Shareholders' Equity (Details)	1 Months Ended
	Sep. 30, 2012 installment	Mar. 30, 2012 installment	Mar. 25, 2011 installment	Jan. 31, 2011 CHF	Oct. 31, 2010 CHF	Jul. 31, 2010 CHF	May 31, 2010 CHF	Mar. 31, 2010 installment	Feb. 20, 2013 USD ($)	Nov. 15, 2012 USD ($)	Sep. 28, 2012 USD ($)	Sep. 28, 2012 CHF	Sep. 17, 2012 USD ($)	Aug. 22, 2012 USD ($)	May 23, 2012 USD ($)	Mar. 07, 2012 USD ($)	Sep. 30, 2011 USD ($)	Sep. 30, 2011 CHF	Mar. 09, 2011 USD ($)	May 14, 2010 USD ($)	May 14, 2010 CHF	Mar. 26, 2010 CHF	Mar. 10, 2010 USD ($)	Mar. 10, 2010 CHF
Annual dividend, approved, common stock (in dollars per share)													$ 0.30			$ 0.50			$ 1.00
Number of installments for payment of dividend	2	2	4					4
Dividend per share payable in installments (in dollars per share)													$ 0.15			$ 0.25			$ 0.25
Dividends payable, amount											$ 139,000,000		$ 139,000,000			$ 231,000,000	$ 232,000,000		$ 468,000,000	$ 28,000,000			$ 399,000,000
First installment of dividend per common stock (in dollars per share)															$ 0.25
Second installment of dividend on common stock paid (in dollars per share)														$ 0.25
Dividend per share related to separation											$ 0.30
First installment of dividend per common stock related to separation (in dollars per share)										$ 0.15
Second installment of dividend per common stock related to separation (in dollars per share)									$ 0.15
Annual dividend, approved, common stock (in CHF per share)																								0.90
Dividend paid for common stock (in CHF per share)				0.23	0.23	0.22	0.22
Dividends payable, amount, in CHF																					32,000,000			428,000,000
Par value of common share before reduction (in CHF per share)																						7.60
Common shares, par value (in CHF per share)												6.70						6.70				6.70
Share capital, in CHF												3,258,632,435
Registered common shares											486,363,050	486,363,050
Registered common shares, par value (in CHF per share)												6.70
Share capital, potential maximum increase, value at March 9, 2013, in CHF												1,628,100,000
Share capital, potential maximum increase, shares, at March 9, 2013											243,000,000	243,000,000
Share capital, potential maximum increase, value through conversion, options and warrants, in CHF												321,127,717
Share capital, potential maximum increase, shares, through conversion, options and warrants											47,929,510	47,929,510
Share capital, potential maximum increase, value, through issuance to employees and other persons, in CHF												321,127,717
Share capital, potential maximum increase, shares through issuance to employees and other persons											47,929,510	47,929,510