Share Repurchase Program (Details Textuals) (USD $) In Millions, except Per Share data	6 Months Ended				1 Months Ended			1 Months Ended			6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010	May 31, 2009 Share Repurchase Program May 2009 Member	Jan. 31, 2010 Share Repurchase Program July 2009 [Member]	Jan. 19, 2010 Share Repurchase Program July 2009 [Member]	Jul. 27, 2009 Share Repurchase Program July 2009 [Member]	May 31, 2010 Share Repurchase Program Feb 2010 [Member]	May 26, 2010 Share Repurchase Program Feb 2010 [Member]	Feb. 25, 2010 Share Repurchase Program Feb 2010 [Member]	Jun. 30, 2011 Share Repurchase Program Aug 2010 [Member]	May 31, 2011 Share Repurchase Program Aug 2010 [Member]	May 19, 2011 Share Repurchase Program Aug 2010 [Member]	Aug. 20, 2010 Share Repurchase Program Aug 2010 [Member]
Share Repurchase Program (Textuals) [Abstract]
Authorized amount for repurchase of outstanding common stock	$ 3,050			$ 250		$ 750	$ 750		$ 250	$ 250	$ 241	$ 1,400	$ 1,400	$ 1,000
Authorized amount for additional repurchase of outstanding common stock												400
Repurchase of common stock, shares	35.0		27.0			1.1			3.3		8.3
Average per share price of repurchase of common stock					$ 78.36			$ 76.29			$ 94.84
Payments for Repurchase of Common Stock	$ 783	$ 340			$ 90						$ 783