [Member]	Jun. 30, 2011 Repurchase Program Authorized Period of 2011 [Member]	Dec. 31, 2010 Approved Repurchase Program Period Start in 2007 [Member]	Mar. 18, 2011 Common stock [Member]	Dec. 31, 2010 Common stock [Member]
Business Changes and Developments (Numeric)
Dividends Payable, Amount Per Share				$ 0.25	$ 0.05
Stock Repurchase Program, Authorized Amount	$ 15.0	$ 8.0	$ 10.0

The per share amount of a dividend declared, but not paid, as of the financial reporting date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 32
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

Name:	us-gaap_DividendsPayableAmountPerShare
Namespace Prefix:	us-gaap
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant