Subsequent Events (Details) (USD $) In Billions, except Per Share data, unless otherwise specified	1 Months Ended
	Jul. 31, 2011	Jul. 22, 2011
Bonds issued
Subsequent events:
Subsequent event, date	Jul. 22, 2011
Bonds issued		$ 2
Maturity date description (in years)	5 years
Debt instrument, interest rate (as a percent)		1.95%
Dividend declared
Subsequent events:
Subsequent event, dividend per share amount	0.75
Subsequent event, date	Jul. 26, 2011